DRAFT
2025-05-08 14:31:55
Type: Object/s-Discovery/Classification
Spectroscopic classification of transients
Abstract:
Spectral classification of 2 transients and reclassification of 1 transient.
As part of the Observational Techniques II course at Stockholm University (SU) using the Nordic Optical Telescope (NOT) on La Palma for remote observing on May 7th 2025, we obtained spectroscopic observations of 3 transients. Here we report the classification obtained through spectral matching using GELATO (Harutyunyan et al. 2008) and SNID (Blondin & Tonry 2011). The observations were taken with the ALFOSC instrument mounted on the NOT using gr#4 and a 1.0 arcsec wide slit. The targets reported here were obtained from the Zwicky Transient Facility (ZTF, Bellm et al. 2019).
Below we list the classified objects. All the spectra can be accessed through the Transient Name Server and also the WISeREP repository.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2025jyl [ZTF25aappymi] | 22:38:45.334 | +37:35:57.36 | SN | UGC 12131 | 0.033943 | Blue featureless (with telluric line contamination). | 22:38:45.334 | +37:35:57.36 | SN | 0.03 | |
| TNS | 2025iik [ZTF25aaoefsh] | 17:21:10.121 | +68:27:32.06 | SN Ia | 0.04 | SDSS J172110.16+682739.7 | Redshift from spectral matching. | 17:21:10.121 | +68:27:32.06 | SN Ia | 0.04 | |
| TNS | 2025gjc [ZTF25aalvbwm] | 15:38:58.129 | -22:40:11.38 | SN II | 0.0198 | This SN was previously classified as IIn. We do not see narrow lines in the new spectrum, except maybe for host line contamination. Instead, the P-Cygni profile suggests a Type II classification. | 15:38:58.129 | -22:40:11.38 | SN II | 0.0198 |
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