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Title: Dark matter implications of the WMAP-Planck Haze

Abstract

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{sup −0.8}) than the synchrotron from regularmore » 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.« less

Authors:
;  [1];  [2];  [3]
  1. University of Southern California, 3620 McClintock Ave., SGM 408, Los Angeles, CA 90089 (United States)
  2. California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States)
  3. University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Rd, Berkeley CA 94720 (United States)
Publication Date:
OSTI Identifier:
22524906
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2016; Journal Issue: 03; 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; BUBBLES; COMPARATIVE EVALUATIONS; COSMIC PHOTONS; COSMIC RAY PROPAGATION; CROSS SECTIONS; DETECTION; GALAXY NUCLEI; GAMMA RADIATION; GHZ RANGE; MAGNETIC FIELDS; MICROWAVE RADIATION; MILKY WAY; NONLUMINOUS MATTER; PHOTON EMISSION; SECONDARY EMISSION

Citation Formats

Egorov, Andrey E., Pierpaoli, Elena, Gaskins, Jennifer M., and Pietrobon, Davide. Dark matter implications of the WMAP-Planck Haze. United States: N. p., 2016. Web. doi:10.1088/1475-7516/2016/03/060.
Egorov, Andrey E., Pierpaoli, Elena, Gaskins, Jennifer M., & Pietrobon, Davide. Dark matter implications of the WMAP-Planck Haze. United States. doi:10.1088/1475-7516/2016/03/060.
Egorov, Andrey E., Pierpaoli, Elena, Gaskins, Jennifer M., and Pietrobon, Davide. Tue . "Dark matter implications of the WMAP-Planck Haze". United States. doi:10.1088/1475-7516/2016/03/060.
@article{osti_22524906,
title = {Dark matter implications of the WMAP-Planck Haze},
author = {Egorov, Andrey E. and Pierpaoli, Elena and Gaskins, Jennifer M. and Pietrobon, Davide},
abstractNote = {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{sup −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.},
doi = {10.1088/1475-7516/2016/03/060},
journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 03,
volume = 2016,
place = {United States},
year = {2016},
month = {3}
}