We have discovered a transient in the MACS J0257.1-2325 galaxy-cluster field in imaging acquired by the Hubble Space Telescope SNAP program GO-16729. In exposures taken on August 30, 2022 UT, the transient’s F105W apparent magnitude is 25.17 +- 0.28 mag, and it is not detected in the F606W with a three-sigma upper limit of 27.2 mag. We measure its coordinates to be 02:57:09.3920 -23:26:23.826 (J2000). The transient is offset from two nearby galaxies which, currently both lack a spectroscopic redshift even though MUSE spectroscopy is available. Photometric redshifts (with 95% confidence limits) from the RELICS program are 2.0-1.1+0.6 and 1.5-0.15+0.27. Using current constraints on the lens model, a GLAFIC model finds that the supernova may be multiply imaged if it is at sufficiently high redshift (>~2), although a lack of counter images suggests itis probably not. In either case, the magnification is predicted by the GLAFIC model to be 2 or smaller. Efforts are ongoing to identify additional lens model constraints. A second visit by the GO-16729 program is scheduled for September 8, 2022 UT.
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 | 2022tqq | 02:57:09.392 | -23:26:23.83 | SN | 02:57:09.392 | -23:26:23.83 |