GCN Circular 24485
Subject
LIGO/Virgo S190510g: GRAWITA REM and Loiano optical observations
Date
2019-05-11T15:55:17Z (6 years ago)
From
Aniello Grado at INAF-OAC <aniello.grado@gmail.com>
P. D'Avanzo (INAF-OAB), E. Palazzi (INAF-OAS), G. Greco (Univ. Urbino), S.
Yang (INAF-OAPd), S. Campana (INAF-OAB), G. Stratta (INAF-OAS), A. Rossi
(INAF-OAS), Nicola Masetti (inaf-oas) and E. Brocato on behalf of GRAWITA
report:
We carried out further optical follow-up observations of the LIGO/Virgo GW
trigger S190509g (LVC, GCN Circ. 24442) with the 60-cm robotic telescope
REM located at the La Silla Observatory (Chile). The observations started
at 2019-05-11 at 00:49:48 UT, simultaneously in the g, r, i, z bands (the
REM NIR camera was not operational).
We observed the following galaxies within the 50% probability of the
updated skymap visible from La Silla:
RA(J2000) Dec(J2000) Dist(Mpc)
----------------------------------------------------
J055219-342051 05:52:19.00 -34:20:51.4 138.68
J055149-314446 05:51:49.92 -31:44:46.0 210.86
J054827-325838 05:48:27.60 -32:58:38.1 160.69
J060115-313225 06:01:15.09 -31:32:25.5 191.43
J055425-350235 05:54:25.29 -35:02:35.1 143.88
J055028-334429 05:50:28.73 -33:44:29.3 165.20
J055740-345601 05:57:40.71 -34:56:01.8 146.97
J055949-353200 05:59:49.81 -35:32:00.5 138.04
No clear counterpart for S190509g is found down to a typical 3sigma
magnitude of r > 19 (AB).
We also carried out optical follow-up of the possible transient we reported
in D'Avanzo et al. (GCN Circ. #24455) found in REM images at RA(J2000),
Dec(J2000) = 14:29:15.99, +09:41:12.3 with magnitude r = 17.3 (AB) on
2019-05-10 at 08:07:18 UT. Optical imaging follow-up observations of this
possible transient were carried out with the 1.5m Loiano telescope (Italy)
in the R band on 2019-05-10 at 20:44:08 UT (i.e. about 12.6 hours after the
REM detection reported in GCN Circ. #24455). In the Loiano images the
object is not detected down to a 3-sigma limiting magnitude of R > 20.3
(AB, calibrated against the SDSS). This non-detection is in agreement with
the findings reported by Zhu et al. (GCN Circ. #24479) and favor a fast
transient (like a stellar flare) interpretation for the nature of this
object, although the hypothesis of an image artifact cannot be completely
excluded.