TITLE: GCN CIRCULAR NUMBER: 21763 SUBJECT: LIGO/Virgo G298048: European VLBI Network (EVN) upper limit on 5 GHz compact emission from SSS17a DATE: 17/08/30 09:48:26 GMT FROM: Zsolt Paragi at Euro VLBI Zsolt Paragi (JIVE) 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) Arpad Szomoru (JIVE) Huib van Langevelde (JIVE) Jun Yang (Onsala Space Observatory) for the Euro VLBI team We observed SSS17a (Coulter et al. LVC GCN 21529) at 5 GHz with the European VLBI Network between 12:15—16:15 UT on 26 August 2017. Preliminary analysis shows no compact radio emission detectable on milliarcsecond angular scales above 160 microJy (~5 sigma) in a 1.6 x 1.6 arcsec region. Further observations are planned. 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