[vsnet-grb-info 13437] GRB 130603B: MASTER-Net early observations and optical sloap limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14770
SUBJECT: GRB 130603B: MASTER-Net early observations and  optical sloap limit
DATE:    13/06/05 17:11:24 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

Maria Pruzhinskaya, D.Denisenko, E. Gorbovskoy, V. Lipunov, V.Kornilov, 
D.Kuvshinov, N.Tyurina, N.Shatskiy, P.Balanutsa, D.Zimnukhov, A.Kuznetsov, 
V.V.Chazov
Sternberg Astronomical Institute, Lomonosov Moscow State University


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

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

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

V.Krushinski, I.Zalozhnih,  A. Popov
Ural Federal University, Kourovka

Hugo Levato and Carlos Saffe
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

Claudio Mallamaci, Carlos Lopez and Federico Podest
Observatorio Astronomico Felix Aguilar (OAFA)



MASTER II  robotic telescope (MASTER-Net: http://observ.pereplet.ru)
located in Tunka was pointed to GRB130603B 35 sec after Notice time
and 52 sec after Trigger time (Melandri et al., GCN 14735) in two
mutually perpendicular polarizations.

We didn't find OT at the position reported by Levan et al., GCN 14742
and A. de Ugarte Postigo et al., GCN 14743.

Our photometry (upper limits) during the first 20 minutes until the
clouds started coming in is as follows:


t_UT                   Exp T-T_trig Limit Filter   Tube
-------------------------------------------------------
2013-06-03 15:50:06    10     52    15.4    P|       EAST
2013-06-03 15:50:07    10     53    15.1    P-       WEST
2013-06-03 15:51:06    20    112    15.9    P|       EAST
2013-06-03 15:51:07    20    113    15.8    P-       WEST
2013-06-03 15:52:08    30    174    16.2    P|       EAST
2013-06-03 15:52:08    30    174    16.1    P-       WEST
2013-06-03 15:53:18    50    244    16.7    P|       EAST
2013-06-03 15:53:19    50    245    16.7    P-       WEST
2013-06-03 15:55:01    70    348    16.7    P|       EAST
2013-06-03 15:55:02    70    349    16.6    P-       WEST
2013-06-03 15:56:48    90    454    17.2    P|       EAST
2013-06-03 15:56:49    90    455    16.9    P-       WEST
2013-06-03 15:58:57   120    583    17.6    P|       EAST
2013-06-03 15:58:58   120    584    17.5    P-       WEST
2013-06-03 16:01:43   150    749    18.0    P|       EAST
2013-06-03 16:01:43   150    749    17.6    P-       WEST
2013-06-03 16:04:54   180    940    18.0    P|       EAST
2013-06-03 16:04:54   180    940    17.5    P-       WEST

The OT upper limit available on the plot :

http://master.sai.msu.ru/static/OT/grb130306B.gif

We have tried to compare our data with the photometry from the large
telescopes in the filters similar to ours. In fact, we have used the
observations in r filter.
The following data have been published so far.

Afterglow:

t+5.8 hours r=20.94  WHT  Levan et al., GCN 14742
t+5.8 hours r=20.9   NOT  A. de Ugarte Postigo et al., GCN 14743
t+7.5 hours r=21.2   Gemini-South  Cucchiara et al., GCN 14748

Large aperture to include both objects:

t+12.2 hours r'=20.8  P60 (Palomar 60 inch)  Cenko et al., GCN 14761
t+14.78 hours r'=20.78 RATIR (1.5m Harold Johnson)  Eleonora Troja et
al., GCN 14764

We were not able to use the Swift UVOT data in the white light (De
Pasquale et al., GCN 14759) since their exact times of mid-exposures
are not easy to determine.
Obviously, the last two points involve the host galaxy.
In order to constrain the slope we have used the data from WHT, NOT
and Gemini South.
The results are presented here:

http://master.sai.msu.ru/static/OT/grb130306B_all.gif

Thus, supposing the power law of the fading afterglow

F ~ t^-alpha

we are providing the following limitation:

alpha < 0.84.

The message may be cited.