Spectral estimation, and corresponding time-frequency representation for nonstationary signals, is a cornerstone in geophysical signal processing and interpretation. The last 10–15 years have seen the development of many new high-resolution decompositions that are often fundamentally different from Fourier and wavelet transforms. These conventional techniques, like the short-time Fourier transform and the continuous wavelet transform, show some limitations in terms of resolution (localization) due to the trade-off between time and frequency localizations and smearing due to the finite size of the time series of their template. Well-known techniques, like autoregressive methods and basis pursuit, and recently developed techniques, such as empirical mode decomposition and the synchrosqueezing transform, can achieve higher time-frequency localization due to reduced spectral smearing and leakage. We first review the theory of various established and novel techniques, pointing out their assumptions, adaptability, and expected time-frequency localization. We illustrate their performances on a provided collection of benchmark signals, including a laughing voice, a volcano tremor, a microseismic event, and a global earthquake, with the intention to provide a fair comparison of the pros and cons of each method. Finally, their outcomes are discussed and possible avenues for improvements are proposed.
Time-Frequency Representation of Microseismic Signals using the SSTUT Technology
Resonance frequencies could provide useful information on the deformation occurring during fracturing experiments or CO2 management, complementary to the microseismic events distribution. An accurate time-frequency representation is of crucial importance to interpret the cause of resonance frequencies during microseismic experiments. The popular methods of Short-Time Fourier Transform (STFT) and wavelet analysis have limitations in representing close frequencies and dealing with fast varying instantaneous frequencies and this is often the nature of microseismic signals. The synchrosqueezing transform (SST) is a promising tool to track these resonant frequencies and provide a detailed time-frequency representation. Here we apply the synchrosqueezing transform to microseismic signals and also show its potential to general seismic signal processing applications.
Spectral estimation, and corresponding time-frequency representation for nonstationary signals, is a cornerstone in geophysical signal processing and interpretation. The last 10–15 years have seen the development of many new high-resolution decompositions that are often fundamentally different from Fourier and wavelet transforms. These conventional techniques, like the short-time Fourier transform and the continuous wavelet transform, show some limitations in terms of resolution (localization) due to the trade-off between time and frequency localizations and smearing due to the finite size of the time series of their template. Well-known techniques, like autoregressive methods and basis pursuit, and recently developed techniques, such as empirical mode decomposition and the synchrosqueezing transform, can achieve higher time-frequency localization due to reduced spectral smearing and leakage. We first review the theory of various established and novel techniques, pointing out their assumptions, adaptability, and expected time-frequency localization. We illustrate their performances on a provided collection of benchmark signals, including a laughing voice, a volcano tremor, a microseismic event, and a global earthquake, with the intention to provide a fair comparison of the pros and cons of each method. Finally, their outcomes are discussed and possible avenues for improvements are proposed.
Time-Frequency Representation of Microseismic Signals using the SSTUT Technology
Resonance frequencies could provide useful information on the deformation occurring during fracturing experiments or CO2 management, complementary to the microseismic events distribution. An accurate time-frequency representation is of crucial importance to interpret the cause of resonance frequencies during microseismic experiments. The popular methods of Short-Time Fourier Transform (STFT) and wavelet analysis have limitations in representing close frequencies and dealing with fast varying instantaneous frequencies and this is often the nature of microseismic signals. The synchrosqueezing transform (SST) is a promising tool to track these resonant frequencies and provide a detailed time-frequency representation. Here we apply the synchrosqueezing transform to microseismic signals and also show its potential to general seismic signal processing applications.
Invariant Mass Distribution of Jet Pairs Produced in Association with a W bos...accatagliato
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb^-1. The observed distribution has an excess in the 120-160 GeV/c^2 mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this letter we report studies of the properties of this excess.
