[vsnet-grb-info 20162] GRB 171205A: RATAN observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22258
SUBJECT: GRB 171205A: RATAN observations
DATE:    17/12/16 15:59:25 GMT
FROM:    Sergei Trushkin at Special Astrophys. Obs.,Russia  <sergei.trushkin at gmail.com>

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TITLE:   GCN  CIRCULAR
NUMBER:
SUBJECT: GRB171205A: RATAN-600 observations
DATE:  17/12/16
FROM: Sergei Trushkin at SAO RAS, Russia, <satr at sao.ru>

S.A. Trushkin, A.K. Erkenov, P.G. Tsybulev and N.A. Nizhelskij (SAO RAS)
report:

We have observed GRB 171205A (D'Elia et al.; GCN Circ. 22177) with
the RATAN-600 radio telescope at 4.7 and 8.2 GHz from December 9 to
December 16 2017 daily. We have detected a radio fluxes within the RA
errors of the source detected with VLA (Laskar et al.; GCN Circ. 22216).
The mean flux densities are equal 15 +- 2 and 19 +- 2 mJy at 4.7 and 8.2
GHz respectively. But we must notice that there is a known NVSS source
J110939.0-123330  (32 mJy at 1.4 GHz), also detected in the
GLEAM multi-frequency survey: J110938-123334 in the field of GRB 171205A
(J110939.5-123518).
We have probably detected contributions from both sources with the
RATAN arcmin-beams. Thus if we subtract the fluxes from the
NVSS source, using the power-law fitting of its spectrum
we can estimate the refined fluxes from GRB 171205A:  < 3 mJy at 4.7 GHz
and 10 +- 3 mJy at 8.2 GHz for mean epoch: December 12 (MJD 58099.0),
i.e. ~7.3 days after the burst.
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