Observations of the Ultra-compact X-Ray Binary 4U 1543-624 in Outburst with NICER, INTEGRAL, Swift, and ATCA
Ludlam RM, Shishkovsky L, Bult PM, Miller JM, Zoghbi A, Strohmayer TE, Reynolds M, Natalucci L, Miller-Jones JCA, Jaisawal GK, Guillot S, Gendreau KC, Garcia J, Fiocchi M, Fabian AC, Chakrabarty D, Cackett EM, Bahramian A, Arzoumanian Z, Altamirano D (2019)
Publication Type: Journal article
Publication year: 2019
Journal
Book Volume: 883
Journal Issue: 1
Abstract
We report on X-ray and radio observations of the ultra-compact X-ray binary 4U 1543-624 taken in August 2017 during an enhanced accretion episode. We obtained Neutron Star Interior Composition Explorer (NICER) monitoring of the source over a similar to 10 day period during which target-of-opportunity observations were also conducted with Swift, INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), and the Australia Telescope Compact Array. Emission lines were measured in the NICER X-ray spectrum at similar to 0.64 keV and similar to 6.4 keV that correspond to O and Fe, respectively. By modeling these line components, we are able to track changes in the accretion disk throughout this period. The innermost accretion flow appears to move inwards from hundreds of gravitational radii (R-g = GM/c(2)) at the beginning of the outburst to <8.7 R-g at peak intensity. We do not detect the source in radio, but are able to place a 3 sigma upper limit on the flux density at 27 mu Jy beam(-1). Comparing the radio and X-ray luminosities, we find that the source lies significantly away from the range typical of black holes in the L-r-L-x plane, suggesting a neutron star primary. This adds to the evidence that neutron stars (NSs) do not follow a single track in the L-r-L-x plane, limiting its use in distinguishing between different classes of NSs based on radio and X-ray observations alone.
Authors with CRIS profile
Involved external institutions
National Aeronautics and Space Administration (NASA)
United States (USA) (US)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
University of Michigan
United States (USA) (US)
Technical University of Denmark / Danmarks Tekniske Universitet (DTU)
Denmark (DK)
Curtin University
Australia (AU)
University of Cambridge
United Kingdom (GB)
Wayne State University (WSU)
United States (USA) (US)
University of Southampton
United Kingdom (GB)
National Center for Scientific Research / Centre national de la recherche scientifique (CNRS)
France (FR)
Michigan State University
United States (USA) (US)
United States (USA) (US)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
Italy (IT)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
University of Michigan
United States (USA) (US)
Technical University of Denmark / Danmarks Tekniske Universitet (DTU)
Denmark (DK)
Curtin University
Australia (AU)
University of Cambridge
United Kingdom (GB)
Wayne State University (WSU)
United States (USA) (US)
University of Southampton
United Kingdom (GB)
National Center for Scientific Research / Centre national de la recherche scientifique (CNRS)
France (FR)
Michigan State University
United States (USA) (US)
How to cite
APA:
Ludlam, R.M., Shishkovsky, L., Bult, P.M., Miller, J.M., Zoghbi, A., Strohmayer, T.E.,... Altamirano, D. (2019). Observations of the Ultra-compact X-Ray Binary 4U 1543-624 in Outburst with NICER, INTEGRAL, Swift, and ATCA. Astrophysical Journal, 883(1). https://doi.org/10.3847/1538-4357/ab3806
MLA:
Ludlam, R. M., et al. "Observations of the Ultra-compact X-Ray Binary 4U 1543-624 in Outburst with NICER, INTEGRAL, Swift, and ATCA." Astrophysical Journal 883.1 (2019).
BibTeX: Download