DRAFT
2025-07-24 09:30:58
Type: Object/s-Discovery/Classification
Bibcode: 2025TNSAN.227....1G
Detection of young transient AT2025rza in the giant elliptical galaxy Centaurus A
Authors: P.J. Groot (Radboud/UCT/SAAO) , M. Mlangeni (UCT/SAAO), O. Mogawana (UCT/SAAO), G. Ramsay (Armagh/Warwick), H. Tranin (Barcelona), J. van Roestel (Amsterdam), P.M. Vreeswijk (Radboud), F. Stoppa (Oxford)
Source Group: BlackGEM
Keywords: Transient, Nova, Supernova, Photometry, Time-domain, Surveys, Galaxy
Abstract:
The BlackGEM consortium announces the discovery of the young transient BGEM J132508.95-430244.3/AT2025rza, 4 arcminutes away from the center of the giant elliptical galaxy Centaurus A. In the latest observations the transient is detected at q=18.6, corresponding to an absolute magnitude of -9.1, when adopting a distance of 3.5 Mpc towards Centaurus A. The relatively slow rise is more indicative of a nova than a supernova but spectroscopic confirmation is needed.

The BlackGEM consortium reports the detection of BGEM J132508.95-430244.3/AT2025rza at RA,DEC (ICRS) = 201.287308 -43.045653
= 13:25:08.954 -43:02:44.35. The transient was first detected at 2025-07-22 23:39:16 UT at q=19.42 +/- 0.10, with no detections in the BlackGEM u- and i-bands and brightened on the subsequent night to q=18.59 +-/- 0.06 and i = 18.55 +/- 0.1. The last non-detection of the source was on 2025-07-20 23:49:59 UT at 6-sigma limit for transients of q>20.1.

AT2025rza is located in the outskirts of the giant elliptical galaxy Centaurus A, at ~4 arcminutes from the center of Centaurus A. Adopting a distance to Centaurus A of 3.5 Mpc, the transient is currently at absolute magnitude of -9.1.

The relatively slow rise is more indicative of a nova than a supernova, but spectroscopic confirmation is needed.

BlackGEM is designed, built and operated at the ESO La Silla Observatory, Chile by a consortia of universities and institutes, including
Radboud, NOVA, KU Leuven, Armagh, Barcelona, Tel Aviv, Weizmann, HUJI, Potsdam, Hamburg, DTU Space, Manchester, Warwick, Durham, UC Davis, TexasTech, LCO, Valparaiso.

Show current TNS values
Catalog Name Reported RA Reported DEC Reported Obj-Type Reported Redshift Host Name Host Redshift Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2025rza 13:25:08.954 -43:02:44.35 13:25:08.954 -43:02:44.35

Comments