- Christian Baker analyzed Herschel PACS spectroscopy data of dwarf galaxy NGC 5195 to determine characteristics of its cold gas and dust using a PDR model.
- Key emission lines were detected including [C II], [N II], [O I]63, and [O I]145. [O III] was below the detection threshold.
- Ratios of emission lines to total infrared flux suggested a heating efficiency about an order of magnitude lower than NGC 5195's companion galaxy M51.
- Analysis of line ratios indicated gas densities of log(n/cm-3) between 2.0-3.0 and radiation intensities of logG0 between 2.5-3.3.
Contribution to the investigation of wind characteristics and assessment of w...Université de Dschang
M. Bawe Gerard Nfor, Jr. a soutenu sa thèse de Doctorat/Phd en Physique, option Mécanique-Énergétique ce 19 mai 2016 dans la salle des conférences de l'Université de Dschang. A l'issue de la soutenance, le jury présidé par le Prof. Anaclet Fomethe lui a décerné, à l'unanimité de ses membres, la mention très honorable.
Voici la présentation powerpoint qu'il a effectuée dans le cadre de cette soutenance.
This document presents a methodology for estimating wind speed in suburban areas. Wind speed data was collected at the Zagreb-Maksimir Observatory in Croatia. The study estimated wind speed at 2m using gradient methods and Monin-Obukhov similarity theory, taking into account stability corrections. Effective roughness length was estimated according to wind direction, with higher values for western winds. Estimated wind speeds matched observed values well, with closer matches when accounting for roughness length variations. The methodology allows extrapolating wind data to other heights for modeling and applications in the wider suburban area.
A.G. A. Abdelkawy, A.M.K. Shaltout, M.M. Beheary and A. Bakry
Department of Astronomy and Meteorology, Faculty of Science, Al-Azhar University, Cairo, Egypt. Postal Code 11884.
The Chaos and Stability of Firefly Algorithm Adjacent IndividualTELKOMNIKA JOURNAL
In this paper, in order to overcome the defect of the firefly algorithm, for example, the slow
convergence rate, low accuracy and easily falling into the local optima in the global optimization search,
we propose a dynamic population firefly algorithm based on chaos. The stability between the fireflies is
proved, and the similar chaotic phenomenon in firefly algorithm can be simulated.
1) Thermal waves in Saturn's atmosphere were analyzed using infrared observations from 2003-2013.
2) Maps were compiled from multiple instruments and analyzed using power spectral analysis to detect thermal waves.
3) Waves with different wavelengths were found to trace chemical species at different altitudes in Saturn's atmosphere. Large wave trains were detected in late 2003 and 2004.
The document discusses methods for characterizing the global environment using satellite data to help overcome challenges posed by weather effects on missile defense sensors. It describes adjusting infrared imagery thresholds to approximate radar observations, extracting weather event boundaries, projecting 3D shapes onto a model Earth, and using an existing satellite constellation to provide continuous coverage. The goal is to determine visibility and sensor performance to optimize sensor selection and placement for missile defense.
Validation of wind resource assessment process based on CFD Jean-Claude Meteodyn
Wind resource assessment requires nowadays more efficient tools to provide an accurate evaluation of production in order to reduce costs.As onshore wind farms are built in more complex terrains, it is necessary to find a new method to provide a fine evaluation of energy which reduces the error during the data extrapolation process. This explains why CFD models have become a standard for WRA in specific conditions.This presentation is focused on the wind speed and energy yield prediction carried out for a 29MW wind farm project. The accuracy of the wind modeling is investigated by the cross validation between the different met masts around the site. The net energy prediction P50 is compared against real wind farm performance data during a blind test organized by EWEA in 2013. More than 50 companies have been involved in order to compare methods results.
Use of mesoscale modeling to increase the reliability of wind resource assess...Jean-Claude Meteodyn
During wind farm design phase, the wind direction distribution is a crucial information for wind turbine layout optimization. However, in complex terrains, the wind rose at hub height of the wind turbines can be quite different from met mast measurement.The study shows that in complex terrains, the use of mesoscale modeling provides a complement to met mast measurement. It allows to better determine the turbine-specific wind rose and to reduce the uncertainty in wind resource assessment. The coupling of mesoscale and CFD model allows to produce high resolution wind map, by taking into account both mesoscale and microscale terrain effects.
Contribution to the investigation of wind characteristics and assessment of w...Université de Dschang
M. Bawe Gerard Nfor, Jr. a soutenu sa thèse de Doctorat/Phd en Physique, option Mécanique-Énergétique ce 19 mai 2016 dans la salle des conférences de l'Université de Dschang. A l'issue de la soutenance, le jury présidé par le Prof. Anaclet Fomethe lui a décerné, à l'unanimité de ses membres, la mention très honorable.
Voici la présentation powerpoint qu'il a effectuée dans le cadre de cette soutenance.
This document presents a methodology for estimating wind speed in suburban areas. Wind speed data was collected at the Zagreb-Maksimir Observatory in Croatia. The study estimated wind speed at 2m using gradient methods and Monin-Obukhov similarity theory, taking into account stability corrections. Effective roughness length was estimated according to wind direction, with higher values for western winds. Estimated wind speeds matched observed values well, with closer matches when accounting for roughness length variations. The methodology allows extrapolating wind data to other heights for modeling and applications in the wider suburban area.
A.G. A. Abdelkawy, A.M.K. Shaltout, M.M. Beheary and A. Bakry
Department of Astronomy and Meteorology, Faculty of Science, Al-Azhar University, Cairo, Egypt. Postal Code 11884.
The Chaos and Stability of Firefly Algorithm Adjacent IndividualTELKOMNIKA JOURNAL
In this paper, in order to overcome the defect of the firefly algorithm, for example, the slow
convergence rate, low accuracy and easily falling into the local optima in the global optimization search,
we propose a dynamic population firefly algorithm based on chaos. The stability between the fireflies is
proved, and the similar chaotic phenomenon in firefly algorithm can be simulated.
1) Thermal waves in Saturn's atmosphere were analyzed using infrared observations from 2003-2013.
2) Maps were compiled from multiple instruments and analyzed using power spectral analysis to detect thermal waves.
3) Waves with different wavelengths were found to trace chemical species at different altitudes in Saturn's atmosphere. Large wave trains were detected in late 2003 and 2004.
The document discusses methods for characterizing the global environment using satellite data to help overcome challenges posed by weather effects on missile defense sensors. It describes adjusting infrared imagery thresholds to approximate radar observations, extracting weather event boundaries, projecting 3D shapes onto a model Earth, and using an existing satellite constellation to provide continuous coverage. The goal is to determine visibility and sensor performance to optimize sensor selection and placement for missile defense.
Validation of wind resource assessment process based on CFD Jean-Claude Meteodyn
Wind resource assessment requires nowadays more efficient tools to provide an accurate evaluation of production in order to reduce costs.As onshore wind farms are built in more complex terrains, it is necessary to find a new method to provide a fine evaluation of energy which reduces the error during the data extrapolation process. This explains why CFD models have become a standard for WRA in specific conditions.This presentation is focused on the wind speed and energy yield prediction carried out for a 29MW wind farm project. The accuracy of the wind modeling is investigated by the cross validation between the different met masts around the site. The net energy prediction P50 is compared against real wind farm performance data during a blind test organized by EWEA in 2013. More than 50 companies have been involved in order to compare methods results.
Use of mesoscale modeling to increase the reliability of wind resource assess...Jean-Claude Meteodyn
During wind farm design phase, the wind direction distribution is a crucial information for wind turbine layout optimization. However, in complex terrains, the wind rose at hub height of the wind turbines can be quite different from met mast measurement.The study shows that in complex terrains, the use of mesoscale modeling provides a complement to met mast measurement. It allows to better determine the turbine-specific wind rose and to reduce the uncertainty in wind resource assessment. The coupling of mesoscale and CFD model allows to produce high resolution wind map, by taking into account both mesoscale and microscale terrain effects.
Thermal stratification in cfd modelling for wind resource assessmentJean-Claude Meteodyn
Up to know CFD computations in wind resource assessment mainly focused on wind statistics treatment, and then considered average thermal structure of the atmosphere. With an increasing demand for a more accurate description of these statistics, including time series, there is a need for considering more specific situations, and particularly stable thermal stratifications (ref 1). We present here a new turbulence model allowing to consider the strongly stable cases in CFD computations.
The document discusses formulas for calculating the gravitational effects of topographic-isostatic masses on airborne and satellite gravity gradiometry measurements. It derives integral formulas in ellipsoidal approximation for computing the gravitational potential, gradients, and tensor due to various topographic-isostatic models. The formulas separate the computations into spherical and ellipsoidal components. They are applied to calculate the gravitational tensor at GOCE satellite altitude using a 5-arcminute digital elevation model. The approach uses mass-lines to approximate ellipsoidal volume elements for numerical evaluation.
A kiloparsec scale_internal_shock_collision_in_the_jet_of_a_nearby_radio_galaxySérgio Sacani
This document summarizes observations of a collision between two knots (B and C) in the jet of the nearby radio galaxy 3C 264 using Hubble Space Telescope imaging from 1994 to 2014. Knot B was found to have an apparent speed of 7.0c, much faster than other knots. Knots B and C showed simultaneous brightening in 2014, indicating the beginning of their collision. Analysis suggests the collision will dissipate kinetic energy with a conversion efficiency to radiation of at least 0.1%, providing a way to study particle acceleration in astrophysical jets.
Application of extreme learning machine for estimating solar radiation from s...mehmet şahin
This paper presents an extreme learning machine (ELM) model to estimate solar radiation in Turkey using satellite data from the National Oceanic and Atmospheric Administration advanced very high-resolution radiometer from 20 locations. The ELM model uses land surface temperature, altitude, latitude, longitude, month, and city as inputs to estimate solar radiation. The ELM model provided better estimation accuracy than an artificial neural network model and was about 23.5 times faster to train, demonstrating the potential of ELM for solar radiation estimation using remote sensing data.
