[vsnet-grb-info 14462] GRB 140129B: MASTER OT early light curve

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15776
SUBJECT: GRB 140129B:  MASTER OT early light curve
DATE:    14/01/30 08:54:54 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <gcncirc at observ.inetcomm.ru>

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

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

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

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

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

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 the  GRB140129B  78 sec after notice time and 105 
sec after trigger time at 2014-01-29 12:52:54 UT (Bernardini et al., GCN 
15765).
Such a long pointing time is due to internal mount pointing error under 
strong Siberian frost, which was automatically solved. A set of images 
with increasing exposures was obtained with the field at zenith distance 
75 deg and setting. On our first (20s exposure) image we found optical 
transient at the SWIFT optical transient position. 
The unfiltered magnitude is about ~14m (Ivanov et al., GCN 15766).

    Our coordinates measured from the combination of 7 images are 
coincident with Swift UVOT position taking into account the error box 
reported by Bernardini et al., GCN 15765 and Swift-XRT position (Goad et 
al., GCN 15770):


     R.A.        Dec.            Err
21 47 01.71 +26 12 22.8     +/-0.5 arcsec

    The object is visible on 6 images, gradually fading below the detection
limit on the 7th image. The results of our photometry are given in table 
below:

T_start   T-T_trig Tm-T_trig   Exp,s Elevation  Mag
----------------------------------------------------
12:52:54   105        115       20     15.5     14.4
12:54:03   174        189       30     15.3     15.4
12:55:28   259        284       50     15.1     15.9
12:57:15   366        401       70     14.9     16.2
12:59:19   490        540      100     14.6     17.0
13:02:11   662        727      130     14.2     17.3
13:05:28   859        944      170     13.7     17.7
13:09:21  1091       1181      180     12.7     18.0
13:13:20  1330       1540      360     11.6    <18.4    # coadd 2 image

In the table above 'T' is time of exposure beginning, 'Tm' is mid-exposure 
time.
The power law slope is alpha = 1.42.

The GRB140129B duration is small (T_90 < 2 sec, Palmer et al., GCN 15774), 
but spectrum is soft and this burst must be  faint long GRB (Pal'shin, 
privet communication; Palmer et al., GCN 15774).

Animation of seven frames by MASTER-Tunka is uploaded to
http://master.sai.msu.ru/static/GRB/GRB140129B-MASTER-Tunka-anim.gif

The light curve is available here:
http://master.sai.msu.ru/static/GRB/GRB140129B_last.png

Take the opportunity we would like to congratulate our first author from 
Siberia Vladimir  Poleshchuk  with the birth of the grandchild.

The message  may be cited.