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GCN Circular 19116

Subject
GRB 160227A: MASTER prompt OT Detection and LC
Date
2016-02-29T17:15:15Z (9 years ago)
From
Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru>
V.Krushinski, I.Zalozhnich, A. Popov
Ural State University, Kourovka

E. Gorbovskoy, V. Lipunov, N.Tyurina, V.Kornilov, P.Balanutsa, 
A.Kuznetsov, D.Kuvshinov
Lomonosov Moscow State University,
Sternberg Astronomical Institute, Moscow State University

A.Gabovich, V.Yurkov, Yu.Sergienko, D.Varda
Blagoveschensk Educational State University, Blagoveschensk

K.Ivanov, N.M.Budnev, O.Gres, V.A.Poleshchuk
Irkutsk State University

A. Tlatov, V.Senik, A.V. Parhomenko, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

R. Rebolo, M. Serra-Ricart, N. Lodieu, G. Israelian
The Instituto de Astrofisica de Canarias


Five telescopes of  MASTER Net of   robotic telescope   participated in 
the observation of the GRB 160227A. Two telescopes  detected 
prompt  optical emission. We discovery very strong OT variations with time 
~100 sec correlated with gamma ray flux (Sakamoto et al., 19106).

MASTER-Ural  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Ural was pointed to the  GRB160227A 30 sec after notice time 
and 115 sec after trigger time at 2016-02-27 19:34:03 UT. On our first 
(20s exposure)  set we  found 1 optical transient within SWIFT error-box 
(Siegel et al GCN 19098; Gorbovskoy et al GCN 19099) at a position:
RA   12h 59m 14.13s
Dec +78d 40m 44.2s
With magnitude automatical magnitude ~ 17.3
We definetly see OT  at a number of single and coadd images. OT was 
observed during ~ 1 hours. We see OT decay from 17.0 to 19.1 mag in the 
time interval from 115 to 2647 sec atger the trigger.
The 5-sigma upper limit has been about 17.5 mag on first single image and 
up to 19.5 mag at on coadd images in later time.

MASTER-Kislovodsk  robotic telescope (MASTER-Net: 
http://observ.pereplet.ru) 
located in Kislovodsk was pointed to the  GRB160227A  (Siegel et al GCN 
19098) 52 sec after notice time and 137 sec after trigger time at 
2016-02-27 19:34:25 UT. On our first (30s exposure)  set we  marginaly see 
optical transient (Siegel et al GCN 19098, Gorbovskoy et al GCN 19099) 
within SWIFT error-box.  OT also definetly seen at a number of coadd 
images. OT was observed for about 4 hours. We see OT decay from 18.1 to ~ 
20.5 mag in the time interval from 152 to 12900 sec atger the trigger.
The 5-sigma upper limit has been about 17.5 mag on first single image and 
up to 21.0 mag at on coadd images in later time.


MASTER-IAC  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in IAC was pointed to the  GRB160227A 49 sec after notice time and 
137 sec after trigger time at 2016-02-27 19:34:25 UT. On our first (30s 
exposure)  set we haven`t found optical transient  within SWIFT error-box. 
The observations started on evening sky (Sun altitude ~ -6 deg). 
Therefore, the first exposure upper limit is very low.  We definetly see 
OT  at a number of coadd images, starting ~ 1 hour after the trigger. OT 
was observed for about 2 hours. We see OT decay from 19.0 to 20.0 mag in 
the time interval from 3400 to 9200 sec atger the trigger.
The 5-sigma upper limit has been about 14.5 mag (due to bright evening sky 
) on first single image and up to 21.0 mag at on coadd images in later 
time.


MASTER-Tunka  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Astrophysical Center Tunka  was pointed to the  GRB160227A 17 
sec after notice time and 103 sec after trigger time at 2016-02-27 19:33:51 UT. On our first 
(20s exposure)  set we haven`t found optical transient  within SWIFT 
error-box. The observations made on not very well weather condition and 
was finished 10 after GRB, due to snow coming.
The 5-sigma upper limit has been about 15.3 mag on first single image.


MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in Blagoveschensk was pointed to the  GRB160227A  8 sec after 
notice time and 93 sec after trigger time at 2016-02-27 19:33:41 UT. On 
our first (20s exposure)  set we haven`t found optical transient  within 
SWIFT error-box.
The 5-sigma upper limit has been about 16.0 mag on first single image.


Out preliminary photometry results available at table 1
Light curve available here: http://master.sai.msu.ru/static/grb160227.png


Table 1.

T0-Tmig Expt.   Mag          Site            Coadd
-------|-------|------|---------------------|------
125     20      17.0     MASTER Ural
152     30      18.1     MASTER Kislovodsk
174     30      18.5     MASTER Ural
207     120     17.8     MASTER Kislovodsk     3
231     40      17.7     MASTER Ural
299     50      18.9     MASTER Ural
383     70      19.6     MASTER Ural
485     90      17.9     MASTER Ural
607     110     18.0     MASTER Ural
621     550     18.7     MASTER Kislovodsk     4
757     140     18.7     MASTER Ural
935     170     18.2     MASTER Ural
1133    180     19.1     MASTER Ural
1349    180     19.0     MASTER Ural
1566    180     18.9     MASTER Ural
1765    1080    18.9     MASTER Kislovodsk     6
1781    180     19.1     MASTER Ural
1998    180     19.1     MASTER Ural
2647    900     19.1     MASTER Ural           5
2789    360     19.7     MASTER Kislovodsk     2
3423    540     19.0     MASTER IAC            3
4261    900     19.2     MASTER IAC            5
4527    900     19.4     MASTER Kislovodsk     5
5966    1080    19.5     MASTER Kislovodsk     6
6401    1800    20.0     MASTER IAC           10
7771    3600    19.9     MASTER IAC           20
9196    1800    19.8     MASTER IAC           10
10608   1620    20.9     MASTER Kislovodsk     9
12824   1800    20.3     MASTER Kislovodsk    10


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