Estimation of global solar radiation by using machine learning methodsmehmet şahin
In this study, global solar radiation (GSR) was estimated based on 53 locations by using ELM, SVR, KNN, LR and NU-SVR methods. Methods were trained with a two-year data set and accuracy of the mentioned methods was tested with a one-year data set. The data set of each year was consisting of 12 months. Whereas the values of month, altitude, latitude, longitude, vapour pressure deficit and land surface temperature were used as input for developing models, GSR was obtained as output. Values of vapour pressure deficit and land surface temperature were taken from radiometry of NOAA-AVHRR satellite. Estimated solar radiation data were compared with actual data that were obtained from meteorological stations. According to statistical results, most successful method was NU-SVR method. The RMSE and MBE values of NU-SVR method were found to be 1,4972 MJ/m2 and 0,2652 MJ/m2, respectively. R value was 0,9728. Furthermore, worst prediction method was LR. For other methods, RMSE values were changing between 1,7746 MJ/m2 and 2,4546 MJ/m2. It can be seen from the statistical results that ELM, SVR, k-NN and NU-SVR methods can be used for estimation of GSR.
This document discusses finding the optimal trajectory for an artillery projectile using dynamic programming. It first describes the methodology used, including modeling the projectile motion and factors that affect the trajectory like wind velocity. It then discusses using muzzle velocity as the criterion to determine the optimal selection. Different combinations of muzzle velocity and angle of firing are computed to hit a target at a given distance. Finally, it explains how a dynamic programming algorithm is applied using these combinations and the Bellman equation to determine the minimum velocity needed to hit the target, which is the optimal choice as it requires the lowest amount of propellant.
Inference of homogeneous_clouds_in_an_exoplanet_atmosphereSérgio Sacani
1) New visible and infrared observations of the exoplanet Kepler-7b were analyzed to determine its atmospheric properties and detect the presence of clouds.
2) The observations found a westward shift in Kepler-7b's optical phase curve and placed upper limits on its thermal emission that remained undetected in Spitzer bandpasses.
3) The data suggests Kepler-7b has optically thick, high-altitude clouds located west of the substellar point, composed possibly of silicates. The clouds help explain Kepler-7b's unusually high geometric albedo and visible flux that cannot be attributed to thermal emission or molecular hydrogen scattering alone.
Comparative Calibration Method Between two Different Wavelengths With Aureole...Waqas Tariq
A multi-stage method for calibration of sunphotometer is proposed by combining comparison calibration method between two different wavelengths with aureole observation method for long wavelength calibration. Its effectiveness in reducing the influences for calibration due to molecular and aerosolfs extinction in the unstable turbidity conditions is clarified. By comparing the calculated results with the proposed method and the existing individually calibration method, it is found that the proposed method is superior to the existing method in terms of calibration accuracy. Namely, Through a comparison between ILM and the proposed method using band 0.87um as reference, the largest calibration errors are 0.0014, 0.0428 by PM are lower than that by ILM (0.011,0.0489) for sky radiances with no error and -3~+3%, -5~+5% errors. By analyzing the observation data of 15 days with POM-1 Skyradiometer, the largest standard deviation of calibration constants by PM is 0.02016, and is lower than that by ILM (0.03858).
A Study of Non-Gaussian Error Volumes and Nonlinear Uncertainty Propagation f...Justin Spurbeck
The ever-growing resident space object population poses a continual threat in that a hyper velocity impact is likely to be catastrophic to an active satellite. To avoid these scenarios, space operators compute a probability of collision metric for each potential conjunction. Uncertainty trends are studied in the conjunction plane and operational decisions to mitigate any high-risk situations are made based off this information. There are many methods of uncertainty propagation and probability of collision formulations and knowledge of their realism is required to maintain a sustainable space environment. Thus, this research studies the effect of Chan, Alfano, Foster, Gaussian mixture, and Monte Carlo probability of collision calculations and their correlation to uncertainty realism metrics. The linear, unscented transform, entropy-based, and Monte Carlo propagation techniques are utilized alongside the collision calculations and it is shown that there are important correlations any space operator should be aware of to support maintenance of a healthy spacecraft.
1) The document presents a technique for automatically correcting for ion travel time when mass calibrating a single quadrupole mass spectrometer. This allows a single calibration to be used over all mass ranges and scan speeds.
2) By deriving an equation for ion transmission time as a function of mass and scan speed, the mass shift due to varying scan speeds can be calculated and subtracted from acquired data.
3) Empirical testing showed the technique reduced initial mass shifts by at least 85% for all masses and scan speeds, with no residual shift over 0.1 m/z. The combined calibration provides effective mass calibration across an instrument's operating ranges.
Polarized reflected light from the Spica binary systemSérgio Sacani
Close binary systems often show linear polarization varying
over the binary period, usually attributed to light scattered
from electrons in circumstellar clouds1–3
. One of the brightest
close binary systems is Spica (alpha Virginis) consisting of
two B-type stars orbiting with a period of just over four days.
Past observations of Spica have shown low polarization with
no evidence for variability4–6. Here we report new high-precision polarization observations of Spica that show variation
with an amplitude of about 200 parts per million. By including
polarized radiative transfer in a binary star model, we show
that the phase-dependent polarization is mainly due to light
reflected from the primary component of the binary system
off the secondary component and vice versa. The stars reflect
only a few per cent of the incident light, but the reflected light
is very highly polarized. The polarization results show that the
binary orbit is clockwise and the position angle of the line of
nodes is 130.4° ± 6.8°, in agreement with intensity interferometer results7
. We suggest that reflected light polarization
may be much more important in binary systems than has previously been recognized and may be a way of detecting previously unrecognized close binaries.
An ultrahot gas-giant exoplanet with a stratosphereSérgio Sacani
Infrared radiation emitted from a planet contains information
about the chemical composition and vertical temperature profile
of its atmosphere1–3. If upper layers are cooler than lower layers,
molecular gases will produce absorption features in the planetary
thermal spectrum4,5
. Conversely, if there is a stratosphere—
where temperature increases with altitude—these molecular
features will be observed in emission6–8. It has been suggested that
stratospheres could form in highly irradiated exoplanets9,10, but
the extent to which this occurs is unresolved both theoretically11,12
and observationally3,13–15. A previous claim for the presence of a
stratosphere14 remains open to question, owing to the challenges
posed by the highly variable host star and the low spectral resolution
of the measurements3
. Here we report a near-infrared thermal
spectrum for the ultrahot gas giant WASP-121b, which has an
equilibrium temperature of approximately 2,500 kelvin. Water
is resolved in emission, providing a detection of an exoplanet
stratosphere at 5σ confidence. These observations imply that a
substantial fraction of incident stellar radiation is retained at high
altitudes in the atmosphere, possibly by absorbing chemical species
such as gaseous vanadium oxide and titanium oxide
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
Titan’s Topography and Shape at the Endof the Cassini MissionSérgio Sacani
With the conclusion of the Cassini mission, we present an updated topographic map of Titan,including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets availablefrom the mission. We use radial basis func tions to interpolate the sparse data set, which covers only ∼9%of Titan’s global area. The most notable updates to the topography include higher coverage of the polesof Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We alsopresent a statistical analysis of the error in the derived products and perform a global minimization on aprofile-by-profile basis to account for observed biases in the input data set. We find a greater flattening ofTitan than measured, additional topographic rises in Titan’s southern hemisphere and better constrain thepossible locations of past and present liquids on Titan’s surface.
This document provides an overview and validation of Re.SunTM, a software tool for assessing solar resources worldwide using mesoscale weather modeling and coupling techniques. Re.SunTM runs the WRF mesoscale numerical weather model to generate meteorological data, then applies clear sky models incorporating aerosol and gas data to estimate solar radiation indices. It was validated against measurements from 9 complex sites, showing a mean bias of 0.64% and root mean square error of 4%. Statistics demonstrate Re.SunTM can estimate average annual global solar radiation to within 4.14% of measured for 80% of cases. The document concludes Re.SunTM is useful for solar applications requiring site-specific resource assessment.
Exact Analytical Expression for Outgoing Intensity from the Top of the Atmosp...IOSR Journals
This research is a part of the work devoted on the application of analytical Discrete Ordinate (ADO) method to the polarized monochromatic radiative transfer equation undergoing anisotropic scattering with source function matrix in a finite coupled Atmosphere –Ocean media having flat interface boundary conditions involving specular reflection and transmission matrix. Discontinuities in the derivatives of the Stokes vector with respect to the cosine of the polar angle at smooth interface between the two media with different refractive indices (air and water) is tackled by using a suitable quadrature scheme devised earlier. Atmosphere and ocean are assumed to be homogeneous. No stratification is adopted in the two media. Exact expression for the
emergent radiation intensity vector from the top of the atmosphere is derived. Exact expressions for the emergent polarized radiation intensity vector from the air-water interface as well as from any point of the two medium in any direction can also be derived in terms of eigenvectors and eigenvalues.
This study implements a Bayesian statistical framework to calibrate the SCOPE process-based simulator for simulating gross primary production (GPP) and top-of-canopy reflectance at a spruce flux tower site in the Czech Republic. Markov chain Monte Carlo simulation is used to quantify the uncertainty in SCOPE input parameters by comparing simulated and measured reflectance and GPP data. The results show the posterior parameter distributions have lower uncertainty than the prior distributions. Simulated half-hourly GPP over the growing season using maximum a posteriori parameter estimates matches the measured data. Future work will estimate seasonal parameter variations to improve GPP simulation accuracy.
