CaltechAUTHORS
Published July 2013 | Version Submitted + Published
Journal Article Open

GRO J1008-57: an (almost) predictable transient X-ray binary

Creators

  • 1. ROR icon University of Erlangen-Nuremberg
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon University of Maryland, Baltimore County
  • 4. ROR icon Goddard Space Flight Center
  • 5. ROR icon University of California, San Diego
  • 6. ROR icon CEA Saclay
  • 7. ROR icon Leibniz Institute for Astrophysics Potsdam
  • 8. ROR icon Universities Space Research Association
  • 9. ROR icon University of Tübingen
  • 10. ROR icon University of Alicante

Abstract

A study of archival RXTE, Swift, and Suzaku pointed observations of the transient high-mass X-ray binary GRO J1008−57 is presented. A new orbital ephemeris based on pulse arrival-timing shows the times of maximum luminosities during outbursts of GRO J1008−57 to be close to periastron at orbital phase − 0.03. This makes the source one of a few for which outburst dates can be predicted with very high precision. Spectra of the source in 2005, 2007, and 2011 can be well described by a simple power law with high-energy cutoff and an additional black body at lower energies. The photon index of the power law and the black-body flux only depend on the 15–50 keV source flux. No apparent hysteresis effects are seen. These correlations allow us to predict the evolution of the pulsar's X-ray spectral shape over all outbursts as a function of just one parameter, the source's flux. If modified by an additional soft component, this prediction even holds during GRO J1008−57's 2012 type II outburst.

Additional Information

© 2013 ESO. Article published by EDP Sciences. Received 31 January 2013; Accepted 9 May 2013. Published online 08 July 2013. We thank the RXTE-, Swift- and Suzaku-teams for their role in scheduling all observations used within this paper and for accepting our proposals. We especially thank Evan Smith for his help in scheduling the RXTE observations in 2011 April. Many thanks to Hans Krimm for providing the BAT-spectrum during the 2012 giant outburst. We acknowledge funding by the Bundesministerium für Wirtschaft und Technologie under Deutsches Zentrum für Luft- und Raumfahrt grants 50OR0808, 50OR0905, 50OR1113, and the Deutscher Akademischer Austauschdienst. This work has been partially supported by the Spanish Ministerio de Ciencia e Innovación through projects AYA2010-15431 and AIB2010DE-00054. All figures shown in this paper were produced using the SLXfig module, developed by John E. Davis. We thank the referee for her/his helpful comments and suggestions.

Attached Files

Published - aa21203-13.pdf

Submitted - 1305.2936v1.pdf

Files

1305.2936v1.pdf

Files (2.2 MB)

Name Size
md5:e8a288da0d4d73e5fc822e980ad77389
1.1 MB Preview Download
md5:a7e19294326c9b361739a88b71130c96
1.0 MB Preview Download

Additional details

Identifiers

Eprint ID
41380
Resolver ID
CaltechAUTHORS:20130918-103408804

Related works

Describes
http://arxiv.org/abs/1305.2936 (URL)

Funding

Bundesministerium für Wirtschaft und Technologie
Deutsches Zentrum für Luft- und Raumfahrt
50OR0808
Deutsches Zentrum für Luft- und Raumfahrt
50OR0905
Deutsches Zentrum für Luft- und Raumfahrt
50OR1113
Deutscher Akademischer Austauschdienst
Spanish Ministerio de Ciencia e Innovación
AYA2010-15431
Spanish Ministerio de Ciencia e Innovación
AIB2010DE-00054

Dates

Created
2013-09-18
Created from EPrint's datestamp field
Updated
2021-11-10
Created from EPrint's last_modified field