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Title: SWIFT OBSERVATIONS OF 1FGL J1018.6–5856

We report on X-ray properties of the gamma-ray binary 1FGL J1018.6–5856 using observations obtained with the Swift X-ray telescope. Using 54 observations made between MJD 55575 and 55984, we find that the X-ray flux is modulated at a period of 16.57 ± 0.11 days, which is consistent with previous reports based on gamma-ray data. We find that the X-ray maximum at phase 0 previously reported may not be a persistent feature of the source: the dramatic increases at phase 0 were only detected for ∼100 days and were not detected thereafter. Rather, the persistent sinusoidal maximum seems to be at phase 0.3-0.4, and is misaligned with the gamma-ray (GeV) peak. We also find evidence that the source's X-ray flux is correlated with the spectral hardness in the 0.5-10 keV band. Such a correlation has also been reported in the gamma-ray binaries LS 5039 and LS I +61°303 and can help us to understand the X-ray emission mechanisms of the sources.
Authors:
; ;  [1] ;  [2]
  1. Department of Physics, McGill University, Rutherford Physics Building, Montreal, QC H3A 2T8 (Canada)
  2. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22270875
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 775; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; BINARY STARS; CORRELATIONS; COSMIC X-RAY SOURCES; GAMMA ASTRONOMY; GAMMA RADIATION; GEV RANGE; KEV RANGE; TELESCOPES; X RADIATION; X-RAY SPECTRA