At present, with the development of wind power project in China, there are more and more projects located at the complex terrain and complex environment. At the same time, since the large planned area of project, the complex mountain area, and limited number of met mast, even without met mast, in order to the reliable development of the wind power project, it is important that how to do the wind resource assessment without actual measurement wind data and other conditions such as less reliable wind data, and the met mast was not considered representative. This paper will use the atmospheric model to do mesoscale simulation calculation of wind resources, and then combine with CFD technology to downscaling computation to get high resolution wind power assessment result. Finally, in order to confirm the validity of this application in the actual project, the comparison between calculation values and measurement values is carried out. The verification result through the actual data of different met mast shows that the wind resource assessment method which combines the CFD and mesoscale technologies is reliable. The main contribution of the article is to provide the reference model and approach for regional planning and large scale wind resource assessment when there isn’t enough adequate and effective wind data.
Closed-Form Performance Analysis of Dual Polarization Based MIMO System in Sh...IJERA Editor
In this paper, the problem of dual polarization based MIMO Processing in Shadowed-Rician (SR) fading land mobile satellite (LMS) channels is studied. It is shown in literature that polarization is used as a interference rejection method; and, most of the existing analytical results are not in closed-form. In this paper, we derive the closed-form expressions of the moment generating (MGF) function of the received signal-to-noise ratio of the MRC based receiver in SR fading LMS channels. Then we provide closed-form expressions of the symbol error rate (SER) by using MGF approach. The analytical diversity order and capacity of the considered scheme is also derived. It is shown by by derived closed-form capacity expression that the capacity of the considered dual polarization based scheme is improved; and it is found very useful in practical satellite communication systems.
Este documento describe las características básicas de los músculos esqueléticos. Explica que los músculos son órganos carnosos que se contraen y provocan el movimiento del cuerpo, y mantienen la postura y equilibrio. Describe las diferentes porciones de los músculos como el vientre y los extremos, y cómo se insertan en los huesos a través de los tendones. También clasifica los músculos por su número de cabezas, colas o vientres, y por la acción muscular que producen
This document outlines problems and proposed solutions across several departments and programs at Sejong University. It discusses issues with course management, bio-convergence engineering, information security, globalization, and volunteer work programs. Specific problems identified include unnecessary courses, large class sizes, lack of executive skills courses, unclear department changes, curriculum mistakes, and inadequate hacking practice courses. Solutions proposed are providing more specialized course choices, expanding courses/faculty, adding executive skills courses, clearer communication, curriculum planning consideration, and inclusion of more hacking practice courses. The conclusion states addressing these problems could help students achieve success.
Thermal stratification in cfd modelling for wind resource assessmentJean-Claude Meteodyn
Up to know CFD computations in wind resource assessment mainly focused on wind statistics treatment, and then considered average thermal structure of the atmosphere. With an increasing demand for a more accurate description of these statistics, including time series, there is a need for considering more specific situations, and particularly stable thermal stratifications (ref 1). We present here a new turbulence model allowing to consider the strongly stable cases in CFD computations.
The document discusses formulas for calculating the gravitational effects of topographic-isostatic masses on airborne and satellite gravity gradiometry measurements. It derives integral formulas in ellipsoidal approximation for computing the gravitational potential, gradients, and tensor due to various topographic-isostatic models. The formulas separate the computations into spherical and ellipsoidal components. They are applied to calculate the gravitational tensor at GOCE satellite altitude using a 5-arcminute digital elevation model. The approach uses mass-lines to approximate ellipsoidal volume elements for numerical evaluation.
A kiloparsec scale_internal_shock_collision_in_the_jet_of_a_nearby_radio_galaxySérgio Sacani
This document summarizes observations of a collision between two knots (B and C) in the jet of the nearby radio galaxy 3C 264 using Hubble Space Telescope imaging from 1994 to 2014. Knot B was found to have an apparent speed of 7.0c, much faster than other knots. Knots B and C showed simultaneous brightening in 2014, indicating the beginning of their collision. Analysis suggests the collision will dissipate kinetic energy with a conversion efficiency to radiation of at least 0.1%, providing a way to study particle acceleration in astrophysical jets.
Application of extreme learning machine for estimating solar radiation from s...mehmet şahin
This paper presents an extreme learning machine (ELM) model to estimate solar radiation in Turkey using satellite data from the National Oceanic and Atmospheric Administration advanced very high-resolution radiometer from 20 locations. The ELM model uses land surface temperature, altitude, latitude, longitude, month, and city as inputs to estimate solar radiation. The ELM model provided better estimation accuracy than an artificial neural network model and was about 23.5 times faster to train, demonstrating the potential of ELM for solar radiation estimation using remote sensing data.
Estimation of global solar radiation by using machine learning methodsmehmet şahin
In this study, global solar radiation (GSR) was estimated based on 53 locations by using ELM, SVR, KNN, LR and NU-SVR methods. Methods were trained with a two-year data set and accuracy of the mentioned methods was tested with a one-year data set. The data set of each year was consisting of 12 months. Whereas the values of month, altitude, latitude, longitude, vapour pressure deficit and land surface temperature were used as input for developing models, GSR was obtained as output. Values of vapour pressure deficit and land surface temperature were taken from radiometry of NOAA-AVHRR satellite. Estimated solar radiation data were compared with actual data that were obtained from meteorological stations. According to statistical results, most successful method was NU-SVR method. The RMSE and MBE values of NU-SVR method were found to be 1,4972 MJ/m2 and 0,2652 MJ/m2, respectively. R value was 0,9728. Furthermore, worst prediction method was LR. For other methods, RMSE values were changing between 1,7746 MJ/m2 and 2,4546 MJ/m2. It can be seen from the statistical results that ELM, SVR, k-NN and NU-SVR methods can be used for estimation of GSR.
This document discusses finding the optimal trajectory for an artillery projectile using dynamic programming. It first describes the methodology used, including modeling the projectile motion and factors that affect the trajectory like wind velocity. It then discusses using muzzle velocity as the criterion to determine the optimal selection. Different combinations of muzzle velocity and angle of firing are computed to hit a target at a given distance. Finally, it explains how a dynamic programming algorithm is applied using these combinations and the Bellman equation to determine the minimum velocity needed to hit the target, which is the optimal choice as it requires the lowest amount of propellant.
Inference of homogeneous_clouds_in_an_exoplanet_atmosphereSérgio Sacani
1) New visible and infrared observations of the exoplanet Kepler-7b were analyzed to determine its atmospheric properties and detect the presence of clouds.
2) The observations found a westward shift in Kepler-7b's optical phase curve and placed upper limits on its thermal emission that remained undetected in Spitzer bandpasses.
3) The data suggests Kepler-7b has optically thick, high-altitude clouds located west of the substellar point, composed possibly of silicates. The clouds help explain Kepler-7b's unusually high geometric albedo and visible flux that cannot be attributed to thermal emission or molecular hydrogen scattering alone.
Comparative Calibration Method Between two Different Wavelengths With Aureole...Waqas Tariq
A multi-stage method for calibration of sunphotometer is proposed by combining comparison calibration method between two different wavelengths with aureole observation method for long wavelength calibration. Its effectiveness in reducing the influences for calibration due to molecular and aerosolfs extinction in the unstable turbidity conditions is clarified. By comparing the calculated results with the proposed method and the existing individually calibration method, it is found that the proposed method is superior to the existing method in terms of calibration accuracy. Namely, Through a comparison between ILM and the proposed method using band 0.87um as reference, the largest calibration errors are 0.0014, 0.0428 by PM are lower than that by ILM (0.011,0.0489) for sky radiances with no error and -3~+3%, -5~+5% errors. By analyzing the observation data of 15 days with POM-1 Skyradiometer, the largest standard deviation of calibration constants by PM is 0.02016, and is lower than that by ILM (0.03858).
A Study of Non-Gaussian Error Volumes and Nonlinear Uncertainty Propagation f...Justin Spurbeck
The ever-growing resident space object population poses a continual threat in that a hyper velocity impact is likely to be catastrophic to an active satellite. To avoid these scenarios, space operators compute a probability of collision metric for each potential conjunction. Uncertainty trends are studied in the conjunction plane and operational decisions to mitigate any high-risk situations are made based off this information. There are many methods of uncertainty propagation and probability of collision formulations and knowledge of their realism is required to maintain a sustainable space environment. Thus, this research studies the effect of Chan, Alfano, Foster, Gaussian mixture, and Monte Carlo probability of collision calculations and their correlation to uncertainty realism metrics. The linear, unscented transform, entropy-based, and Monte Carlo propagation techniques are utilized alongside the collision calculations and it is shown that there are important correlations any space operator should be aware of to support maintenance of a healthy spacecraft.
1) The document presents a technique for automatically correcting for ion travel time when mass calibrating a single quadrupole mass spectrometer. This allows a single calibration to be used over all mass ranges and scan speeds.
2) By deriving an equation for ion transmission time as a function of mass and scan speed, the mass shift due to varying scan speeds can be calculated and subtracted from acquired data.
3) Empirical testing showed the technique reduced initial mass shifts by at least 85% for all masses and scan speeds, with no residual shift over 0.1 m/z. The combined calibration provides effective mass calibration across an instrument's operating ranges.
Polarized reflected light from the Spica binary systemSérgio Sacani
Close binary systems often show linear polarization varying
over the binary period, usually attributed to light scattered
from electrons in circumstellar clouds1–3
. One of the brightest
close binary systems is Spica (alpha Virginis) consisting of
two B-type stars orbiting with a period of just over four days.
Past observations of Spica have shown low polarization with
no evidence for variability4–6. Here we report new high-precision polarization observations of Spica that show variation
with an amplitude of about 200 parts per million. By including
polarized radiative transfer in a binary star model, we show
that the phase-dependent polarization is mainly due to light
reflected from the primary component of the binary system
off the secondary component and vice versa. The stars reflect
only a few per cent of the incident light, but the reflected light
is very highly polarized. The polarization results show that the
binary orbit is clockwise and the position angle of the line of
nodes is 130.4° ± 6.8°, in agreement with intensity interferometer results7
. We suggest that reflected light polarization
may be much more important in binary systems than has previously been recognized and may be a way of detecting previously unrecognized close binaries.
