TITLE:   GCN CIRCULAR
NUMBER:  22350
SUBJECT: e-MERLIN detection of GRB 171205A
DATE:    18/01/16 08:29:20 GMT
FROM:    Miguel Perez-Torres at IAA-CSIC  <torres@iaa.es>

Miguel Perez-Torres (IAA-CSIC), J. Moldon (JBCA), E. Varenius (JBCA), R. Beswick
(JBCA), Antxon Alberdi (IAA-CSIC), S. Bradley Cenko (NASA), and Assaf Horesh
(HUJI) report:

We observed GRB 171205A (D'Elia et al., GCN 22177) with the electronic
Multi-Element Radio Linked Interferometer Network (eMERLIN) on 2017 Dec 20 (from
20.06 UT until 20.35 UT) and on 2017 Dec 21 (from 21.06 UT until 21.31 UT), for
a total of 12.7 hr.

The observations were carried out with a five-array telescope (Mk2, Pi, Da, De,
Cm) at a central frequency of 5.1 GHz, with a bandwidth of 512 MHz.  The
synthesized beam was of 0.22x0.030 sq. arcsec at a position angle of 17.7 deg. 

We clearly detected GRB 171205A with a peak flux density of 7.9 mJy/beam.  The
off-source rms was of 0.05 mJy/b, and the calibration uncertainty is about 5%,
for a total uncertainty in the GRB flux density of 0.4 mJy.  

We thank the e-MERLIN staff for the time allocation and their help with the
observations.