BROADBAND X-RAY PROPERTIES OF THE GAMMA-RAY BINARY 1FGL J1018.6–5856
- Department of Physics/KIPAC, Stanford University, Stanford, CA 94305-4060 (United States)
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)
- Inter University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India)
- Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States)
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark)
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States)
- Department of Physics, McGill University, Rutherford Physics Building, 3600 University Street, Montreal, QC H3A 2T8 (Canada)
- Istituto Nazionale di Astrofisica, INAFIAPS, via del Fosso del Cavaliere, I-00133 Roma (Italy)
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
- Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
We report on NuSTAR, XMM-Newton, and Swift observations of the gamma-ray binary 1FGL J1018.6–5856. We measure the orbital period to be 16.544 ± 0.008 days using Swift data spanning 1900 days. The orbital period is different from the 2011 gamma-ray measurement which was used in the previous X-ray study of An et al. using ∼400 days of Swift data, but is consistent with a new gamma-ray solution reported in 2014. The light curve folded on the new period is qualitatively similar to that reported previously, having a spike at phase 0 and broad sinusoidal modulation. The X-ray flux enhancement at phase 0 occurs more regularly in time than was previously suggested. A spiky structure at this phase seems to be a persistent feature, although there is some variability. Furthermore, we find that the source flux clearly correlates with the spectral hardness throughout all orbital phases, and that the broadband X-ray spectra measured with NuSTAR, XMM-Newton, and Swift are well fit with an unbroken power-law model. This spectrum suggests that the system may not be accretion-powered.
- OSTI ID:
- 22522274
- Journal Information:
- Astrophysical Journal, Vol. 806, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Periodic Emission from the Gamma-Ray Binary 1FGL J1018.6-5856
INTEGRAL OBSERVATIONS OF THE {gamma}-RAY BINARY 1FGL J1018.6-5856