An ultrahot gas-giant exoplanet with a stratosphereSérgio Sacani
Infrared radiation emitted from a planet contains information
about the chemical composition and vertical temperature profile
of its atmosphere1–3. If upper layers are cooler than lower layers,
molecular gases will produce absorption features in the planetary
thermal spectrum4,5
. Conversely, if there is a stratosphere—
where temperature increases with altitude—these molecular
features will be observed in emission6–8. It has been suggested that
stratospheres could form in highly irradiated exoplanets9,10, but
the extent to which this occurs is unresolved both theoretically11,12
and observationally3,13–15. A previous claim for the presence of a
stratosphere14 remains open to question, owing to the challenges
posed by the highly variable host star and the low spectral resolution
of the measurements3
. Here we report a near-infrared thermal
spectrum for the ultrahot gas giant WASP-121b, which has an
equilibrium temperature of approximately 2,500 kelvin. Water
is resolved in emission, providing a detection of an exoplanet
stratosphere at 5σ confidence. These observations imply that a
substantial fraction of incident stellar radiation is retained at high
altitudes in the atmosphere, possibly by absorbing chemical species
such as gaseous vanadium oxide and titanium oxide
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity
Titan’s Topography and Shape at the Endof the Cassini MissionSérgio Sacani
With the conclusion of the Cassini mission, we present an updated topographic map of Titan,including all the available altimetry, SARtopo, and stereophotogrammetry topographic data sets availablefrom the mission. We use radial basis func tions to interpolate the sparse data set, which covers only ∼9%of Titan’s global area. The most notable updates to the topography include higher coverage of the polesof Titan, improved fits to the global shape, and a finer resolution of the global interpolation. We alsopresent a statistical analysis of the error in the derived products and perform a global minimization on aprofile-by-profile basis to account for observed biases in the input data set. We find a greater flattening ofTitan than measured, additional topographic rises in Titan’s southern hemisphere and better constrain thepossible locations of past and present liquids on Titan’s surface.
This document provides an overview and validation of Re.SunTM, a software tool for assessing solar resources worldwide using mesoscale weather modeling and coupling techniques. Re.SunTM runs the WRF mesoscale numerical weather model to generate meteorological data, then applies clear sky models incorporating aerosol and gas data to estimate solar radiation indices. It was validated against measurements from 9 complex sites, showing a mean bias of 0.64% and root mean square error of 4%. Statistics demonstrate Re.SunTM can estimate average annual global solar radiation to within 4.14% of measured for 80% of cases. The document concludes Re.SunTM is useful for solar applications requiring site-specific resource assessment.
Exact Analytical Expression for Outgoing Intensity from the Top of the Atmosp...IOSR Journals
This research is a part of the work devoted on the application of analytical Discrete Ordinate (ADO) method to the polarized monochromatic radiative transfer equation undergoing anisotropic scattering with source function matrix in a finite coupled Atmosphere –Ocean media having flat interface boundary conditions involving specular reflection and transmission matrix. Discontinuities in the derivatives of the Stokes vector with respect to the cosine of the polar angle at smooth interface between the two media with different refractive indices (air and water) is tackled by using a suitable quadrature scheme devised earlier. Atmosphere and ocean are assumed to be homogeneous. No stratification is adopted in the two media. Exact expression for the
emergent radiation intensity vector from the top of the atmosphere is derived. Exact expressions for the emergent polarized radiation intensity vector from the air-water interface as well as from any point of the two medium in any direction can also be derived in terms of eigenvectors and eigenvalues.
This study implements a Bayesian statistical framework to calibrate the SCOPE process-based simulator for simulating gross primary production (GPP) and top-of-canopy reflectance at a spruce flux tower site in the Czech Republic. Markov chain Monte Carlo simulation is used to quantify the uncertainty in SCOPE input parameters by comparing simulated and measured reflectance and GPP data. The results show the posterior parameter distributions have lower uncertainty than the prior distributions. Simulated half-hourly GPP over the growing season using maximum a posteriori parameter estimates matches the measured data. Future work will estimate seasonal parameter variations to improve GPP simulation accuracy.
At present, with the development of wind power project in China, there are more and more projects located at the complex terrain and complex environment. At the same time, since the large planned area of project, the complex mountain area, and limited number of met mast, even without met mast, in order to the reliable development of the wind power project, it is important that how to do the wind resource assessment without actual measurement wind data and other conditions such as less reliable wind data, and the met mast was not considered representative. This paper will use the atmospheric model to do mesoscale simulation calculation of wind resources, and then combine with CFD technology to downscaling computation to get high resolution wind power assessment result. Finally, in order to confirm the validity of this application in the actual project, the comparison between calculation values and measurement values is carried out. The verification result through the actual data of different met mast shows that the wind resource assessment method which combines the CFD and mesoscale technologies is reliable. The main contribution of the article is to provide the reference model and approach for regional planning and large scale wind resource assessment when there isn’t enough adequate and effective wind data.
Closed-Form Performance Analysis of Dual Polarization Based MIMO System in Sh...IJERA Editor
In this paper, the problem of dual polarization based MIMO Processing in Shadowed-Rician (SR) fading land mobile satellite (LMS) channels is studied. It is shown in literature that polarization is used as a interference rejection method; and, most of the existing analytical results are not in closed-form. In this paper, we derive the closed-form expressions of the moment generating (MGF) function of the received signal-to-noise ratio of the MRC based receiver in SR fading LMS channels. Then we provide closed-form expressions of the symbol error rate (SER) by using MGF approach. The analytical diversity order and capacity of the considered scheme is also derived. It is shown by by derived closed-form capacity expression that the capacity of the considered dual polarization based scheme is improved; and it is found very useful in practical satellite communication systems.
Este documento describe las características básicas de los músculos esqueléticos. Explica que los músculos son órganos carnosos que se contraen y provocan el movimiento del cuerpo, y mantienen la postura y equilibrio. Describe las diferentes porciones de los músculos como el vientre y los extremos, y cómo se insertan en los huesos a través de los tendones. También clasifica los músculos por su número de cabezas, colas o vientres, y por la acción muscular que producen
This document outlines problems and proposed solutions across several departments and programs at Sejong University. It discusses issues with course management, bio-convergence engineering, information security, globalization, and volunteer work programs. Specific problems identified include unnecessary courses, large class sizes, lack of executive skills courses, unclear department changes, curriculum mistakes, and inadequate hacking practice courses. Solutions proposed are providing more specialized course choices, expanding courses/faculty, adding executive skills courses, clearer communication, curriculum planning consideration, and inclusion of more hacking practice courses. The conclusion states addressing these problems could help students achieve success.
The Job Hunt & Your Personal Campaign: What's your brand?KristinaBurrows3
The document discusses how personal branding and social media presence are important for job seekers. It emphasizes that individuals should think of their job search or career development as a "personal campaign" to market their unique value and skills. Employers are increasingly looking at candidates' online profiles and digital footprint to assess fit and qualifications for a role. The document provides tips for using social media strategically during the job hunt, such as engaging in industry communities and maintaining a professional online identity that highlights one's qualifications and interests.
Este documento resume los principales tejidos del cuerpo humano, incluyendo epitelio, tejido conectivo, tejido muscular y tejido nervioso. Describe las características y funciones de cada tejido, así como sus subtipos. El epitelio se clasifica según su número de capas y función. El tejido conectivo incluye tejido conjuntivo, cartilaginoso, adiposo, óseo y sanguíneo/linfático. Los tres tipos de tejido muscular son estriado esquelético, estriado
The Complete Guide to Enterprise Work Management Blake Howell
The document provides an overview of enterprise work management (EWM) solutions. It discusses how work is often disconnected and chaotic due to using multiple tools, which leads to inefficiencies and wasted time. EWM aims to address this by providing a single, unified platform to manage work across the entire lifecycle from initial request to final report. This gives leaders visibility into who is working on what, whether it is the right work, and if work is on track. The document outlines how EWM can benefit teams by streamlining request intake, collaboration, status reporting, and more to improve productivity compared to using various point solutions.
Este documento resume los principales tejidos del cuerpo humano, incluyendo epitelio, tejido conectivo, muscular y nervioso. Describe las características y funciones de cada tejido, así como sus componentes celulares. El epitelio se clasifica en simple, estratificado y glandular. El tejido conectivo incluye tejido conjuntivo, cartilaginoso, adiposo, óseo y sanguíneo/linfático. Los tres tipos de tejido muscular son estriado esquelético, estriado cardiaco y l
Este documento presenta las instrucciones para la realización y entrega del trabajo académico del curso de Gerencia de Proyectos de la Universidad Alas Peruanas. Incluye detalles sobre la publicación del trabajo, fechas límite, criterios de evaluación y preguntas que deben ser respondidas como parte del trabajo.
