TITLE: GCN CIRCULAR NUMBER: 21940 SUBJECT: LIGO/Virgo G298048: Record of all e-MERLIN results to date on SSS17a DATE: 17/09/28 11:12:37 GMT FROM: Zsolt Paragi at Euro VLBI Javier Moldon, Rob Beswick (JBCA, The University of Manchester) et al. for the EuroVLBI team We conducted a total of 22 e-MERLIN observations of SSS17a (Coulter et al. LVC GCN 21529) from Aug 23 to Sep 22, 2017 for about 5 hours per run. The observing frequency was centred at 5 GHz with a bandwidth of 512 MHz. The average synthesized beam size was about 200 mas x 30 mas at a position angle of about 0 deg. There are no significant detections in individual runs or in different combinations of adjacent runs coincident with the position of the transient. The 3-sigma upper limits in microJy/beam are listed below (first six runs were already reported in LVC GCN 21804). UTC date and times refer to the middle of the experiments: run00 2017-08-23 15:36:28 110 run01 2017-08-24 15:33:42 90 run02 2017-08-25 15:30:26 97 run03 2017-08-26 15:30:26 112 run04 2017-08-27 15:30:22 87 run05 2017-08-28 15:30:26 82 run06 2017-08-31 15:01:26 109 run07 2017-09-01 15:01:26 114 run08 2017-09-02 15:04:42 144 run09 2017-09-03 15:01:26 166 run10 2017-09-04 15:01:26 147 run11 2017-09-05 15:31:29 162 run12 2017-09-10 14:54:42 126 run13 2017-09-11 14:44:42 151 run14 2017-09-12 14:03:28 113 run15 2017-09-14 13:26:42 147 run16 2017-09-15 14:03:28 106 run17 2017-09-16 14:03:28 118 run18 2017-09-17 14:03:28 111 run19 2017-09-18 14:03:28 111 run20 2017-09-21 14:18:28 132 run21 2017-09-22 13:34:42 121 Additional observations are planned with e-MERLIN to continue the monitoring of the transient source. Euro VLBI team members: Ivan Agudo (IAA Granada) Tao An (Shanghai Astronomical Observatory) Philippe Bacon (APC Université Paris Diderot) Rob Beswick (JBO-Manchester University) Carolina Casadio (MPIfR-Bonn) Eric Chassande-Mottin (APC Université Paris Diderot) Sándor Frey (Konkoly Observatory) Marcello Giroletti (IRA-INAF) Peter Jonker (SRON) Mark Kettenis (JIVE) Benito Marcote (JIVE) Javier Moldon (JBO-Manchester University) Zsolt Paragi (JIVE) Arpad Szomoru (JIVE) Huib van Langevelde (JIVE) Jun Yang (Onsala Space Observatory) e-MERLIN is a National Facility operated by the University of Manchester at Jodrell Bank Observatory on behalf of STFC. -- Zsolt Paragi Head of User Support Joint Institute for VLBI ERIC (JIVE) Web: http://www.jive.eu Oude Hoogeveensedijk 4 Phone: +31 (0)521-596-536 7991 PD Dwingeloo Mobile: +31 (0)629-034-718 the Netherlands Fax: +31 (0)521-596-539