2011ATel.3148....1K

Swift/XRT carried out a 983-s observation starting at 3 Feb 2011 21:29:03 UTC at a pointing location chosen so that both IGR J17091-3624 and IGR J17098-3628 were in the field of view. IGR J17091-3624 is strongly detected in the XRT image in Photon Counting mode, consistent with the proposed identification of the outburst source from the Swift/BAT data (Krimm et al., ATel #3144). There is no detection of any X-ray flux from IGR J17098-3628.

The data are fitted by an absorbed power-law model (Reduced chi2 = 0.76) with the following parameters:

N_H = 1.10 ± 0.3 x 10^22 cm-2

Gamma = 1.73 ± 0.29

Flux (0.3-10 keV) = 4.3 ± 0.5 x 10^-10 erg/s/cm-2

We note that the spectrum was affected by pile up. The source was not detected in the Swift/UVOT, which is consistent with the large absorption.

Further Swift monitoring observations in Windowed Timing mode have been requested.