DRAFT
2025-05-30 17:05:58
Type: Object/s-Discovery/Classification
ePESSTO+ spectroscopic classification of optical transients
Authors: S. P. Cosentino (University of Catania), C. F. Aster (Cardiff), A. Reguitti (INAF, IT), T. Petrushevska (Nova Gorica), L. Galbany (ICE-CSIC), A. Aryan, Y.-H. Lee, C.-H. Lai, T.-W. Chen (NCU, Taiwan), J. Anderson (ESO), T. Müller Bravo (Southampton), M. Gromadzki (Warsaw), C. Inserra (Cardiff), E. Kankare (Turku), P. J. Pessi (Stockholm), S. Benetti (INAF-OAPd), O. Yaron (Weizmann), D. R. Young (QUB), J. Tonry, L. Denneau, H. Weiland, R. Siverd (IfA, University of Hawaii), N. Erasmus, W. Koorts (South African Astronomical Observatory), A. Jordan, V. Suc (UAI, Obstech), S. J. Smartt, K. W. Smith (Oxford/QUB), S. Srivastav, H. Stevance (Oxford), M. Fulton, M. McCollum, T. Moore, M. Nicholl, J. Weston (QUB), L. Shingles (GSI/QUB), L. Rhodes (Oxford), J. Sommer (LMU/QUB), A. Rest (STScI), C. Stubbs (Harvard)
Source Group: ePESSTO+
Keywords: Transient, Supernova, Optical, Spectroscopy
Abstract:
This report includes classifications of 1 Type Ia, 1 Type II, 1 SN and 1 blue and featureless object. We encourage followup observations.

ePESSTO+, the advanced Public ESO Spectroscopic Survey for Transient Objects (Smartt et al. 2015 2015A&A...579A..40S), reports the following supernova classifications.

Targets were supplied by the ATLAS survey (Smith et al. 2020 2020PASP..132h5002S), the Zwicky Transient Facility ZTF (Bellm et al. 2019 2019PASP..131a8002B) - data stream processed through the Lasair broker (Smith, Williams, Young et al. 2019 2019RNAAS...3...26S).

Observations were performed on the ESO New Technology Telescope (NTT) at La Silla on the night of 2025 May 29, using EFOSC2 with Grism 13 (3985-9315A, 18A resolution) and Grism 11 (3380-7520A, 16A resolution). Classifications were done using NGSF (Next Generation SuperFit; AstroNote 2022-191, Howell et al. 2005 2005ApJ...634.1190H) and DASH (Muthukrishna et al. 2019 2019ApJ...885...85M ).

The classification spectra and additional details can be obtained from http://www.pessto.org (via WISeREP) and the IAU Transient Name Server.

The classified objects are listed in the Related Objects table below.

Show current TNS values
Catalog Name Reported RA Reported DEC Reported Obj-Type Reported Redshift Host Name Host Redshift Source Phase (days) Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2025lfn [ZTF25aargdqx] 20:11:40.779 -08:07:46.34 SN Ia 0.109 WISEA J201140.50-080744.7 Post peak Redshift from host H-alpha emission line. Confirmed by DASH and NGSF. Good match with Type Ia using DASH and NGSF. 20:11:40.779 -08:07:46.34 SN Ia 0.109
TNS 2025lzu [ATLAS25fob] 21:39:55.025 +06:00:11.66 SN The spectrum is blue and featureless. 21:39:55.025 +06:00:11.66 SN
TNS 2025lsr [ZTF25aarrupv] 19:54:21.540 -18:42:51.24 SN WISEA J195421.68-184246.5 The spectrum is blue and shows possible H-alpha and He II emission lines at a redshift of 0.044, along with other emission features between 5400 and 6000 Angs (observed frame). The exact classification remains uncertain at this stage. Assuming this redshift, the transient currently has an absolute magnitude of M_r ≈ –17.7 mag. 19:54:21.540 -18:42:51.24 SN
TNS 2025lwz [ATLAS25fjc] 22:54:43.675 +07:51:43.23 SN II 0.024 WISEA J225443.49+075149.9 0.0236 Post peak Redshift from the host spectroscopy at NED. Good match with Type II using NGSF. 22:54:43.666 +07:51:43.39 SN IIn 0.023586

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