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J -factors for self-interacting dark matter in 20 dwarf spheroidal galaxies

Bergström, Sebastian ; Catena, Riccardo ; Chiappo, Andrea ; Conrad, Jan ; Eurenius, Björn ; Eriksson, Magdalena ; Högberg, Michael ; Larsson, Susanna ; Olsson, Emelie and Unger, Andreas , et al. (2018) In Physical Review D 98(4).
Abstract

Dwarf spheroidal galaxies are among the most promising targets for indirect dark matter (DM) searches in γ rays. The γ-ray flux from DM annihilation in a dwarf spheroidal galaxy is proportional to the J-factor of the source. The J-factor of a dwarf spheroidal galaxy is the line-of-sight integral of the DM mass density squared times σannvrel (σannvrel)0, where σannvrel is the DM annihilation cross-section times relative velocity vrel=|vrel|, angle brackets denote average over vrel, and (σannvrel)0 is the vrel-independent part of σannvrel. If σannvrel is constant in vrel, J-factors only depend on the DM space distribution in the source. However, if σannvrel varies with vrel, as in the presence of DM self-interactions, J-factors also... (More)

Dwarf spheroidal galaxies are among the most promising targets for indirect dark matter (DM) searches in γ rays. The γ-ray flux from DM annihilation in a dwarf spheroidal galaxy is proportional to the J-factor of the source. The J-factor of a dwarf spheroidal galaxy is the line-of-sight integral of the DM mass density squared times σannvrel (σannvrel)0, where σannvrel is the DM annihilation cross-section times relative velocity vrel=|vrel|, angle brackets denote average over vrel, and (σannvrel)0 is the vrel-independent part of σannvrel. If σannvrel is constant in vrel, J-factors only depend on the DM space distribution in the source. However, if σannvrel varies with vrel, as in the presence of DM self-interactions, J-factors also depend on the DM velocity distribution, and on the strength and range of the DM self-interaction. Models for self-interacting DM are increasingly important in the study of the small scale clustering of DM, and are compatible with current astronomical and cosmological observations. Here we derive the J-factor of 20 dwarf spheroidal galaxies from stellar kinematic data under the assumption of Yukawa DM self-interactions. J-factors are derived through a profile likelihood approach, assuming either Navarro-Frenk-White (NFW) or cored DM profiles. We also compare our results with J-factors derived assuming the same velocity for all DM particles in the target galaxy. We find that this common approximation overestimates the J-factors by up to 1 order of magnitude. J-factors for a sample of DM particle masses and self-interaction coupling constants, as well as for NFW and cored density profiles, are provided electronically, ready to be used in other projects.

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type
Contribution to journal
publication status
published
subject
in
Physical Review D
volume
98
issue
4
article number
043017
publisher
American Physical Society
external identifiers
  • scopus:85052628243
ISSN
2470-0010
DOI
10.1103/PhysRevD.98.043017
language
English
LU publication?
no
id
5934f679-fce3-4fcb-a156-65da4d338857
date added to LUP
2022-04-04 11:27:04
date last changed
2022-04-20 01:10:09
@article{5934f679-fce3-4fcb-a156-65da4d338857,
  abstract     = {{<p>Dwarf spheroidal galaxies are among the most promising targets for indirect dark matter (DM) searches in γ rays. The γ-ray flux from DM annihilation in a dwarf spheroidal galaxy is proportional to the J-factor of the source. The J-factor of a dwarf spheroidal galaxy is the line-of-sight integral of the DM mass density squared times σannvrel (σannvrel)0, where σannvrel is the DM annihilation cross-section times relative velocity vrel=|vrel|, angle brackets denote average over vrel, and (σannvrel)0 is the vrel-independent part of σannvrel. If σannvrel is constant in vrel, J-factors only depend on the DM space distribution in the source. However, if σannvrel varies with vrel, as in the presence of DM self-interactions, J-factors also depend on the DM velocity distribution, and on the strength and range of the DM self-interaction. Models for self-interacting DM are increasingly important in the study of the small scale clustering of DM, and are compatible with current astronomical and cosmological observations. Here we derive the J-factor of 20 dwarf spheroidal galaxies from stellar kinematic data under the assumption of Yukawa DM self-interactions. J-factors are derived through a profile likelihood approach, assuming either Navarro-Frenk-White (NFW) or cored DM profiles. We also compare our results with J-factors derived assuming the same velocity for all DM particles in the target galaxy. We find that this common approximation overestimates the J-factors by up to 1 order of magnitude. J-factors for a sample of DM particle masses and self-interaction coupling constants, as well as for NFW and cored density profiles, are provided electronically, ready to be used in other projects.</p>}},
  author       = {{Bergström, Sebastian and Catena, Riccardo and Chiappo, Andrea and Conrad, Jan and Eurenius, Björn and Eriksson, Magdalena and Högberg, Michael and Larsson, Susanna and Olsson, Emelie and Unger, Andreas and Wadman, Rikard}},
  issn         = {{2470-0010}},
  language     = {{eng}},
  number       = {{4}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review D}},
  title        = {{J -factors for self-interacting dark matter in 20 dwarf spheroidal galaxies}},
  url          = {{http://dx.doi.org/10.1103/PhysRevD.98.043017}},
  doi          = {{10.1103/PhysRevD.98.043017}},
  volume       = {{98}},
  year         = {{2018}},
}