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GCN Circular 25477

LIGO/Virgo S190814bv: LCO Photometry of DG19wxnjc/AT2019npv
2019-08-26T04:30:11Z (5 years ago)
Michael Coughlin at Caltech/LIGO <>
Michael Coughlin, Tomas Ahumada, and Shreya Anand report on behalf of Global Relay of Observatories Watching Transients Happen (GROWTH):

We observed the transient DG19wxnjc/AT2019npv (Goldstein et al. GCN 25393) with the Siding Springs 2m Spectral imager of Las Cumbres Observatory (LCO) on 2019-08-22 from 16:31:28 UTC to 16:41:30 UTC and on 2019-08-24 from 19:11:45 UTC to 19:27:47 UTC. On the first night, we report non-detection upper limits of g > 21.3 +/- 0.1, r > 21.2 +/- 0.1, and i > 21.1 +/- 0.1 with 180 s exposures in all three filters.  Our second night of observations yielded detections of the transient with 300 s exposures in all three filters. Using references from the DECam Legacy Survey (DECaLS), we performed image differencing of our night 2 epochs and report photometry estimates of i = 21.9 +/- 0.2 and r = 22.5 +/- 0.2, with a low significance detection in g-band, g ~< 23.  We caution that we used an average of r-band and z-band DECaLS templates to perform image subtraction for the i-band image due to the unavailability of i-band references with DECaLS, making it difficult to make confident statements about the i-band evolution of the transient.

We encourage further photometric follow-up, and more observations are planned.
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