2002/02/28 by Rudy Wijnands, Jon M. Miller, J. M. Miller +1
Earth and Planetary Sciences · Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Bursting #Context (archaeology) #Earth Systems and Cosmic Evolution #Light curve #Luminosity #Transient (computer programming) #astro-ph
paper · pdf · doi:10.1086/342788
Accepte for publication in ApJ, 11 July 2002
arxiv created 2002/07/11 · openalex publication_date 2002/10/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present Chandra /ACIS observations of the bursting X-ray transient SAX J1747.0-2853 performed on 2001 July 18. We detected a bright source at the position of R.A. = 17 h 47 m 02 60 and decl. = -28°52'58 9 (J2000.0, with a 1 σ error of ~0 7), consistent with the BeppoSAX and ASCA positions of SAX J1747.0-2853 and with the Ariel V position of the transient GX +0.2-0.2, which was active during the 1970s. The 0.5-10 keV luminosity of the source during our observations was ~ 3 × 10 35 ergs s -1 (assuming a distance of 9 kpc), demonstrating that the source was in a low-level accretion state. We also report on the long-term light curve of the source as observed with the all-sky monitor on board the Rossi X-Ray Timing Explorer . After the initial 1998 outburst, two more outbursts (in 2000 and 2001) were detected with peak luminosities about 2 orders of magnitude larger than our Chandra luminosity. Our Chandra observation falls between those two outbursts, making the outburst history for SAX J1747.0-2853 complex. Those bright 2000 and 2001 outbursts, combined with the likely extended period of low-level activity between those outbursts, strongly suggest that the classification of SAX J1747.0-2853 as a faint X-ray transient was premature. It might be possible that the other faint X-ray transients can also exhibit bright, extended outbursts that would eliminate the need for a separate subclass of X-ray transients. We discuss our results also in the context of the behavior of X-ray binaries accreting at low levels with luminosities around 10 35 ergs s -1 , a poorly studied accretion rate regime.