IOSR Journal of Applied Physics (IOSR-JAP) is an open access international journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A new universal formula for atoms, planets, and galaxiesIOSR Journals
In this paper a new universal formula about the rotation velocity distribution of atoms, planets, and galaxies is presented. It is based on a new general formula based on the relativistic Schwarzschild/Minkowski metric, where it has been possible to obtain expressions for the rotation velocity - and mass distribution versus the distance to the atomic nucleus, planet system centre, and galactic centre. A mathematical proof of this new formula is also given. This formula is divided into a Keplerian(general relativity)-and a relativistic(special relativity) part. For the atomic-and planet systems the Keplerian distribution is followed, which is also in accordance with observations.
According to the rotation velocity distribution of the galaxies the rotation velocity increases very rapidly from the centre and reaches a plateau which is constant out to a great distance from the centre. This is in accordance with observations and is also in accordance with the main structure of rotation velocity versus distance from different galaxy measurements.
Computer simulations were also performed to establish and verify the rotation velocity distributions in the atomic – planetary- and galaxy system, according to this paper. These computer simulations are in accordance with observations in two and three dimensions. It was also possible to study the matching percentage in these calculations showing a much higher matching percentage between theoretical and observational values by this new formula.
Mapping spiral structure on the far side of the Milky WaySérgio Sacani
Little is known about the portion of the Milky Way lying beyond the Galactic center at distances
of more than 9 kiloparsec from the Sun. These regions are opaque at optical wavelengths
because of absorption by interstellar dust, and distances are very large and hard to measure.
We report a direct trigonometric parallax distance of 20:4þ2:8
2:2 kiloparsec obtained with the Very
Long Baseline Array to a water maser source in a region of active star formation. These
measurements allow us to shed light on Galactic spiral structure by locating the ScutumCentaurus
spiral arm as it passes through the far side of the Milky Way and to validate a
kinematic method for determining distances in this region on the basis of transverse motions.
End point of_black_ring_instabilities_and_the_weak_cosmic_censorship_conjectureSérgio Sacani
We produce the first concrete evidence that violation of the weak cosmic censorship conjecture can occur
in asymptotically flat spaces of five dimensions by numerically evolving perturbed black rings. For certain
thin rings, we identify a new, elastic-type instability dominating the evolution, causing the system to settle to
a spherical black hole. However, for sufficiently thin rings the Gregory-Laflamme mode is dominant, and the
instability unfolds similarly to that of black strings, where the horizon develops a structure of bulges connected
by necks which become ever thinner over time.
Exocometary gas in_th_hd_181327_debris_ringSérgio Sacani
An increasing number of observations have shown that gaseous debris discs are not an
exception. However, until now we only knew of cases around A stars. Here we present the first
detection of 12CO (2-1) disc emission around an F star, HD 181327, obtained with ALMA
observations at 1.3 mm. The continuum and CO emission are resolved into an axisymmetric
disc with ring-like morphology. Using a Markov chain Monte Carlo method coupled with
radiative transfer calculations we study the dust and CO mass distribution. We find the dust is
distributed in a ring with a radius of 86:0 0:4 AU and a radial width of 23:2 1:0 AU. At
this frequency the ring radius is smaller than in the optical, revealing grain size segregation
expected due to radiation pressure. We also report on the detection of low level continuum
emission beyond the main ring out to 200 AU. We model the CO emission in the non-LTE
regime and we find that the CO is co-located with the dust, with a total CO gas mass ranging
between 1:2 10 6 M and 2:9 10 6 M, depending on the gas kinetic temperature and
collisional partners densities. The CO densities and location suggest a secondary origin, i.e.
released from icy planetesimals in the ring. We derive a CO cometary composition that is
consistent with Solar system comets. Due to the low gas densities it is unlikely that the gas is
shaping the dust distribution.
Magnetic interaction of_a_super_cme_with_the_earths_magnetosphere_scenario_fo...Sérgio Sacani
Solar eruptions, known as Coronal Mass Ejections (CMEs), are
frequently observed on our Sun. Recent Kepler observations of super
ares
on G-type stars have implied that so called super-CMEs, possessing kinetic
energies 10 times of the most powerful CME event ever observed on the Sun,
could be produced with a frequency of 1 event per 800-2000 yr on solar-
like slowly rotating stars. We have performed a 3D time-dependent global
magnetohydrodynamic simulation of the magnetic interaction of such a CME
cloud with the Earth's magnetosphere. We calculated the global structure
of the perturbed magnetosphere and derive the latitude of the open-closed
magnetic eld boundary. We also estimated energy
uxes penetrating the
Earth's ionosphere and discuss the consequences of energetic particle
uxes
on biological systems on early Earth.
We present long-baseline Atacama Large Millimeter/submillimeter Array (ALMA) observations of
the 870 m continuum emission from the nearest gas-rich protoplanetary disk, around TW Hya, that
trace millimeter-sized particles down to spatial scales as small as 1 AU (20 mas). These data reveal
a series of concentric ring-shaped substructures in the form of bright zones and narrow dark annuli
(1{6AU) with modest contrasts (5{30%). We associate these features with concentrations of solids
that have had their inward radial drift slowed or stopped, presumably at local gas pressure maxima.
No signicant non-axisymmetric structures are detected. Some of the observed features occur near
temperatures that may be associated with the condensation fronts of major volatile species, but the
relatively small brightness contrasts may also be a consequence of magnetized disk evolution (the
so-called zonal
ows). Other features, particularly a narrow dark annulus located only 1 AU from the
star, could indicate interactions between the disk and young planets. These data signal that ordered
substructures on AU scales can be common, fundamental factors in disk evolution, and that high
resolution microwave imaging can help characterize them during the epoch of planet formation.
Keywords: protoplanetary disks | planet-disk interactions | stars: individual (TW Hydrae)
A new universal formula for atoms, planets, and galaxiesIOSR Journals
In this paper a new universal formula about the rotation velocity distribution of atoms, planets, and galaxies is presented. It is based on a new general formula based on the relativistic Schwarzschild/Minkowski metric, where it has been possible to obtain expressions for the rotation velocity - and mass distribution versus the distance to the atomic nucleus, planet system centre, and galactic centre. A mathematical proof of this new formula is also given. This formula is divided into a Keplerian(general relativity)-and a relativistic(special relativity) part. For the atomic-and planet systems the Keplerian distribution is followed, which is also in accordance with observations.
According to the rotation velocity distribution of the galaxies the rotation velocity increases very rapidly from the centre and reaches a plateau which is constant out to a great distance from the centre. This is in accordance with observations and is also in accordance with the main structure of rotation velocity versus distance from different galaxy measurements.
Computer simulations were also performed to establish and verify the rotation velocity distributions in the atomic – planetary- and galaxy system, according to this paper. These computer simulations are in accordance with observations in two and three dimensions. It was also possible to study the matching percentage in these calculations showing a much higher matching percentage between theoretical and observational values by this new formula.
Mapping spiral structure on the far side of the Milky WaySérgio Sacani
Little is known about the portion of the Milky Way lying beyond the Galactic center at distances
of more than 9 kiloparsec from the Sun. These regions are opaque at optical wavelengths
because of absorption by interstellar dust, and distances are very large and hard to measure.
We report a direct trigonometric parallax distance of 20:4þ2:8
2:2 kiloparsec obtained with the Very
Long Baseline Array to a water maser source in a region of active star formation. These
measurements allow us to shed light on Galactic spiral structure by locating the ScutumCentaurus
spiral arm as it passes through the far side of the Milky Way and to validate a
kinematic method for determining distances in this region on the basis of transverse motions.
