[vsnet-grb-info 22230] LIGO/Virgo S190426c: Continued infrared wide-field search with Palomar Gattini-IR

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24329
SUBJECT: LIGO/Virgo S190426c: Continued infrared wide-field search with Palomar Gattini-IR
DATE:    19/04/28 15:04:06 GMT
FROM:    Matthew Hankins at Caltech  <mhankins at caltech.edu>

M. Hankins (Caltech), K. De (Caltech), M. Coughlin (Caltech), M. M.

Kasliwal (Caltech), S. M. Adams (Caltech), I. Andreoni (Caltech), S.

Anand (Caltech), L. Singer (NASA GSFC), T. Ahumada (UMD),  A. Moore

(ANU), J. Soon (ANU), M. Ashley (UNSW), T. Travouillon (ANU), R. Lau (ISAS JAXA)


report on behalf of the Palomar Gattini-IR team and the larger GROWTH

(Global Relay of Observatories Watching Transients Happen)

collaboration


We report continuing wide-field near-infrared follow-up observations (GCN #24284)

of the localization region of the gravitational wave event S190426c (GCN

#24237) by the Palomar Gattini-IR survey (Moore and Kasliwal 2019).

Gattini-IR is a newly commissioned near-IR camera with a field of view

of 25 square degrees mounted on a robotic 30 cm telescope at Palomar

observatory.


We started customized Target of Opportunity observations at UT

2019-04-28 03:28. The tiling was optimally determined and triggered

using the GROWTH Target of Opportunity marshal (Coughlin et al. 2019a,

Kasliwal et al. 2019b). We imaged a total of 1900 square degrees,

covering 94% of the probability region of the event for 1 to 5 epochs

until UT 2019-04-28 12:33. Each field visit consisted of a sequence of

8 dithers of 8 second exposures each on the field, which were

processed and stacked with the Palomar Gattini-IR data reduction

pipeline (De et al., in prep.). The typical limiting magnitude of each

stacked epoch (64 second exposure time) was between 14.5 and 15.5 AB mag

in J-band, and shallower than usual due to poor weather conditions.

No viable counterparts without previous history of variability were identified.