Michael J. Lundquist, David J. Sand (UA), Jillian Rastinejad, Kerry
Paterson (Northwestern), Jennifer Andrews (UA), Wen-fai Fong,
(Northwestern), Sam Wyatt, Eric Christensen, Alex Gibbs, Frank Shelly (UA),
report on behalf of the SAGUARO collaboration:
We initiated observations of 36 fields (each 5 deg^2, totalling 180 deg^2)
within the LVC localization region for the GW trigger S200114f (LVC Circ
26734) starting on 2020-01-14 at 4:15 UT (2.12 hours after the GW trigger)
with the 1.5m Catalina Sky Survey (CSS) telescope on Mt. Lemmon, AZ. The
typical limiting magnitudes of single pointings are G~21 mag (calibrated to
We have posted our pointings to the Treasure Map, and encourage others to
do the same:
We perform real-time processing and image subtraction (described in
Lundquist et al. 2019, ApJL, 881, 2). After discarding known moving
objects, stellar sources and known transients (cross-correlating with the
Transient Name Server and the ZTF alert stream), we find no strong
candidates that we believe to be associated with the GW event with S/N>5.
Due to the uncertain nature of the GW event however, we report 5
additional, less likely candidates below for completeness. These are
possibly variable stars or AGN. All magnitudes are based on our difference
imaging and have been calibrated to Gaia G band.
Name | RA | Dec | AB Mag | Mag Error | Notes
SAGUARO20a 07:13:08.744 14:00:07.313 20.19 0.11 (a),
SAGUARO20b 06:59:34.961 22:36:29.456 19.94 0.10 (a)
SAGUARO20c 07:05:34.026 22:44:44.495 20.67 0.20 (a), (b)
SAGUARO20d 07:20:21.244 07:35:19.555 19.85 0.10 (a)
SAGUARO20e 07:04:10.181 16:27:38.455 19.29 0.07 (d)
(a) Possible Variable Star
(b) Coincident with faint PS1 source
(c) Faded by 0.78 mag over 30 min
(d) Nuclear; possible AGN
SAGUARO is supported by the National Science Foundation under Award Nos.
AST-1909358 and AST-1908972.