Angular power spectrum of the diffuse gamma-ray emission as measured by the Fermi Large Area Telescope and constraints on its dark matter interpretation
Abstract
The isotropic gamma-ray background arises from the contribution of unresolved sources, including members of confirmed source classes and proposed gamma-ray emitters such as the radiation induced by dark matter annihilation and decay. Clues about the properties of the contributing sources are imprinted in the anisotropy characteristics of the gamma-ray background. We use 81 months of Pass 7 Reprocessed data from the Fermi Large Area Telescope to perform a measurement of the anisotropy angular power spectrum of the gamma-ray background. We analyze energies between 0.5 and 500 GeV, extending the range considered in the previous measurement based on 22 months of data. We also compute, for the first time, the cross-correlation angular power spectrum between different energy bins. We find that the derived angular spectra are compatible with being Poissonian, i.e. constant in multipole. Moreover, the energy dependence of the anisotropy suggests that the signal is due to two populations of sources, contributing, respectively, below and above ∼2 GeV. Finally, using data from state-of-the-art numerical simulations to model the dark matter distribution, we constrain the contribution from dark matter annihilation and decay in Galactic and extra-Galactic structures to the measured anisotropy. These constraints are competitive with those that can be derived from the average intensity of the isotropic gamma-ray background.
Additional Information
© 2016 American Physical Society. Received 23 August 2016; published 9 December 2016. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States; the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Études Spatiales in France. We thank Dr. Shin'ichiro Ando for useful discussion and for providing us with the lower limits on the decay lifetime from Ref. [96]. We also thank Professor John F. Beacom for the valuable discussion during the last stages of the work. M. F. gratefully acknowledges support from the Netherlands Organization for Scientific Research (NWO) through a Vidi grant (P. I.: Dr. Shin'ichiro Ando), from the the Leverhulme Trust and the project MultiDark CSD2009-00064. The Dark Cosmology Centre is funded by the Danish National Research Foundation (DNRF). J. Z. is supported by the European Union (EU) under a Marie Curie International Incoming Fellowship, Contract No. PIIF-GA-2013-62772. J. G. acknowledges support from National Aeronautics and Space Adminstration (NASA) through Einstein Postdoctoral Fellowship Grant No. PF1-120089 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under Contract No. NAS8-03060, and from a Marie Curie International Incoming Fellowship, Contract No. PIIF-GA-2013-628997. G. A. G. V. is supported by Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) FONDECYT/POSTODOCTORADO/3160153, the Spanish MINECO's Consolider Ingenio 2010 Programme under Grant No. MultiDark CSD2009-00064 and also partly by Ministerio de Economia (MINECO) under Grant No. FPA2012-34694. M. A. S. C. is a Wenner-Gren Fellow and acknowledges the support of the Wenner-Gren Foundations to develop his research. E. K. thanks J. U. Lange for useful discussion on the bias in CP due to binning presented in Sec. IV A. F. P. acknowledges support from the Spanish Ministerio de Competitividad y Innovacion (MICINNs) Consolider-Ingenio 2010 Programme under Grant No. MultiDark CSD2009-00064, MINECO Centro de Excelencia Severo Ochoa Programme under Grant No. SEV-2012-0249 and MINECO Grant No. AYA2014-60641-C2-1-P. F. Z. acknowledges the support of the NWO through a Veni grant.Attached Files
Published - PhysRevD.94.123005.pdf
Submitted - 1608.07289v1.pdf
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Additional details
- Eprint ID
- 72689
- Resolver ID
- CaltechAUTHORS:20161209-095519730
- NASA
- Department of Energy (DOE)
- Commissariat à l'Energie Atomique (CEA)
- Centre National de la Recherche Scientifique (CNRS)
- Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)
- Agenzia Spaziale Italiana (ASI)
- Istituto Nazionale di Fisica Nucleare (INFN)
- Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- High Energy Accelerator Research Organization (KEK)
- Japan Aerospace Exploration Agency (JAXA)
- Knut and Alice Wallenberg Foundation
- Swedish Research Council
- Swedish National Space Board
- Istituto Nazionale di Astrofisica (INAF)
- Centre National d'Études Spatiales (CNES)
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)
- Leverhulme Trust
- MultiDark CSD2009-00064
- Ministerio de Competitividad y Innovacion (MICINN)
- Danish National Research Foundation
- PIIF-GA-2013-62772
- Marie Curie Fellowship
- PF1-120089
- NASA Einstein Postdoctoral Fellowship
- NAS8-03060
- NASA
- PIIF-GA-2013-628997
- Marie Curie Fellowship
- 3160153
- Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)
- FPA2012-34694
- Ministerio de Economia (MINECO)
- Wenner-Gren Foundation
- SEV-2012-0249
- Centro de Excelencia Severo Ochoa Programme
- AYA2014-60641-C2-1-P
- Ministerio de Economia (MINECO)
- Created
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2016-12-09Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field