GRB 201010A

K. L. Page (U Leicester), S. D. Barthelmy (GSFC),
N. J. Klingler (PSU), N. P. M. Kuin (UCL-MSSL) and
A. Y. Lien (GSFC/UMBC) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 14:49:24 UT, the Swift Burst Alert Telescope (BAT) triggered and
located SGR 1830-0645 or GRB 201010A (trigger=999571).  
Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 277.675, -6.758, which is 
   RA(J2000)  =  18h 30m 42s
   Dec(J2000) = -06d 45' 30"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows a single peak
structure with a duration of no more than 0.128 sec.  The peak count rate
was ~1600 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 14:50:30.9 UT, 67.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 277.6702, -6.7550 which
is equivalent to:
   RA(J2000)  = 18h 30m 40.85s
   Dec(J2000) = -06d 45' 18.0"
with an uncertainty of 2.2 arcseconds (radius, 90% containment). This
location is 20 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 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 1.11
x 10^22 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 71 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. The 8'x8' region for the list of sources generated on-board 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
region. No correction has been made for the large, but uncertain, extinction
expected. 

Due to its short duration (BAT trigger duration of 8 ms, although 
the immediately available lightcurve is only available at 128 ms 
resolution), the soft spectrum (not visible above 50 keV) and its
location in the Galactic bulge near the plane (lon,lat) = (24.5, 1.5)
we suspect that this event may be a new Soft Gamma Repeater, which
we would name SGR 1830-0645. 

Burst Advocate for this burst is K. L. Page (klp5 AT leicester.ac.uk). 
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/)

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2915 s of XRT Photon Counting mode data and 5 UVOT
images for GRB 201010A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 277.67385, -6.75455 which is equivalent
to:

RA (J2000): 18h 30m 41.72s
Dec (J2000): -06d 45' 16.4"

with an uncertainty of 1.4 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.

S. Belkin (IKI), A. Pozanenko (IKI), A. Zhornichenko (KIAM), N. Pankov 
(HSE), A. Novichonok (Petrozavodsk State University, KIAM),   Sh. 
Ehgamberdiev (UBAI) report on behalf of IKI-GRB-FuN:

We observed the field of new SGR 1830-0645 (Page et al., GCN 28594
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 ; 
Gogus et al., ATEL 14085) originally detected by Swift (trigger=999571) 
and also named as GRB 201010A with Kitab-ISON RC-36  telescope in 
R-filter. Observation started on Oct. 10 (UT) 15:21:08, i.e. 31.7 
minutes after trigger.

The field is extremely crowded. Within  enhanced XRT position (Osborne 
et al., GCN 28596
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 ) we found  a source which is also presented in the 
DSS2 (R) image but not listed in USNO-B1.0. In our images we cannot 
discriminate the sources. We performed aperture photometry which include 
this source and nearby Northern source listed in USNO-B1.0 0832-0432584 
(R2=13.54) in two stacked images. The image A is at midpoint 0.02343 
days and the image (B) is at midpoint 0.03835 days after trigger. By 
comparison of the two photometric results (A) R=14.16 +/- 0.06 and (B) 
R=14.20 +/- 0.07 we do not observe any variability and hence we do not 
detect optical activity of SGR 1830-0645.

Formal photometry of the field in both epochs (A,B) is following

Date,      UT start, t-T0,    Exp.,  Filter, OT,   Err.,  UL
                     (mid, days)

(A)2020-10-10  15:21:08 0.02343   240    R       n/d    n/d   17.0
(B)2020-10-10  15:21:08 0.03835  2480    R       n/d    n/d   18.0

The photometry is based on nearby USNO-B1.0 star, R2 magnitude

USNO_B10_id  R2
0832-0432530 15.34
0832-0433055 13.04

Y.-D. Hu, A. Sota, A. J. Castro-Tirado, E. Fernandez-Garcia (IAA-CSIC), C. Perez del Pulgar, A. Castellon, I. Carrasco (Univ. de Malaga) on behalf of a larger collaboration, report:

Following the detection of SGR 1830-0645/GRB201010A by Swift (Page et al. GCNC 28594), optical images in the I-band were obtained at the 1.5m OSN telescope in Granada (Spain) starting at 20:35 (Oct 10), i.e. ~5.8 h postburst. No optical afterglow is detected in the image within the enhanced Swift/XRT error box (Osborne et al. GCNC 28596) down to I=20.1, which is in agreement with the non-detections reported by Lipunov et al. (GCNC 28595) and Belkin et al. (GCNC 28597).

We thank the staff at OSN for their excellent support.