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Outbursts from the SFXT IGR J17544-2619 detected by Swift

ATel #7137; H. A. Krimm (CRESST/GSFC/USRA) and P. Romano (INAF-IASF Palermo)
on 25 Feb 2015; 01:19 UT
Credential Certification: Hans A. Krimm (Hans.Krimm@nasa.gov)

Subjects: X-ray, Binary, Transient, Pulsar

Referred to by ATel #: 7141

The Swift/BAT transient monitor has detected a series of flares from the HMXB/SFXT IGR J17544-2619 (e.g. Romano et al, 2014, A&A, 562, A2). Significant activity from this source was detected during the following observations:

DATE MJD..... .....UTC..... EXP(s) RATE (ct/s/cm^2) MCRAB SNR
2015-Feb-21 57073 23:39:01 1344 0.014 +/- 0.003 65 5.4
2015-Feb-22 57073 01:06:21 1056 0.020 +/- 0.005 91 4.1
2015-Feb-22 57073 01:25:17 704 0.011 +/- 0.003 48 3.1
2015-Feb-22 57073 07:35:17 192 0.034 +/- 0.009 152 3.7
*2015-Feb-22 57073 07:51:33 656 0.043 +/- 0.005 197 9.2
2015-Feb-22 57073 13:43:25 984 0.012 +/- 0.003 53 3.6

All count rates are in the 15-50 keV band. The starred exposure also triggered on-board, but below the threshold to generate an automatic slew.

Swift/XRT observations were obtained as a Target of Opportunity, on 2015-02-24 from 17:11:55 to 17:28:25 UT (0.9 ks net exposure, about 51 hours after the flare), and yield a 3-sigma upper limit of 2.1E-2 ct/s.

The last Swift outburst of this source was detected on 2014 Oct 10 (Romano et al. 2015, A&AL, in press, arXiv:1502.04717). See ATel #6566 for a list of previous outbursts.

Swift/BAT transient monitor light curve for IGR J17544-2619