{
  "bibcode": "2019GCN.26485....1M",
  "body": "O. McBrien, S. J. Smartt, K. W. Smith, D. R. Young, J. Gillanders. S. Srivastav, P. Clark, D. O'Neill, M. Fulton, S. McLaughlin (QUB), K.C. Chambers , M. E. Huber, A.S.B. Schultz, T. de Boer, J. Bulger, J. Fairlamb, C.C. Lin, T. Lowe, E. Magnier , R. J. Wainscoat, M. Willman (IfA, Univ. Hawaii), A. Rest (STScI), C. Stubbs (Harvard), T.-W. Chen (Stockholm) on behalf of the Pan-STARRS collaboration report:\n\nWe report the Pan-STARRS1 (Chambers et al. 2016, arXiv:1612.05560)\ndiscovery of an intrinsically faint optical transient in the 80%\nprobability contour of the compact binary merger event S191213g (The\nLIGO Scientific Collaboration and the Virgo Collaboration, GCN 26402).\n\nThe object, PS19hgw, was discovered on MJD 58833.305 (UTC 2019-12-16\n07:19:12) at a magnitude of 19.4 +/- 0.1 in the PS1-i band and\ncoordinates RA = 01:55:41.94, Dec = +31:25:04.4. We have registered it\non the TNS as AT2019wxt (McLaughlin et al. AstroNote 2019-154).\nPan-STARRS1 was observing part of the skymap (LALInference.fits) of\nS191213g during routine survey operations and its ongoing Pan-STARRS\nsearch for kilonovae (Smartt et al. AstroNote 2019-48). We had two more\ndetections on the same night, in the same filter. All exposures were\n45 seconds in duration.\n\nWe have no previous detections at the location of the transient with\nPan-STARRS, or indeed with ATLAS either (Tonry et al. 2018, PASP, 130,\n4505). There are no previous detections in the public ZTF transient\nstream (Bellm et al. 2018, PASP, 131, 995) as ingested in Lasair\n(Smith et al. 2019, RNAAS, 3, 26).\n\nWe had no detection on the previous night, MJD 58832.305 (UTC\n2019-12-15 07:19:12), but only one frame was taken in poor conditions\nand the limit is not constraining (>19.4 in the PS1-i band).\n\nThe most recent limits and photometry are: \n\nMJD           | mag    | err   | filter\n58829.348 |  <21.0 |   ...   | z \n58830.379 |  <20.3 |   ...   | z \n58830.379 |  <20.3 |   ...   | z \n58832.305 |  <19.4 |   ...   | i \n58833.335 |  19.37 | 0.07 | i\n58833.320 |  19.32 | 0.07 | i \n58833.305 |  19.38 | 0.05 | i \n\nPS19hgw/AT2019wxt shows an association with the galaxy KUG 0152+311 at\na redshift z = 0.036 (144 Mpc, NED). The current luminosity distance\nestimate accompanying the GW trigger, available through the\nLALInference.fits.gz skymap (GCN 26417), is 200 +/- 80 Mpc, placing\nPS19hgw/AT2019wxt within the plausible time-volume for association\nwith this event. The distance modulus to PS19hgw/AT2019wxt is 35.8,\ngiving an absolute magnitude at discovery of -16.5 in the PS1 i-band\n(assuming foreground extinction of A_i = 0.1). We note that this is 2\nmagnitudes brighter than AT2017gfo was at +3days after merger, but no\nless encourage spectroscopic follow-up of this object.",
  "circularId": 26485,
  "createdOn": 1576684952000,
  "email": "omcbrien02@qub.ac.uk",
  "subject": "LIGO/Virgo S191213g: Pan-STARRS1 discovery of a potential optical counterpart",
  "submitter": "O. McBrien at QUB  <omcbrien02@qub.ac.uk>",
  "eventId": "LIGO/Virgo S191213g"
}