End point of_black_ring_instabilities_and_the_weak_cosmic_censorship_conjectureSérgio Sacani
We produce the first concrete evidence that violation of the weak cosmic censorship conjecture can occur
in asymptotically flat spaces of five dimensions by numerically evolving perturbed black rings. For certain
thin rings, we identify a new, elastic-type instability dominating the evolution, causing the system to settle to
a spherical black hole. However, for sufficiently thin rings the Gregory-Laflamme mode is dominant, and the
instability unfolds similarly to that of black strings, where the horizon develops a structure of bulges connected
by necks which become ever thinner over time.
Exocometary gas in_th_hd_181327_debris_ringSérgio Sacani
An increasing number of observations have shown that gaseous debris discs are not an
exception. However, until now we only knew of cases around A stars. Here we present the first
detection of 12CO (2-1) disc emission around an F star, HD 181327, obtained with ALMA
observations at 1.3 mm. The continuum and CO emission are resolved into an axisymmetric
disc with ring-like morphology. Using a Markov chain Monte Carlo method coupled with
radiative transfer calculations we study the dust and CO mass distribution. We find the dust is
distributed in a ring with a radius of 86:0 0:4 AU and a radial width of 23:2 1:0 AU. At
this frequency the ring radius is smaller than in the optical, revealing grain size segregation
expected due to radiation pressure. We also report on the detection of low level continuum
emission beyond the main ring out to 200 AU. We model the CO emission in the non-LTE
regime and we find that the CO is co-located with the dust, with a total CO gas mass ranging
between 1:2 10 6 M and 2:9 10 6 M, depending on the gas kinetic temperature and
collisional partners densities. The CO densities and location suggest a secondary origin, i.e.
released from icy planetesimals in the ring. We derive a CO cometary composition that is
consistent with Solar system comets. Due to the low gas densities it is unlikely that the gas is
shaping the dust distribution.
Magnetic interaction of_a_super_cme_with_the_earths_magnetosphere_scenario_fo...Sérgio Sacani
Solar eruptions, known as Coronal Mass Ejections (CMEs), are
frequently observed on our Sun. Recent Kepler observations of super
ares
on G-type stars have implied that so called super-CMEs, possessing kinetic
energies 10 times of the most powerful CME event ever observed on the Sun,
could be produced with a frequency of 1 event per 800-2000 yr on solar-
like slowly rotating stars. We have performed a 3D time-dependent global
magnetohydrodynamic simulation of the magnetic interaction of such a CME
cloud with the Earth's magnetosphere. We calculated the global structure
of the perturbed magnetosphere and derive the latitude of the open-closed
magnetic eld boundary. We also estimated energy
uxes penetrating the
Earth's ionosphere and discuss the consequences of energetic particle
uxes
on biological systems on early Earth.
We present long-baseline Atacama Large Millimeter/submillimeter Array (ALMA) observations of
the 870 m continuum emission from the nearest gas-rich protoplanetary disk, around TW Hya, that
trace millimeter-sized particles down to spatial scales as small as 1 AU (20 mas). These data reveal
a series of concentric ring-shaped substructures in the form of bright zones and narrow dark annuli
(1{6AU) with modest contrasts (5{30%). We associate these features with concentrations of solids
that have had their inward radial drift slowed or stopped, presumably at local gas pressure maxima.
No signicant non-axisymmetric structures are detected. Some of the observed features occur near
temperatures that may be associated with the condensation fronts of major volatile species, but the
relatively small brightness contrasts may also be a consequence of magnetized disk evolution (the
so-called zonal
ows). Other features, particularly a narrow dark annulus located only 1 AU from the
star, could indicate interactions between the disk and young planets. These data signal that ordered
substructures on AU scales can be common, fundamental factors in disk evolution, and that high
resolution microwave imaging can help characterize them during the epoch of planet formation.
Keywords: protoplanetary disks | planet-disk interactions | stars: individual (TW Hydrae)
Evidence for a_distant_giant_planet_in_the_solar_systemSérgio Sacani
A descoberta de um novo planeta, atualmente não é uma manchete que chama tanto assim a atenção das pessoas. Muito disso, graças ao Telescópio Espacial Kepler, que já descobriu quase 2000 exoplanetas e todo instante uma nova descoberta é anunciada, certo? Mais ou menos, a descoberta anunciada hoje, dia 20 de Janeiro de 2016, é um pouco diferente, pois não se trata de um exoplaneta, e sim de um novo planeta no Sistema Solar, e esse é um fato que intriga os astrônomos a muitos e muitos anos.
Porém, temos que ir com calma com esses anúncios. No artigo aceito para publicação no The Astronomical Journal (artigo no final do post), os autores, Mike Brown e Konstantin Batygin, do Instituto de Tecnologia da Califórnia, apresentaram o que eles dizem ser evidências circunstâncias fortes para a existência de um grande planeta ainda não descoberto, talvez, com uma massa 10 vezes a massa da Terra, orbitando os confins do nosso Sistema Solar, muito além da órbita de Plutão. Os cientistas inferiram sua presença, por meio de anomalias encontradas nas órbitas de seis objetos do chamado Cinturão de Kuiper.
O objeto, que os pesquisadores estão chamando de Planeta Nove, não chega muito perto do Sol, no ponto mais próximo da sua órbita ele fica a 30.5 bilhões de quilômetros, ou seja, cinco vezes a distância entre o Sol e Plutão. Apesar do seu grande tamanho, ele é muito apagado, e por isso ninguém até o momento conseguiu observá-lo.
Não existe ainda uma confirmação observacional da descoberta, mas as evidências são tão fortes que fizeram com que outros especialistas como Chad Trujilo do Observatório Gemini no Havaí e David Nesvorny, do Southwest Research Institute em Boulder no Colorado, ficassem impressionados e bem convencidos de que deve mesmo haver um grande planeta nas fronteiras da nossa vizinhança cósmica.
Motions for systems and structures in space, described by a set denoted Avd. ...Premier Publishers
In order to describe general motions and matter in space, functions for angular velocity and density are assumed and denoted Avd, as an abbreviation. The framework provides a unified approach to motions at different scales. It is analysed how Avd enters and rules, in terms of results from equations, in field experiments and observations at Earth. Chaos may organize according to Avd, such that more order, Cosmos, appear in complex nonlinear dynamical systems. This reveals that Avd may be governing and that deterministic systems can be created without assuming boundaries and conditions for initial values and forces from outside. A mathematical model for the initiation of Logos (when a paper accelerates into a narrow circular orbit), was described, and denoted local implosion; Li. The theorem for dl, provides discrete solutions to a power law, and this is related to locations of satellites and moons.
The characterization of_the_gamma_ray_signal_from_the_central_milk_way_a_comp...Sérgio Sacani
Past studies have identified a spatially extended excess of ∼1-3 GeV gamma rays from the region
surrounding the Galactic Center, consistent with the emission expected from annihilating dark
matter. We revisit and scrutinize this signal with the intention of further constraining its characteristics
and origin. By applying cuts to the Fermi event parameter CTBCORE, we suppress the tails
of the point spread function and generate high resolution gamma-ray maps, enabling us to more
easily separate the various gamma-ray components. Within these maps, we find the GeV excess
to be robust and highly statistically significant, with a spectrum, angular distribution, and overall
normalization that is in good agreement with that predicted by simple annihilating dark matter
models. For example, the signal is very well fit by a 36-51 GeV dark matter particle annihilating to
b
¯b with an annihilation cross section of σv = (1−3)×10−26 cm3
/s (normalized to a local dark matter
density of 0.4 GeV/cm3
). Furthermore, we confirm that the angular distribution of the excess is
approximately spherically symmetric and centered around the dynamical center of the Milky Way
(within ∼0.05◦
of Sgr A∗
), showing no sign of elongation along the Galactic Plane. The signal is
observed to extend to at least ' 10◦
from the Galactic Center, disfavoring the possibility that this
emission originates from millisecond pulsars.
