TITLE:   GCN CIRCULAR
NUMBER:  24440
SUBJECT: LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
DATE:    19/05/10 05:47:43 GMT
FROM:    Gregg Hallinan at OVRO-LWA  <gh@astro.caltech.edu>

Dillon Dong (Caltech), Gregg Hallinan (Caltech), Dale Frail (NRAO) and
Kunal Mooley (NRAO/Caltech) report:

The VLA Sky Survey observed a field containing the nuclear optical
transient  ZTF19aassfws (Perley et al., GCN 24331) on 2019-04-12 at UT
14:16:53, 14 days prior to the compact object merger candidate S190426c
(LVC et al.; GCN 24237). There is no archival 3GHz source at the
transient location, with a local 3 sigma upper limit of 390uJy. This
rules out a radio-luminous AGN with a specific luminosity greater than
9x10^28 erg/s/Hz at the spectroscopic redshift reported by Cenko (GCN
24430).

The VLA Sky Survey (VLASS) is a multi-epoch, 2-4 GHz survey with the
Karl G. Jansky Very Large Array (VLA) covering the full sky north of
declination = -40 degrees at ~2.5" resolution to a 1-sigma depth of
~120uJy/beam per epoch. Observations and data reduction for the VLASS
are carried out by staff of the National Radio Astronomy Observatory
(NRAO). The NRAO is a facility of the National Science Foundation
operated under cooperative agreement by Associated Universities, Inc.