GCN Circular 36289

D.L.A. Pieterse (Radboud), H. Tranin (Barcelona), J. van Roestel (Amsterdam), P.J. Groot (Radboud, UCT, SAAO), P.M. Vreeswijk (Radboud), S. Bloemen (Radboud) and P.G. Jonker (Radboud) report on behalf of the BlackGEM/MeerLICHT Consortium:

Following the DECam candidate counterparts to S240422ed reported by (Hu et al., GCN 36273
Not found
 
 
), we looked at archival data of the the 0.6m BlackGEM/MeerLICHT telescope array located at the ESO La Silla, Chile and SAAO Sutherland, South Africa observatories.

We detect DECam candidates AT 2024hdr
Not found
 
 
 and AT 2024hdq
Not found
 
 
 as nuclear transients in archival 60s q-band (440-720 nm) images of BlackGEM and MeerLICHT. We therefore conclude that these are not the GW counterpart.
No  Name        night range            q_mag range
1   AT 2024hdr
Not found
 
 
  2023/12/06-2024/04/23  19.0-19.5
2   AT 2024hdq
Not found
 
 
  2022/12/31-2024/12/03  18.6-19.2

We report transient limiting magnitudes for the other DECam candidates from (Hu et al., GCN 36273
Not found
 
 
):
No  Name        limmag filter  date-obs
1   AT 2024hdk
Not found
 
 
  >19.6  i       2024-04-08 00:12:33
2   AT 2024hdn
Not found
 
 
  >19.6  q       2024-04-23 21:25:02
3   AT 2024hdm
Not found
 
 
  >19.9  q       2024-04-23 21:20:59
4   AT 2024hdl
Not found
 
 
  >20.0  i       2024-04-17 23:46:19
5   AT 2024hdo
Not found
 
 
  >20.3  q       2024-04-23 23:26:45
6   AT 2024hdp
Not found
 
 
  >19.9  q       2024-04-23 19:39:27

Transient candidates were extracted using the BlackBOX/ZOGY pipeline, where astrophotometric calibrations are performed using Gaia DR3 photometry and astrometry. Possible asteroids are filtered using the daily-updated lists of known asteroids from the Minor Planet Center. All magnitudes quoted are on the AB system.

The BlackGEM/MeerLICHT telescope are designed, installed and operated by a consortium of the following universities and institutions: Radboud University, Netherlands Research School for Astronomy NOVA, KU Leuven, Armagh Observatory and Planetarium, Technical University of Denmark, Hebrew University of Jerusalem, South African Astronomical Observatory, Tel Aviv University, Texas Tech University, University of Amsterdam, University of Barcelona, University of California at Davis, University of Cape Town, University of Durham, University of Hamburg, University of Manchester, University of Oxford, University of Potsdam, University of Valparaiso, University of Warwick, Weizmann Institute