El documento resume las características principales del hígado y la vesícula biliar. El hígado consta de dos lóbulos separados por el ligamento falciforme y presenta dos caras y dos bordes. Se localiza en el hipocondrio derecho y se fija mediante varios ligamentos. La vesícula biliar se localiza en la fosa vesicular en la cara inferior del hígado, tiene forma de piña y está irrigada por la arteria cística. Se continúa con el conducto cístico que luego forma el colédoco,
Este documento resume la anatomía del sistema óseo humano, dividiéndolo en tres regiones principales: cráneo, tronco y extremidades. En la región del cráneo, describe los huesos del neurocráneo como el frontal, occipital, parietales, esfenoides y etmoides, detallando sus características. En la región del tronco, describe la columna vertebral, costillas y esternón. Finalmente, en la región de las extremidades detalla los huesos del brazo, antebrazo, mano, cadera, pierna
El documento describe la anatomía del sistema respiratorio. Los pulmones se encuentran en la cavidad torácica y están rodeados por las pleuras. El mediastino divide los pulmones y contiene estructuras como el corazón y los vasos sanguíneos principales. Los pulmones reciben sangre a través de las arterias pulmonares para oxigenarse y la devuelven a través de las venas pulmonares. Están inervados por los nervios simpáticos y parasimpáticos y drenan linfa a través de los conductos linfá
La piel está compuesta de tres capas principales: la epidermis, la dermis y la hipodermis. La epidermis contiene queratinocitos, melanocitos, células de Langerhans y células de Merkel. La dermis contiene vasos sanguíneos, folículos pilosos, glándulas sudoríparas y receptores sensitivos como los corpúsculos de Meissner, Pacini y Ruffini. La piel tiene funciones de protección, termorregulación, percepción de estímulos e inmunidad.
Introduction to Streaming Distributed Processing with StormBrandon O'Brien
Contact:
https://www.linkedin.com/in/brandonjobrien
@hakczar
Introducing streaming data concepts, Storm cluster architecture, Storm topology architecture, and demonstrate working example of a WordCount topology for SIGKDD Seattle chapter meetup.
Presented by Brandon O'Brien
Code example: https://github.com/OpenDataMining/brandonobrien
Meetup: http://www.meetup.com/seattlesigkdd/events/222955114/
Este portafolio de anatomía pertenece a Kerly Johana Pérez Gabilanes, una estudiante del segundo semestre de la carrera de Enfermería en la Facultad de Ciencias de la Salud de la Universidad Técnica de Ambato durante el año 2016. El portafolio fue realizado bajo la guía del Dr. Gustavo Moreno.
Direct and indirect speech (basic) english con audiosallanlot90
Direct speech refers to reporting what someone said verbatim, using quotation marks. Indirect speech reports the essence of what someone said without using quotation marks by changing the verb tenses and pronouns. The document provides examples of how direct speech converts to indirect speech by changing verbs from present to past tense, changing pronouns, and modifying adverbs of time. It also outlines the basic structures for direct and indirect speech.
Herschel far infrared_spectroscopy_of_the_galactic_centerSérgio Sacani
The document summarizes observations from the Herschel Space Observatory of the Galactic Center region, focusing on a spectral scan toward Sagittarius A*. Key findings include:
1) Strong emission from atomic fine structure lines and rotationally excited lines of molecules like CO, H2O and HCO+ are detected.
2) The excitation of the CO ladder is consistent with either a hot isothermal gas component at 103.1 K and 104 cm-3, or a distribution of warmer gas at higher densities, with most CO at 300 K.
3) The detected molecular features suggest heating is from a combination of UV irradiation and shocks in the gas, rather than very enhanced X-ray or cosmic
The shadow _of_the_flying_saucer_a_very_low_temperature_for_large_dust_grainsSérgio Sacani
Os astrónomos usaram o ALMA e os telescópios do IRAM para fazer a primeira medição direta da temperatura dos grãos de poeira grandes situados nas regiões periféricas de um disco de formação planetária que se encontra em torno de uma estrela jovem. Ao observar de forma inovadora um objeto cujo nome informal é Disco Voador, os astrónomos descobriram que os grãos de poeira são muito mais frios do que o esperado: -266º Celsius. Este resultado surpreendente sugere que os modelos teóricos destes discos precisam de ser revistos.
Uma equipa internacional liderada por Stephane Guilloteau do Laboratoire d´Astrophysique de Bordeaux, França, mediu a temperatura de enormes grãos de poeira que se encontram em torno da jovem estrela 2MASS J16281370-2431391 na região de formação estelar Rho Ophiuchi, a cerca de 400 anos-luz de distância da Terra.
Esta estrela encontra-se rodeada por um disco de gás e poeira — chamado disco protoplanetário, uma vez que se encontra na fase inicial da formação de um sistema planetário. Este disco é visto de perfil quando observado a partir da Terra e a sua aparência em imagens no visível levou a que se lhe desse o nome informal de Disco Voador.
Os astrónomos utilizaram o ALMA para observar o brilho emitido pelas moléculas de monóxido de carbono no disco da 2MASS J16281370-2431391. As imagens revelaram-se extremamente nítidas e descobriu-se algo estranho — em alguns casos o sinal recebido era negativo. Normalmente um sinal negativo é fisicamente impossível, mas neste caso existe uma explicação, que leva a uma conclusão surpreendente.
A thirty-four billion solar mass black hole in SMSS J2157–3602, the most lumi...Sérgio Sacani
From near-infrared spectroscopic measurements of the Mg II emission line doublet, we estimate the black hole (BH) mass of the quasar, SMSS J215728.21–360215.1, as being (3.4 ± 0.6) × 1010 M⊙ and refine the redshift of the quasar to be z = 4.692. SMSS J2157 is the most luminous known quasar, with a 3000 Å luminosity of (4.7 ± 0.5) × 1047 erg s−1 and an estimated bolometric luminosity of 1.6 × 1048 erg s−1 , yet its Eddington ratio is only ∼0.4. Thus, the high luminosity of this quasar is a consequence of its extremely large BH – one of the most massive BHs at z > 4.
This document summarizes a study measuring the transverse beam emittance at the Energy Selection System (ESS) of the KIRAMS-430 superconducting cyclotron. The researchers used a quadrupole variation method, where they varied the magnetic strength of a quadrupole magnet and measured the resulting beam size at a beam profile monitor. They analyzed the measurements using both linear matrix formalism and particle tracking simulations. The results from both analysis methods were consistent with emittances calculated from Monte Carlo simulations within the measurement uncertainties. The study demonstrated the feasibility of using the quadrupole variation method to characterize the beam quality at the ESS ion beamline.
- Astrônomos descobriram que uma pequena estrela, do tamanho de Júpiter, possui uma tempestade muito parecida com a Grande Mancha Vermelha e que está ali, persistente por dois anos.
- Enquanto nos planetas, esse tipo de característica é normal, em estrelas essa é a melhor evidência encontrada até hoje.
- A estrela é chamada de W1906+40 e pertence a uma classe de objetos frios chamados de Anãs-L.
- Elas são consideradas estrelas pois fundem átomos e geram luz, como o Sol faz, enquanto que as anãs marrons são conhecidas como estrelas que falharam, pois elas não possuem o processo de fusão atômica em seu interior.
- Nesse novo estudo os astrônomos foram capazes de verificar as mudanças na atmosfera da estrela por dois anos. A técnica usada foi semelhante à de detecção de exoplanetas, analisando a curva de luz da estrela, que apresentava quedas, mas que não era por questão de planetas.
- Os astrônomos usaram o Spitzer e estudaram a luz infravermelha da estrela, que revelou uma gigantesca mancha escura que não era uma mancha magnética estelar, mas sim uma tempestade com um diâmetro equivalente ao de 3 Terras. O spitzer foi capaz de estudar camadas diferentes da atmosfera da estrela e esses dados junto com os dados do Kepler, revelaram com clareza a tempestade estelar.
- Futuras observações serão realizadas usando os dois equipamentos para tentar identificar esse tipo de tempestade em anãs marrons, por exemplo, e tentar descobrir se esse tipo de fenômeno é muito comum, ou é raro no universo.
Global collapse of_molecular_clouds_as_a_formation_mechanism_for_the_most_mas...Sérgio Sacani
This document summarizes observations of the massive star-forming cloud SDC335 made using Spitzer, Herschel, Mopra, and ALMA. It finds that SDC335 contains over 5500 solar masses of gas distributed in a network of filaments that converge on a central hub region. ALMA observations reveal two massive cores within this hub region, the most massive of which contains over 500 solar masses of gas. Kinematic analysis of molecular line data from Mopra and ALMA indicates that the cloud is undergoing global collapse, with infalling gas bringing additional material at a rate of over 2.5 solar masses per year to the central region, which could double its mass within the next few million years and allow
Future ground arrays for ultrahigh-energy cosmic rays: recent updates and per...Toshihiro FUJII
The document summarizes recent updates on future ground-based arrays for detecting ultra-high energy cosmic rays. It discusses key findings from UHECR observations including the energy spectrum measured by the Telescope Array and Pierre Auger Observatory experiments. There is good agreement between the two experiments within systematic uncertainties, though the second break point in the energy spectrum occurs at a slightly higher energy for TA. It also summarizes mass composition results from Xmax distributions, finding the data is best described by a mix of light and intermediate mass nuclei. No significant photons or neutrinos have been detected at the highest energies that would be expected from the GZK effect.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
This document analyzes the performance of cognitive radio networks using maximal ratio combining over correlated Rayleigh fading channels. It presents a simple analytical method to derive closed-form expressions for the probabilities of detection and false alarm. The key findings are:
1) The detection probability is a monotonically increasing function of the number of antennas, as more antennas provides more diversity gain.
2) Antenna correlation degrades the sensing performance compared to independent antennas. Higher correlation results in lower detection probability.
3) Complementary receiver operating characteristic curves illustrate that both higher signal-to-noise ratio and lower antenna correlation improve detection performance by increasing the detection probability and decreasing the probability of miss at a given false alarm probability.
A highly magnetized twin-jet base pinpoints a supermassive black holeSérgio Sacani
Supermassive black holes (SMBH) are essential for the production of jets in radio-loud active galactic nuclei (AGN). Theoretical
models based on (Blandford & Znajek 1977, MNRAS, 179, 433) extract the rotational energy from a Kerr black hole, which could
be the case for NGC1052, to launch these jets. This requires magnetic fields on the order of 103 G to 104 G. We imaged the vicinity
of the SMBH of the AGN NGC1052 with the Global Millimetre VLBI Array and found a bright and compact central feature that is
smaller than 1.9 light days (100 Schwarzschild radii) in radius. Interpreting this as a blend of the unresolved jet bases, we derive the
magnetic field at 1 Schwarzschild radius to lie between 200 G and 8:3 104 G consistent with Blandford & Znajek models.
