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ATEL # 2225; R D Saxton (ESAC), R. Duro (Bamberg), A. Read (Leicester), P. Esquej (Leicester)
on 4 Oct 2009; 10:48 UT
Password Certification: Richard Saxton (firstname.lastname@example.org)
Subjects: X-ray, Binaries, Black Holes, Transients
The X-ray binary, SWIFT J1753.5-0127, discovered in outburst by the Swift BAT in 2005 (Palmer et al. 2005, ATel #546) was observed during an XMM-Newton slew on September 3rd 2009, with a 0.2-10 keV count rate of 118 c/s. Such bright sources suffer from heavy pile-up in the EPIC-pn camera during slews and the real count rate is estimated to be ~250 c/s.
After excluding the inner 10" of the PSF and using single-pixel events only, to minimise pile-up effects, a spectral fit gives a 0.2-10 keV flux of 9.7+/-1.0E-10 ergs/s/cm^2 and a 2-10 keV flux of 6.6+/-0.9E-10 ergs/s/cm^2.
The spectrum requires a power-law plus disk blackbody model for an acceptable fit and the disk temperature can be constrained to 0.34 (+0.17 / -0.09) keV (90% confidence for one free parameter).
This is very much in line with X-ray observations performed post-outburst which show that the source remains in the low/hard state while very gradually increasing in brightness (see Miller and Rykoff, Atel #1066).
This source was spotted using the XMM-Newton slew data quick analysis tool whose results are available at: http://xmm.esac.esa.int/external/xmm_products/slew_results/web_slew.shtml
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