TITLE: GCN CIRCULAR NUMBER: 30280 SUBJECT: GRB 210619B: Liverpool Telescope First Hour Observations DATE: 21/06/20 19:09:26 GMT FROM: Manisha Shrestha at Liverpool John Moores U M. Shrestha (Liverpool JMU), A. Gomboc (Univ. Nova Gorica), C. Guidorzi (Univ. Ferrara) , S. Kobayashi (LJMU), A. Melandri (INAF), C. Mundell (Univ. Bath), R. Smith (LJMU) , I.A. Steele (LJMU), report on behalf of a wider collaboration: We observed the field of Swift GRB 210619B (D'Avanzo et al. GCN 30261; Jelinek et al. GCN 30263; Lipunov et al. GCN 30259; Zhao et al. GCN 30261; Kong et al. GCN 30265; Axelsson et al. GCN 30270; de Ugarte Postigo et al. GCN 30272; Zheng et al. GCN 30273; Blazek et al. GCN 30274; Kann et al. GCN 30275; Svinkin et al. GCN 30276; Xin et al. GCN 30277; Perley et al. GCN 30271 ) with the 2.0m Liverpool Telescope (LT), La Palma on 2021 June 20 starting at 00:21:14.141 UT for a period of 2 hours using the MOPTOP optical imaging polarimeter in the r’ band. Data was calibrated with respect to nearby APASS secondary standard stars. We confirm the optical counterpart reported by Swift UVOT (GCN 30261). At T=1318 seconds after the BAT trigger time, we measure r’ = 16.1 mag. Detailed analysis is ongoing. ________________________________ Important Notice: Liverpool John Moores University was established as a Higher Education Corporation under section 121 of the Education Reform Act 1988. Further information about Liverpool John Moores University can be found at https://www.ljmu.ac.uk/about-us The information in this email and any attachments is for the sole use of the intended recipient(s). If you are not an intended recipient, or a person responsible for delivering it to an intended recipient, you should delete it from your system immediately without disclosing its contents elsewhere and advise the sender by returning the email or by telephoning a number contained in the body of the email. No responsibility is accepted for loss or damage arising from viruses or changes made to this message after it was sent and the recipient must ensure that the email (and attachments) are virus free. The views contained in this email are those of the author and not necessarily those of Liverpool John Moores University. We will use the personal data information provided by you to respond to your email. For information about how we process personal data and monitor communications please see our Privacy Notice. https://www.ljmu.ac.uk/legal/privacy-and-cookies