DRAFT
2025-03-07 11:10:51
Type: Object/s-Discovery/Classification
Bibcode: 2025TNSAN..79....1C
adH0cc spectroscopic classification of SN 2025ctp
Source Group: adH0cc
Abstract:
We have obtained an optical spectrum of SN 2025ctp, which shows it to be a Type IIb supernova at maximum light. The supernova occurred in the same galaxy as the Type Ia supernova SN 2016ys.
The adH0cc programme for an "accurate determination of H0 with core-collapse supernovae" reports the classification of the optical transient SN 2025ctp. The target was supplied by the Zwicky Transient Facility ZTF (Kulkarni 2018, 2018ATel11266....1K) and the ATLAS survey (Tonry et al. 2018, 2018PASP..130f4505T) . The observations were performed on the night of 2025 March 07 with the ESO Very Large Telescope UT1, equipped with the FORS2 spectrograph and grism 300V, covering a wavelength range from 3400 to 9600 Å at a resolution of 10 Å.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Source | Phase | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2025ctp [ZTF25aagzocg] | 07:12:14.633 | +07:13:54.42 | SN IIb | 0.028 | UGC 3738 | 0.028343 | ZTF | 0 to 3 | The spectrum shows broad P Cygni features of He along with the Ca triplet, charachteristic of young Type IIb supernovae. GELATO (Harutyunyan et al. 2008, 2008A&A...488..383H) found good matches with the spectrum of SN 1993J 2 days after maximum light. We adopted the redshift of the host galaxy. The SN occured at the outskirts of a galaxy which hosted SN 2016ys, a well-observed Type Ia supernova, useful for cosmological analyses. | 07:12:14.632 | +07:13:54.38 | SN IIb | 0.028343 |
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