Spectroscopic Classifications of Optical Transients with the Lick Shane telescope

ATel #16643; K. Taggart, R. J. Foley (UCSC), Q. Wang (JHU)
on 6 Jun 2024; 21:05 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Kirsty Taggart (k.taggart@ucsc.edu)

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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 and ZTF. All observations were made on 2024 June 05 UT. Classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

 
Name         | IAU Name| RA (J2000)  | Dec (J2000)  |   z     | Type  | Phase | Notes 
ZTF24aaosqtp | 2024jgx | 14:15:38.64 | +50:08:52.12 | 0.07563 |  Ia   |  -6   | 1 
PS24dcv	     | 2024jvv | 16:15:17.63 | +50:27:18.29 | 0.0583  |  Ia   |  -5   | 2 
ZTF24aaqaroi | 2024kce | 12:29:49.55 | +08:12:48.47 | 0.003   | Ia-pec|       | 3 
ZTF24aaqiqpw | 2024kee | 16:01:26.40 | +71:24:10.61 | 0.039037|  SN   | peak  | 4 

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 6355 velocity of -15,600 km/s. (2) The Si is relatively weak. We measure the Si 6355 velocity as -13,400 km/s. (3) The spectrum displays a strong change in spectral slope at ~5500 A. It appears blue on the redward side of this wavelength and red on the blueward side. There is strong Ti II absorption consistent with a cool photosphere. There are several relatively narrow spectral features with FWHM < 5000 km/s, indicating a low photospheric velocity. The SN is located 12.8 arcmin from the center of M49, corresponding to 62.2 kpc in projection. Assuming the SN is associated with M49, and thus having a redshift of 0.003, we measure a Ca II NIR triplet velocity of -15,600 km/s, significantly larger than expected from the narrow lines. The O I 7774 feature has two minima, corresponding to -9300 and -14,000 km/s, respectively. The spectrum is broadly similar to peculiar thermonuclear SNe PTF09dav (Sullivan et al., 2011, 732, 118) and SN 2016hnk (Galbany et al., 2019, A&A, 630, 76; Jacobson-Galan et al., 2020, ApJ, 896, 165). The SN is currently at m ~ 16.5 mag and rising. At the distance of M49, it is currently at M = -15.2 mag. (4) The spectrum has a blue, hot continuum consistent with a young core-collapse supernova. There is faint, narrow H-alpha at the host redshift.