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LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates

15 Jun 2023

With the 3kk imager at the 2m Fraunhofer telescope at Wendelstein Observatory, Germany, we have observed the highest probability candidate host galaxies.

With the 3kk imager at the 2m Fraunhofer telescope at Wendelstein Observatory, Germany, we have observed the highest probability candidate host galaxies based on their sky position and DESI spectroscopic redshift with respect to the 3D localization of event S230615az. Observations took place between MJD 60110.8 and MJD 60110.9, 3-4 hours after the gravitational wave candidate event. Using Legacy Survey DR10 imaging as a template where available, we perform difference imaging and do not detect any viable candidate counterparts. We report the following upper limits within a ~7'x7' field around the given coordinates: RA(J2000) [deg] | dec(J2000) [deg] | date_obs [UTC] | filters | lim_mag(AB, 5sigma) 167.3605 | 29.5734 | 2023-06-15T21:27:32.858393 | r,i | 22.9, 22.7 167.6634 | 28.3207 | 2023-06-15T21:48:52.763590 | r,i | 22.6, 22.6 167.7216 | 30.1690 | 2023-06-15T21:38:13.808422 | r,i | 22.8, 22.6 168.0171 | 27.5943 | 2023-06-15T21:16:55.039852 | r,i | 22.7, 22.5 169.5725, 28.2641 | 2023-06-15T23:10:35.119420 | r,i | 22.6, 22.3 174.2707 | 24.1003 | 2023-06-15T21:59:32.521545 | r,i | 22.3, 22.3 175.6390 | 26.4931 | 2023-06-15T20:48:24.528448 | r,i | 22.6, 22.3 149.4729| 36.3526 | 2023-06-15T21:06:05.721774 | r,i | 22.3, 22.3 We have also followed up the GROWTH-India candidate counterparts reported by GCN 33974 consistent with the gravitational wave event S230615az. We report the following upper limits: Name | date_obs [UTC] | filters | lim_mag(AB, 5sigma) GIT230615aa | 2023-06-15T22:29:56.229398 | r | 22.7 GIT230615ab | 2023-06-15T22:38:41.867278 | g | 21.9 GIT230615ab |2023-06-15T22:47:20.897141| r | 22.7 Magnitudes are not corrected for Milky Way extinction.