Classification certificate for object 2016gkm
TNS Classification Report No. 3451 [ 2019TNSCR1236....1G ]

Date Received (UTC): 2019-01-30 03:44:13
Sender: Dr. Lluís Galbany
Group: None

Lluís Galbany (Pitt), Carles Badenes (Pitt), David Law (STScI), Joseph D Gelfand (NYU) report/s a classification of object: SN 2016gkm

Type: SN Ib/c
Redshift: 0.017

Remarks: We report the classification of AT2016gkm as a type Ib/c supernova. The spectrum was found serendipitously in an integral field spectroscopy observation of the galaxy within the SDSS-IV MaNGA survey. We extracted a 2-arcsec aperture spectrum at that location and used GELATO (Harutyunyan et al., 2008, A&A, 488, 383) to compare it to a set of spectra of several SN types. The best fit was to SN Ic 2004gk at +134 days past max, although fits of similar quality arre found to SN Ib 2009jf at +83 days past max. The main nebular lines of stripped envelope SNe are found in the spectrum: Mg I] λ4571, [O I] λλ6300,6364, [Ca II] λλ7291,7323, [O II] λλ7320,7330, and Ca II NIR. Considering that the object was discovered on Sep 21st 2016 and the last non-detection was four months before the discovery (May 5th 2016), the spectrum is from 108 days after discovery, which puts a lower limit for the actual epoch.

The following Classification spectrum was provided:

Obsdate: 2017-01-07 00:00:00
Instrument: Other
Telescope: Other

Remarks: Spectrum from the BOSS spectrograph at APO used in the SDSS-IV MaNGA survey.

Details of the object and its spectra can be viewed here: https://wis-tns.weizmann.ac.il/object/2016gkm