AstroNote 2025-246

We report the spectroscopic classification of 7 transients mainly discovered/co-discovered by the BlackGEM telescope array (Groot et al. 2024) as part of the BlackGEM pilot verification program “Discovering the hidden gems in the transient sky” (PI: Blagorodnova).

The observations were performed on the night of 2025 July 30th UT with the NOT telescope, equipped with the ALFOSC spectrograph and 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 the Python package SNID SAGE (https://github.com/FiorenSt/SNID-SAGE, F. Stoppa in prep. 2025)

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.