Further analysis of the References- part 2. Some further analyses about directional recoil, cross sections, galaxy Physics and experiment-optimizations techniques.
VIA Forum Astroparticle Physics Forum COSMOVIA
Author: O.M. Lecian.
Title: LHAASO Further references- part2.
28/03/2020
http://viavca.in2p3.fr/2010c_o_s_m_o_v_i_a__forum_sd24fsdf4zerfzef4ze5f4dsq34sdteerui45788789745rt7yr68t4y54865h45g4hfg56h45df4h86d48h48t7uertujirjtiorjhuiofgrdsqgxcvfghfg5h40yhuyir/viewtopic.php?f=73&t=3705&sid=c56cbf76f87536fc4c3ff216d9edaba2
The build up_of_the_c_d_halo_of_m87_evidence_for_accretion_in_the_last_gyrSérgio Sacani
Observações recentes obtidas com o Very Large Telescope do ESO mostraram que Messier 87, a galáxia elíptica gigante mais próximo de nós, engoliu uma galáxia inteira de tamanho médio no último bilhão de anos. Uma equipe de astrônomos conseguiu pela primeira vez seguir o movimento de 300 nebulosas planetárias brilhantes, encontrando evidências claras deste evento e encontrando também excesso de radiação emitida pelos restos da vítima completamente desfeita.
Discovery of rotational modulations in the planetary mass companion 2m1207b i...Sérgio Sacani
Rotational modulations of brown dwarfs have recently provided powerful constraints on the properties
of ultra-cool atmospheres, including longitudinal and vertical cloud structures and cloud evolution.
Furthermore, periodic light curves directly probe the rotational periods of ultra-cool objects. We
present here, for the first time, time-resolved high-precision photometric measurements of a planetarymass
companion, 2M1207b. We observed the binary system with HST/WFC3 in two bands and with
two spacecraft roll angles. Using point spread function-based photometry, we reach a nearly photonnoise
limited accuracy for both the primary and the secondary. While the primary is consistent with
a flat light curve, the secondary shows modulations that are clearly detected in the combined light
curve as well as in di↵erent subsets of the data. The amplitudes are 1.36% in the F125W and 0.78%
in the F160W filters, respectively. By fitting sine waves to the light curves, we find a consistent period
of 10.7+1.2
−0.6 hours and similar phases in both bands. The J- and H-band amplitude ratio of 2M1207b
is very similar to a field brown dwarf that has identical spectral type but di↵erent J-H color. Importantly,
our study also measures, for the first time, the rotation period for a directly imaged extra-solar
planetary-mass companion.
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.
PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST/STISSérgio Sacani
Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude
region on Europa – spectroscopic detection of off-limb line emission from the dissociation
products of water. Here, we present Hubble Space Telescope (HST) direct images of Europa in
the far ultraviolet (FUV) as it transited the smooth face of Jupiter, in order to measure absorption
from gas or aerosols beyond the Europa limb. Out of ten observations we found three in which
plume activity could be implicated. Two show statistically significant features at latitudes similar
to Roth et al., and the third, at a more equatorial location. We consider potential systematic
effects that might influence the statistical analysis and create artifacts, and are unable to find any
that can definitively explain the features, although there are reasons to be cautious. If the
apparent absorption features are real, the magnitude of implied outgassing is similar to that of the
Roth et al. feature, however the apparent activity appears more frequently in our data.
First discovery of_a_magnetic_field_in_a_main_sequence_delta_scuti_star_the_k...Sérgio Sacani
Coralie Neiner do Laboratory for Space Studies and Astrophysics Instrumentation, LESIA (CNRS/Observatoire de Paris/UPMC/Université Paris Diderot) e Patricia Lampens (Royual OIbservatory of Belgium), descobriram a primeira estrela magnética do tipo delta Scuti, através de observações espectropolarimétricas, realizadas com o telescópio CFHT. As estrelas do tipo delta Scuti, são estrelas pulsantes, sendo que algumas delas mostram assinaturas atribuídas para um segundo tipo de pulsação. A descoberta mostra que isso é na verdade a assinatura de um campo magnético. Essa descoberta tem importantes implicações para o entendimento do interior das estrelas.
Dois tipos de estrelas pulsantes existem entre as estrelas com massa entre 1.5 e 2.5 vezes a massa do Sol: as estrelas do tipo delta Scuti e as estrelas do tipo gamma Dor. A teoria nos diz que as estrelas com temperatura entre 6900 e 7400 graus Kelvin podem ter ambos os tipos de pulsação. Essas são então chamadas de estrelas híbridas. Contudo, o satélite Kepler da NASA tem detectado um grande número de estrelas híbridas com temperaturas maiores ou menores do que esse limite pensado anteriormente. A existência dessas estrelas híbridas com temperaturas maiores é algo muito controverso, já que desafia o nosso entendimento sobre as estrelas pulsantes do tipo delta Scuti e gamma Dor.
Why Does the Atmosphere Rotate? Trajectory of a desorbed moleculeJames Smith
As a step toward understanding why the Earth's atmosphere "rotates" with the Earth, we use using Geometric (Clifford) Algebra to investigate the trajectory of a single molecule that desorbs vertically upward from the Equator, then falls back to Earth without colliding with any other molecules. Sample calculations are presented for a molecule whose vertical velocity is equal to the surface velocity of the Earth at the Equator (463 m/s) and for one with a vertical velocity three times as high. The latter velocity is sufficient for the molecule to reach the Kármán Line (100,000 m). We find that both molecules fall to Earth behind the point from which they desorbed: by 0.25 degrees of latitude for the higher vertical velocity, but by only 0.001 degrees for the lower.
Periodic mass extinctions_and_the_planet_x_model_reconsideredSérgio Sacani
The 27 Myr periodicity in the fossil extinction record has been con-
firmed in modern data bases dating back 500 Myr, which is twice the time
interval of the original analysis from thirty years ago. The surprising regularity
of this period has been used to reject the Nemesis model. A second
model based on the sun’s vertical galactic oscillations has been challenged
on the basis of an inconsistency in period and phasing. The third astronomical
model originally proposed to explain the periodicity is the Planet
X model in which the period is associated with the perihelion precession
of the inclined orbit of a trans-Neptunian planet. Recently, and unrelated
to mass extinctions, a trans-Neptunian super-Earth planet has been proposed
to explain the observation that the inner Oort cloud objects Sedna
and 2012VP113 have perihelia that lie near the ecliptic plane. In this
Letter we reconsider the Planet X model in light of the confluence of the
modern palaeontological and outer solar system dynamical evidence.
Key Words: astrobiology - planets and satellites - Kuiper belt:
general - comets: general
Saturns fast spin_determined_from_its_gravitational_field_and_oblatenessSérgio Sacani
ARtigo descreve o novo método usado para determinar com precisão o período de rotação do planeta Saturno. Uma das grandes questões da astronomia. De acordo com o artigo o período de rotação de Saturno é de 10 horas 32 minutos e 45 segundos (+/- 46 segundos).