Short-time homomorphic wavelet estimation UT Technology
Wavelet estimation plays an important role in many seismic processes like impedance inversion, amplitude versus offset (AVO) and full waveform inversion (FWI). Statistical methods of wavelet estimation away from well control are a desirable tool to support seismic signal processing. One of these methods based on Homomorphic analysis has long intrigued as a potentially elegant solution to the wavelet estimation problem. Yet a successful implementation has proven difficult. We propose here a method based short-time homomorphic analysis which includes elements of the classical cepstrum analysis and log spectral averaging. Our proposal increases the number of segments, thus reducing estimation variances. Results show good performance on realistic synthetic examples.
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.
Milky Way White Dwarfs as Sub-GeV to Multi-TeV Dark Matter DetectorsSérgio Sacani
We show that Milky Way white dwarfs are excellent targets for dark matter
(DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate
sensitivity to DM annihilating within white dwarfs into long-lived or boosted mediators and
producing detectable gamma rays. Depending on the Galactic DM distribution, we set new
constraints on the spin-independent scattering cross section down to 10−45 − 10−41 cm2 in
the sub-GeV DM mass range, which is multiple orders of magnitude stronger than existing
limits. For a generalized NFW DM profile, we find that our white dwarf constraints exceed
spin-independent direct detection limits across most of the sub-GeV to multi-TeV DM mass
range, achieving sensitivities as low as about 10−46 cm2. In addition, we improve earlier
versions of the DM capture calculation in white dwarfs, by including the low-temperature
distribution of nuclei when the white dwarf approaches crystallization. This yields smaller
capture rates than previously calculated by a factor of a few up to two orders of magnitude,
depending on white dwarf size and the astrophysical system.
Observations of Gamma-Ray Bursts with the Fermi-Large Area TelescopeVlasios Vasileiou
Brief introduction to the history and science of Gamma Ray Bursts and a report of the latest observational results of the Fermi-Large Area Telescope on GRBs.
Invariant Mass Distribution of Jet Pairs Produced in Association with a W bos...accatagliato
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 fb^-1. The observed distribution has an excess in the 120-160 GeV/c^2 mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this letter we report studies of the properties of this excess.
Short-time homomorphic wavelet estimation UT Technology
Wavelet estimation plays an important role in many seismic processes like impedance inversion, amplitude versus offset (AVO) and full waveform inversion (FWI). Statistical methods of wavelet estimation away from well control are a desirable tool to support seismic signal processing. One of these methods based on Homomorphic analysis has long intrigued as a potentially elegant solution to the wavelet estimation problem. Yet a successful implementation has proven difficult. We propose here a method based short-time homomorphic analysis which includes elements of the classical cepstrum analysis and log spectral averaging. Our proposal increases the number of segments, thus reducing estimation variances. Results show good performance on realistic synthetic examples.
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.
Milky Way White Dwarfs as Sub-GeV to Multi-TeV Dark Matter DetectorsSérgio Sacani
We show that Milky Way white dwarfs are excellent targets for dark matter
(DM) detection. Using Fermi and H.E.S.S. Galactic center gamma-ray data, we investigate
sensitivity to DM annihilating within white dwarfs into long-lived or boosted mediators and
producing detectable gamma rays. Depending on the Galactic DM distribution, we set new
constraints on the spin-independent scattering cross section down to 10−45 − 10−41 cm2 in
the sub-GeV DM mass range, which is multiple orders of magnitude stronger than existing
limits. For a generalized NFW DM profile, we find that our white dwarf constraints exceed
spin-independent direct detection limits across most of the sub-GeV to multi-TeV DM mass
range, achieving sensitivities as low as about 10−46 cm2. In addition, we improve earlier
versions of the DM capture calculation in white dwarfs, by including the low-temperature
distribution of nuclei when the white dwarf approaches crystallization. This yields smaller
capture rates than previously calculated by a factor of a few up to two orders of magnitude,
depending on white dwarf size and the astrophysical system.
Observations of Gamma-Ray Bursts with the Fermi-Large Area TelescopeVlasios Vasileiou
Brief introduction to the history and science of Gamma Ray Bursts and a report of the latest observational results of the Fermi-Large Area Telescope on GRBs.
