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Title: Fermi LAT search for internal bremsstrahlung signatures from dark matter annihilation

Abstract

A commonly encountered obstacle in indirect searches for galactic dark matter is how to disentangle possible signals from astrophysical backgrounds. Given that such signals are most likely subdominant, the search for pronounced spectral features plays a key role for indirect detection experiments; monochromatic gamma-ray lines or similar features related to internal bremsstrahlung, in particular, provide smoking gun signatures. We perform a dedicated search for the latter in the data taken by the Fermi gamma-ray space telescope during its first 43 months. To this end, we use a new adaptive procedure to select optimal target regions that takes into account both standard and contracted dark matter profiles. The behaviour of our statistical method is tested by a subsampling analysis of the full sky data and found to reproduce the theoretical expectations very well. The limits on the dark matter annihilation cross-section that we derive are stronger than what can be obtained from the observation of dwarf galaxies and, at least for the model considered here, collider searches. While these limits are still not quite strong enough to probe annihilation rates expected for thermally produced dark matter, future prospects to do so are very good. In fact, we already find a weakmore » indication, with a significance of 3.1σ (4.3σ) when (not) taking into account the look-elsewhere effect, for an internal bremsstrahlung-like signal that would correspond to a dark matter mass of ∼150 GeV; the same signal is also well fitted by a gamma-ray line at around 130 GeV. Although this would be a fascinating possibility, we caution that a much more dedicated analysis and additional data will be necessary to rule out or confirm this option.« less

Authors:
 [1];  [2]; ;  [3];  [4]
  1. II. Institute for Theoretical Physics, University of Hamburg, Luruper Chaussee 149, DE-22761 Hamburg (Germany)
  2. National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing (China)
  3. Physik-Department T30d, Technische Universität München, James-Franck-Straße, 85748 Garching (Germany)
  4. Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 Munich (Germany)
Publication Date:
OSTI Identifier:
22280058
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2012; Journal Issue: 07; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANNIHILATION; ASTROPHYSICS; COSMOLOGY; CROSS SECTIONS; GALAXIES; GAMMA RADIATION; GEV RANGE; INTERNAL BREMSSTRAHLUNG; MONOCHROMATIC RADIATION; NONLUMINOUS MATTER; TELESCOPES

Citation Formats

Bringmann, Torsten, Huang, Xiaoyuan, Ibarra, Alejandro, Vogl, Stefan, and Weniger, Christoph, E-mail: torsten.bringmann@desy.de, E-mail: x_huang@bao.ac.cn, E-mail: ibarra@tum.de, E-mail: stefan.vogl@tum.de, E-mail: weniger@mppmu.mpg.de. Fermi LAT search for internal bremsstrahlung signatures from dark matter annihilation. United States: N. p., 2012. Web. doi:10.1088/1475-7516/2012/07/054.
Bringmann, Torsten, Huang, Xiaoyuan, Ibarra, Alejandro, Vogl, Stefan, & Weniger, Christoph, E-mail: torsten.bringmann@desy.de, E-mail: x_huang@bao.ac.cn, E-mail: ibarra@tum.de, E-mail: stefan.vogl@tum.de, E-mail: weniger@mppmu.mpg.de. Fermi LAT search for internal bremsstrahlung signatures from dark matter annihilation. United States. doi:10.1088/1475-7516/2012/07/054.
Bringmann, Torsten, Huang, Xiaoyuan, Ibarra, Alejandro, Vogl, Stefan, and Weniger, Christoph, E-mail: torsten.bringmann@desy.de, E-mail: x_huang@bao.ac.cn, E-mail: ibarra@tum.de, E-mail: stefan.vogl@tum.de, E-mail: weniger@mppmu.mpg.de. Sun . "Fermi LAT search for internal bremsstrahlung signatures from dark matter annihilation". United States. doi:10.1088/1475-7516/2012/07/054.
@article{osti_22280058,
title = {Fermi LAT search for internal bremsstrahlung signatures from dark matter annihilation},
author = {Bringmann, Torsten and Huang, Xiaoyuan and Ibarra, Alejandro and Vogl, Stefan and Weniger, Christoph, E-mail: torsten.bringmann@desy.de, E-mail: x_huang@bao.ac.cn, E-mail: ibarra@tum.de, E-mail: stefan.vogl@tum.de, E-mail: weniger@mppmu.mpg.de},
abstractNote = {A commonly encountered obstacle in indirect searches for galactic dark matter is how to disentangle possible signals from astrophysical backgrounds. Given that such signals are most likely subdominant, the search for pronounced spectral features plays a key role for indirect detection experiments; monochromatic gamma-ray lines or similar features related to internal bremsstrahlung, in particular, provide smoking gun signatures. We perform a dedicated search for the latter in the data taken by the Fermi gamma-ray space telescope during its first 43 months. To this end, we use a new adaptive procedure to select optimal target regions that takes into account both standard and contracted dark matter profiles. The behaviour of our statistical method is tested by a subsampling analysis of the full sky data and found to reproduce the theoretical expectations very well. The limits on the dark matter annihilation cross-section that we derive are stronger than what can be obtained from the observation of dwarf galaxies and, at least for the model considered here, collider searches. While these limits are still not quite strong enough to probe annihilation rates expected for thermally produced dark matter, future prospects to do so are very good. In fact, we already find a weak indication, with a significance of 3.1σ (4.3σ) when (not) taking into account the look-elsewhere effect, for an internal bremsstrahlung-like signal that would correspond to a dark matter mass of ∼150 GeV; the same signal is also well fitted by a gamma-ray line at around 130 GeV. Although this would be a fascinating possibility, we caution that a much more dedicated analysis and additional data will be necessary to rule out or confirm this option.},
doi = {10.1088/1475-7516/2012/07/054},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 07,
volume = 2012,
place = {United States},
year = {2012},
month = {7}
}