scholarly journals Angular power spectrum of the diffuse gamma-ray emission as measured by the Fermi Large Area Telescope and constraints on its dark matter interpretation

2016 ◽  
Vol 94 (12) ◽  
Author(s):  
Mattia Fornasa ◽  
Alessandro Cuoco ◽  
Jesús Zavala ◽  
Jennifer M. Gaskins ◽  
Miguel A. Sánchez-Conde ◽  
...  
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Gamma Ray ◽  
Large Area ◽  
Angular Power Spectrum ◽  
Gamma Ray Emission

scholarly journals Search for dark matter signatures in the gamma-ray emission towards the Sun with the Fermi Large Area Telescope

2020 ◽  
Vol 102 (2) ◽  
Author(s):  
M. N. Mazziotta ◽  
F. Loparco ◽  
D. Serini ◽  
A. Cuoco ◽  
P. De La Torre Luque ◽  
...  
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
The Sun ◽  
Large Area ◽  
Gamma Ray Emission

scholarly journals Search for gamma-ray emission from dark matter annihilation in the large magellanic cloud with the fermi large area telescope

2015 ◽  
Vol 91 (10) ◽  
Author(s):  
Matthew R. Buckley ◽  
Eric Charles ◽  
Jennifer M. Gaskins ◽  
Alyson M. Brooks ◽  
Alex Drlica-Wagner ◽  
...  
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Large Area ◽  
Dark Matter Annihilation ◽  
Gamma Ray Emission

scholarly journals On a Possible Origin of the Gamma-ray Excess around the Galactic Center

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Alternative Explanation ◽  
Gamma Ray ◽  
Galactic Center ◽  
The Self ◽  
Large Area ◽  
Mhd Turbulence ◽  
The Standard Model

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

scholarly journals Statistical modelling of the cosmological dispersion measure

2021 ◽  
Vol 502 (2) ◽  
pp. 2615-2629
Author(s):  
Ryuichi Takahashi ◽  
Kunihito Ioka ◽  
Asuka Mori ◽  
Koki Funahashi
Keyword(s):  
Dark Matter ◽  
Correlation Function ◽  
Probability Distribution ◽  
Power Spectrum ◽  
Free Electron ◽  
Statistical Modelling ◽  
Dispersion Measure ◽  
Host Galaxies ◽  
Angular Power Spectrum ◽  
Bias Factor

ABSTRACT We have investigated the basic statistics of the cosmological dispersion measure (DM)—such as its mean, variance, probability distribution, angular power spectrum, and correlation function—using the state-of-the-art hydrodynamic simulations, IllustrisTNG300, for the fast radio burst cosmology. To model the DM statistics, we first measured the free-electron abundance and the power spectrum of its spatial fluctuations. The free-electron power spectrum turns out to be consistent with the dark matter power spectrum at large scales, but it is strongly damped at small scales (≲  Mpc) owing to the stellar and active galactic nucleus feedback. The free-electron power spectrum is well modelled using a scale-dependent bias factor (the ratio of its fluctuation amplitude to that of the dark matter). We provide analytical fitting functions for the free-electron abundance and its bias factor. We next constructed mock sky maps of the DM by performing standard ray-tracing simulations with the TNG300 data. The DM statistics are calculated analytically from the fitting functions of the free-electron distribution, which agree well with the simulation results measured from the mock maps. We have also obtained the probability distribution of source redshift for a given DM, which helps in identifying the host galaxies of FRBs from the measured DMs. The angular two-point correlation function of the DM is described by a simple power law, $\xi (\theta) \approx 2400 (\theta /{\rm deg})^{-1} \, {\rm pc}^2 \, {\rm cm}^{-6}$, which we anticipate will be confirmed by future observations when thousands of FRBs are available.

scholarly journals Gamma-Ray Emission of the Kes 73/1E 1841-045 Region Observed with the Fermi Large Area Telescope

2017 ◽  
Vol 837 (1) ◽  
pp. 69 ◽  
Author(s):  
Paul K. H. Yeung ◽  
Albert K. H. Kong ◽  
P. H. Thomas Tam ◽  
C. Y. Hui ◽  
Jumpei Takata ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Large Area ◽  
Gamma Ray Emission
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