Science Express Paper by: Kevin B. Stevenson et al.GOASA
- Spectroscopic phase curve observations of the exoplanet WASP-43b using the Hubble Space Telescope revealed a distinct increase in flux as the dayside rotated into view, peaking prior to secondary eclipse.
- Analysis of the spectrally resolved phase curves showed wavelength-dependent amplitudes, phase shifts, and eclipse depths, allowing inference of the temperature structure and molecular abundances at 15 orbital phases.
- Atmospheric modeling found water to be the dominant absorber influencing the phase-resolved emission spectra. The data showed large day-night temperature variations at all measured altitudes and a monotonically decreasing temperature with pressure.
Detection of the_central_star_of_the_planetary_nebula_ngc_6302Sérgio Sacani
The document summarizes the detection of the central star of the planetary nebula NGC 6302 using new observations from the Hubble Space Telescope's Wide Field Camera 3. Key points:
1) The central star is directly detected for the first time at the center of the nebula, confirming its location but not at the center of the inner dust torus.
2) Photometry of the central star yields a reddening value of c=3.1, corresponding to AV=6.6 magnitudes of extinction, mostly from circumstellar dust.
3) Estimates of the stellar temperature, luminosity, and distance suggest a fairly massive central star of around 0.64 solar masses that is evolving rapidly and fading over time
Probing the jet_base_of_blazar_pks1830211_from_the_chromatic_variability_of_i...Sérgio Sacani
This document summarizes ALMA observations of the blazar PKS 1830-211 taken over multiple epochs in 2012. The blazar is lensed by a foreground galaxy, producing two resolved images (NE and SW) separated by 1". The observations were taken at frequencies corresponding to 350-1050 GHz in the blazar rest frame. Analysis of the flux ratio between the two images over time and frequency revealed a remarkable frequency-dependent behavior, implying a "chromatic structure" in the blazar jet. This is interpreted as evidence for a "core-shift effect" caused by plasmon ejection very near the base of the jet. The observations provide a unique probe of activity in the region where plasma acceleration occurs in blazar
The deep blue_color_of_hd189733b_albedo_measurements_with_hst_stis_at_visible...Sérgio Sacani
The document summarizes a study that measured the geometric albedo of the exoplanet HD 189733b across visible wavelengths using Hubble Space Telescope observations. It found an albedo of 0.40 ± 0.12 at 290-450 nm that decreased to below 0.12 at 450-570 nm, suggesting optically thick clouds reflecting light at shorter wavelengths and sodium absorption suppressing reflection beyond 450 nm. This wavelength-dependent albedo implies HD 189733b would appear deep blue in color at visible wavelengths.
X-rays from a Central “Exhaust Vent” of the Galactic Center ChimneySérgio Sacani
Using deep archival observations from the Chandra X-ray Observatory, we present an analysis of
linear X-ray-emitting features located within the southern portion of the Galactic center chimney,
and oriented orthogonal to the Galactic plane, centered at coordinates l = 0.08◦
, b = −1.42◦
. The
surface brightness and hardness ratio patterns are suggestive of a cylindrical morphology which may
have been produced by a plasma outflow channel extending from the Galactic center. Our fits of the
feature’s spectra favor a complex two-component model consisting of thermal and recombining plasma
components, possibly a sign of shock compression or heating of the interstellar medium by outflowing
material. Assuming a recombining plasma scenario, we further estimate the cooling timescale of this
plasma to be on the order of a few hundred to thousands of years, leading us to speculate that a
sequence of accretion events onto the Galactic Black Hole may be a plausible quasi-continuous energy
source to sustain the observed morphology
The canarias einstein_ring_a_newly_discovered_optical_einstein_ringSérgio Sacani
This document reports the discovery of a newly discovered optical Einstein ring (ER) called the "Canarias Einstein Ring". It was discovered serendipitously in imaging data from the Dark Energy Camera. Follow-up spectroscopy with the Gran Telescopio CANARIAS confirmed the nature of the system, with the lens being an early-type galaxy at a redshift of z=0.581 and the source being a starburst galaxy at z=1.165. Analysis of the system determined the Einstein radius to be 2.16 arcseconds and the total enclosed mass producing the lensing effect to be 1.86 ± 0.23 × 1012 solar masses.
This document characterizes the neutron field in the instrument calibration facility rig room at ANSTO in Australia. Four standard methods were used to determine the fractional room return scatter and ambient dose equivalent response of the reference neutron monitor. The shadow shield method from ISO 10647 was adopted, using a truncated conical shield. It found a monitor reading of 200.40 uSv/h at 1m and fractional room return scatter of 1.210E-04. The objectives were to characterize the room's neutron scattering properties and calibrate the facility's neutron monitor standards.
A fast atmospheric correction algorithm applied to landsat tm imagesweslyj
This document describes a fast atmospheric correction algorithm for Landsat TM images. The algorithm proceeds in two steps:
1) It calculates ground reflectance for each pixel based on precomputed planetary albedo functions for standard atmospheres, aerosol types, and optical depths.
2) It approximately corrects for the adjacency effect by taking the average reflectance in a neighborhood of pixels and applying weighting functions to differences in reflectance.
Towards the identification of the primary particle nature by the radiodetecti...Ahmed Ammar Rebai PhD
This document summarizes a study using the CODALEMA experiment to analyze radio signals from air showers and identify properties of primary cosmic ray particles. It describes:
1) Analyzing time delays of radio signals compared to a plane wavefront hypothesis and finding systematic deviations, indicating the wavefront is curved.
2) Developing a model to reconstruct the emission center position based on fitting time delays to a parabolic function dependent on curvature radius and antenna distances.
3) Applying the model to 450 selected CODALEMA events and comparing reconstructed shower core positions to results from other models, finding consistency.
Mapping the Skies of Ultracool Worlds: Detecting Storms and Spots with Extrem...Sérgio Sacani
Extremely large telescopes (ELTs) present an unparalleled opportunity to study the magnetism,
atmospheric dynamics, and chemistry of very low mass stars (VLMs), brown dwarfs, and exoplanets.
Instruments such as the Giant Magellan Telescope - Consortium Large Earth Finder (GMT/GCLEF),
the Thirty Meter Telescope’s Multi-Objective Diffraction-limited High-Resolution Infrared Spectrograph
(TMT/MODHIS), and the European Southern Observatory’s Mid-Infrared ELT Imager and Spectrograph (ELT/METIS) provide the spectral resolution and signal-to-noise (S/N) necessary to Doppler
image ultracool targets’surfaces based on temporal spectral variations due to surface inhomogeneities.
Using our publicly-available code, Imber, developed and validated in Plummer & Wang (2022), we
evaluate these instruments’abilities to discern magnetic star spots and cloud systems on a VLM star
(TRAPPIST-1); two L/T transition ultracool dwarfs (VHS J1256−1257 b and SIMP J0136+0933); and
three exoplanets (Beta Pic b and HR 8799 d and e). We find that TMT/MODHIS and ELT/METIS are
suitable for Doppler imaging the ultracool dwarfs and Beta Pic b over a single rotation. Uncertainties
for longitude and radius are typically . 10◦
, and latitude uncertainties range from ∼ 10◦
to 30◦
.
TRAPPIST-1’s edge-on inclination and low υ sin i provide a challenge for all three instruments while
GMT/GCLEF and the HR 8799 planets may require observations over multiple rotations. We compare
the spectroscopic technique, photometry-only inference, and the combination of the two. We find
combining spectroscopic and photometric observations can lead to improved Bayesian inference of
surface inhomogeneities and offers insight into whether ultracool atmospheres are dominated by spotted
or banded features.
Mapping the Skies of Ultracool Worlds: Detecting Storms and Spots with Extrem...
bakerca2Thesis2s
1. Draft version April 17, 2015
Preprint typeset using LATEX style emulateapj v. 01/23/15
NGC5195 PDR MODELLING OF COLD GAS AND DUST USING HERSCHEL PACS SPECTROSCOPY
Christian Baker and Supervisor: Christine Wilson
McMaster University
Draft version April 17, 2015
ABSTRACT
Data from the Herschel Space Observatory Photodetector Array Camera and Spectrometer (PACS)
spectroscopy as part of the Very Nearby Galaxies Survey (VNGS) has revealed ISM gas characteristics
for dwarf galaxy NGC 5195, the companion to M51, using spectral lines [C II]158 [N II]122, [O I]63, [O
I]145, and [O III]88. With these observed flux values we compare to a predicted flux from a photon
dominated region (PDR) model to determine the characteristics of the cold gas and then compare
to other recently studied galaxies. We find an averaged [C II]/FTIR value of 4.4×10−4
which falls
an order of magnitude under comparable galaxies. We find a logG0 of 2.5-3.3 and a log(n/cm−3
) of
2.0-3.0.
1. INTRODUCTION
We study the S0 galaxy NGC 5195, the companion
to M51, for its cooling properties. NGC 5195 is lo-
cated at a distance of 7.7±1.0 Mpc away (Tonry et al.
2001). By observing the cooling properties we aim to use
a PDR model to determine gas characteristics of NGC
5195 which will allow us to compare with other galaxies.
Of particular interest is M51 as NGC 5195 is a compan-
ion galaxy and has interacted with M51. This follows the
general goals of the (VGNS) which are to probe the prop-
erties of gas and dust in the interstellar medium (ISM)
of 13 galaxies. NGC 5195 is not one of these galaxies but
data was taken for it at the same time as M51. Thanks
spectroscopy from the PACS instrument offers us fine
structure lines of [C II]158 [N II]122, [O I]63, [O I]145, and
[O III]88 at resolutions better than 12” (see Table 1).