The distribution and_annihilation_of_dark_matter_around_black_holesSérgio Sacani
Uma nova simulação computacional feita pela NASA mostra que as partículas da matéria escura colidindo na extrema gravidade de um buraco negro pode produzir uma luz de raios-gamma forte e potencialmente observável. Detectando essa emissão forneceria aos astrônomos com uma nova ferramenta para entender tanto os buracos negros como a natureza da matéria escura, uma elusiva substância responsável pela maior parte da massa do universo que nem reflete, absorve ou emite luz.
RADAR - RAdio Detection And Ranging
This is the Part 1 of 2 of RADAR Introduction.
For comments please contact me at solo.hermelin@gmail.com.
For more presentation on different subjects visit my website at http://www.solohermelin.com.
Part of the Figures were not properly downloaded. I recommend viewing the presentation on my website under RADAR Folder.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Body fluids_tonicity_dehydration_hypovolemia_hypervolemia.pptx
Nikola Godinović "The very high energy gamma ray astronomy"
1. VHE Gamma- ray astronomy
- tool for fundamental physics
Nikola Godinović
University of Split - FESB
2. Outline
• Gamma-ray telescopes/detector
• IACT (H.E.S.S.,MAGIC,VERITAS (50 GeV –
100TeV)
• Satelite (Fermi, AGILE) (20 MeV – 300 GeV)
• Fundamental physics probed by gamma-rays
• Dark mattter search
• Lorentz inavriance violation
• Extraglactic background light
• Origin of cosmics ray
• Future prospects
3. Messangers from space
Gravity wave
Multimessanger astronomy is on stage
LIGO/VIRGO
GW170817
Fermi GRB Mon
GRB 170817A
IceCube-170922A
MAGIC VHE flare
TXS 0506+056
5. Current IACT telecopes for VHE gammas
http://tevcat.uchicago.edu/
MAGIC
H.E:S.S:
VERITAS
VHE gammas - tool to study the most violen proces and to probe fundamental physics
1989 Crab nebula, standard candle E > 1TeV, flux=2 × 10-7 m-2 s-1 (“standard candle”)
9. Generation of VHE gamma ray
-
0
+
(TeV)
p+ (>>TeV)
matter
Hadronic model of emission
(TeV)
Invers Compton
(eV)
B
e- (TeV) Synchroton radiation
(eV-keV)
Leptonic model emission
• Hadronic model of emission
• Leptonic model of emission
Disentangle hadronic from
leptonic gamma ray origin
=> shape of spectrum
energy E
0decay
ICSy
12. Evidence for DM and search method
• Overwhelming evidence for a Dark Mater
component in the Universe
• Particle candidates in-line with observations:
Weakly Interacting Massive Particles (WIMPs).
Several BSM theories predict WIMPs (SUSY,
Extra dimensions, ...)
• WIMPs mass range: O(10) GeV – O(100) TeV
• Indirect DM searches aimed at detectingng
secondary SM products (including gamma-
rays) from annihilation or decay of DM particles
• Gamma-rays as final states are of major
interest because:
• trace back to abundance /distributioon of DM
• show peculiar spectral features (smocking guns)
• Indirect Dark Matter searches are needed to
confirm signals in direct and/or accelerator
searches are THE Dark Matter
Last results from the Planck satellite,
Wb h2 0.022
WDM h2 0.12
confirm that about 85% of the matter in the Universe is dark
WDE h2 0.31
As often remarked, this would lead
to another Copernican revolution:
We are not the center of the Universe
+We are not made of what most of the Universe is made of !
weak-scale mass(~MZ) + weak inte
→ cold
→ many candidates in theories which
→ predictive!
‘only’ 90 or• Weakly Interacting Massive
• WIMP miracle:
• Why WIMP?
• such particle would self-annihilate in the early un
Universe’s expansion becomes too quick. This the
exact observed amount of DM!
