Spectroscopic Classification of Optical Transients with the Lick Shane telescope
ATel #17358; K. Taggart, K. C. Patra, R. J. Foley (UCSC)
on 23 Aug 2025; 21:19 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Kirsty Taggart (k.taggart@ucsc.edu)
Subjects: Optical, Supernovae
We report the following classifications of optical transients from spectroscopic observations with the Kast spectrograph on the Shane telescope. The targets were supplied by ATLAS, ZTF and the Young Supernova Experiment. All observations were made on 2025 Aug 22 UT. Classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) and visual matching.
Name | IAU Name | RA (J2000) | Dec (J2000) | z | Type | Phase | Notes
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ATLAS25jly | 2025tws | 16:25:20.30 | +25:12:45.35 | 0.064 | Ia | peak | (1)
PS25gqy | 2025umo | 16:58:04.22 | +19:28:00.94 | 0.051 | Ia | -5d | (2)
ZTF25abkeyrv | 2025usw | 18:27:30.10 | +36:06:21.71 | 0.056 | Iax | pre‑peak | (3)
ZTF25aankyog | 2025iek | 15:55:01.67 | +03:56:55.66 | 0.1467 | IIn | | (4)
Notes:
When the redshift is given to 2 decimal places, it is derived from the SN spectrum. Otherwise, the redshift is determined from the host galaxy.
(1) We measure a Si II 6355 velocity of -11,300 km/s.
(2) We measure a Si II 6355 velocity of -11,400 km/s.
(3) The spectrum is consistent with SN 2002cx with a phase of -4.5 days. The blue side of the spectrum is well matched to that of SN 2002cx, while the red side appears to be more affected by host-galaxy contamination.
(4) The H-alpha line exhibits a narrow component with a FWHM velocity of approximately 450 km/s and an intermediate-width (or broad) component with a FWHM velocity of roughly 2,450 km/s.