Young remmants of_type_ia_supernovae_and_their_progenitors_a_study_of_snr_g19_03Sérgio Sacani
Type Ia supernovae, with their remarkably homogeneous light curves and spectra, have been used as
standardizable candles to measure the accelerating expansion of the Universe. Yet, their progenitors
remain elusive. Common explanations invoke a degenerate star (white dwarf) which explodes upon
reaching close to the Chandrasekhar limit, by either steadily accreting mass from a companion star
or violently merging with another degenerate star. We show that circumstellar interaction in young
Galactic supernova remnants can be used to distinguish between these single and double degenerate
progenitor scenarios. Here we propose a new diagnostic, the Surface Brightness Index, which can
be computed from theory and compared with Chandra and VLA observations. We use this method
to demonstrate that a double degenerate progenitor can explain the decades-long
ux rise and size
increase of the youngest known Galactic SNR G1.9+0.3. We disfavor a single degenerate scenario.
We attribute the observed properties to the interaction between a steep ejecta prole and a constant
density environment. We suggest using the upgraded VLA to detect circumstellar interaction in
the remnants of historical Type Ia supernovae in the Local Group of galaxies. This may settle the
long-standing debate over their progenitors.
Subject headings: ISM: supernova remnants | radio continuum: general | X-rays: general | bi-
naries: general | circumstellar matter | supernovae: general | ISM: individual
objects(SNR G1.9+0.3)
We discovered two transient events in the Kepler eld with light curves that strongly suggest they
are type II-P supernovae. Using the fast cadence of the Kepler observations we precisely estimate
the rise time to maximum for KSN2011a and KSN2011d as 10.50:4 and 13.30:4 rest-frame days
respectively. Based on ts to idealized analytic models, we nd the progenitor radius of KSN2011a
(28020 R) to be signicantly smaller than that for KSN2011d (49020 R) but both have similar
explosion energies of 2.00:3 1051 erg.
The rising light curve of KSN2011d is an excellent match to that predicted by simple models of
exploding red supergiants (RSG). However, the early rise of KSN2011a is faster than the models
predict possibly due to the supernova shockwave moving into pre-existing wind or mass-loss from the
RSG. A mass loss rate of 10 4 M yr 1 from the RSG can explain the fast rise without impacting
the optical
ux at maximum light or the shape of the post-maximum light curve.
No shock breakout emission is seen in KSN2011a, but this is likely due to the circumstellar inter-
action suspected in the fast rising light curve. The early light curve of KSN2011d does show excess
emission consistent with model predictions of a shock breakout. This is the rst optical detection of
a shock breakout from a type II-P supernova.
Evidence for a_distant_giant_planet_in_the_solar_systemSérgio Sacani
A descoberta de um novo planeta, atualmente não é uma manchete que chama tanto assim a atenção das pessoas. Muito disso, graças ao Telescópio Espacial Kepler, que já descobriu quase 2000 exoplanetas e todo instante uma nova descoberta é anunciada, certo? Mais ou menos, a descoberta anunciada hoje, dia 20 de Janeiro de 2016, é um pouco diferente, pois não se trata de um exoplaneta, e sim de um novo planeta no Sistema Solar, e esse é um fato que intriga os astrônomos a muitos e muitos anos.
Porém, temos que ir com calma com esses anúncios. No artigo aceito para publicação no The Astronomical Journal (artigo no final do post), os autores, Mike Brown e Konstantin Batygin, do Instituto de Tecnologia da Califórnia, apresentaram o que eles dizem ser evidências circunstâncias fortes para a existência de um grande planeta ainda não descoberto, talvez, com uma massa 10 vezes a massa da Terra, orbitando os confins do nosso Sistema Solar, muito além da órbita de Plutão. Os cientistas inferiram sua presença, por meio de anomalias encontradas nas órbitas de seis objetos do chamado Cinturão de Kuiper.
O objeto, que os pesquisadores estão chamando de Planeta Nove, não chega muito perto do Sol, no ponto mais próximo da sua órbita ele fica a 30.5 bilhões de quilômetros, ou seja, cinco vezes a distância entre o Sol e Plutão. Apesar do seu grande tamanho, ele é muito apagado, e por isso ninguém até o momento conseguiu observá-lo.
Não existe ainda uma confirmação observacional da descoberta, mas as evidências são tão fortes que fizeram com que outros especialistas como Chad Trujilo do Observatório Gemini no Havaí e David Nesvorny, do Southwest Research Institute em Boulder no Colorado, ficassem impressionados e bem convencidos de que deve mesmo haver um grande planeta nas fronteiras da nossa vizinhança cósmica.
Motions for systems and structures in space, described by a set denoted Avd. ...Premier Publishers
In order to describe general motions and matter in space, functions for angular velocity and density are assumed and denoted Avd, as an abbreviation. The framework provides a unified approach to motions at different scales. It is analysed how Avd enters and rules, in terms of results from equations, in field experiments and observations at Earth. Chaos may organize according to Avd, such that more order, Cosmos, appear in complex nonlinear dynamical systems. This reveals that Avd may be governing and that deterministic systems can be created without assuming boundaries and conditions for initial values and forces from outside. A mathematical model for the initiation of Logos (when a paper accelerates into a narrow circular orbit), was described, and denoted local implosion; Li. The theorem for dl, provides discrete solutions to a power law, and this is related to locations of satellites and moons.
The characterization of_the_gamma_ray_signal_from_the_central_milk_way_a_comp...Sérgio Sacani
Past studies have identified a spatially extended excess of ∼1-3 GeV gamma rays from the region
surrounding the Galactic Center, consistent with the emission expected from annihilating dark
matter. We revisit and scrutinize this signal with the intention of further constraining its characteristics
and origin. By applying cuts to the Fermi event parameter CTBCORE, we suppress the tails
of the point spread function and generate high resolution gamma-ray maps, enabling us to more
easily separate the various gamma-ray components. Within these maps, we find the GeV excess
to be robust and highly statistically significant, with a spectrum, angular distribution, and overall
normalization that is in good agreement with that predicted by simple annihilating dark matter
models. For example, the signal is very well fit by a 36-51 GeV dark matter particle annihilating to
b
¯b with an annihilation cross section of σv = (1−3)×10−26 cm3
/s (normalized to a local dark matter
density of 0.4 GeV/cm3
). Furthermore, we confirm that the angular distribution of the excess is
approximately spherically symmetric and centered around the dynamical center of the Milky Way
(within ∼0.05◦
of Sgr A∗
), showing no sign of elongation along the Galactic Plane. The signal is
observed to extend to at least ' 10◦
from the Galactic Center, disfavoring the possibility that this
emission originates from millisecond pulsars.
Further analysis of the References- part 2. Some further analyses about directional recoil, cross sections, galaxy Physics and experiment-optimizations techniques.
VIA Forum Astroparticle Physics Forum COSMOVIA
Author: O.M. Lecian.
Title: LHAASO Further references- part2.
28/03/2020
http://viavca.in2p3.fr/2010c_o_s_m_o_v_i_a__forum_sd24fsdf4zerfzef4ze5f4dsq34sdteerui45788789745rt7yr68t4y54865h45g4hfg56h45df4h86d48h48t7uertujirjtiorjhuiofgrdsqgxcvfghfg5h40yhuyir/viewtopic.php?f=73&t=3705&sid=c56cbf76f87536fc4c3ff216d9edaba2
The build up_of_the_c_d_halo_of_m87_evidence_for_accretion_in_the_last_gyrSérgio Sacani
Observações recentes obtidas com o Very Large Telescope do ESO mostraram que Messier 87, a galáxia elíptica gigante mais próximo de nós, engoliu uma galáxia inteira de tamanho médio no último bilhão de anos. Uma equipe de astrônomos conseguiu pela primeira vez seguir o movimento de 300 nebulosas planetárias brilhantes, encontrando evidências claras deste evento e encontrando também excesso de radiação emitida pelos restos da vítima completamente desfeita.
