TITLE: GCN CIRCULAR NUMBER: 42675 SUBJECT: LIGO/Virgo/KAGRA S251112cm: TROVE Vetting of TNS Candidates DATE: 25/11/13 22:30:11 GMT FROM: Noah Franz at University of Arizona/Steward Observatory <noahfranz13@gmail.com> N. Franz (U. Arizona), N. Vieira (Northwestern), C. D. Kilpatrick (Northwestern), D. J. Sand (U. Arizona), B. Subrayan (U. Arizona), G. Hosseinzadeh (UC San Diego), M. Shrestha (Monash U), K. D. Alexander (U. Arizona), W. Fong (Northwestern), report on behalf of the TROVE collaboration: We analyzed candidate counterparts to the LIGO/Virgo/KAGRA (LVK) gravitational wave event S251112cm (GCN 42650) using the Multi-messenger Tool for Rapid Object Vetting and Examination (TROVE). We searched within the 95th percentile localization region for candidate optical counterparts in host galaxies at the approximate luminosity distance of S251112cm. We further crossmatch to minor planet and point source catalogs and rule out sources that do not appear photometrically similar to kilonova light curves. For additional details, see the vetting procedures described in N. Franz, et al., 2025, arXiv:2510.17104. Below, we report all candidates that remain viable after running our vetting procedure using publicly available information on all publicly reported sources, to date, on the Transient Name Server (TNS). We include their TNS identifier, coordinates, cumulative probability at the coordinate location in the latest LVK map, most likely host redshift, most recent magnitude, and the initial reporting group. Candidates are ranked using a scoring procedure designed to identify kilonova counterparts to GW events (N. Franz, et al., 2025, arXiv:2510.17104). The reported candidates are not clearly identified as kilonovae, but we note that the progenitor system of S251112cm is poorly constrained given the exceptional attributes of the event as reported by LIGO: a probability of the system containing a neutron star < 8%, probability of containing a sub-solar mass object >99%, and a chirp mass in the range 0.1 to 0.87 solar masses. | TNS Name | RA [HMS] | Dec [DMS] | Localization Probability Contour | Most likely Host-z | Most recent public magnitude | Discovery Survey | Comments | | ------- | ------ | ------- | ------- | ------- | ------- | ------- | ------- | | AT2025adht | 12:00:24.350 |+49:02:51.95 | 0.83 | 0.11 +/- 0.07 (photo-z) | g=21.4 +/- 0.2 | ZTF | | | AT2025adgp | 01:47:46.202 | -51:49:25.52 | 0.20 | 0.06 +/- 0.02 (photo-z) | o=19.1 +/- 0.05 | BlackGEM | ATLAS pre-detection ~6 hours before S251112cm. This candidate was initially presented in GCN42663 and the ATLAS pre-detections were noted in GCN 42666. | | AT2025adhf | 02:43:44.411 | -55:19:06.44 | 0.15 | 0.11 +/- 0.02 (photo-z) | o=19.22 +/- 0.05 | ATLAS | ATLAS pre-detections in the ~week leading up to S251112cm. | | AT2025adhs | 04:12:56.396 | -54:11:46.41 | 0.09 | 0.04 (spec-z) | o=20.71 +/- 0.22 | BlackGEM | | We encourage additional follow up of these candidates to determine whether they remain viable counterparts to S251112cm. We note that there are 10 other transients reported to the TNS in the 95% localization region that we rule out for other reasons (e.g., excessive pre-detections, incorrect host distance as compared to S251112cm, etc.): AT2025adhj, AT2025addc, AT2025adhr, AT2025adhu, AT2025adhg, AT2025addb, AT2025adhh, AT2025adda, AT2025adhe, AT2025adgq. View this GCN Circular online at https://gcn.nasa.gov/circulars/42675. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...