MMIRS Near-infrared Spectroscopy and Imaging of SN 2016bkv
ATel #8861; D. Milisavljevic, I. Chilingarian, P. Berlind, D. Patnaude, A. Kamble, J. Parrent (Harvard-Smithsonian Center for Astrophysics), Raffaella Margutti (NYU)
on 24 Mar 2016; 05:29 UT
Credential Certification: D. Milisavljevic (firstname.lastname@example.org)
Subjects: Infra-Red, Optical, Supernovae
We obtained moderate resolution (R ~ 2000-3000) near-infrared spectra (covering 0.995 - 2.4 micron) of SN 2016bkv on March 23.3 UT using the MMT and Magellan Infrared Spectrograph (MMIRS; McLeod et al. 2012, PASP, 124, 1318) mounted on the MMT 6.5m telescope. Our observations were prompted by K. Itagaki's discovery of a supernova candidate in NGC 3184 that was posted on the Transient Name Server. Preliminary reduction of our data using procedures outlined in Chilingarian et al. (2015, PASP, 127, 406) show mostly continuum emission with only one identifiable emission feature centered near 1.085 micron having a full-width-half-maximum of approximately 100 Angstroms. Correcting for the redshift of NGC 3184 (z=0.002; Strauss et al. 1992, ApJS, 83, 29, via NED), we identify this weak emission as He I 1.083.
We retrieved optical spectra of SN 2016bkv recently obtained by Hosseinzadeh et al. (ATel #8859) from the Transient Name Server and compared the two data sets. We find that the He I 1.083 emission line profile observed in our data has the same velocity width as weak Halpha emission seen in their data. We interpret these findings to be consistent with Hosseinzadeh et al.'s classification of SN 2016bkv to be a young Type II (or potentially Type IIn) supernova.
Finally, we note that multiple pre-explosion Hubble Space Telescope images of NGC 3184 covering the region surrounding SN 2016bkv exist. We retrieved a WFC2/F555W image obtained 2001-01-24 (Proposal ID 8602; PI: Filippenko) from the Hubble Legacy Archive and performed a preliminary alignment with our acquisition K-band image. A small cluster of stars is clearly visible at the location of SN 2016bkv.
Further observations are planned and a robust image registration to pinpoint a potential progenitor star is underway.