TITLE: GCN CIRCULAR NUMBER: 8279 SUBJECT: Trigger 324561: IGR J08408-4503 detected by Swift DATE: 08/09/21 08:27:17 GMT FROM: David Palmer at LANL V. Mangano (INAF-IASFPA), W. H. Baumgartner (GSFC/UMBC), A. P. Beardmore (U Leicester), D. N. Burrows (PSU), N. Gehrels (NASA/GSFC), S. D. Hunsberger (PSU), V. La Parola (INAF-IASFPA), D. M. Palmer (LANL), P. Romano (INAF-IASFPA), B. Sbarufatti (INAF-IASFPA), M. Stamatikos (NASA/ORAU) and E. Troja (INAF-IASFPA) report on behalf of the Swift Team: At 07:55:08 UT, the Swift Burst Alert Telescope (BAT) imaged and located Trigger 325461. Swift slewed immediately to the location. The BAT on-board calculated location is RA, Dec 130.138, -45.045 which is RA(J2000) = 08h 40m 33s Dec(J2000) = -45d 02' 40" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). As is typical for an image trigger, there are no obvious variations in the TDRSS lightcurve. This location is consistent with the Supergiant Fast X-ray Transient (SFXT) source IGR J08408-4503 (= LM Vel). The XRT began observing the field at 07:57:32.6 UT, 143.7 seconds after the BAT trigger. XRT found an X-ray source located at RA, Dec 130.1974, -45.0591 which is equivalent to: RA(J2000) = 08h 40m 47.37s Dec(J2000) = -45d 03' 32.7" with an uncertainty of 4.9 arcseconds (radius, 90% containment). This location is 159 arcseconds from the BAT onboard position, within the BAT error circle, and is consistent with the SFXT IGR J08408-4503. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 400 seconds with the V filter starting 881 seconds after the BAT trigger. Analysis will be reported later. Burst Advocate for this burst is V. Mangano (vanessa AT ifc.inaf.it). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)