TITLE:   GCN CIRCULAR
NUMBER:  30020
SUBJECT: GRB 210515C: Swift detection of a burst
DATE:    21/05/15 20:50:24 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@inaf.it>

A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), J. A. Kennea (PSU),
K. L. Page (U Leicester), B. Sbarufatti (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 20:02:01 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a GRB 210515C (trigger=1048618). 
The BAT on-board calculated location is RA, Dec 1.050, -15.011 which is 
  RA(J2000) = 00h 04m 12.00s,
  Dec(J2000) = -15d 00' 39.6"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty). 
There is no lightcurve currently available to estimate the duration. 

Using promptly downlinked data we find an uncatalogued X-ray source
located at RA, Dec 1.09221, -14.95325 which is equivalent to:
   RA(J2000)  = 00h 04m 22.13s
   Dec(J2000) = -14d 57' 11.7"
with an uncertainty of 4.9 arcseconds (radius, 90% containment). This
position may be improved as more data are received; the latest position
is available at https://www.swift.ac.uk/sper. No spectrum from the
promptly downlinked event data is yet available to determine the column
density. 

No UVOT data are available at this time. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT 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/)