{
  "bibcode": "2020GCN.27057....1H",
  "body": "Ulrich Hopp, Matthias Kluge, Claus Goessl, Christoph Ries,\nMichael Schmidt (University Observatory Munich, LMU, Munich Germany)\n\nAT2019wxt = PS19hgw was reported as a potential optical counterpart\nfor the LIGO/Virgo S191213g target at RA = 01:55:41.94,\nDec = +31:25:04.4, McBrien et al. 2019 (GCN26485). Follow-up\nphotometry pointed towards a blue and fastly faiding object (Huber\net al. 2019, GCN 26577). Follow-up spectroscopy favored the\nidentification as a supernova similar to SN2011fu of type SN IIb\n(Valeev et al. 2019, GCN 26591 and references therein).\n\nWe here present three channel optical and near-infrared photometry\nin g', i' and J taken with the 3KK camera (Lang-Bardl et al., 2016,\nSPIE 9908) mounted at the 2m telescope of the Wendelstein Observatory\n(University of Munich). Five epochs were obtained from shortly after\ndetection until about 20 days after maximum. A further\nimage set was taken after the SN faded below our detection limit.\nThat image served for difference image photometry of the SN to\nminimize the impact of the host galaxy light on the SN photometry.\nThe SN location is within the disk of the spiral host galaxy\nKUG 0152+311. On our images, the SN appears to be in a inter-arm\narea of the spiral galaxy.\n\nEigth comparison stars within the detector field served as magnitude\nreference for our aperture photometry. Magnitudes were obtained through\nthe CDS Strassbourg portal from SDSS DR9 (g', i') and 2MASS (J)\ncatalogs. Errors in the below table include the statistical error\nof the SN measurement and of the zero-point determination.\n\n  Date        UT      g'   +/-  i'   +/-    J   +/-  exp.time\n                                                     sec\n\n2019 12 18         19.78 0.08 20.10 0.09 20.26 0.08 1560\n2019 12 19         19.83 0.11 19.84 0.09 19.18 0.11 2340\n2019 12 21         20.10 0.06 19.83 0.06 18.96 0.10 1560\n2019 12 29         22.77 0.05 20.92 0.06 19.75 0.11 1560\n2020 01 06         23.68 0.08 22.64 0.07 20.69 0.12 1560\n2020 01 14        <24.0      <22.7      <21.0\n\nOur data around the maximum agree with previously reported optical\nphotometry (e.g. CGN 26485, 26500, 26503, 26517, 26577). Only one\nNIR observation was reported so far (D'Avanco et al. 2019 GCN 26499).\n\nOur data show that the object was very blue in the maximum phase but\nturned to a much redder color during the decline. The decline\nwas fast with a rate of delta mag/5d 1.12 in g', 0.80 in i', and 0.54\nin J, respectively. Our decline rates confirm the early estimate of\nHuber et al. in g' and i' obtained shortly after maximum. These rates\nare much faster than the decline of SN2011fu (see Kumar et al.\n2013 MNRAS 431, 308).\n\n\n***************************************************************************\n*\t\t\t         Dr. Ulrich Hopp                          *\n***************************************************************************\n* Universitaetssternwarte Muenchen    *  Tel.:     + 89 2180 5997         *\n*   Scheiner Str. 1                   *  Fax.:     + 89 2180 6003         *\n*   D 81679 Muenchen                  *  Tel.-MPE: + 89 30000 3913        *\n*   Germany                           *  email:                           *\n* und                                 *          hopp@usm.uni-muenchen.de *\n* MPI f. Extraterrestische Physik     *          hopp@usm.lmu.de          *\n*    Postfach 1312                    *          hopp@mpe.mpg.de          *\n*    85741 Garching                   *                                   *\n***************************************************************************\n*               http://www.usm.lmu.de/people/hopp/hopp.html               *\n***************************************************************************",
  "circularId": 27057,
  "createdOn": 1581601669000,
  "email": "hopp@mpe.mpg.de",
  "subject": "LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations",
  "submitter": "Ulrich Hopp at U Observatory Munich  <hopp@mpe.mpg.de>",
  "eventId": "LIGO/Virgo S191213g"
}