Swift observations of an outburst of the SFXT AX J1845.0-0433/IGR J18450-0435
ATel #2102; P. Romano (INAF-IASF Palermo), S. Barthelmy (GSFC), R. Margutti (Univ Bicocca&OAB), C. Guidorzi (U. Ferrara), L. Sidoli (INAF-IASF Milano), J. A. Kennea (PSU), V. La Parola (INAF-IASF Palermo), D. N. Burrows (PSU), P. Esposito (INAF-IASF Milano), P. A. Evans (U. Leicester), H. A. Krimm (CRESST/GSFC/USRA), N. Gehrels (GSFC), S. Vercellone (INAF-IASF Palermo)
on 28 Jun 2009; 18:33 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Pat Romano (firstname.lastname@example.org)
Subjects: X-ray, Gamma Ray, Request for Observations, Binary, Transient
Referred to by ATel #: 4095
Swift has observed a new outburst from the Supergiant Fast X-ray
Transient AX J1845.0-0433/IGR J18450-0435.
The Swift Burst Alert Telescope (BAT) triggered
on it on 2009 June 28 at 08:06:03 UT (image trigger=355911).
Swift slewed to the target, so that the XRT began observing the
field at about 795 seconds after the BAT trigger.
Using the BAT data set from T-239 to T+963 s from the recent
telemetry downlink, we find that the time-averaged spectrum from
T+8.4 to T+790.7 s is best fit by a simple
power-law model with a photon index of 2.41 +/- 0.34 (90% cl.).
The fluence in the 15-150 keV band is (1.1 +/- 0.2)E-06 erg/cm2.
The Swift/XRT data (WT mode, 795-806 s since the trigger;
PC mode, 808-829 s) show a decaying light curve with an initial
count rate of 2 counts/s.
The PC spectrum only contains 23 photons, so only an estimate
of the observed flux (in the 0.3-10 keV energy band) can be derived,
at ~3E-10 erg/cm2/s.
Previously, Swift caught a flare from this source on 2005 November 4.
The historical light curve from the BAT hard X-ray
transient monitor (Krimm et al, 2006, ATel #904; 15-50 keV) can be found at http://swift.gsfc.nasa.gov/docs/swift/results/transients/weak/IGRJ18450-0435/