In order to investigate the cooling properties of the in-
terstellar medium (ISM), fine structure lines such as [C
II]158 [N II]122, [O I]63, [O I]145, and [O III]88 can be used.
These lines show gas cooling by de-excitation via photon
emission. In particular the [C II] line traces both neutral
and ionized gas, the [O I] lines trace neutral gas, and
the [N II] and [O III] lines trace ionized gas. Due to the
various emission lines tracing different parts of the gas,
we can use the [C II] emission, a tracer of photon domi-
nated regions (PDRs), even though it also traces ionized
gas (with an ionization potential of only 11.26 eV). In
comparison the [N II] and [O III] lines have ionization
potentials of 14.5 eV and 35 eV and thus require a hard
radiation field.
We probe these lines using the Herschel PACS
(Poglitsch et al. 2010) in order to investigate the ISM in
NGC 5195 using a PDR model, as well as comparing it
to recent studies on M51,and Centaurus A.(Parkin et al.
2013; Parkin et al. 2014). We use the spectra obtained
to investigate the gas component of NGC 5195, and the
PDR model of Kaufman et al. (1999, 2006) to estimate
the properties of the ISM.
A PDR model predicts the physical characteristics
through the hydrogen nucleus density, n, and the
strength of the far-ultraviolet (FUV) radiation field in
units of the Habing Field, G0 = 1.6×10−3
erg cm−2
s−1
bakerca2@mcmaster.ca
(Habing 1968). Kaufman’s model (Kaufman 1999, 2006)
gives a method to use the line ratios and total in-
frared luminosity to determine n and G0. Our data
uses the readily available analysis tool the PDR Toolbox
(PDRT) (Pound & Wolfire 2008); which may be found
at http://dustem.astro.umd.edu/pdrt. PDR models as-
sume a plane-parallel, semi-infinite slab geometry and
include a complex chemical network, thermal balance,
and radiative transfer.
Our comparisons to Cen A and M51 will include find-
ing an average [C II]/FT IR value to compare to 4 × 10−3
of M51 and 8.4 × 10−3
of Cen A (Parkin et al. 2013;
Parkin et al. 2014). We also will compare heating effi-
ciency which is determined from ([C II]+[O I]63)/FT IR.
This same value when used in conjunction with [C II]/[O
I]63 will give values to compare to n and G0.
Organization of this paper is as follows: Section 2 de-
scribes the data and the processing of said data, Section
3 describes the gas characteristics, and Section 4 com-
pares these observations to theoretical models as well as
other recently studied galaxies.
2. OBSERVATIONS
2.1. PACS spectroscopy
We obtained the PACS spectroscopy of NGC 5195 from
the Guaranteed Time Project of the VGNS (PI; C. D.
Wilson). Maps were obtained for [C II]158 [N II]122, [O
I]63, [O I]145, and [O III]88. Properties of the observations
can be seen in Table 1. Images were handed to us already
reduced and ready for analysis (Parkin T. J.). The [C II]
and [N II] lines were mapped in a 3 × 3 set of overlap-
ping footprints that cover a square area of 47” on a side.
The [O I]63 line was mapped in a 5 × 5 grid. The [O
I]145 and [O III]88 lines were mapped in a 2 × 2 grid. T.
J. Parkin (private communication) describes the data re-
duction as follows: ”The raw data was processed by T. J.
Parkin up to Level 2 using the Herschel Interactive Pro-
cessing Environment (HIPE; Ott 2010) version 9.0.2649
with calibration files FM,41. The standard pipeline for
unchopped gratings scans was used. The Level 2 PACS
spectral cubes were then passed to the line fitting and
map making program PACSman 3.52 (Lebouteiller et al.
2012), where the spectral lines in each raster were fit with
a Gaussian line profile and a second order baseline. The
2. 2
[C II]
1E-08 2E-08 3E-08 4E-08 5E-08 6E-08 7E-08 8E-08
[N II]
1E-09 2E-09 3E-09 4E-09 5E-09 6E-09 7E-09 8E-09
[O I]63
1E-08 2E-08 3E-08 4E-08 5E-08 6E-08 7E-08 1E-09 2E-09 3E-09 4E-09 5E-09 6E-09 7E-09
[O III]
[O I]145
1E-09 2E-09 3E-09 4E-09 5E-09 6E-09
Fig. 1.— Maps of NGC 5195 displaying Herschel PACS spectroscopic observations of fine structure lines at native resolution and pixel
scale. North is up and east is to the right. Units are W m−2.
3. 3
resulting line fits were then integrated to obtain fluxes,
then maps were produced by projecting fluxes from each
raster on an oversampled common grid with final pixel
scale of 3.133”.” The reduced images can be seen in Fig-
ure 1.
2.2. Additional Data
A total infrared flux map was also obtained from Tara
Parkin which was made using reprocessed photometry
(Bendo et al. 2012) at 24 µm from the Multiband Imag-
ing Photometer for Spitzer (Rieke et al. 2004) instrument
on the Spitzer Space Telescope (Werner et al. 2004) in
combination with published PACS photometry data at
70 and 160 µm (Mentuch Cooper et al. 2012). Parkin
was then able to estimate the the total far-infrared inten-
sity using the empirical equation (Galametz et al. 2013):
IT IR = (2.133 ± 0.095)v24I24 + (0.681 ± 0.028)v70I70
+(1.125 ± 0.010)v160I160
(1)
The map created from this process can be seen in Figure
2.
2.3. Data treatment for analysis
Before any data analysis on the maps we convolved the
maps to share a full width half maximum (FWHM) of
the [C II] map ( 11.5”) using a Gaussian function using
the STARLINK software’s gausmooth function. Once
convolved the images were also aligned and then tested
with large apertures covering the entire map to see if flux
was lost in the convolving process. We lose under 1% of
the total flux and consider flux to be conserved under the
transformations. Calibration uncertainty for PACS data
is at ±30% which is primarily small offsets in pointing
and drifting of the detector response (PACS OM). Un-
certainties listed in tables are from the uncertainty maps
in the raw data however to give a more precise look at
the data as all of the maps are equally affected by the
calibration uncertainty. [O III] and [O I]145 were below
a mean signal-to-noise ratio (SNR) of 9 across the a 30”
aperture and have been discounted from most analysis.
[O I]145 has a peak SNR of 27 but falls off rapidly as you
can see in Table 2, so we use the peak flux in Section 3.2
but not the mean value.
3. PHYSICAL CHARACTERISTICS OF THE GAS
3.1. Line Emission Morphology
As can be seen in Figure 1 the distributions for most
lines is similar, with peaks in the centre. As previously
discussed we reject the [O III]. The low signal-to-noise
is evident in the uneven distribution of the map where
we would expect a peaked distribution like the other de-
tected lines. Using starlink’s beamfit command we find
it fails to determine a beam width for [O I]145 and [O
III]88. It does provide fits for the full width at half max-
imum (FWHM) of 26”, 21” and 15” for [C II], [N II]122
and [O I]63 which agrees with what we can see visually.
As seen in Table 3 our peak flux is 2-3 times greater
than an average over a 30” aperture. Overall morphology
looks elliptical as there is no visible spiral arm structure.
In Table 4 we observe our well detected lines in a ratio
with FT IR. Here we have used the mean and peak values
again. [C II] contributes the most of the lines studied,
with [O I]63 coming in close behind. Emission from [C II]
and [O I]63 account for up to 0.004% of total emission.
This is a factor of 10 lower than what was observed in
NGC 5195’s companion, M51 (Parkin et al. 2013).
3.2. Heating Efficiency
We can use ([C II]+[O I]63)/FT IR as a proxy to the
heating efficiency (Tielens & Hollenbach 1985). This
value is a measure of the amount of interstellar FUV
radiation that gets converted via the photoelectric effect
into gas heating divided by the fraction of its energythat
is deposited into the dust grains. We will be using it with
the ratio of [C II]/[O I]63 to use the heating efficiency to
predict characteristics of the gas. A map of ([C II]+[O
I]63)/FT IR can be seen in Figure 3. With the ratios of
([C II]+[O I]63)/FT IR and [C II]/[O I]63 we can start
modelling our PDR’s as seen in Section 4.1. There is a
deficit in the center of Figure 3 which suggests reduced
heating efficiency in this region. This is consistent with
what was found in M51 by Parkin et al (2013).
The [O I] lines can give an estimate of the temperature
as displayed in Figure 4 of Liseau et al. (2006). Given
that our [O I]145 is poorly detected we attempt to get a
rough estimate of the temperature if the gas is optically
thick or optically thin by using the peak values where the
signal-to-noise is somewhat decent. We find [O I]63/[O
I]145 to be 10±1 and as the lines intersect close to there
we can estimate the temperature as being T ≥200 K and
n ≥ 103
cm−3
.
With the ratios of ([C II]+[O I]63)/FT IR and [C II]/[O
I]63 we can start modelling our PDR’s as seen in Section
4.1.
3.3. Ionized Gas Fraction
The fraction of emission originating in HII regions is of
particular interest as opposed to emission from ionized
gas. We estimated the fraction of [C II] emission origi-
nates from ionized gas versus neutral gas. The [N II]205
line is commonly used to determine the [N II]122/[N II]205
which can be used to determine the ionized gas density.
We lack the [N II]205 line which we need. Often we es-
timate the [N II] ratio when this happens, such as using
the Galactic value when appropriate as Malhotra et al.
(2001) did. Parkin found however that this disagreed
with other methods (Parkin et al. 2013; Kramer et al.
2005).
