TITLE:   GCN CIRCULAR
NUMBER:  17789
SUBJECT: GRB 150430A: Swift detection of a burst
DATE:    15/04/30 00:57:56 GMT
FROM:    Jamie A. Kennea at PSU/Swift-XRT  <kennea@swift.psu.edu>

V. D'Elia (ASDC), J. A. Kennea (PSU), T. Sakamoto (AGU) and
M. H. Siegel (PSU) report on behalf of the Swift Team:

At 00:21:28 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 150430A (trigger=639433).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 326.491, -27.928 which is 
  RA(J2000) = 21h 45m 57.8s
  Dec(J2000) = -27d 55' 40.8''
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). 

The XRT began observing the field at 00:23:18.0 UT, 80 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 326.47958, -27.90212 which is equivalent to:
  RA(J2000)  = 21h 45m 55.1s
  Dec(J2000) = -27d 54' 07.6''
with an uncertainty of 5 arcseconds (radius, 90% containment). This
location is 100 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

UVOT data is unavailable at this time. 

Note, due to a telemetry drop-out no GCN Notices were sent for this
burst, and limited information is available at this time. We will send
further GCN Circulars as we know more. 

Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.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.)