On the observational behaviour of the highly polarized Type IIn supernova SN 2017hcc. Issue 3 (11th July 2019)

• Record Type: Journal Article
• Authors: Kumar, Brajesh; Eswaraiah, Chakali; Singh, Avinash; Sahu, D K; Anupama, G C; Kawabata, K S; Yamanaka, Masayuki; Otsubo, Ikki; Pandey, S B; Nakaoka, Tatsuya; Kawabata, Miho; Aryan, Amar; Akitaya, Hiroshi
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 488:Issue 3(2019)
• Page Start: 3089
• Page End: 3099
• Publication Date: 2019-07-11
• Subjects: techniques: photometric -- techniques: polarimetric -- techniques: spectroscopic -- supernovae: general -- supernovae: individual: SN 2017hcc; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz1914
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present the results based on photometric ( Swift UVOT), broad-band polarimetric ( V and R bands) and optical spectroscopic observations of the Type IIn supernova (SN) 2017hcc. Our study is supplemented with spectropolarimetric data available in literature for this event. The post-peak light-curve evolution is slow (∼0.2 mag 100 d −1 in b band). The spectrum of ∼+27 d shows a blue continuum with narrow emission lines, typical of a Type IIn SN. Archival polarization data along with the Gaia DR2 distances have been utilized to evaluate the interstellar polarization (ISP) towards the SN direction which is found to be P ISP = 0.17 ± 0.02 per cent and θISP = 140° ± 3°. To extract the intrinsic polarization of SN 2017hcc, both the observed and the literature polarization measurements were corrected for ISP. We noticed a significant decline of ∼3.5 per cent ( V band) in the intrinsic level of polarization spanning a period of ∼2 months. In contrast, the intrinsic polarization angles remain nearly constant at all epochs. Our study indicates a substantial variation in the degree of asymmetry in either the ejecta and/or the surrounding medium of SN 2017hcc. We also estimate a mass-loss rate of $\dot{M}$ = 0.12 M⊙ yr −1 (for v $\mathrm{ w}$ = 20 km s −1 ) which suggests that the progenitor of SN 2017hcc is most likely a luminous blue variable.