The X‐Ray Spectra of Black Hole X‐Ray Novae in Quiescence as Measured byChandra

2001/11/30 by A. K. H. Kong, Albert K. H. Kong, J. E. McClintock +7 · 16 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Earth Systems and Cosmic Evolution #astro-ph

paper · pdf · doi:10.1086/339501

9 pages, 6 figures, accepted for publication in ApJ

arxiv created 2002/01/14 · openalex publication_date 2002/05/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31

Abstract

We present Chandra observations of black hole X-ray novae V404 Cyg, A0620-00, GRO J1655-40, and XTE J1550-564 in quiescence. Their quiescent spectra can be well fitted by a power-law model with number slope α ~ 2. While a coronal (Raymond-Smith) model is also a statistically acceptable representation of the spectra, the best-fit temperatures of these models is ~5 times higher than that seen in active stellar coronae. These four spectra of quiescent X-ray novae are all consistent with that expected for accretion via an advection-dominated accretion flow and inconsistent with that expected from a stellar corona. This evidence for continued accretion in quiescence further strengthens the case for the existence of event horizons in black holes. Both A0620-00 and GRO J1655-40 were fainter than in previous observations, while V404 Cyg was more luminous and varied by a factor of 2 in a few kiloseconds. A reanalysis of the X-ray data for XTE J1550-564 shows that (like V404 Cyg and A0620-00) its luminosity exceeds the maximum prediction of the coronal model by a large factor. The 0.3-7 keV luminosities of the four sources studied are in the range from ~10 30 to 10 33 ergs s -1 .

Citations

• Thermal X-Ray Line Emission from Accreting Black Holes
• The 1996 outburst of GRO J1655-40: the challenge of interpreting the multiwavelength spectra
• X-RAY NOVAE

Cited by

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• A Chandra observation of the old open cluster M 67
• Origin of X-ray emission from transient black hole candidates in quiescence
• X‐Ray Studies of Two Neutron Stars in 47 Tucanae: Toward Constraints on the Equation of State
• The distances to Galactic low-mass X-ray binaries: consequences for black hole luminosities and kicks
• On the Lack of Thermal Emission from the Quiescent Black Hole XTE J1118+480: Evidence for the Event Horizon
• A Unicorn in Monoceros: the 3M_\odot dark companion to the bright, nearby red giant V723 Mon is a non-interacting, mass-gap black hole candidate
• Infrared contamination in Galactic X-ray novae
• Revisiting the radio/X-ray flux correlation in the black hole V404 Cyg: from outburst to quiescence
• Chandra Detection of XTE J1650-500 in Quiescence and the Minimum Luminosity of Black Hole X-Ray Binaries
• The Spectrum of the Black Hole X‐Ray Nova V404 Cygni in Quiescence as Measured byXMM‐Newton
• Quiescent X-ray/optical counterparts of the black hole transient H 1705-250
• Polarized synchrotron emission in quiescent black hole X-ray transients
• The discovery of X-ray binaries in the Sculptor dwarf spheroidal galaxy
• The X-ray/ -ray spectrum of XTE J1550-564 in the very high state