• as a bonus, any theory which tries to explain the
generally introduces new stable EW mass particle
• DM with a mass ~MZ clusters in a way
confirmed by observations. (true for
mDM>~ 1 MeV)
Revisiting the WIMP Miracle
Ωdm = 0.23×
10− 26
cm3
·s− 1
⇥σv⇤
⇥
Dark Matter Abundance from Thermal Production
Cosmological
Measurement
Weak Scale
Physics
A larger cross-section would account for
PAMELA and a surprise at LHC
Th
surγ,
ν,
e±,
p±
D-
decay
@≤Mz
<σv> ∼10-26 cm3s-1
13. Strategy for indirect DM serach
• Find the source/region of high density dark
matter
• As close as possible
• Low astophycical background
• Model the measured gamma-ray flux for the
selecetd DM anihillation process in order to be
able to find out mass of DM if you are lukcy or
in case of non-detection of gamma rays to put
the upper limit <σv>
Upper limits on Annihilation Crosssection
14. Particle physics term:
▪ thermally-averaged velocity-weighted
annihilation cross section
▪ mχ-dark matter mass
▪ Differential gamma ray yield per
annihilation dN/dE summed over all
the n possible channels that
produce photons
Dark matter annihilation signal
with:
l -position along the
line of sight,
Δ𝛀 - observed solid
angle,
𝛒 - DM density profile
𝛔𝐯
Particle phsyics
terma
Astrophysical
terma
Integral flux
16. 1. Continuum: hadronization and/or decay of W/Z, quarks, leptons…
2. Line from prompt annihilation in two photons
not at tree level: suppressed but clear signature at DM mass !
3. Final state radiation
4. Virtual internal bremsstrahlung
Dark matter annihilation signals in gamma-rays
Thermal relic cross section for WIMPs:
• For the continuum signal : σv ~ 3 × 10−26 cm3s−1
• For the prompt line signal : σv ~ 10−29cm3s−1
17. DM decay to gamma - spectral features
Line spectral features
but loop susspresd
of a universal form, almost independent of the un
ing particle physics model [16, 17]. Defining the p
multiplicity as
dNX ¯X
≡
1 dσχ χ →X ¯X γ
,
X ɣ, Z H
18. Dark matter targets for VHE gamma-ray searches
Aquarius, Springel et al. Nature 2008
▪ DM density profile matters
▪ Astrophysical background matters as well
Galactic Centre (GC) o
Proximity (~8kpc)
o High DM content
DM profile : core? cusp?
o High astrophysical bck
/ source confusion
Galaxy satellites of the Milky Way
o Many of them within the 100 kpc from GC
o Low astrophysical background
o DM dominated
Substructures in
the Galactic halo
o Lower signal
o Cleaner signal
(once found)
Galactic halo
o Large statistics
o Galactic diffuse
background
19. Where to look for Dark Matter
Galactic centre
+ Highest J-‐factor
− High astroph. bkg
− Uncertainties on inner DM distribution
(Southern Hemisphere)
DM Clumps
+ Free from astroph. kg.
+ Neraby and numerous
− To be found
− Bright enough
Galactic halo
+ High J-factor
− Not fully-free from astro. Bkg.
− Extended
(Southern Hemisphere)
Dwarf Galaxies
+ DM dominated (high M/L ratios)
+ Free from astroph. bkg
+ Close (<~100 kpc)
+ Slightly extended at most
+ ~20 new optimal dSphs discovered
+ Less uncertainties on on J-‐factors
− J-‐factors ~100 lower than for GC
Galaxy Clusters?
+ Huge amount of DM
− High astroph. bkg
− Distant
− Extended
− Uncertainties J-‐factors Wisely choose /balance between
pro and contra parameters for DM search
20. MAGIC & Fermi Combined analysis
Due to expected universality of DM properties, a joint likelihood function 𝓛
can be constructed as a product of the particular likelihood function for each of
the data samples and instruments.
