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Title: Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and

Abstract

We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky {gamma}-ray survey in the 20 MeV to >300 GeV energy range, provides a new opportunity to test particle dark matter models through the expected {gamma}-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant {gamma}-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the {gamma}-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10{sup -9} photons cm{sup -2}s{sup -1}. Using recent stellar kinematic data, the {gamma}-ray flux limits are combined with improved determinations of the dark matter density profile in 8 of the 14 candidate dwarfs to place limits on the pair annihilation cross-section ofWIMPs inmore » several widely studied extensions of the standard model, including its supersymmetric extension and other models that received recent attention. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g. in models where supersymmetry breaking occurs via anomaly mediation. The {gamma}-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA e{sup +}e{sup -} data, including low-mass wino-like neutralinos and models with TeV masses pair-annihilating into muon-antimuon pairs.« less

Authors:
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Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
979949
Report Number(s):
SLAC-PUB-13949
arXiv:1001.4531; TRN: US1003416
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Astrophys.J.712:147-158,2010
Additional Journal Information:
Journal Name: Astrophys.J.712:147-158,2010
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANNIHILATION; ENERGY RANGE; GALAXIES; MILKY WAY; NONLUMINOUS MATTER; PHOTONS; SPECTRA; STANDARD MODEL; SUPERSYMMETRY; TARGETS; TELESCOPES; TEST PARTICLES; Astrophysics, Phenomenology-HEP,ASTRO

Citation Formats

Abdo, A A, Ackermann, M, Ajello, M, Atwood, W B, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Bloom, E D, Bonamente, E, Borgland, A W, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, T H, Buson, S, Caliandro, G A, and /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC /UC, Santa Cruz /INFN, Pisa /DAPNIA, Saclay /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /IASF, Milan /George Mason U. /NASA, Goddard. Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and. United States: N. p., 2010. Web. doi:10.1088/0004-637X/712/1/147.
Abdo, A A, Ackermann, M, Ajello, M, Atwood, W B, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Bloom, E D, Bonamente, E, Borgland, A W, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, T H, Buson, S, Caliandro, G A, & /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC /UC, Santa Cruz /INFN, Pisa /DAPNIA, Saclay /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /IASF, Milan /George Mason U. /NASA, Goddard. Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and. United States. https://doi.org/10.1088/0004-637X/712/1/147
Abdo, A A, Ackermann, M, Ajello, M, Atwood, W B, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Bloom, E D, Bonamente, E, Borgland, A W, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, T H, Buson, S, Caliandro, G A, and /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC /UC, Santa Cruz /INFN, Pisa /DAPNIA, Saclay /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /IASF, Milan /George Mason U. /NASA, Goddard. 2010. "Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and". United States. https://doi.org/10.1088/0004-637X/712/1/147. https://www.osti.gov/servlets/purl/979949.
@article{osti_979949,
title = {Observations of MilkyWay Dwarf Spheroidal galaxies with the Fermi-LAT detector and},
author = {Abdo, A A and Ackermann, M and Ajello, M and Atwood, W B and Baldini, L and Ballet, J and Barbiellini, G and Bastieri, D and Bechtol, K and Bellazzini, R and Berenji, B and Bloom, E D and Bonamente, E and Borgland, A W and Bregeon, J and Brez, A and Brigida, M and Bruel, P and Burnett, T H and Buson, S and Caliandro, G A and /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /SLAC /UC, Santa Cruz /INFN, Pisa /DAPNIA, Saclay /INFN, Trieste /Trieste U. /INFN, Padua /Padua U. /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /Washington U., Seattle /IASF, Milan /George Mason U. /NASA, Goddard},
abstractNote = {We report on the observations of 14 dwarf spheroidal galaxies with the Fermi Gamma-Ray Space Telescope taken during the first 11 months of survey mode operations. The Fermi telescope, which is conducting an all-sky {gamma}-ray survey in the 20 MeV to >300 GeV energy range, provides a new opportunity to test particle dark matter models through the expected {gamma}-ray emission produced by pair annihilation of weakly interacting massive particles (WIMPs). Local Group dwarf spheroidal galaxies, the largest galactic substructures predicted by the cold dark matter scenario, are attractive targets for such indirect searches for dark matter because they are nearby and among the most extreme dark matter dominated environments. No significant {gamma}-ray emission was detected above 100 MeV from the candidate dwarf galaxies. We determine upper limits to the {gamma}-ray flux assuming both power-law spectra and representative spectra from WIMP annihilation. The resulting integral flux above 100 MeV is constrained to be at a level below around 10{sup -9} photons cm{sup -2}s{sup -1}. Using recent stellar kinematic data, the {gamma}-ray flux limits are combined with improved determinations of the dark matter density profile in 8 of the 14 candidate dwarfs to place limits on the pair annihilation cross-section ofWIMPs in several widely studied extensions of the standard model, including its supersymmetric extension and other models that received recent attention. With the present data, we are able to rule out large parts of the parameter space where the thermal relic density is below the observed cosmological dark matter density and WIMPs (neutralinos here) are dominantly produced non-thermally, e.g. in models where supersymmetry breaking occurs via anomaly mediation. The {gamma}-ray limits presented here also constrain some WIMP models proposed to explain the Fermi and PAMELA e{sup +}e{sup -} data, including low-mass wino-like neutralinos and models with TeV masses pair-annihilating into muon-antimuon pairs.},
doi = {10.1088/0004-637X/712/1/147},
url = {https://www.osti.gov/biblio/979949}, journal = {Astrophys.J.712:147-158,2010},
number = ,
volume = ,
place = {United States},
year = {Wed May 26 00:00:00 EDT 2010},
month = {Wed May 26 00:00:00 EDT 2010}
}