We instead estimate the [N II]122/[N II]205 at various
ionized gas densities constrained using the [S III]18.71/[S
III]33.48 which was provided by Tara Parkin (private com-
munication) as n ≤ 102
cm−3
. Parkin obtained this value
using Spitzer low resolution IRS spectrum with the line
fitting program PAHfit (Smith et al. 2007) to obtain line
fluxes for the various lines giving a [S III]18.71/[S III]33.48
ratio of 0.35±0.02 which compared to a theoretical curve
(Snijders et al. 2007) indicates that n ≤ 102
cm−3
. By
taking 4 different estimates all within the range speci-
fied by the silicon ratio we can account for how different
approaches may lead to different estimates.
3.4. Adjustments and Corrections
Kaufman’s PDR model (Kaufman et al. 1999) requires
two adjustments to our observed line fluxes. We must re-
move the fraction of [C II] flux that comes from ionized
4. 4
TABLE 1
Properties of our Herschel Observations
Line Wavelength (µm) FWHMa (”) Integration Time (s) OBSID
[O I] 63.184 9.3 5578 1342223763
145.525 11 1968 1342223766
[O III] 88.356 9.3 1216 1342223765
[N II] 121.898 10 3974 1342223767
[C II] 157.741 11.5 2288 1342223764
aValues are from the PACS Observer’s Manual and the SPIRE Observer’s Manual
All data taken on 2011-07-07.
5E-05 0.0001 0.00015 0.0002 0.00025 0.0003
Fig. 2.— The calculated total infrared intensity using Equation 1 at a resolution of 12”. Units are 10−4 W m−2. This map was aligned
with the previous maps but not convolved to the same resolution as 11.5” is close enough to 12” that it will not cause problems for the
analysis.
TABLE 2
Peak and mean signal-to-noise ratio of all observed lines
Line Mean Peak
[C II] (158 µm) 89.2 178.5
[N II] (122 µm) 11.8 26.6
[O I] (63 µm) 25.1 72.6
[O I] (145 µm) 8.1 26.7
[O III] (188 µm) 5.0 8.7
gas. We also must take into account that Kaufman’s
model is a plane-parallel slab with incident radiation
from only one side, the side we observe emission from
TABLE 3
Observed Flux in a 30” aperture and peak flux
Line Mean (10−9 W m−2) Peak (10−9 W m−2
[C II] (158 µm) 36.6 ±0.2 83.2 ±0.5
[N II] (122 µm) 3.1±0.1 7.2 ±0.3
[O I] (63 µm) 21.5±0.4 61 ±1
in the far-infrared cooling lines. As we cannot guarantee
the cloud’s orientation faces us we use Kaufman’s advice
that the velocity dispersion for many clouds combined
with an assumption that the [O I]63 will become opti-
cally thick much faster than either [C II] or the total
5. 5
0.001 0.002 0.003 0.004 0.005 0.006
Fig. 3.— The heating efficiency map of ([C II]+[O I]63)/FT IR.
TABLE 4
Line to total infrared flux ratio in NGC5195
Line Mean 10−4 Line/FT IR Peak 10−4 Line/FT IR
[C II] (158 µm) 4.4±0.2 2.44 ±0.01
[N II] (122 µm) 0.37±0.01 0.211±0.009
[O I] (63 µm) 2.6±0.5 1.79±0.03
infrared flux means that we only see half the total [O
I]63 flux. Thus we double this value for use in our PDR
model.
Table 5 indicates 4 guessed ratios starting with the the-
oretical lower limit for the [N II]122/[N II]205 ratio(Wright
et al. 1991; Bennett et al. 1994) and going to the theoret-
ical ratio at n = 100 cm−3
. By subtracting the predicted
ionized portion from the total flux we can divide the flux
by the total to obtain the fraction of neutral gas and thus
apply this fraction to our [C II] flux. As a check that our
guessed ratios are reasonably we can quickly compare to
observed ratios for the Milky Way, which fall between 1.0
and 1.6 (Wright et al. 1991).
The correction uses predicted [C II]158/[N II]205 val-
ues as a function of electron density in her study of
M51 using Solar Gas abundances of C/H=1.4 × 10−4
and N/H=7.9 × 10−5
(Parkin et al. 2013). It varies
from 3.2 ±0.3 at an assumed [N II]122/[N II]205=0.7 to
3.1±0.3N II]122/[N II]205=1 and 2 and finally 3.0±0.3 at
N II]122/[N II]205=3.
Kaufman’s paper (Kaufman et al. 1999) recommends
that the total infrared flux be reduced by a factor of two
to account for the optically thin infrared continuum flux
coming from both the front and back sides of the gas
cloud. We have applied this correction to our infrared
flux to ensure our PDR model is accurate.
4. RESULTS AND COMPARISONS
4.1. PDR modelling
We use PDRT for our modelling (Pound & Wolfire
2008; Kaufman et al. 2006). The model assumes
the PDR is a plane-parallel semi-infinite slab and is
parametrized by two free variables, the hydrogen gas
density, n, and the strength of the impinging FUV
radiation field normalized by the Habing field 1.6 ×
10−3
erg cm−2
s−1
(Habing 1968). This model includes
thermal balance, chemical network, and radiative trans-
fer, and produces grids of predicted structure in terms of
two line ratios, [C II]/[O I]63 and ([C II]+[O I]63)/FT IR
along axes of G0 and n. Figure 4 shows the line ra-
tio maps for [C II]/[O I]63 on the left and([C II]+[O
I]63)/FT IR on the right. First we look at Figure 5 left
is the uncorrected mean values. We are now using the
30% calibration uncertainty as it will be important in
determining the potential values. Figure 5 right shows
the corrected peak values being used. Figure 6 repeats
this but for mean corrected values.
We can ignore the low–G0 high–n solutions by consid-
ering the number of clouds emitting within our beam.
If you compare the model predicted [C II] emission for
low–G0 and high–n solutions to our observed [C II] emis-
sion we find that we would require multiple PDR regions
of order of magnitude 103
, which is a very high number
of clouds along our line of sight (Kramer et al. 2005).
Therefore, we ignore solutions in the bottom right of our
plots. We also switch to the mean value for the final
plots as our uncorrected mean at least had a crossover
region of allowed G0 and n values.
Prior to applying the corrections, our plots were sug-
gesting somewhat low–G0 and low–n solutions. This was
fixed once our corrections were made. Surprisingly, the
varying of neutral [C II] compared to ionized [C II] as
based on the estimated ionization density did not make
6. 6
TABLE 5
Estimated N II ratios predict neutral C II emission fraction
Assumed [N II]122/[N II]205 Predicted [C II]158/[N II]205 Assumed ionized Neutral C II
Gas Density (fraction of total)
0.7 8.1 ±0.3 1 0.63 ±0.03
1 11.6 ±0.5 9.2 0.75 ±0.04
2 23 ±1 45 0.88 ±0.05
3 34.8 ±1.5 100 0.92 ±0.05
Fig. 4.— [C II]/[O I]63 is on the left and([C II]+[O I]63)/FT IR is on the right. These are colour maps of constant value for the line
ratios. As can be seen in Figures 5 and 6 the lines trace along paths of the same colour.
a large difference after it left the theoretical lower limit.
With this and the removal of the lower right solution, we
can determine a logG0 of 2.5-3.3 and a log(n/cm−3
) of
2.0-3.0.
If we use Figure 1 from Kaufman et al. (1999) we can
determine the surface temperature of the gas is between
200K and 300K. Prior to corrections we would have esti-
mated the temperature as anywhere from 200K to 1000K.
This agrees with our oxygen ratio temperature that we
determined earlier, despite using a line that was poorly
detected.
4.2. M51 and Cen A
Unlike M51 or Cen A, we did not model arms or disk
regions separately as the object is not extended. Table 6
shows the logG0 and log(n/cm−3
) values for the different
regions of M51, Cen A, and the single region of NGC
5195.
NGC 5195 has similar values to previously studied
galaxies and resembles the average Cen A values as well
as M51’s center values. Both Cen A and NGC 5195 have
TABLE 6
Properties of the gas derived from the PDR model
Object log(n/c−3) logG0 T(K)
NGC 5195 2.0-3.0 2.5-3.3 200-300
M51 nucleus 3.5-4.25 3.25-4.0 240-475
M51 center 2.5-4.0 2.5-3.5 170-680
M51 arms 2.0-3.75 1.75-3.0 100-760
M51 interarm 2.25-3.75 1.5-3.0 80-550
Cen A 2.75-3.75 1.75-2.75 110-260
References: T. J. Parkin (2013; 2014)
smaller ranges on temperature as compared to M51. Per-
haps spiral arm structure contributes to the increase in
surface temperature by allowing new stars to form more
easily which in turn would heat the gas.
5. CONCLUSIONS
Using Herschel PACS observations of the important
fine-structure lines [C II]158 [N II]122, [O I]63, [O I]145,
and [O III]88, we measure several diagnostic ratios to
compare NGC 5195 with M51 and Cen A. With the the-
oretical lower limit for [N II]122/[N II]205 of 0.7 producing
7. 7
Fig. 5.— Uncorrected mean on the left, uncorrected peak on the right
a PDR model with no lower limits, we can assume this
is not likely the physical characteristics of the galaxy.
Therefore, we know that between 8% and 25% of the
observed [C II] emission originates in ionized gas.
We determined a logG0 of 2.5-3.3 and a log(n/cm−3
)
of 2.0-3.0. When compared to PDR models this gives a
temperature range of between 200K and 300K. This is
similar to Cen A and certain regions of M51, however
M51 exhibits much higher max temperatures, perhaps
due to its spiral arms. This temperature range and hy-
drogen density agree with the potentially unreliable re-
sults from using the [O I]63/[O I]145 ratio.
I would like to extend my thanks to my supervisor
Christine Wilson for her extensive help on this project, as
well as Maximilien Schirm for his help in understanding
PDR models.
APPENDIX
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