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Swift/XRT follow-up observation of the field of XTE J1719-291

ATEL # 1451; N. Degenaar, D. Altamirano, M. Klein-Wolt and R. Wijnands (University of Amsterdam)
on 31 Mar 2008; 15:14 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: Rudy Wijnands (rudy@space.mit.edu)

Subjects: X-ray, Request for Observations, Binaries, Transients

We report on a Swift/XRT follow-up observation of the field of the newly discovered X-ray transient XTE J1719-291 (Markwardt & Swank, ATEL #1442). The observation was performed on 2008-03-30 and had a duration of approximately 5 ksec. The XRT data shows one clear source within the 7 arcminute RXTE error circle for XTE J1719-291 (ATEL #1442). The position coordinates (J2000) of this object, which we designate Swift J171916.9-290410, are found to be R.A. = 17:19:16.97 and Dec. = -29:04:10.35, with an uncertainty of 3.8 arcseconds. There are no known objects in the Simbad or Rosat source catalogs consistent with this Swift/XRT position, which suggests that Swift J171916.9-290410 is associated with the new X-ray transient XTE J1719-291.

The Swift/XRT spectrum could be fitted with a simple absorbed power law model with a hydrogen column density of Nh~0.67 (-0.15,+0.4) E22 cm-2 and a photon index of ~3.0 (-0.3, +0.9). With these parameters we find absorbed and unabsorbed 2-10 keV fluxes of ~1.1 E-12 erg/cm2/s and ~1.2 E-12 erg/cm2/s respectively. This is more than a factor of 10 lower than the RXTE/PCA detection of XTE J1719-291 on 2008-03-25 (ATEL #1442). If Swift J171916.9-290410 and XTE J1719-291 are indeed the same source, the current Swift/XRT detection is consistent with the reported decline in flux of XTE J1719-291 (ATEL #1442). For a distance of 8 kpc, the deduced Swift/XRT flux translates into a source luminosity of ~9 E33 erg/s (corrected for absorption). To conclusively identify Swift J171916.9-290410 with XTE J1719-291 requires further X-ray monitoring (to confirm a decline in flux). Observations in other wavelength regimes are encouraged as well.

We thank the Swift team for scheduling the observation.


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