[vsnet-grb-info 25498] GRB200412B: GROWTH India detection of afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27598
SUBJECT: GRB200412B: GROWTH India detection of afterglow
DATE:    20/04/17 06:59:26 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb at iitb.ac.in>

H. Kumar, M. Khandagale, K. Deshmukh, V. Bhalerao(IITB), G. C. Anupama, B. Kumar, A. Singh, A. Dutta, S. Barway(IIA), P. Dorji (IAO), U. Stanzin (IAO), report on behalf of the GROWTH collaboration:

We observed GRB200412B reported by Fermi GBM Team (GCN 27547) and Burgess J. et al, (GCN 27548) with 0.7m robotic GROWTH-India telescope. We switched from tiled observations to targeted follow-up based on the afterglow identification by Lipunov V. et al, (GCN 27555) at RA(J2000) = 18:33:15.33  Dec(J2000) = +62:31:57.0 . The field was observed multiple times in g and r filters with 550 sec exposure time, starting about 7.4 hours after the trigger. We clearly detect the afterglow emission. The decay is well-described by a power law with alpha = 1.05 +/- 0.14 for g band data and 0.85 +/- 0.17 for r band data.

We obtained the following results:
------------------------------------------------------------------
 JD(Start)| Exposure(sec) | Filter | Mag | lim_Mag |
------------------------------------------------------------------
2458952.1903 | 550 |  g  |  18.301+/-0.034 |  20.92  
2458952.3277 | 550 |  g  |  18.590+/-0.039 |  20.54   
2458952.3601 | 550 |  g  |  18.761+/-0.040 |  20.52
2458952.3768 | 550 |  g  |  18.826+/-0.039 |  20.56
2458952.4216 | 550 |  g  |  18.984+/-0.041 |  20.65
2458952.1982 | 550 |  r  |  17.854+/-0.027 |  20.83     
2458952.3356 | 550 |  r  |  17.998+/-0.036 |  20.32   
2458952.3681 | 550 |  r  |  18.231+/-0.031 |  20.58
2458952.3847 | 550 |  r  |  18.314+/-0.039 |  20.65
2458952.4295 | 550 |  r  |  18.379+/-0.033 |  20.77
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The GROWTH India Telescope (GIT) is a 70-cm telescope with a 0.7 degree field of view, set up by the Indian Institute of Astrophysics and the Indian Institute of Technology Bombay with support from the Indo-US Science and Technology Forum (IUSSTF) and the Science and Engineering Research Board (SERB) of the Department of Science and Technology (DST), Government of India (https://sites.google.com/view/growthindia/). It is located at the Indian Astronomical Observatory (Hanle), operated by the Indian Institute of Astrophysics (IIA).