GCN Circular 36142

G.Antipov, V.Lipunov, P.Balanutsa (Lomonosov MSU), D.Buckley (SAAO), K.Zhirkov,A.Kuznetsov,
N.Tiurina, E.Gorbovskoy, Ya.Kechin, D.Vlasenko, Yu.Tselik,I.Gorbunov,
V.Vladimirov,D.Zimnukhov, V.Senik, A.Yudin,A.Chasovnikov, D.Cheryasov(Lomonosov MSU,SAI,PhysicsDepartment),
O.Gress,N.Budnev(ISU),
A.Sosnovskij (Crimean Astrophysical Observatory, RAS),
C.Francile.  F. Podesta, R.Podesta (Observatorio Astronomico Felix AguilarOAFA),
R. Rebolo, M. Serra(The Instituto de Astrofisica de Canarias),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity)

MASTER Global robotic net (http://observ.pereplet.ru Lipunov et al.,2010,Advances in Astronomy,2010,30L)
started  EP 240416A (Cheng et al. #GCN 36138, Triggertime= 2024-04-16 02:42:13UT,
Notice=2024-04-16T16:41:11, Center R.A.,Dec. = 203.150 -13.612)
optical (unfiltered) observation at 3 MASTER observatories.


MASTER-Kislovodsk robotic telescope  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to EP240416A error-box
66152 sec after trigger time at 2024-04-16 21:04:45 UT, with upper limit up to  19.4 mag. The observations began at zenith distance = 56 deg. The sun  altitude  is -36.6 deg.

MASTER-Tavrida robotic telescope  located in Russia was pointed to the EP errorbox  66334 sec after trigger time at 2024-04-16 21:07:47 UT, with upper limit up to  17.8 mag. The observations began at zenith distance = 57 deg. The sun  altitude  is -35.0 deg.

MASTER-SAAO robotic telescope  located in South Africa (South African Astronomical Observatory) was pointed to the EP Alert 240416.11 errorbox 67795 sec after trigger time at 2024-04-16 21:32:08 UT, with upper limit up to  20.0 mag. The observations began at zenith distance = 22 deg. The sun  altitude  is -63.6 deg.

The galactic latitude b = 48 deg., longitude l = 319 deg.

There is no OT (Chen et al. #GCN 36139) in MASTER database since 2003y, that can confirm Kinder optical afterglow.

Observation and analysis will be continued.
We obtained the following upper limits.

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________
   66213 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 04.43s , -13d 07m 01.2s) |   C |   120 | 18.1 |
   66333 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 04.43s , -13d 07m 01.2s) |   C |   360 | 18.8 |  Coadd
   67353 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 04.43s , -13d 07m 01.2s) |   C |  2400 | 19.4 |  Coadd
   66213 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 03.54s , -13d 30m 11.3s) |   C |   120 | 17.7 |
   66333 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 03.54s , -13d 30m 11.3s) |   C |   360 | 18.7 |  Coadd
   67353 | 2024-04-16 21:04:45 |   MASTER-Kislovodsk | (13h 33m 03.53s , -13d 30m 11.2s) |   C |  2400 | 19.4 |  Coadd
   66353 | 2024-04-16 21:07:05 |   MASTER-Kislovodsk | (13h 32m 58.66s , -13d 30m 51.0s) |   C |   120 | 18.1 |
   66353 | 2024-04-16 21:07:05 |   MASTER-Kislovodsk | (13h 32m 59.58s , -13d 07m 40.7s) |   C |   120 | 18.2 |
   66395 | 2024-04-16 21:07:47 |      MASTER-Tavrida | (13h 32m 43.07s , -12d 57m 28.7s) |   C |   120 | 14.9 |
   66493 | 2024-04-16 21:09:26 |   MASTER-Kislovodsk | (13h 32m 57.78s , -13d 29m 55.6s) |   C |   120 | 18.1 |
   66493 | 2024-04-16 21:09:26 |   MASTER-Kislovodsk | (13h 32m 58.79s , -13d 06m 45.2s) |   C |   120 | 18.2 |