Combination improves sensitivity
IRF of each experiments and event list do
not need to be comabined and average
See also: J. Aleksić, J. Rico, M. Mar=nez JCAP 10 (2012) 032 and M.L. Ahnen et al. JCAP 02 (2016) 039
26. Lorentz Invariance Violation
• QG effects may cause violations of Lorentz Invariance (LIV)
speed of light in vacuum may acquire a dependence on its
energy → vγ(Eγ)≠c
• The Lorentz-Invariance violating terms are typically expanded
using a series of powers of the photon energy Eγ over the
Quantum Gravity mass MQG,n:
• The Quantum-Gravity Mass MQG
• Sets the energy (mass) scale at which QG effects become important.
Is expected to be of the order of the Planck Mass and most likely
smaller than it
fects may cause violations of Lorentz Invariance (LIV)
ed of light in vacuum may acquire a dependence on its energy → υγ(Eγ
)≠c.
orentz-Invariance violating terms are typically expanded using a series of powers
photon energy Eγ
over the Quantum Gravity mass MQG
:
e sn
={-1,0,+1} is a model-dependent factor.
uantum-Gravity Mass MQG
ts the energy (mass) scale at which QG effects become important.
expected to be of the order of the Planck Mass and most likely smaller than it
Lorentz-Invariance ViolationLorentz-Invariance Violation
• QG effects may cause violations of Lorentz Invariance (LIV)
→ speed of light in vacuum may acquire a dependence on its energy → υγ(Eγ
)≠c.
• The Lorentz-Invariance violating terms are typically expanded using a series of powers
of the photon energy Eγ
over the Quantum Gravity mass MQG
:
where sn
={-1,0,+1} is a model-dependent factor.
•The Quantum-Gravity Mass MQG
• Sets the energy (mass) scale at which QG effects become important.
• Is expected to be of the order of the Planck Mass and most likely smaller than it
Lorentz-Invariance ViolationLorentz-Invariance Violation
where sn={-1,0,+1} is a
model-dependent factor
27. Lorentz Invariance Violation
• Since E 𝛾 < MQG,nc2 , the sum is dominated by the lowest-order term (n) with
sn≠0, usually n=1 or 2 (“linear” and “quadratic” LIV respectively):
• If the speed of light depends on its energy, then two photons with energies
Eh>El emitted simulatneously will arrive at different times. For sn=+1 (speed
retardation):
• We want to constrain LIV -> set lower limit on MQG,n by measuring the
upper limit of Δt between photons of different energies
, the sum is dominated by the lowest-order
≠ 0, usually n= 1 or 2 (“ linear” and “ quadratic” LIV respectively
sn
= + 1 or -1 for subluminal and superluminal speeds respective
are many models that allow such LIV violations, and some othe
y require them (e.g. stringy-foam model J. Ellis et al. 2008).
peed of light depends on its energy, then two photons with en
d together will arrive at di6erent times. For sn
= + 1 (speed retar
Lorentz-Invariance ViolationLorentz-Invariance Violation
sn=+1 or -1 is for subluminal and superluminal respectively
e , the sum is dominated by the lowest-order term (n)
sn
≠ 0, usually n= 1 or 2 (“ linear” and “ quadratic” LIV respectively):
re sn
= + 1 or -1 for subluminal and superluminal speeds respectively.
e are many models that allow such LIV violations, and some others that
ally require them (e.g. stringy-foam model J. Ellis et al. 2008).
e speed of light depends on its energy, then two photons with energies Eh
> El
ted together will arrive at di6erent times. For sn
= + 1 (speed retardation):
want to constraint LIV →Set lower limits on MQG,n
accomplish that by setting upper limits on the time delay Δt between photons
6erent energies.