Discovery of rotational modulations in the planetary mass companion 2m1207b i...Sérgio Sacani
Rotational modulations of brown dwarfs have recently provided powerful constraints on the properties
of ultra-cool atmospheres, including longitudinal and vertical cloud structures and cloud evolution.
Furthermore, periodic light curves directly probe the rotational periods of ultra-cool objects. We
present here, for the first time, time-resolved high-precision photometric measurements of a planetarymass
companion, 2M1207b. We observed the binary system with HST/WFC3 in two bands and with
two spacecraft roll angles. Using point spread function-based photometry, we reach a nearly photonnoise
limited accuracy for both the primary and the secondary. While the primary is consistent with
a flat light curve, the secondary shows modulations that are clearly detected in the combined light
curve as well as in di↵erent subsets of the data. The amplitudes are 1.36% in the F125W and 0.78%
in the F160W filters, respectively. By fitting sine waves to the light curves, we find a consistent period
of 10.7+1.2
−0.6 hours and similar phases in both bands. The J- and H-band amplitude ratio of 2M1207b
is very similar to a field brown dwarf that has identical spectral type but di↵erent J-H color. Importantly,
our study also measures, for the first time, the rotation period for a directly imaged extra-solar
planetary-mass companion.
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.
PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST/STISSérgio Sacani
Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude
region on Europa – spectroscopic detection of off-limb line emission from the dissociation
products of water. Here, we present Hubble Space Telescope (HST) direct images of Europa in
the far ultraviolet (FUV) as it transited the smooth face of Jupiter, in order to measure absorption
from gas or aerosols beyond the Europa limb. Out of ten observations we found three in which
plume activity could be implicated. Two show statistically significant features at latitudes similar
to Roth et al., and the third, at a more equatorial location. We consider potential systematic
effects that might influence the statistical analysis and create artifacts, and are unable to find any
that can definitively explain the features, although there are reasons to be cautious. If the
apparent absorption features are real, the magnitude of implied outgassing is similar to that of the
Roth et al. feature, however the apparent activity appears more frequently in our data.
First discovery of_a_magnetic_field_in_a_main_sequence_delta_scuti_star_the_k...Sérgio Sacani
Coralie Neiner do Laboratory for Space Studies and Astrophysics Instrumentation, LESIA (CNRS/Observatoire de Paris/UPMC/Université Paris Diderot) e Patricia Lampens (Royual OIbservatory of Belgium), descobriram a primeira estrela magnética do tipo delta Scuti, através de observações espectropolarimétricas, realizadas com o telescópio CFHT. As estrelas do tipo delta Scuti, são estrelas pulsantes, sendo que algumas delas mostram assinaturas atribuídas para um segundo tipo de pulsação. A descoberta mostra que isso é na verdade a assinatura de um campo magnético. Essa descoberta tem importantes implicações para o entendimento do interior das estrelas.
Dois tipos de estrelas pulsantes existem entre as estrelas com massa entre 1.5 e 2.5 vezes a massa do Sol: as estrelas do tipo delta Scuti e as estrelas do tipo gamma Dor. A teoria nos diz que as estrelas com temperatura entre 6900 e 7400 graus Kelvin podem ter ambos os tipos de pulsação. Essas são então chamadas de estrelas híbridas. Contudo, o satélite Kepler da NASA tem detectado um grande número de estrelas híbridas com temperaturas maiores ou menores do que esse limite pensado anteriormente. A existência dessas estrelas híbridas com temperaturas maiores é algo muito controverso, já que desafia o nosso entendimento sobre as estrelas pulsantes do tipo delta Scuti e gamma Dor.
Why Does the Atmosphere Rotate? Trajectory of a desorbed moleculeJames Smith
As a step toward understanding why the Earth's atmosphere "rotates" with the Earth, we use using Geometric (Clifford) Algebra to investigate the trajectory of a single molecule that desorbs vertically upward from the Equator, then falls back to Earth without colliding with any other molecules. Sample calculations are presented for a molecule whose vertical velocity is equal to the surface velocity of the Earth at the Equator (463 m/s) and for one with a vertical velocity three times as high. The latter velocity is sufficient for the molecule to reach the Kármán Line (100,000 m). We find that both molecules fall to Earth behind the point from which they desorbed: by 0.25 degrees of latitude for the higher vertical velocity, but by only 0.001 degrees for the lower.
Periodic mass extinctions_and_the_planet_x_model_reconsideredSérgio Sacani
The 27 Myr periodicity in the fossil extinction record has been con-
firmed in modern data bases dating back 500 Myr, which is twice the time
interval of the original analysis from thirty years ago. The surprising regularity
of this period has been used to reject the Nemesis model. A second
model based on the sun’s vertical galactic oscillations has been challenged
on the basis of an inconsistency in period and phasing. The third astronomical
model originally proposed to explain the periodicity is the Planet
X model in which the period is associated with the perihelion precession
of the inclined orbit of a trans-Neptunian planet. Recently, and unrelated
to mass extinctions, a trans-Neptunian super-Earth planet has been proposed
to explain the observation that the inner Oort cloud objects Sedna
and 2012VP113 have perihelia that lie near the ecliptic plane. In this
Letter we reconsider the Planet X model in light of the confluence of the
modern palaeontological and outer solar system dynamical evidence.
Key Words: astrobiology - planets and satellites - Kuiper belt:
general - comets: general
Saturns fast spin_determined_from_its_gravitational_field_and_oblatenessSérgio Sacani
ARtigo descreve o novo método usado para determinar com precisão o período de rotação do planeta Saturno. Uma das grandes questões da astronomia. De acordo com o artigo o período de rotação de Saturno é de 10 horas 32 minutos e 45 segundos (+/- 46 segundos).
Young remmants of_type_ia_supernovae_and_their_progenitors_a_study_of_snr_g19_03Sérgio Sacani
Type Ia supernovae, with their remarkably homogeneous light curves and spectra, have been used as
standardizable candles to measure the accelerating expansion of the Universe. Yet, their progenitors
remain elusive. Common explanations invoke a degenerate star (white dwarf) which explodes upon
reaching close to the Chandrasekhar limit, by either steadily accreting mass from a companion star
or violently merging with another degenerate star. We show that circumstellar interaction in young
Galactic supernova remnants can be used to distinguish between these single and double degenerate
progenitor scenarios. Here we propose a new diagnostic, the Surface Brightness Index, which can
be computed from theory and compared with Chandra and VLA observations. We use this method
to demonstrate that a double degenerate progenitor can explain the decades-long
ux rise and size
increase of the youngest known Galactic SNR G1.9+0.3. We disfavor a single degenerate scenario.
We attribute the observed properties to the interaction between a steep ejecta prole and a constant
density environment. We suggest using the upgraded VLA to detect circumstellar interaction in
the remnants of historical Type Ia supernovae in the Local Group of galaxies. This may settle the
long-standing debate over their progenitors.
Subject headings: ISM: supernova remnants | radio continuum: general | X-rays: general | bi-
naries: general | circumstellar matter | supernovae: general | ISM: individual
objects(SNR G1.9+0.3)
We discovered two transient events in the Kepler eld with light curves that strongly suggest they
are type II-P supernovae. Using the fast cadence of the Kepler observations we precisely estimate
the rise time to maximum for KSN2011a and KSN2011d as 10.50:4 and 13.30:4 rest-frame days
respectively. Based on ts to idealized analytic models, we nd the progenitor radius of KSN2011a
(28020 R) to be signicantly smaller than that for KSN2011d (49020 R) but both have similar
explosion energies of 2.00:3 1051 erg.
