DRAFT
2025-03-27 21:56:27
Type: Object/s-Discovery/Classification
NOT spectroscopic classifications of optical transients discovered/co-discovered by the BlackGEM survey
Authors: Nadejda Blagorodnova (ICCUB), David Jones (IAC), Gerard García Moreno (ICCUB), Erez A. Zimmerman (WIS), Moses Mlangeni (UCT/SAAO), Marco A. Gómez-Muñoz (ICCUB), Hugo Tranin (ICCUB)
Source Group: BlackGEM
Abstract:
We report the spectroscopic classification with NOT/ALFOSC of optical transients, including a broad-line SN Ic and a SN IIn.

We report the spectroscopic classification of 8 objects, 7 of which were discovered/co-discovered by the BlackGEM telescope array (Groot et al. 2024). The observations were taken as part of the BlackGEM pilot verification program “Discovering the hidden gems in the transient sky” (70-204, PI: Blagorodnova).

The observations were performed on the night of 2025 March 26th UT with the NOT telescope, equipped with the ALFOSC spectrograph with the low-resolution grism #4 and slits of 1.0 and 1.3 arcsec, covering a wavelength range from 3500-9600 Å at a resolution of 16.2 Å and 21 Å respectively. 

Classifications were done using Next Generation SuperFit (NGSF; Astronote 2022-191) via the WISeREP (Yaron et al. 2012) web interface. 

Based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias.

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 Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2025etc [ATLAS25daj] 11:16:35.678 -03:41:50.09 SN Ia 0.095 WISEA J111635.48-034148.5 11:16:35.678 -03:41:50.09 SN Ia 0.095
TNS 2025alg [ATLAS25bdp] 13:11:46.381 -14:10:41.36 SN II 0.04 GALEXASC J131146.30-141037.7 13:11:46.381 -14:10:41.36 SN II 0.04
TNS 2025dcd [ATLAS25cgr] 12:12:07.397 +23:57:28.82 SN Ia 0.0649 WISEA J121207.45+235729.6 0.0649 12:12:07.397 +23:57:28.82 SN Ia 0.064
TNS 2025ddc [ATLAS25chu] 12:09:05.668 +15:52:10.85 SN Ic-BL 0.07 SDSS J120905.62+155210.5 12:09:05.626 +15:52:11.11 SN Ic-BL 0.07
TNS 2025dht [BGEM J110701.75+035738.4] 11:07:01.750 +03:57:38.49 SN IIn 0.0613 WISEA J110701.86+035737.1 The proximity of a stellar source can affect the extraction of the spectrum. 11:07:01.750 +03:57:38.49 SN IIn 0.0613
TNS 2025err [ATLAS25csk] 08:19:35.291 +21:02:44.43 SN Ia 0.01 WISEA J081935.29+210244.2 08:19:35.291 +21:02:44.43 SN Ia 0.1
TNS 2025fdq [ZTF25aajygin] 13:41:00.427 +39:03:29.44 SN II 0.02 SDSS J134100.38+390324.7 0.02022211 13:41:00.427 +39:03:29.44 SN II 0.02
TNS 2025feb [ZTF25aajmuaa] 13:55:13.092 +05:26:22.46 SN Ia 0.094439 WISEA J135513.05+052624.1 0.094439 13:55:13.092 +05:26:22.46 SN Ia 0.094

Comments

Nadejda
Blagorodnova Mujortova