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Dark matter implications of the WMAP-Planck Haze

Egorov, Andrey E. and Gaskins, Jennifer M. and Pierpaoli, Elena and Pietrobon, Davide (2016) Dark matter implications of the WMAP-Planck Haze. Journal of Cosmology and Astroparticle Physics, 2016 (3). Art. No. 060. ISSN 1475-7516. doi:10.1088/1475-7516/2016/03/060.

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Gamma rays and microwave observations of the Galactic Center and surrounding areas indicate the presence of anomalous emission, whose origin remains ambiguous. The possibility of dark matter annihilation explaining both signals through prompt emission at gamma rays and secondary emission at microwave frequencies from interactions of high-energy electrons produced in annihilation with the Galactic magnetic fields has attracted much interest in recent years. We investigate the dark matter interpretation of the Galactic Center gamma-ray excess by searching for the associated synchrotron emission in the WMAP and Planck microwave data. Considering various magnetic field and cosmic-ray propagation models, we predict the synchrotron emission due to dark matter annihilation in our Galaxy, and compare it with the WMAP and Planck data at 23–70 GHz. In addition to standard microwave foregrounds, we separately model the microwave counterpart to the Fermi Bubbles and the signal due to dark matter annihilation, and use component separation techniques to extract the signal associated with each template from the total emission. We confirm the presence of the Haze at the level of ≈7% of the total sky intensity at 23 GHz in our chosen region of interest, with a harder spectrum (I ~ ν^(−0.8)) than the synchrotron from regular cosmic-ray electrons. The data do not show a strong preference towards fitting the Haze by either the Bubbles or dark matter emission only. Inclusion of both components provides a better fit with a dark matter contribution to the Haze emission of ≈20% at 23 GHz, however, due to significant uncertainties in foreground modeling, we do not consider this a clear detection of a dark matter signal. We set robust upper limits on the annihilation cross section by ignoring foregrounds, and also report best-fit dark matter annihilation parameters obtained from a complete template analysis. We conclude that the WMAP and Planck data are consistent with a dark matter interpretation of the gamma-ray excess.

Item Type:Article
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URLURL TypeDescription Paper
Pierpaoli, Elena0000-0002-7957-8993
Additional Information:© 2016 IOP Publishing Ltd and Sissa Medialab srl. Received 14 October 2015. Accepted 24 February 2016. Published 31 March 2016. It is a pleasure to thank Loris Colombo for extensive help with the CMB emission modeling and Planck data interpretation, Andrew Strong for valuable consultations on GALPROP, and Antony Lewis for assistance with GetDist. AE and EP acknowledge the support of NASA grant NNX13AP25G and the usage of the computers at the USC High Performance Computing Center. JG acknowledges support from NASA through Einstein Postdoctoral Fellowship grant PF1-120089 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060, and from a Marie Curie International Incoming Fellowship in the project "IGMultiWave (PIIF-GA-2013-628997) - ADD". We also acknowledge the use of the LevelScheme package for Mathematica developed by Mark Caprio [77], it greatly helped in preparation of high-quality plots. In addition, this research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Some of the results in this paper have been derived using the HEALPix [59] package.
Funding AgencyGrant Number
NASA Einstein Postdoctoral FellowshipPF1-120089
Marie Curie FellowshipPIIF-GA-2013-628997
Department of Energy (DOE)DE-AC02-05CH11231
Subject Keywords:dark matter theory, cosmic ray theory, absorption and radiation processes
Issue or Number:3
Record Number:CaltechAUTHORS:20160602-115053898
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Official Citation:Andrey E. Egorov et al JCAP03(2016)060
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:67573
Deposited By: Tony Diaz
Deposited On:02 Jun 2016 19:07
Last Modified:11 Nov 2021 03:51

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