Optical and UV studies of type Ia supernovae SN 2009ig and SN 2012cg
Abstract
We present an extensive optical-ultraviolet photometry and analysis of a series of optical spectra of type Ia supernovae SN 2009ig and SN 2012cg. The observations range from -15 to +185 d for SN 2009ig and from -14 to 316 d for SN 2012cg, with respect to maximum light in B band. Both SN 2009ig and SN 2012cg exhibit similar properties. They have similar decline rate parameter (Δm15(B)true = 0.92 ± 0.04 for SN 2009ig and 0.93 ± 0.06 for SN 2012cg) and B band peak absolute magnitude (-19.45 ± 0.40 mag for SN 2009ig and -19.50 ± 0.31 mag for SN 2012cg). Their early spectra show high-velocity features in Si II and Ca II lines. The strong Fe III, Si III, and weak Si II λ5972 line during pre-maximum phase are indicative of hot photosphere. The post-maximum velocity evolution shows a plateau like phase with velocities ∼13 000 km s-1 for SN 2009ig and ∼10 000 km s-1 for SN 2012cg. Both events show spectral evolution similar to normal SNe Ia and fall in LVG and Core Normal subgroup. Both have smaller strength ratio [R(Si II) = 0.17 for SN 2009ig and 0.20 for SN 2012cg] consistent with smaller Δm15(B). Peak bolometric luminosities (log L_bol^max) of these events are estimated as 43.17 ± 0.16 and 43.24 ± 0.11 erg s-1 suggesting that 0.60 ± 0.20 M⊙ of 56Ni was synthesized in the explosion of SN 2009ig and 0.72 ± 0.31 M⊙ in SN 2012cg.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 2019
- DOI:
- 10.1093/mnras/stz1358
- Bibcode:
- 2019MNRAS.487.1886C
- Keywords:
-
- supernovae: general;
- supernovae: individual: SN 2009ig;
- supernovae: individual: SN 2012cg;
- galaxies: individual: NGC 1015;
- galaxies: individual: NGC 4424