Lorentz-Invariance ViolationLorentz-Invariance Violation
28. Phenomenological Approach
• Need very fast transinet phenomena providing “time stamp” for the
simultaneous emission of different gamma ray energies
• Fast GRB
• AGN flare
• Regular pulsed emission (Crab pulsar)
• Figure of merrit: MQG ∼(L ΔE) /(cΔt)
• ΔE – the lever arm
• for the instrument (instrumental limit)
• for the observed energies (observing source)
• Δt: the time resolution
• time resolution of the instrument (instrumental limit)
• the bining time to have enough statistics (observing source)
• L: the typical distance of the source
• Measure ΔE and Δt from data and calculate QG scale EQG
• The meaning of EQG is the energy scale at which QG is effective ..
29. LIV & FERMI GRB 090510
• Even a tiny variation in photon speed, when accumulated over cosmological light-
travel times, may be revealed by observing sharp features in γ-ray burst (GRB)
light-curves
• FERMI GRB 090510 emission up to ∼31 GeV from the distant and short
GRB 090510.
• No evidence for the LIV, a lower limit of 1.2EPlanck on the scale of a linear energy
dependence is set
• These results support Lorentz invariance and disfavor models in which a quantum
nature of space-time alters the speed of light, giving it a linear dependence on
photon energy
● We constrained small changes in the speed of light caused by linear and quadratic
perturbations in (Eγ
/MQG
).
● Using two independent techniques, we have placed strong limits on linear
perturbations for both super- and sub-luminal speeds that were all higher than the
Planck Mass.
Initial results on GRB 090510Initial results on GRB 090510
Abdo et al. 2009, Nature 462, 331
Abdo et al. 2009, Nature 462, 331
30. LIV & Crab Pulsar
• MAGIC has detected emission from the Crab Pulsar up to 0.5
TeV for the main pulse P1, and up to 1.5 TeV for the inter-
pulse P2
• The spectrum of both pulses is consistent with a power-law,
however a significant difference was found between the
reconstructed spectral indices of P1 and P2, the latter being
harder
• Maximum likelihood method is constructed containing two
parameters
• LIV produces mean phase delay
c- speed of light, dCrab- pulsar disatnce, PCrab-pulsar period
31. LIV & Crab pulsar
Data samples used:
• 19 observation periods.
• 19 different IRFs
• Systematic uncertanity
studied and included in
the limits
A profile likehood analysis of
pulsar events reconstructed
for energies above 400 GeV
finds no signficant variation
in arrival time as the energy
increase.
95 % CL lower limits are
obatined on LIV energy scale
are obatined (linear and
quadratic)
Pulsar are useful to study
time of flight diferences of
energetic photons. Stable
and continum emission
ensure limits improvement
over time.
55 Gev < E < 100 GeV 600 Gev < E < 1200 GeV
400 Gev < E < 600 GeV 600 Gev < E < 1200 GeV
32. Caveat in LIV search
How to disentangle propagation delays
from source intrinsic delay?
observe sources at different redshifts and
check delay proportional to distance.
use geometrical time stamps (pulsars).
37. Summary
• There is a clear interplay between gamma ray
astrophysics and fundemental physics
• Study the progattion of phootns over cosmological
distances
• Search for dark matter and new particles in phootn
spectrum
• Study physics of extreme enviroemnts
• VHE gamma ray astrophysics is exploring regions
beyond the reach of accelerators
• CTA with factor ten better sensitivity than current
IACTs is just around corner
• New instruments are planed (e-ASTROGRAM,
COMPAIR) or going to be upgarde (HAWC,
LHASSO) ...
39. Indircet DM search
The gamma- ray flux from WIMP annihilation is proportional to:
• The number density squared of particles, i.e., ρ2;
• The WIMP annihilation cross section today, σ;
• The mean WIMP velocity v;
• Volume of the sky observed within a solid angle Ω;
• Number of gamma-rays produced per annihilation at a given energy, also
known
as the energy spectrum (dN/dE)
Therefore, after measuring the flux in gamma-rays from a given source, we
compare that with background expectations. If no excess is observed, we can
choose a DM density profile and select an annihilation final state needed for
dN/dE, and then derive a limit on the ratio <σv>/mχ
2 according to equation above.
This is the basic idea behind experimental limits.