TITLE:   GCN CIRCULAR
NUMBER:  27320
SUBJECT: GRB 200306A: Swift detection of a burst
DATE:    20/03/06 00:38:35 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

K. K. Simpson (PSU), D. M. Palmer (LANL) and B. Sbarufatti (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 00:19:40 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 200306A (trigger= 959917).  Swift slewed immediately to the burst. 
Due to communications outages, no BAT data is immediately available at this 
time, but the complete data set will be available after upcoming downlinks 
to the ground. 

Using promptly downlinked data we find a bright, uncatalogued X-ray
source with an enhanced position: RA, Dec 101.1050, -62.0058 which is
equivalent to:
   RA(J2000)  = 06h 44m 25.20s
   Dec(J2000) = -62d 00' 20.9"
with an uncertainty of 3.6 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. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 8.67
x 10^20 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 3.02e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of nominal 150.000 seconds with the
White  filter starting 85s seconds after the BAT trigger. Automatic
processing failed because of connectivity issues on the ground. 
Further analysis will be available once the full dataset gets on the
ground. 

Burst Advocate for this burst is K. K. Simpson (kira.simpson1984 AT gmail.com). 
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/)