{
  "bibcode": "2019GCN.23962....1S",
  "body": "J. Selsing (DAWN/NBI), Z.P. Zhu (NAOC), D. Xu (NAOC), D. Malesani��\n(DAWN/NBI, DARK/NBI), D. Nespral (IAC), D. Gandolfi (Univ. Turin), and��\nJ. Telting (NOT), report on behalf of a larger collaboration:\n\nWe have observed the optical afterglow of GRB 190311A (Troja et al.,��\nGCN 23946; Goad et al., GCN 23950; Veres & Meegan, GCN 23953) with the��\n2.5-m Nordic Optical Telescope (NOT). We have obtained an r+z imaging��\nsequence using the ALFOSC instrument, with 4x300 and 5x300 s exposure in��\nthe r and z band, respectively. Imaging observations began 9.4 hr after��\nthe BAT trigger.\n\nIn the images we clearly detect the optical counterpart of GRB 190311A,��\nas previously reported (Zhu et al., GCN 23948; Pozanenko et al., GCN��\n23947; Gorbovskoy et al., GCN 23949; Belkin et al., GCN 23951; Mao et��\nal., GCN 23954; Peris & Fernandez-Soto, GCN 23959).\n\nWe calibrate the photometric zeropoints against the Pan-STARRS catalog\nand derive the following magnitudes for the optical counterpart:\n\nr = 21.88 +- 0.03 AB mag\nz = 21.26 +- 0.04 AB mag\n\nThe source is centred at the position:\n\nRA (J2000.0) = 14:08:15.726\nDEC (J2000.0) = +53:30:02.74\n\nwith the astrometric solution calibrated against the 2MASS catalog.",
  "circularId": 23962,
  "createdOn": 1552427233000,
  "email": "jselsing@dark-cosmology.dk",
  "subject": "GRB 190311A: NOT optical counterpart",
  "submitter": "Jonatan Selsing at DARK/NBI  <jselsing@dark-cosmology.dk>",
  "eventId": "GRB 190311A"
}