[vsnet-grb-info 20612] GRB 180512A: Swift detection of a burst

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22710
SUBJECT: GRB 180512A: Swift detection of a burst
DATE:    18/05/12 23:01:48 GMT
FROM:    Alex Deich at Penn State U  <aud375 at psu.edu>

A. Deich (PSU), S. D. Barthelmy (GSFC), D. N. Burrows (PSU),
J.D. Gropp (PSU), S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC) and
F. E. Marshall (NASA/GSFC) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 22:01:47 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180512A (trigger=832119).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 201.953, +21.406 which is 
  RA(J2000) = 13h 27m 49s
  Dec(J2000) = +21d 24' 23"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 550 sec.  The main pulse starts at
~T+400 s and ends at ~T+550 s. The peak count rate
was ~1000 counts/sec (15-350 keV), at ~500 sec after the trigger. 

The XRT began observing the field at 22:05:20.1 UT, 213.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 201.93846, 21.40271 which is equivalent
to:
  RA(J2000)  = 13h 27m 45.23s
  Dec(J2000) = +21d 24' 09.8"
with an uncertainty of 4.4 arcseconds (radius, 90% containment). This
location is 50 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.73
x 10^20 cm^-2 (Willingale et al. 2013). 

No UVOT data are available at this time. 

Burst Advocate for this burst is A. Deich (aud375 AT psu.edu). 
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.)