skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: FERMI GAMMA-RAY HAZE VIA DARK MATTER AND MILLISECOND PULSARS

Abstract

We study possible astrophysical and dark matter (DM) explanations for the Fermi gamma-ray haze in the Milky Way halo. As representatives of various DM models, we consider DM particles annihilating into W {sup +} W {sup -}, b b-bar , and e {sup +} e {sup -}. In the first two cases, the prompt gamma-ray emission from DM annihilations is significant or even dominant at E > 10 GeV, while inverse Compton scattering (ICS) from annihilating DM products is insignificant. For the e {sup +} e {sup -} annihilation mode, we require a boost factor of order 100 to get significant contribution to the gamma-ray haze from ICS photons. Possible astrophysical sources of high-energy particles at high latitudes include type Ia supernovae (SNe) and millisecond pulsars (MSPs). Based on our current understanding of Ia SNe rates, they do not contribute significantly to gamma-ray flux in the halo of the Milky Way. As the MSP population in the stellar halo of the Milky Way is not well constrained, MSPs may be a viable source of gamma-rays at high latitudes provided that there are {approx}(2-6) x 10{sup 4} of MSPs in the Milky Way stellar halo. In this case, pulsed gamma-ray emissionmore » from MSPs can contribute to gamma rays around few GeV, while the ICS photons from MSP electrons and positrons may be significant at all energies in the gamma-ray haze. The plausibility of such a population of MSPs is discussed. Consistency with the Wilkinson Microwave Anisotropy Probe (WMAP) microwave haze requires that either a significant fraction of MSP spin-down energy is converted into e {sup +} e {sup -} flux or the DM annihilates predominantly into leptons with a boost factor of order 100.« less

Authors:
;
Publication Date:
OSTI Identifier:
21464581
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 722; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/722/2/1939; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANISOTROPY; ANNIHILATION; ASTROPHYSICS; COMPTON EFFECT; COSMIC RADIATION; GAMMA RADIATION; GEV RANGE 10-100; MILKY WAY; NONLUMINOUS MATTER; PHOTON EMISSION; PHOTONS; POSITRONS; PULSARS; SUPERNOVAE; ANTILEPTONS; ANTIMATTER; ANTIPARTICLES; BASIC INTERACTIONS; BINARY STARS; BOSONS; COSMIC RADIO SOURCES; ELASTIC SCATTERING; ELECTROMAGNETIC INTERACTIONS; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; EMISSION; ENERGY RANGE; ERUPTIVE VARIABLE STARS; FERMIONS; GALAXIES; GEV RANGE; INTERACTIONS; IONIZING RADIATIONS; LEPTONS; MASSLESS PARTICLES; MATTER; PARTICLE INTERACTIONS; PHYSICS; RADIATIONS; SCATTERING; STARS; VARIABLE STARS

Citation Formats

Malyshev, Dmitry, Cholis, Ilias, and Gelfand, Joseph D., E-mail: dm137@nyu.ed, E-mail: ijc219@nyu.ed, E-mail: jg168@astro.physics.nyu.ed. FERMI GAMMA-RAY HAZE VIA DARK MATTER AND MILLISECOND PULSARS. United States: N. p., 2010. Web. doi:10.1088/0004-637X/722/2/1939.
Malyshev, Dmitry, Cholis, Ilias, & Gelfand, Joseph D., E-mail: dm137@nyu.ed, E-mail: ijc219@nyu.ed, E-mail: jg168@astro.physics.nyu.ed. FERMI GAMMA-RAY HAZE VIA DARK MATTER AND MILLISECOND PULSARS. United States. doi:10.1088/0004-637X/722/2/1939.
Malyshev, Dmitry, Cholis, Ilias, and Gelfand, Joseph D., E-mail: dm137@nyu.ed, E-mail: ijc219@nyu.ed, E-mail: jg168@astro.physics.nyu.ed. Wed . "FERMI GAMMA-RAY HAZE VIA DARK MATTER AND MILLISECOND PULSARS". United States. doi:10.1088/0004-637X/722/2/1939.
@article{osti_21464581,
title = {FERMI GAMMA-RAY HAZE VIA DARK MATTER AND MILLISECOND PULSARS},
author = {Malyshev, Dmitry and Cholis, Ilias and Gelfand, Joseph D., E-mail: dm137@nyu.ed, E-mail: ijc219@nyu.ed, E-mail: jg168@astro.physics.nyu.ed},
abstractNote = {We study possible astrophysical and dark matter (DM) explanations for the Fermi gamma-ray haze in the Milky Way halo. As representatives of various DM models, we consider DM particles annihilating into W {sup +} W {sup -}, b b-bar , and e {sup +} e {sup -}. In the first two cases, the prompt gamma-ray emission from DM annihilations is significant or even dominant at E > 10 GeV, while inverse Compton scattering (ICS) from annihilating DM products is insignificant. For the e {sup +} e {sup -} annihilation mode, we require a boost factor of order 100 to get significant contribution to the gamma-ray haze from ICS photons. Possible astrophysical sources of high-energy particles at high latitudes include type Ia supernovae (SNe) and millisecond pulsars (MSPs). Based on our current understanding of Ia SNe rates, they do not contribute significantly to gamma-ray flux in the halo of the Milky Way. As the MSP population in the stellar halo of the Milky Way is not well constrained, MSPs may be a viable source of gamma-rays at high latitudes provided that there are {approx}(2-6) x 10{sup 4} of MSPs in the Milky Way stellar halo. In this case, pulsed gamma-ray emission from MSPs can contribute to gamma rays around few GeV, while the ICS photons from MSP electrons and positrons may be significant at all energies in the gamma-ray haze. The plausibility of such a population of MSPs is discussed. Consistency with the Wilkinson Microwave Anisotropy Probe (WMAP) microwave haze requires that either a significant fraction of MSP spin-down energy is converted into e {sup +} e {sup -} flux or the DM annihilates predominantly into leptons with a boost factor of order 100.},
doi = {10.1088/0004-637X/722/2/1939},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 722,
place = {United States},
year = {2010},
month = {10}
}