TNS Classification Report No. 21909 [ 2025TNSCR3449....1W ]

Date Received (UTC): 2025-08-29 14:56:59
Sender: David O'Neill
Group: GOTO

I. Worssam, M. Pursiainen, J. Lyman, D. O'Neill, T. Killestein, K. Ackley, M. Dyer, K. Ulaczyk, D. Steeghs, D. Galloway, V. Dhillon, P. O'Brien, G. Ramsay, K. Noysena, R. Kotak, R. Breton, J. Casares, L. Nuttall, B. Godson, A. Kumar on behalf of GOTO collaboration report/s a classification of object: AT 2025seu

Type: Other
Redshift: 0.2544

Remarks: Blue continuum with no particular notable line features. Exact classification is difficult and we leave the target as "Other". However, we note that the event is similar to the Luminous, Fast coolers found in passive galaxies (Nicholl et al. 2023) based on it's luminosity, evolution time scale, the featureless spectrum and the associating with a passive galaxy. Further observations are encouraged. Redshift from astronote #2025-270.

The following Classification spectrum was provided:

Obsdate: 2025-08-29 02:12:56
Instrument: ALFOSC
Telescope: Nordic Optical Telescope

Details of the object and its spectra can be viewed here: https://sandbox.wis-tns.org/object/2025seu