Multi-state observations of the Galactic Black Hole XTE J1752-223: Evidence for an intermediate black hole spin

Sep, 2010
9 pages
Published in:
  • Mon.Not.Roy.Astron.Soc. 410 (2011) 2497
e-Print:

Citations per year

2010201320162019202202468
Abstract: (arXiv)
The Galactic Black hole candidate XTE J1752-223 was observed during the decay of its 2009 outburst with the Suzaku and XMM-Newton observatories. The observed spectra are consistent with the source being in the ''intermediate`` and ''low-hard state`` respectively. The presence of a strong, relativistic iron emission line is clearly detected in both observations and the line profiles are found to be remarkably consistent and robust to a variety of continuum models. This strongly points to the compact object in \j\ being a stellar-mass black hole accretor and not a neutron star. Physically-motivated and self-consistent reflection models for the Fe-\ka\ emission-line profile and disk reflection spectrum rule out either a non-rotating, Schwarzchild black hole or a maximally rotating, Kerr black hole at greater than 3sigma level of confidence. Using a fully relativistic line function in which the black hole spin parameter is a variable, we have formally constrained the spin parameter to be 0.52±0.11(1σ)0.52\pm0.11 (1\sigma). Furthermore, we show that the source in the low--hard state still requires an optically--thick disk component having a luminosity which is consistent with the LT4L\propto T^4 relation expected for a thin disk extending down to the inner--most stable circular orbit. Our result is in contrast to the prevailing paradigm that the disk is truncated in the low-hard state.
Note:
  • Accepted for publication in MNRAS, 9 pages, 9 figures