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Title: DARK MATTER SEARCH USING CHANDRA OBSERVATIONS OF WILLMAN 1 AND A SPECTRAL FEATURE CONSISTENT WITH A DECAY LINE OF A 5 keV STERILE NEUTRINO

Abstract

We report the results of a search for an emission line from radiatively decaying dark matter in the Chandra X-ray Observatory spectrum of the ultra-faint dwarf spheroidal galaxy Willman 1. 99% confidence line flux upper limits over the 0.4-7 keV Chandra bandpass are derived and mapped to an allowed region in the sterile neutrino mass-mixing angle plane that is consistent with recent constraints from Suzaku X-ray Observatory and Chandra observations of the Ursa Minor and Draco dwarf spheroidals. A significant excess to the continuum, detected by fitting the particle-background-subtracted source spectrum, indicates the presence of a narrow emission feature with energy 2.51 {+-} 0.07(0.11) keV and flux [3.53 {+-} 1.95(2.77)] x 10{sup -6} photons cm{sup -2} s{sup -1} at 68% (90%) confidence. Interpreting this as an emission line from sterile neutrino radiative decay, we derive the corresponding allowed range of sterile neutrino mass and mixing angle using two approaches. The first assumes that dark matter is solely composed of sterile neutrinos, and the second relaxes that requirement. The feature is consistent with the sterile neutrino mass of 5.0 {+-} 0.2 keV and a mixing angle in a narrow range for which neutrino oscillations can produce all of the dark mattermore » and for which sterile neutrino emission from the cooling neutron stars can explain pulsar kicks, thus bolstering both the statistical and physical significance of our measurement.« less

Authors:
 [1];  [2]
  1. Department of Astronomy, University of Maryland, College Park, MD (United States)
  2. Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1547 (United States)
Publication Date:
OSTI Identifier:
21448900
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 714; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/714/1/652; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; KEV RANGE 01-10; NEUTRINO OSCILLATION; NEUTRINOS; NEUTRON STARS; NONLUMINOUS MATTER; PHOTONS; PULSARS; RADIATIVE DECAY; WEINBERG ANGLE; X-RAY GALAXIES; BOSONS; COSMIC RADIO SOURCES; COSMIC RAY SOURCES; COSMIC X-RAY SOURCES; DECAY; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; GALAXIES; KEV RANGE; LEPTONS; MASSLESS PARTICLES; MATTER; PARTICLE DECAY; STARS

Citation Formats

Loewenstein, Michael, and Kusenko, Alexander. DARK MATTER SEARCH USING CHANDRA OBSERVATIONS OF WILLMAN 1 AND A SPECTRAL FEATURE CONSISTENT WITH A DECAY LINE OF A 5 keV STERILE NEUTRINO. United States: N. p., 2010. Web. doi:10.1088/0004-637X/714/1/652.
Loewenstein, Michael, & Kusenko, Alexander. DARK MATTER SEARCH USING CHANDRA OBSERVATIONS OF WILLMAN 1 AND A SPECTRAL FEATURE CONSISTENT WITH A DECAY LINE OF A 5 keV STERILE NEUTRINO. United States. https://doi.org/10.1088/0004-637X/714/1/652
Loewenstein, Michael, and Kusenko, Alexander. Sat . "DARK MATTER SEARCH USING CHANDRA OBSERVATIONS OF WILLMAN 1 AND A SPECTRAL FEATURE CONSISTENT WITH A DECAY LINE OF A 5 keV STERILE NEUTRINO". United States. https://doi.org/10.1088/0004-637X/714/1/652.
@article{osti_21448900,
title = {DARK MATTER SEARCH USING CHANDRA OBSERVATIONS OF WILLMAN 1 AND A SPECTRAL FEATURE CONSISTENT WITH A DECAY LINE OF A 5 keV STERILE NEUTRINO},
author = {Loewenstein, Michael and Kusenko, Alexander},
abstractNote = {We report the results of a search for an emission line from radiatively decaying dark matter in the Chandra X-ray Observatory spectrum of the ultra-faint dwarf spheroidal galaxy Willman 1. 99% confidence line flux upper limits over the 0.4-7 keV Chandra bandpass are derived and mapped to an allowed region in the sterile neutrino mass-mixing angle plane that is consistent with recent constraints from Suzaku X-ray Observatory and Chandra observations of the Ursa Minor and Draco dwarf spheroidals. A significant excess to the continuum, detected by fitting the particle-background-subtracted source spectrum, indicates the presence of a narrow emission feature with energy 2.51 {+-} 0.07(0.11) keV and flux [3.53 {+-} 1.95(2.77)] x 10{sup -6} photons cm{sup -2} s{sup -1} at 68% (90%) confidence. Interpreting this as an emission line from sterile neutrino radiative decay, we derive the corresponding allowed range of sterile neutrino mass and mixing angle using two approaches. The first assumes that dark matter is solely composed of sterile neutrinos, and the second relaxes that requirement. The feature is consistent with the sterile neutrino mass of 5.0 {+-} 0.2 keV and a mixing angle in a narrow range for which neutrino oscillations can produce all of the dark matter and for which sterile neutrino emission from the cooling neutron stars can explain pulsar kicks, thus bolstering both the statistical and physical significance of our measurement.},
doi = {10.1088/0004-637X/714/1/652},
url = {https://www.osti.gov/biblio/21448900}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 714,
place = {United States},
year = {2010},
month = {5}
}