111. Sensitivity projections for dark matter searches with the Fermi large area telescopeGabrijela Zaharijas, Collaboration Fermi LAT, 2016, original scientific article Abstract: The nature of dark matter is a longstanding enigma of physics; it may consist of particles beyond the Standard Model that are still elusive to experiments. Among indirect searchtechniques, which look for stable products from the annihilation or decay of dark matter particles, or from axions coupling to high-energy photons, observations of the γ -ray sky have come to prominence over the last few years, because of the excellent sensitivity of the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope mission. The LAT energy range from 20 meV to above 300 GeV is particularly well suited for searching for products of the interactions of dark matter particles. In this report we describe methods used to search for evidence of dark matter with the LAT, and review the status of searches performed with up to six years of LAT data. We also discuss the factors that determine the sensitivities of these searches, including the magnitudes of the signals and the relevant backgrounds, considering both statistical and systematic uncertainties. We project the expected sensitivities of each search method for 10 and 15 years of LAT data taking. In particular, we find that the sensitivity of searches targeting dwarf galaxies, which provide the best limits currently, will improve faster than the square root of observing time. Current LAT limits for dwarf galaxies using six years of data reach the thermal relic level for masses up to 120 GeV for the bb ̄ annihilation channel for reasonable dark matter density profiles. With projected discoveries of additional dwarfs, these limits could extend to about 250 GeV. With as much as 15 years of LAT data these searches would be sensitive to dark matter annihilations at the thermal relic cross section for masses to greater than 400 GeV (200 GeV) in the bb ̄(τ+τ−) annihilation channels.
Keywords: dark matter, gamma rays
Published in RUNG: 20.06.2016; Views: 4629; Downloads: 0
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114. Constraints on the Galactic Dark Matter signal from the Fermi-LAT measurement of the diffuse gamma-ray emissionGabrijela Zaharijas, 2012, published scientific conference contribution Abstract: We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi Large Area Telescope with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We set both, conservative dark matter limits requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission and limits derived based on modeling the foreground astrophysical diffuse emission. Uncertainties in several parameters which characterize conventional astrophysical emission are taken into account using a profile likelihood formalism. The resulting limits impact the range of particle masses over which dark matter thermal production in the early Universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as annihilation of dark matter.
Keywords: gamma rays, Galactic diffuse emission, dark matter serach
Published in RUNG: 03.05.2016; Views: 4398; Downloads: 0
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117. Galactic Dark Matter signal and the Fermi-LAT measurement of the diffuse gamma-ray emissionGabrijela Zaharijas, published scientific conference contribution Abstract: We study diffuse gamma-ray emission at intermediate Galactic latitudes measured by the Fermi LAT with the aim of searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We present and improve upon conservative dark matter limits obtained with no modeling of the foreground astrophysical diffuse emission. We do so, by taking into account uncertainties in several parameters which characterize conventional astrophysical emission and using a profile likelihood formalism. The resulting limits impact the range of particle masses over which dark matter thermal production in the early Universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as annihilation of dark matter.
Keywords: Dark matter, high-energy gamma rays
Published in RUNG: 21.03.2016; Views: 4453; Downloads: 0
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118. Prospects On Testing Lorentz Invariance Violation With The Cherenkov Telescope ArrayM. K. Daniel, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Keywords: Cherenkov Telescope Array (CTA), Lorentz Invariance Violation (LIV), Very High Energy (VHE) gamma-rays, fundamental physics probes, Active Galactic Nuclei (AGN), Gamma Ray Bursts (GRBs), pulsars
Published in RUNG: 14.03.2016; Views: 4584; Downloads: 221
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119. Prospects for Gamma-Ray Bursts detection by the Cherenkov Telescope ArrayE. Bissaldi, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Keywords: Cherenkov Telescope Array, Gamma-Ray Bursts, very-high energy (VHE) gamma-ray emission, observational strategy optimization
Published in RUNG: 11.03.2016; Views: 4893; Downloads: 212
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120. Redshift measurement of Fermi Blazars for the Cherenkov Telescope ArrayP. Goldoni, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, 2015, published scientific conference contribution Keywords: Cherenkov Telescope Array, very-high energy gamma-ray emission, active galactic nuclei, blazars, blazar redshift measurements, observational strategy optimization
Published in RUNG: 11.03.2016; Views: 4969; Downloads: 235
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