GOTO-FAST reports the classifications of the following optical transients. The observations were obtained on the Nordic Optical Telescope (NOT) on the nights of 2025 Aug 30 and 2025 Aug 31 using the ALFOSC spectrograph with Gr4 grating (3200-9600 Å, R ~360). The transients were classified using SNID-SAGE (Stoppa 2025), SNID (Blondin & Tonry 2007) and GELATO (Harutyunyan et al. 2008).
Targets were supplied by the Gravitational-wave Optical Transient Observer GOTO (Steeghs et al. 2022, Dyer et al. 2024) and ATLAS survey (Smith et al. 2020).
The candidate TDE event 2025vjw / GOTO25gin displays absorption features we identify as Ca H and K as well as tentative broad features that may be He. Template matching suggests a TDE-H-He classification at z=0.21. We note that this is consistent with the photometric redshift of the host from Legacy Surveys of z=0.210±0.005. While Type Ia SNe are often found in or near the nucleus of galaxies, a redshift of z=0.21 would result in a peak magnitude (m_L ~ 18.73 mag) in excess of M < -21, unlikely for a type Ia SN. While it is possible for SLSNe to achieve such luminosities, we note that the host galaxy appears red and elliptical in nature in Legacy Surveys imaging and the Tractor catalogue, and thus, is an unlikely host for a SLSN. If indeed a TDE, this could be a member of the “TDE featureless” class based on the persistent blue featureless spectra and the bright luminosity (Mg ~ -21.7). We strongly encourage follow-up of this object in order to determine its nature.
The classified objects are listed below in the Related Objects Table.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Source | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2025vhj [ATLAS25kia] | 21:56:36.368 | -10:07:05.89 | SN Ia | 0.084 | Good matches to type Ia around peak. Classification in agreement with previous classification report (Fremling et al. #21930). Redshift from host. | 21:56:36.368 | -10:07:05.89 | SN Ia | 0.084 | |||
| TNS | 2025wdo [ATLAS25ksd] | 01:22:22.871 | -21:16:25.52 | SN Ia | 0.07 | Good matches to SN Ia around one week pre-peak. Redshift from template | 01:22:22.880 | -21:16:25.58 | SN Ia | 0.07 | |||
| TNS | 2025whv [GOTO25gnw] | 23:20:30.518 | +12:14:30.03 | SN Ia-91T-like | 0.1 | Consistent with a Type Ia-91bg approaching peak. Redshift from template. | 23:20:30.538 | +12:14:30.25 | SLSN-I | 0.11 | |||
| TNS | 2025wla [GOTO25gol] | 00:04:05.536 | +02:39:35.42 | SN Ia | 0.1 | Consistent with a Type Ia approximately 1 week pre-peak. Redshift from template. | 00:04:05.527 | +02:39:35.65 | SN Ia | 0.1 | |||
| TNS | 2025vrt [GOTO25gkm] | 00:17:44.382 | +05:55:05.74 | SN Ia | 0.07 | Consistent with a Type Ia around peak. Redshift from template. | 00:17:44.386 | +05:55:05.75 | SN Ia | 0.07 | |||
| TNS | 2025wnt [GOTO25gqp] | 04:50:13.272 | +08:08:02.09 | SN Ia | 0.032 | Consistent with a Type Ia around 1 week pre-peak. Redshift from narrow lines. | 04:50:13.279 | +08:08:02.73 | SN Ia | 0.032 | |||
| TNS | 2025wld [GOTO25got] | 04:49:28.249 | +06:59:37.35 | SN Ia | 0.03 | Consistent with a Type Ia 1-2 weeks post peak. Redshift from template. | 04:49:28.249 | +06:59:37.35 | SN Ia | 0.03 | |||
| TNS | 2025vjw [GOTO25gin] | 23:09:00.791 | -07:31:07.73 | Other | 0.21 | Spectrum shows a blue continuum with tentative broad features that could be He as well as features we identify as Ca H and K. Template matching with SNID and SNID-SAGE suggest a TDE classification at z=0.21. However, the lack of strong, unambiguous features precludes definitive typing and we leave as Other. Redshift from template matching and presence of absorption features in spectrum. | 23:09:00.817 | -07:31:07.77 | TDE-H-He | 0.21 |
Comments
Correction: The remark for SN 2025whv should read "Consistent with a Type Ia-91T" and not "Ia-91bg".