Spectroscopic Classifications of Optical Transients with the Lick Shane Telescope

ATel #14986; K. W. Davis, K. Taggart, R. J. Foley (UCSC)
on 20 Oct 2021; 04:21 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ryan Foley (foley@ucsc.edu)

Tweet

We report the following classifications of optical transients from spectroscopic observations with the Kast spectrograph on the Shane telescope. The targets were supplied by the Young Supernova Experiment. All observations were made on 2021 Oct 16 UT. Classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

 
Name        | IAU Name  | RA (J2000)  | Dec (J2000)  |   z     | Type | Phase | Notes 
PS21ksh	    |AT2021aamo | 00:10:21.30 | +19:48:05.71 |  0.059  |  Ia  | peak  | (1) 
PS21kuh	    |AT2021aapa | 04:10:51.02 | -09:37:46.02 |  0.032  | IIn  |       | (2) 
PS21kve	    |AT2021aaqg | 02:25:22.25 | -07:50:33.57 |  0.054  |Ia-91T|  -5   | (3) 

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 H-alpha FWHM velocity of 1,300 km/s. Using a Tully-Fisher distance modulus to the host galaxy, MGC -02-11-023, of 35.69 mag (Theureau et al., 2007, A&A, 465, 71) and correcting for Milky Way extinction, the current absolute magnitude is M_r = -16.8 mag and rising. This is at the low end of the peak luminosity distribution of SNe IIn and the H-alpha line is relatively narrow, perhaps indicating that AT2021aapa is a non-terminal LBV eruption (i.e., a “supernova impostor"). (3) We measure a Si II 6355 velocity of -11,100 km/s.