{
  "bibcode": "2023GCN.33636....1R",
  "body": "Amit K. Ror, Rahul Gupta, S. B. Pandey, A. Aryan, K. Misra (ARIES), A. J.\nCastro-Tirado (IAA-CSIC), D. Bhattacharya (Ashoka University/IUCAA), and V.\nBhalerao (IITB) report on behalf of a larger collaboration:\n\nWe observed the field of GRB 230414B (D'Ai et al. GCN 33612; and Evans et\nal. GCN 33613) using the TANSPEC mounted at the axial port of the 3.6m\nDevasthal Optical Telescope (DOT) of ARIES Nainital. We have taken multiple\nframes with an exposure time of 300 sec each in r, and i filters on\n2023-04-14 and successive nights. We clearly detect the optical afterglow\n(Pankov et al. GCN 33615; Lu et al. GCN 33616; Raman et al. GCN 33618;\nGhosh et al. GCN 33620; Moskvitin et al. GCN 33622; Malesani et al. GCN\n33623; Zhu et al. GCN 33625; Belkin et al. GCN 33628; Fernandez et al. GCN\n33629; Quadri et al. GCN 33630; and Leonini et al. GCN 33634) in each\nindividual image taken on 2023-04-14. We report the preliminary brightness\nof the afterglow to be i = 19.95 +/- 0.16 mag ~ 43 minutes after the BAT\ntrigger. By combining our i-band magnitude with the observations of Raman\net al. GCN 33618, we determine the preliminary flux decay index of 0.60\n+/-0.08. Our observations indicate the slow flux decay behavior of the\nafterglow at the early epoch, as also noted by Malesani et al. GCN\n33623. Late-time\nobservations will further provide insight into jet geometry, circumburst\nmedium, and the total energy of the burst.\n\nThe magnitude quoted is not corrected for the Galactic and host extinctions\nin the direction of the burst. Photometric calibration is performed using\nthe standard stars from the PanSTARRS catalog.\n\n\nThis circular may be cited. 3.6m Devasthal Optical Telescope (DOT) is the\nrecently commissioned facility in the Northern Himalayan region of India\n(long:79 41 04E, lat:29 21 40N, alt:2540m) owned and operated by the\nAryabhatta Research Institute of Observational Sciences (ARIES), Nainital (\nhttps://www.aries.res.in). Authors of this GCN circular thankfully\nacknowledge consistent support from the staff members to run and maintain\nthe 3.6m DOT.",
  "circularId": 33636,
  "createdOn": 1681672898000,
  "email": "rahulbhu.c157@gmail.com",
  "subject": "GRB 230414B: 3.6m DOT Optical observations, slow decay at early epochs",
  "submitter": "Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 230414B"
}