GCN Circular 25458
Subject
LIGO/Virgo S190814bv: DESGW photometry of AT2019npv
Event
Date
2019-08-23T16:23:11Z (6 years ago)
From
James Annis at Fermilab <annis@fnal.gov>
James Annis, Ken Herner, Marcelle Soares-Santos, on behalf of the DESGW Team report:
The counterpart candidate AT2091pv, reported by Goldstein et al (GCN 25393) is near
a galaxy at a z=0.056 (Jonker et al, GCN 25454), which is consistent with the LIGO
distance for S190814bv of 267 +- 52 Mpc (GCN 25324, GCN. 25333). Smartt et al (GCN 25455)
report on Pan-STARRS z-band photometry in an effort to build a light curve, and further
data is reported by Chen et al (25457). Here we provide additional, independent photometry
for the object from the DECam images, which we obtained over 4 epochs.
We obtained several images of the region during the course of each night. We coadded all
images from a given night and bandpass to provide improved S/N. The MJD below refers to
the first exposure from each night; subsequent exposures on a given night were separated
by either ~30 or ~60 minutes. We did not detect the transient on the first night of
observations (MJDs of 58710.27 to 58710.34), likely due to poor observing conditions.
MJD | Band | Mag | MAGERR
58711.247 | i | 21.40 | 0.02
58712.220 | i | 21.54 | 0.02
58712.297 | z | 21.31 | 0.02
58713.262 | i | 21.61 | 0.02
58716.191 | i | 21.69 | 0.02
58716.193 | z | 21.25 | 0.01
These are observed magnitudes, not corrected for reddening. Our z-band photometry is
consistent with the Pan-STARRS within errors. Our i and z band data is fainter than
the Grond photometry by 2sigma using their errors, likely due to their magnitudes
containing galaxy light.
We note that the high quality i-band photometry is consistent with fading of 0.1 mag/day.
Our i-band light curve is well described by the following polynomial:
i-mag = -0.314 x**2 + 0.6951 x - 0.06361, where x = log10(mjd-58710)
The decline seems to be flattening out, and our fit suggests i=21.7 tonight.
*The DESGW Collaboration:
Sahar Allam (Fermilab), James Annis (Fermilab), Iair Arcavi (Tel Aviv U), Tristan Bachmann (U Chicago), Paulo Barchi (INPE & Brandeis U), Thomas Beatty (U of Arizona) Keith Bechtol (U of Wisconsin-Madison), Federico Berlfein (Brandeis U), Antonio Bernardo (U of Sao Paulo), Dillon Brout (U Penn), Robert Butler (Indiana U), Melissa Butner, (Fermilab), Annalisa Calamida (STScI), Hsin-Yu Chen (Harvard U), Chris Conselice (U of Nottingham), Carlos Contreras (STScI), Jeff Cooke (Swinburne U), Chris D���Andrea (U Penn), Tamara Davis (U Queensland), Reinaldo de Carvalho (UNICSUL), H. Thomas Diehl (Fermilab), Zoheyr Doctor (U Chicago), Alex Drlica-Wagner (Fermilab), Maria Drout (U Toronto), Maya Fishbach (U Chicago), Francisco Forster (U de Chile), Ryan Foley (UCSC), Joshua Frieman (Fermilab & U Chicago), Chris Frohmaier (U of Portsmouth), Ori Fox (STScI), Alyssa Garcia (Brandeis U), Juan Garcia-Bellido (U Autonoma de Madrid), Mandeep Gill (SLAC & Stanford U), Robert Gruendl (NCSA), Will Hartley (U College London), Kenneth Herner (Fermilab), Daniel Holz (U Chicago), Jorge Horvath (U of Sao Paulo), D. Andrew Howell (Las Cumbres Observatory), Richard Kessler (U Chicago), Charles Kilpatrick (UCSC), Nikolay Kuropatkin (Fermilab), Ofer Lahav (U College London), Huan Lin (Fermilab), Andrew Lundgren (U of Portsmouth), Martin Makler (CBPF), Clara Martinez-Vazquez (CTIO/NOAO), Curtis McCully (Las Cumbres Observatory), Mitch McNanna (U of Wisconsin-Madison), Robert Morgan (U of Wisconsin-Madison), Gautham Narayan (STScI), Eric Neilsen (Fermilab), Robert Nichol (U of Portsmouth), Antonella Palmese (Fermilab), Francisco Paz-Chinchon (NCSA & UIUC), Matthew Penny (OSU), Maria Pereira (Brandeis U), Sandro Rembold (UFSM), Armin Rest (STScI & JHU), Livia Rocha (U Sao Paulo), Russell Ryan (STScI), Masao Sako (U Penn), Samir Salim (Indiana U), David Sand (U of Arizona), Luidhy Santana-Silva (Valongo Observatory), Daniel Scolnic (Duke U), Nora Sherman (Fermilab), J. Allyn Smith (Austin Peay State U), Mathew Smith (U of Southampton), Marcelle Soares-Santos (Brandeis U), Lou Strolger (STScI), Riccardo Sturani (UFRN), Mark Sullivan (U of Southampton), Masaomi Tanaka (NAOJ), Nozomu Tominaga (Konan U), Douglas Tucker (Fermilab), Yousuke Utsumi (Stanford U), Stefano Valenti (UC Davis), Kathy Vivas (NOAO/CTIO), Alistair Walker (NOAO/CTIO), Sara Webb (Swinburne U), Matt Wiesner (Benedictine U), Brian Yanny (Fermilab), Michitoshi Yoshida (NAOJ), Alfredo Zenteno (NOAO/CTIO)