DRAFT
2024-03-14 17:16:35
Type: Object/s-Discovery/Classification
Bibcode: 2024TNSAN..75....1T
BGEM J191145.30-570804.0 (AT2024egc): discovery of a supernova candidate in ESO 184-25 (44Mpc)
Authors: Hugo Tranin, Nadia Blagorodnova (ICCUB), Fiorenzo Stoppa, Danielle Pieterse, Paul Groot, Paul Vreeswijk (Radboud University ), Jan Van Roestel (University of Amsterdam), Gavin Ramsay (Armagh Observatory and Planetarium), Sara Faris (Tel Aviv University) on behalf of BlackGEM
Source Group: BlackGEM
Keywords: Optical, Time-domain, Supernova
Abstract:
Here we report the BlackGEM discovery of the transient BGEM J191145.30-570804.0 (AT2024egc) in the galaxy ESO 184-25 at magnitude m_q = 17.39 +/- 0.02. At a distance of 44 Mpc, the transient was discovered on MJD = 60383.40 (2024-03-14.40) with an absolute magnitude of M_q = -15.8 +/- 0.1. The last non-detection through forced photometry in ATLAS was on MJD = 60380.39 (5-sig limiting o-band magnitude of 19.1). Early light curve suggests that the transient is rising. Spectroscopic classification is encouraged.

We report a new transient source, most likely a supernova in the galaxy ESO 184-25. We discovered BGEM J191145.30-570804.0 (AT2024egc) on MJD 60383.40 == 2024-03-14.40, at m_q = 17.39 +/- 0.02. There was no detection by ATLAS on MJD 60380.39 == 2024-03-14.39 (down to limiting magnitude mag5sig_o = 19.1), and the five q-band detections within 10 minutes tentatively suggest that the transient is rising. BGEM J191145.30-570804.0 is offset by 1.0 arcsec south, 4.2 arcsec west from ESO 184-25, which is at z = 0.01014 or d = 44 Mpc (from NED), implying an absolute magnitude of M_q = -15.8 (assuming m-M = 33.22, not corrected for extinction which is Av=0.228). Followup observations are encouraged.

BlackGEM is an array of three 65cm telescope system located at ESO La Silla, Chile, designed, built and operated by an international consortium. It features six filters (u,g,q,r,i,z), with the q-band being the broader and more sensitive (440-720nm). With a standard exposure time of 60s, BlackGEM can detect transients as faint as 21st magnitude (q-band in grey sky). More information can be found on the BlackGEM website.

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 2024egc [BGEM J191145.30-570804.0] 19:11:45.308 -57:08:04.06 ESO 184-25 0.01014 19:11:45.308 -57:08:04.06 SN IIn 0.01014

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