TITLE:   GCN CIRCULAR
NUMBER:  27258
SUBJECT: SUBJECT : LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
DATE:    20/02/28 14:42:34 GMT
FROM:    Gu Lim at Seoul National U  <lim9gu@gmail.com>

SUBJECT : LIGO/Virgo S200213t: No significant EM counterparts identified
from continued GECKO observation of host galaxy candidates

Gu Lim (SNU), Myungshin Im (SNU), Gregory S.H. Paek (SNU), Joonho Kim
(SNU), Sungyong Hwang (SNU), Bomi Park (SNU), Sophia Kim (SNU), Changsu
Choi (SNU), Shuhrat A. Ehgamberdiev (UBAI), Otabek Burkhonov (UBAI), Davron
Mirzaqulov (UBAI), Hyung Mok Lee (KASI), on behalf of GECKO team

We performed follow-up observation for host galaxy candidates (Paek et al.
GCN #27067, GCN #27119) continuously using AZT-22 1.5m telescope at
Maidanak Astronomical Observatory in Uzbekistan in the initial and updated
localiztion area of S200213t (Singer et al, GCN #27042) and overlapped
neutrino detection area (Hussain et al, GCN #27043).

No significant EM counterpart candidates were found in the stacked images.
Single images were taken in B and R-band of 180 or 300 seconds. Observation
results are listed below. DEPTH is 5-sigma detection limit for point source
in AB magnitude. Flux calibration is conducted using APASS DR9 catalog.

 NAME                   RA[J2000]       DEC[J2000]
DISTANCE[Mpc]    DATE-OBS [UT]    FILTER  EXPTIME[s] DEPTH[AB]
================================================================================================================================
PGC11312                02:59:27.180 +31:23:09.161    169
 2020-02-14T14:33:57    B       1500        23.35
PGC11312                02:59:27.180 +31:23:09.161    169
 2020-02-20T14:33:12    B        900        23.05
PGC11312                02:59:27.180 +31:23:09.161    169
 2020-02-14T15:01:51    R       1500        22.08
PGC11312                02:59:27.180 +31:23:09.161    169
 2020-02-20T14:50:37    R        900        22.64
UGC02483                03:01:36.753 +31:49:09.293     91
 2020-02-14T16:33:02    B        600        18.42
UGC02483                03:01:36.753 +31:49:09.293     91
 2020-02-20T15:53:40    B        900        22.29
UGC02483                03:01:36.753 +31:49:09.293     91
 2020-02-20T16:11:05    R        900        21.84
2MASS+03014097+3153413  03:01:40.977 +31:53:41.330     97
 2020-02-20T16:34:54    B        900        22.72
2MASS+03014097+3153413  03:01:40.977 +31:53:41.330     97
 2020-02-20T16:52:18    R        900        22.00
2MASS+03012583+3135093  03:01:25.837 +31:35:09.301    254
 2020-02-14T15:39:28    B       1500        23.40
2MASS+03012583+3135093  03:01:25.837 +31:35:09.301    254
 2020-02-20T15:13:47    B        900        23.18
2MASS+03012583+3135093  03:01:25.837 +31:35:09.301    254
 2020-02-14T16:06:57    R       1500        22.88

We thank all staff in Maidanak observatory for performing the observation.
Gravitational-wave EM Counterpart Korean Observatory (GECKO) is a network
of 10+ 0.5m to 1m class telescopes over the world.
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