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ATEL # 1467; Nathalie Degenaar, Diego Altamirano, and Rudy Wijnands (University of Amsterdam)
on 10 Apr 2008; 19:20 UT
Password Certification: Rudy Wijnands (firstname.lastname@example.org)
Subjects: Binaries, Black Holes, Neutron Stars, Transients
After our first Swift/XRT observation (ATEL #1451) of the new, very faint X-ray transient XTE J1719-291 (ATEL #1442), we acquired two additional observations to monitor the flux evolution of this source. The first additional observation was performed on April 3, 2008, and lasted ~2.6 ksec. The source was detected at a count rate which was slightly less than the previous observation (0.045 counts/s versus 0.051 counts/s). The source spectrum could be fitted with an absorbed power-law model using a column density of 6.7E21 cm-2, a photon index of ~2.8 and a 2-10 keV observed flux of ~1.1e-12 erg/cm2/s. The unabsorbed 2-10 keV flux was ~1.3e-12 erg/cm2/s. The values we obtained are consistent with the previous Swift/XRT observation (ATEL #1451).
The second additional observation was obtained on April 9, 2008 and had an exposure time of ~2 ksec. Again the source was clearly detected and when fitting its spectrum with an absorbed power-law model, we obtained a column density of 6+/-1 E21 cm-2, a photon index of 2.5+/-0.2 and a 2-10 keV absorbed flux of ~1.4E-11 erg/cm2/s (unabsorbed 2-10 keV flux was ~1.5e-11 erg/cm2/s). Clearly, the source has become an order of magnitude brighter since the previous Swift/XRT observation and possibly also a bit harder. This brightening of the source strongly suggests that this Swift source is indeed the counterpart of XTE J1719-291. Observations at all wavelengths are encouraged to study this enigmatic transient.
We thank the Swift team for scheduling these observations.