GCN Circular 22695

J.D. Gropp (PSU), A. Deich (PSU), J. A. Kennea (PSU),
S. J. LaPorte (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
B. Sbarufatti (PSU), M. H. Siegel (PSU) and A. Tohuvavohu (PSU) report
on behalf of the Neil Gehrels Swift Observatory Team:

At 19:24:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180510A (trigger=831810).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 276.318, -31.911 which is 
   RA(J2000) = 18h 25m 16s
   Dec(J2000) = -31d 54' 38"
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 70 sec.  The peak count rate
was ~8000 counts/sec (15-350 keV), at ~5 sec after the trigger. 

The XRT began observing the field at 19:26:02.5 UT, 88.3 seconds after
the BAT trigger. XRT found a bright, uncatalogued X-ray source located
at RA, Dec 276.3303, -31.9069 which is equivalent to:
   RA(J2000)  = +18h 25m 19.27s
   Dec(J2000) = -31d 54' 24.8"
with an uncertainty of 5.5 arcseconds (radius, 90% containment). This
location is 40 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. 

The initial flux in the 2.5 s image was 1.09e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 96 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. Because of the density of catalogued stars, further
analysis is required to report an upper limit for any afterglow in the
sub-image. Results from the list of sources generated on-board are not
available at this time. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.26. 

Burst Advocate for this burst is J.D. Gropp (jdg44 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.)