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Title: Fermi variability study of the candidate pulsar binary 2FGL J0523.3–2530

The Fermi source 2FGL J0523.3–2530 has recently been identified as a candidate millisecond pulsar binary with an orbital period of 16.5 hr. We have carried out detailed studies of the source's emission properties by analyzing data taken with the Fermi Large Area Telescope in the 0.2-300 GeV energy range. Long-term, yearly variability from the source has been found, with a factor of four flux variations in 1-300 GeV. From spectral analysis, we find an extra spectral component at 2-3 GeV that causes the source brightening. While no orbital modulations have been found from the Fermi data over the whole period of 2008-2014, orbital modulation in the source's >2 GeV emission is detected during the last 1.5 yr of the Fermi observation. Our results support the millisecond pulsar binary nature of 2FGL J0523.3–2530. Multi-wavelength observations of the source are warranted in order to find any correlated flux variations and thus help determine the origin of the long-term variability, which currently is not understood.
Authors:
;  [1] ;  [2]
  1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)
  2. Department of Physics, The University of Hong Kong, Pokfulam Road (Hong Kong)
Publication Date:
OSTI Identifier:
22370274
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BINARY STARS; EMISSION; GEV RANGE; MASS; NEUTRONS; PULSARS; TELESCOPES; WAVELENGTHS