TITLE: GCN CIRCULAR NUMBER: 21939 SUBJECT: LIGO/Virgo G298048: Further European VLBI Network (EVN) observations of SSS17a DATE: 17/09/28 10:35:27 GMT FROM: Zsolt Paragi at Euro VLBI Zsolt Paragi (JIVE), Jun Yang (OSO), Benito Marcote (JIVE) et al. for the Euro VLBI team Continuing our efforts (LVC GCN 20981, 21804) to detect radio emission from SSS17a (Coulter et al. LVC GCN 21529) on milliarcsecond scales, we observed the transient at 5 GHz with the European VLBI Network between 10:00—14:30 UT on 20 September 2017. The 5 sigma upper limit around the HST/Gaia position (Adams, Kasliwal & Blagorodnova, LVC GCN 21816) is 140 microJy/beam. Further observations are planned. 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) The EVN is a joint facility of independent European, African, Asian, and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project code: RP029. -- 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