The rising light curve of KSN2011d is an excellent match to that predicted by simple models of
exploding red supergiants (RSG). However, the early rise of KSN2011a is faster than the models
predict possibly due to the supernova shockwave moving into pre-existing wind or mass-loss from the
RSG. A mass loss rate of 10 4 M yr 1 from the RSG can explain the fast rise without impacting
the optical
ux at maximum light or the shape of the post-maximum light curve.
No shock breakout emission is seen in KSN2011a, but this is likely due to the circumstellar inter-
action suspected in the fast rising light curve. The early light curve of KSN2011d does show excess
emission consistent with model predictions of a shock breakout. This is the rst optical detection of
a shock breakout from a type II-P supernova.
The network of filaments with embedded clusters surrounding voids, which has been seen in maps derived from
redshift surveys and reproduced in simulations, has been referred to as the cosmic web. A complementary
description is provided by considering the shear in the velocity field of galaxies. The eigenvalues of the shear
provide information regarding whether or not a region is collapsing in three dimensions, which is the condition for
a knot, expanding in three dimensions, which is the condition for a void, or in the intermediate condition of a
filament or sheet. The structures that are quantitatively defined by the eigenvalues can be approximated by isocontours
that provide a visual representation of the cosmic velocity (V) web. The current application is based on
radial peculiar velocities from the Cosmicflows-2 collection of distances. The three-dimensional velocity field is
constructed using the Wiener filter methodology in the linear approximation. Eigenvalues of the velocity shear are
calculated at each point on a grid. Here, knots and filaments are visualized across a local domain of
diameter ~0.1c
SPECTROSCOPIC CONFIRMATION OF THE EXISTENCE OF LARGE, DIFFUSE GALAXIES IN THE...Sérgio Sacani
We recently identified a population of low surface brightness objects in the field of the z = 0.023 Coma cluster,
using the Dragonfly Telephoto Array. Here we present Keck spectroscopy of one of the largest of these “ultradiffuse
galaxies” (UDGs), confirming that it is a member of the cluster. The galaxy has prominent absorption
features, including the Ca II H+K lines and the G-band, and no detected emission lines. Its radial velocity of
cz=6280±120 km s−1 is within the 1σ velocity dispersion of the Coma cluster. The galaxy has an effective
radius of 4.3 ± 0.3 kpc and a Sérsic index of 0.89 ± 0.06, as measured from Keck imaging. We find no indications
of tidal tails or other distortions, at least out to a radius of ∼2re. We show that UDGs are located in a previously
sparsely populated region of the size—magnitude plane of quiescent stellar systems, as they are ∼6 mag fainter
than normal early-type galaxies of the same size. It appears that the luminosity distribution of large quiescent
galaxies is not continuous, although this could largely be due to selection effects. Dynamical measurements are
needed to determine whether the dark matter halos of UDGs are similar to those of galaxies with the same
luminosity or to those of galaxies with the same size.
The mass of_the_mars_sized_exoplanet_kepler_138_b_from_transit_timingSérgio Sacani
Artigo da revista Nature, descreve o trabalho de astrônomos para medir o tamanho e a massa de um exoplaneta parecido com Marte, além de caracterizar por completo o sistema planetário da estrela Kepler-138.
Artigo que descreve a descoberta do exoplaneta Kepler-432b, um exoplaneta mais massivo que Júpiter que orbita uma estrela gigante vermelha bem próximo e numa órbita extremamente alongada.
The Population of the Galactic Center Filaments: Position Angle Distribution ...Sérgio Sacani
We have examined the distribution of the position angle (PA) of the Galactic center filaments with lengths L > 66″ and
<66″ as well as their length distribution as a function of PA. We find bimodal PA distributions of the filaments, and
long and short populations of radio filaments. Our PA study shows the evidence for a distinct population of short
filaments with PA close to the Galactic plane. Mainly thermal, short-radio filaments (<66″) have PAs concentrated
close to the Galactic plane within 60° < PA < 120°. Remarkably, the short filament PAs are radial with respect to the
Galactic center at l < 0° and extend in the direction toward Sgr A*
. On a smaller scale, the prominent Sgr E H II
complex G358.7-0.0 provides a vivid example of the nearly radial distribution of short filaments. The bimodal PA
distribution suggests a different origin for two distinct filament populations. We argue that the alignment of the shortfilament population results from the ram pressure of a degree-scale outflow from Sgr A* that exceeds the internal
filament pressure, and aligns them along the Galactic plane. The ram pressure is estimated to be 2 × 106 cm−3 K at a
distance of 300 pc, requiring biconical mass outflow rate 10−4 Me yr−1 with an opening angle of ∼40°. This outflow
aligns not only the magnetized filaments along the Galactic plane but also accelerates thermal material associated with
embedded or partially embedded clouds. This places an estimate of ∼6 Myr as the age of the outflow.
Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
In today's fast-changing business world, Companies that adapt and embrace new ideas often need help to keep up with the competition. However, fostering a culture of innovation takes much work. It takes vision, leadership and willingness to take risks in the right proportion. Sachin Dev Duggal, co-founder of Builder.ai, has perfected the art of this balance, creating a company culture where creativity and growth are nurtured at each stage.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Dev Dives: Train smarter, not harder – active learning and UiPath LLMs for do...UiPathCommunity
💥 Speed, accuracy, and scaling – discover the superpowers of GenAI in action with UiPath Document Understanding and Communications Mining™:
See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
Get an exclusive demo of the new family of UiPath LLMs – GenAI models specialized for processing different types of documents and messages
This is a hands-on session specifically designed for automation developers and AI enthusiasts seeking to enhance their knowledge in leveraging the latest intelligent document processing capabilities offered by UiPath.
Speakers:
👨🏫 Andras Palfi, Senior Product Manager, UiPath
👩🏫 Lenka Dulovicova, Product Program Manager, UiPath
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
LF Energy Webinar: Electrical Grid Modelling and Simulation Through PowSyBl -...DanBrown980551
Do you want to learn how to model and simulate an electrical network from scratch in under an hour?
Then welcome to this PowSyBl workshop, hosted by Rte, the French Transmission System Operator (TSO)!
During the webinar, you will discover the PowSyBl ecosystem as well as handle and study an electrical network through an interactive Python notebook.
PowSyBl is an open source project hosted by LF Energy, which offers a comprehensive set of features for electrical grid modelling and simulation. Among other advanced features, PowSyBl provides:
- A fully editable and extendable library for grid component modelling;
- Visualization tools to display your network;
- Grid simulation tools, such as power flows, security analyses (with or without remedial actions) and sensitivity analyses;
The framework is mostly written in Java, with a Python binding so that Python developers can access PowSyBl functionalities as well.
What you will learn during the webinar:
- For beginners: discover PowSyBl's functionalities through a quick general presentation and the notebook, without needing any expert coding skills;
- For advanced developers: master the skills to efficiently apply PowSyBl functionalities to your real-world scenarios.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
"Impact of front-end architecture on development cost", Viktor TurskyiFwdays
I have heard many times that architecture is not important for the front-end. Also, many times I have seen how developers implement features on the front-end just following the standard rules for a framework and think that this is enough to successfully launch the project, and then the project fails. How to prevent this and what approach to choose? I have launched dozens of complex projects and during the talk we will analyze which approaches have worked for me and which have not.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
Are you looking to streamline your workflows and boost your projects’ efficiency? Do you find yourself searching for ways to add flexibility and control over your FME workflows? If so, you’re in the right place.
Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
PHP Frameworks: I want to break free (IPC Berlin 2024)Ralf Eggert
In this presentation, we examine the challenges and limitations of relying too heavily on PHP frameworks in web development. We discuss the history of PHP and its frameworks to understand how this dependence has evolved. The focus will be on providing concrete tips and strategies to reduce reliance on these frameworks, based on real-world examples and practical considerations. The goal is to equip developers with the skills and knowledge to create more flexible and future-proof web applications. We'll explore the importance of maintaining autonomy in a rapidly changing tech landscape and how to make informed decisions in PHP development.
This talk is aimed at encouraging a more independent approach to using PHP frameworks, moving towards a more flexible and future-proof approach to PHP development.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...
F0344451
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861. Volume 3, Issue 4 (Mar. - Apr. 2013), PP 44-51
www.iosrjournals.org
www.iosrjournals.org 44 | Page
A new formula for the rotation velocity – and density distribution
of a galaxy
Tony Barrera, Bo Thelin
Barrera Kristiansen AB Granitvägen 12B, S-752 43 Uppsala, Sweden
Solarphotonics HB Granitvägen 12B, S-752 43 Uppsala, Sweden
Abstract: In this paper a new formula about the formation of galaxies is presented. It is based on the
relativistic Schwarzschild metric, where it has been possible to obtain expressions for the rotation velocity - and
mass distribution versus distance to the galactic center.
According to the rotation velocity formula, the rotation velocity raises very rapidly from the center
and reach a plateau which is constant out to big distance from the center. This is in accordance with
observations and is also in accordance with the main structure of rotation velocity versus distance relationships
from different galaxy measurements.
The density distribution formula shows that the density of the galaxy will decrease versus distance
which is in accordance to observations.
Computer simulations were also performed to establish and verify the rotation velocity and density distributions
in the galaxy, according to this paper.
Keywords: Astrophysics, Spiral galaxies and Theory of Relativity
I. Introduction
The mass of a spiral galaxy can be determined from the dependence of its rotational velocity as
a function of the distance from the center of the galaxy. Such a rotational curve has been determined from gas
and stars in the distant parts of our galaxy, far beyond our distance to the center. Unexpectedly, it does not
follow the Keplerian decrease in which the circular rotation velocity v decreases α R-1/2
where R is the distance
to the center. According to the 3:rd law of Kepler the mass of a galaxy can be expressed as : M = v2
R / G
and the rotation velocity as : v = ( G M / R )1/2
where G is the gravitation constant.
By using these formulas it is possible to determine the mass and rotation speed at a certain distance of the
galaxy. According to these formulas both mass and rotation velocity will decrease with increasing distance.
In the 1970s and 1980s radio astronomers discovered that the spiral rotation velocity remains constant with
increasing radius Freeman (1) ,Rubin and Ford (2). They studied neutral hydrogen clouds at 21-cm radio
wavelength and in the optical wavelength in spiral galaxies and found non-Keplerian rotation curves.
This is illustrated in Combes et al.(3) (Figs 3.1-3.3) , where the velocities of many spiral galaxies increase the
velocity very rapidly at small distances up to a constant plateau at larger distances from the galaxy center.
Astronomers discovered that many galaxies rotated at very high velocities.
To explain this most astronomers believe that this is caused by introducing dark matter in the Keplerian
equations above and to keep the galaxies together. They believe that most matter in a galaxy consists of dark
matter and only a minor part consists of ordinary matter which emits light. As constant rotation velocity is
observed now, means that the mass (visible + invisible) increase with distance from the center according to
Keplers equations above. Many astronomers believe that much invisible dark matter is situated outside the
visible part of the galaxy Ostriker et al. (4) and Einasto et al. (5). They found that M increased linearly with R
out to at least 100 kpc. They now believe that around 90% of the mass in a spiral galaxy consist of dark and
invisible matter, Rubin (6),with a mass to light (luminosity) ratio in solar units : M / L ≈ 200 ( Msun / Lsun ).
There is also another possible mass distribution according to the so called King´s model Combes et al. (3) (p.87)
where spiral galaxies follow a M α R2
distribution between mass and distance to center, which is observed.
This means that there are different ideas about mass distribution which observations seems to follow in some
way. The common for these ideas is the lack of ideas how the mass distribution together with constant rotation
velocity distribution coincide with observations at big distance observation.
A trial to solve these problems is done by MOND project, Sanders (7), which is a theoretical model
which might explain flat curves by modification of Newton´s law of gravitation. In this model gravitational
attraction of a given mass M does not decrease as quickly as 1 / R2
at these large distances. The acceleration
and thus the rotational velocity of gas for a given stellar mass will be greater.
In this very paper we have presented a new formula about the formation of galaxies. It is based on the
relativistic Schwarzschild metric, Schwarzschild (8),Einstein (9), where it has been possible to obtain a formula
for the rotation velocity and also a density distribution versus distance to the galactic center. Similar rotation
2. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 45 | Page
velocity profiles to our new formula have also been observed from data published in established books in this
field. These profiles are in accordance to observations. Computer simulations were also performed to establish
and verify the velocity and density distributions suggested in this paper.
According to this rotation velocity formula, the rotation velocity increases very rapidly from the center
and reach a plateau which is constant out to big distance from the center. This has also been observed in many
papers, Sofue and Rubin(10) and Combes et al. (3).
The density distribution formula shows that the density of the galaxy will decrease versus distance
which is in accordance to observations.
As in the MOND project we try to introduce new ways of thinking introducing relativistic metric which
seems to explain observations.
II. Observational data verifying an √𝐱- structure of the galaxy rotation velocity formula
By using the the formulas published the established books Combes et al. (3) and Lang (11) we can
state that we could expect to find a formula for the rotation speed versus distance to the center as a √𝑥-
dependence. Two proofs of that are demonstrated below :
Proof 1
According to, Lang (11) (p. 55), the ratio between mass and luminosity of a galaxy has the following
appearance :
M / L = const L0.35
giving M = const L 1.35
(1)
giving : L = const M (1/1.35)
= const M0.74
(2)
By using Tully –Fischer`s law, Combes et al. (3), (p. 87 ), between luminosity and the rotation speed of the
galaxy gives:
L 𝜶 V4
𝜶 M 0.74
(3)
This means that : V 𝜶 M 0.19
( 4 )
According to Combes et al., (p. 87 ), the correlation between mass and radios is :
M 𝜶 R2
(5)
This means that :
V 𝜶 M 0.19
= R (2 x 0.19)
= R 0.38
( 6)
which has √𝑥- structure between rotation velocity and distance to the center of galaxy.
Proof 2
According to equations (2) and (5) :
L 𝜶 M0.74
𝜶 R (2x 0.74)
(7)
This means that : M / L 𝜶 R2
/ R( 2 x 0.74)
= R0.52
(√𝑥- structure) (8)
This is observed in Fig( 3.12 ) in Combes et al. (3), (p. 85) and Tinsley (12) , where the color index B-V α T α
R.
This means that equation (8) can be rewritten as :
M / L = (V( 1 / 0.19 )
/ V4)
) = V1.26
= R0.52
(9)
means that : V = R0.41
(10)
which gives √𝑥- structure. This means that these investigations show that we should expect
a rotation velocity profile to have a √𝑥- structure between rotation velocity and distance to the center of the
galaxy.
