TITLE:   GCN CIRCULAR
NUMBER:  33380
SUBJECT: GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
DATE:    23/02/28 13:33:13 GMT
FROM:    Gu Lim at Seoul National U  <lim9gu@gmail.com>

Gu Lim (PNU), Donghyun Kim (PNU), Dohyeong Kim (PNU), Myungshin Im
(SNU ARC/SNU), Gregory S.H. Paek (SNU ARC/SNU), Keun-Hong Park (MAAO),
and Seonghun Lim (MAAO) on behalf of GECKO collaboration

We searched for the optical counterpart of a possible short burst GRB
230228A (Dichiara et al. GCN #33378) with the 0.7-m telescope at Miryang
Arirang Astronomical Observatory (MAAO), located at Miryang, Republic of
Korea. We observed the center of Swift-XRT localization (RA, Dec =
01:13:30.73, +44:28:58.4; Evans et al. GCN #33379) +4.09 hours after
report, but could not find any possible transient within the field of view
(28.2' x 28.2'). We performed flux calibration with the PS1 catalog and
used the AB magnitude system. Each depth means 3 and 5 sigma upper limit
for a point source detection. The magnitudes are not corrected for galactic
extinction.

object     exposures  date-obs (UT)       MJD        band Depth(3σ) Depth(5
σ) FWHM(")
=========================================================================================
GRB230228A 60sx8      2023-02-28T09:56:11 60003.414  V    <18.77     <18.21
     2.8

Gravitational wave Electromagnetic wave Counterpart Korean Observatory
(GECKO) is a network of 10+ 0.5m to 1m class telescopes over the world.


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