TITLE:   GCN CIRCULAR
NUMBER:  21542
SUBJECT: LIGO/Virgo G298048: Optical Candidate Shows No Evidence for Previous Activity in Archival SkyMapper Transient Survey Data
DATE:    17/08/18 04:46:27 GMT
FROM:    Anais Moller at Australian National U  <anais.moller@anu.edu.au>

A. M��ller, S. Chang, C. Wolf

We investigate SkyMapper Transient Survey data at the position of the optical source reported by Coulter et al. (LVC GCN 21529), Allam et al. (LVC GCN 21530), Yang et al. (LVC GCN 21531), Melandri et al. (LVC GCN 21532). We obtained subtraction photometry for the coordinates RA = 13:09:48.09 DECL. = -23:22:53.35 finding no evidence of variability between 2015-05-08 and 2017-07-22. The last observations of the SkyMapper Transient Survey of this field was on 2017-07-22 (limiting magnitude 19.6 in i) and 2017-07-21  (limiting magnitude 20.5 magnitude in r, 19.16 in i). 

The data and thumbnails can be found here:
https://www.mso.anu.edu.au/skymapper/smt/extra

The photometry is generated by placing an aperture at the indicated coordinates in difference images.

Further observations are ongoing.