III. The use of Schwarzschild metric
A. The determination of the velocity and density formulas
For a spherically symmetric gravitational field outside a massive non-rotating body in vacuum,the line element
ds becomes according to Schwarzschild (8 ):
ds2
= ( 1 – 2GM / c2
r )c2
dt2
- ( 1 – 2GM /c2
r )-1
dr2
- r2
dθ2
-r2
sin2
θ
d ψ2
(11)
Here r, θ and ψ are spherical coordinates whose origin is at the center of the massive object
with the mass M , which determine the Newtonian gravitational field (GM / r). G is here the
the gravitational constant and r is the distance. By using a polar coordinate system with θ = 0
the following expression from equation (11) is obtained :
ds2
= - γ-1
dr2
- r2
dθ2
+ γ dt2
(12 )
where γ = ( 1 – 2M/r ) , which is the Schwarzschild term Eddington (13)( p.82-85)
3. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 46 | Page
If we study galaxies, the expansion in the space-time appeared to be constant, which means
that the line element could be ds = 0. By using this on equation (12) we obtain :
r2
dθ2
= γ dt2
- γ-1
dr2
(13)
From this formula it is possible to obtain an expression for the angular rotation speed
of a galaxy :
dθ = (1 / r ) ( ( 1 – 2M / r ) dt2
– ( 1 – 2M / r )-1
dr2
)1/2
(14)
If we suggest the space-time to be constant for a galaxy the dr = 0 which gives
dr2
= 0. This means that equation (14) can be rewritten as :
dθ = (1 / r ) ((1 – 2M/r ) dt2
)1/2
(15)
which gives a simpler equation of the angular rotation speed of galaxies :
dθ/ dt = (1 / r ) ((1 – 2M/r ) )1/2
(16)
By introduction of a scale factor k equation (16) will get the following
appearance : dθ/ dt = (k / r ) ((1 – 2M/r ) )1/2
(17)
The formula of the rotation speed (km/s) is obtained from the expression
v = r (dθ/ dt) (18 )
This means that the rotation speed in km/s will be the following expression :
v = k ((1 – 2M/r ) )1/2
( 19 )
and is seen in the theoretical graph of Fig 1 . In this graph the rotation speed is increased
steeply at small radius and reach a constant value after a rather small distance. Fig 1 is a theoretical graph only
verifying the main structure of equation (19).Similar profiles are also seen in the observational graphs of Fig 2.
Many of those graphs follow a clear √𝑥-. structure according to chapter A and equation (19) .
B. The determination of the density formula
By using equation (19) we can now achieve a formula for the mass M and density ρ of the galaxy :
M = (r/2)( 1- v2
/ k ) ( 20 )
By using the volume of a sphere :
V = (4 π r3
) / 3 ( 21 )
the expression of the density of a galaxy is achieved :
ρ = M / V = ( 3 / (8 π r2
) ) ( 1- v2
/ k ) (22 )
Such a graph is seen in Fig 3 , which is a theoretical graph where the total density of a galaxy is decreasing at
larger distancies in accordance to earlier measurements Lang (11) (p.131)
The ratio between r and Rmax in percent is here studied.
Computer simulations were also performed to establish and verify the velocity and density distributions
suggested in this paper. In these simulations 6000 (Fig 4) and 30000 (Fig 5 and 6) “stars” were randomly
distributed like an ellipsoid and following equations (19) and (22). After some time a spiral structure appeared
in accordance with observations. Studies were also performed of the halo of the galaxy from the side (Fig 6).
IV. Discussion
We can se from section 2 that the velocity formula between velocity and distance to the center of the
galaxy has a √𝑥- structure. These facts are based on results presented in ( 3 ) and (11 ) and are not based on
Kepler`s 3:rd law directly. These relationships are observed by the astronomers where the velocity reach a
constant speed between 5 and 10 kpc from the center of the galaxy. A similar structure is also obtained by using
the theory of relativity and the Schwarzschild metric, where a steep raise of the velocity (angular and circular in
km/s) at low distancies is obtained by equation (19 ).After that a plateau is reached which will be dominating
to large distancies.
This is also observed by many astronomers (1) and (2) and have been a controversial discovery,
because it contradict Kepler`3:rd law, which will follow a (1/ √𝑟) - dependence and is not observed in any
galaxies. Therefore the astronomers claim that there must be
a big amount of dark matter in the galaxy, which is the cause of this discrepancy and also hold the galaxies
together at those high rotation speeds.
Similar √𝑥- structures of the velocity curves as our curves have been obtained in the Mond-
project, where a modification of the Newton`s law is applied. This is an interesting approach where an
additional term is applied on the usual 1 / R2
decrease between gravity and distance on galaxy level. However,
we think that applying the theory of relativity here, is a more realistic approach on this galaxy level.
Our model is also in accordance to the density distribution in the galaxy which shows a decreasing profile to
distance, which is in accordance to earlier observations.
4. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 47 | Page
Computer simulations were also performed to establish and verify the rotation velocity and density distributions
in the galaxy, suggested in this paper and giving a strong support of the new formulas and the use of theory of
relativity.
Acknowledgement:
We thank :
Dr. Gunnar Berg at the Mathematical Institution at Uppsala University,
Prof. Krister Kiselman at the Mathematical Institution at Uppsala University,
Dr. Anders Hast at Creative Media Lab at University of Gävle.
Prof. Ewert Bengtsson at Centre for Image Analysis at Uppsala University
Dr.Staffan Yngve at the Physical Institution at Uppsala University
for valuable discussions and critical examinations of the material in this paper.
References:
[1]. Freeman, K. C. ,(1970), Ap. J.,160 , 811
[2]. Rubin, V. C., Ford, W. K., (1970), Ap, J. 150 , 379
[3]. Combes, F., Boisse`,P., Mazure ,A. and Blanchard, A., Galaxies and Cosmology,(2001)
[4]. Ostriker, J.P. ,Peebles, P.J.E., and Yahil,A.,(1974), Ap.J.193, L1
[5]. Einasto, J., Kaasik,A. and Saar,E., (1974),Nature, 250, 309
[6]. Rubin, V.C.,(1993),Proc. Nat. Acad. Sci., 90, 4814
[7]. Sanders, R., H., (2002) Annu. Rev. Astron. Astrophys. Vol 40,p.263-317
[8]. Schwarzschild, K., (1916),Sitz. Acad. Wiss., Physik-Math., Kl. 1 , 189
[9]. Einstein, A., (1916), Ann. Physik, 49, 769
[10]. Sofue, Y., Rubin, V.C., Annu.Rev.Astronom.Astrophys.2001,Vol 39, p. 137-174
[11]. Lang, K.R.,(1998), Astrophysical Formula, Vol. 2
[12]. Tinsley, B., (1981), Mon. Not. Roy. Astron. Soc., 194, 63
[13]. Eddington, A.S. (1923), Mathematical Theory of Relativity.
Figures
Fig 1
Theoretical graph of rotational speed versus distance in the galaxy according to equation (19)
5 10
100
150
50
V
km/s
r
5. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 48 | Page
Fig 2
Rotation curves of spiral galaxies obtained by combining CO data for the central regions, optical for
disks, and HI for outer disk and halo Sofue et al.(10)).
Fig 3
Theoretical graph of density versus distance in the galaxy according to equation (22).
The distance is here the ratio between distance r and maximum distance Rmax in percent.
50
100
100
150
50
ρ
r (% av Rmax)
6. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 49 | Page
Fig 4
Computer simulations of randomly distributed 6000 “stars” distributed like an ellipsoid.
After a while a spiral structure is appeared according to observation and equation (19).
7. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 50 | Page
Fig 5
Computer simulations of randomly distributed 30 000 “stars” distributed like an ellipsoid.
After a while a spiral structure is appeared according to observation and equation (19).
8. A new formula for the rotation velocity – and density distribution of a galaxy
www.iosrjournals.org 51 | Page
Fig 6
Here the same distribution as Fig 5 but from the side. A halo is also appeared after a while.
This is what is observed in most galaxies from the side.