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Updated Position, Flux and Spectrum of XTE J1652-453

ATEL # 2120; C. B. Markwardt (U. Maryland & NASA/GSFC), A. P. Beardmore (U. Leicester), J. Miller (U. Michigan), J. H. Swank (NASA/GSFC)
on 9 Jul 2009; 9:55 UT
Password Certification: Craig B. Markwardt (

Subjects: X-ray, Binaries, Black Holes, Neutron Stars, Transients

XTE J1652-453 continues to be detected in the RXTE PCA monitoring of the galactic center region (ATEL #2107, #2108). The 2-10 keV fluxes on 2009-07-04.5 and 2009-07-08.4 were 140 mCrab and 134 mCrab respectively. In pointed observations, the PCA spectrum is similar in shape to previous reports (ATEL #2107).

Based on an improved analysis of the Swift XRT image, which was significantly piled up (ATEL #2108), we find a revised astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue) of R.A. = 16h52m20.33s, Decl. = -45d20'39.6" (J2000) for the source, with an estimated 90% error radius of 2.5 arcsec.

The Swift XRT photon counting mode spectrum of 2009-07-03 can be fit with an absorbed disk blackbody model, with a column density of (4.1-5.5)E+22 and a color temperature of kT = 0.5-0.7 keV. The absorbed flux was (4-10)E-9 erg/cm2/s, and an unabsorbed flux of (2.6-3.5)E-8 erg/cm2/s in the 0.5-10.0 keV range. Because of significant pile-up, there is considerable systematic uncertainty in these figures (a 35 arcsec exclusion radius was used to avoid the heavily piled up region). For that reason we do not attempt to constrain the high energy components (i.e. power law or Fe line).

The spectrum is consistent with a stellar-mass black hole in the canonical high/soft state.

RXTE PCA scan light curve of XTE J1652-453

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R. E. Rutledge , Editor
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