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Title: Low mass X-ray binaries in the Inner Galaxy: implications for millisecond pulsars and the GeV excess

Journal Article · · Journal of Cosmology and Astroparticle Physics
 [1];  [2];  [3];  [4]
  1. McGill University, Department of Physics, 3600 rue University, Montreal, QC, H3A 2T8 (Canada)
  2. University of Alberta, Department of Physics, CCIS 4-183, Edmonton, AB, T6G 2E1 (Canada)
  3. Fermi National Accelerator Laboratory, Center for Particle Astrophysics, Batavia, IL 60510 (United States)
  4. Ohio State University, Center for Cosmology and AstroParticle Physics (CCAPP), Columbus, OH 43210 (United States)

If millisecond pulsars (MSPs) are responsible for the excess gamma-ray emission observed from the region surrounding the Galactic Center, the same region should also contain a large population of low-mass X-ray binaries (LMXBs). In this study, we compile and utilize a sizable catalog of LMXBs observed in the the Milky Way's globular cluster system and in the Inner Galaxy, as well as the gamma-ray emission observed from globular clusters, to estimate the flux of gamma rays predicted from MSPs in the Inner Galaxy. From this comparison, we conclude that only up to ∼ 4-23% of the observed gamma-ray excess is likely to originate from MSPs. This result is consistent with, and more robust than, previous estimates which utilized smaller samples of both globular clusters and LMXBs. If MSPs had been responsible for the entirety of the observed excess, INTEGRAL should have detected ∼ 10{sup 3} LMXBs from within a 10{sup o} radius around the Galactic Center, whereas only 42 LMXBs (and 46 additional LMXB candidates) have been observed.

OSTI ID:
22679890
Journal Information:
Journal of Cosmology and Astroparticle Physics, Vol. 2017, Issue 05; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
Country of Publication:
United States
Language:
English