SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion

SUNTZEFF, NICHOLAS B.; PERSSON, S.E.; FREEDMAN, WENDY L.; CAIN, C.; TUCKER, BRAD E.; GONZÁLEZ, CONSUELO; CAMPILLAY, ABDO; RABINOWITZ, D.; NUGENT, PETER E.; BROWN, PETER J.; SHAPPEE, B.J.; PHILLIPS, M.M.; SCHMIDT, BRIAN; HOEFLICH, P.; SCALZO, RICHARD; FOLATELLI, GASTÓN; HAMUY, MARIO; BARON, E.; CHILDRESS, MICHAEL J.; SERÓN, JACQUELINE; WALKER, E.S.; CORCO, CARLOS; KRISCIUNAS, KEVIN; MORRELL, NIDIA; CASTELLÓN, SERGIO; PARKER, STU; HSIAO, ERIC Y.; KLOTZ, ALAIN; TURPIN, DAMIEN; BALTAY, C.; PIRO, ANTHONY L.; CONSEIL, EMMANUEL; CONTRERAS, CARLOS; STRITZINGER, MAXIMILIAN D.; BURNS, CHRISTOPHER R.

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Año: 2018 vol. 859

0004-637X

We present detailed ultraviolet, optical, and near-infrared light curves of the Type Ia supernova (SN) 2012fr, which exploded in the Fornax cluster member NGC 1365. These precise high-cadence light curves provide a dense coverage of the flux evolution from -12 to +140 days with respect to the epoch of B-band maximum (). Supplementary imaging at the earliest epochs reveals an initial slow and nearly linear rise in luminosity with a duration of ∼2.5 days, followed by a faster rising phase that is well reproduced by an explosion model with a moderate amount of 56Ni mixing in the ejecta. From our analysis of the light curves, we conclude that: (i) the explosion occurred 1800) luminosity was 16.5 ±0.6 days, (iii) the supernova suffered little or no host-galaxy dust reddening, (iv) the peak luminosity in both the optical and near-infrared was consistent with the bright end of normal Type Ia diversity, and (v) 0.60 ±0.15 M o of 56Ni was synthesized in the explosion. Despite its normal luminosity, SN 2012fr displayed unusually prevalent high-velocity Ca ii and Si ii absorption features, and a nearly constant photospheric velocity of the Si ii λ6355 line at ∼12,000 that began ∼5 days before . We also highlight some of the other peculiarities in the early phase photometry and the spectral evolution. SN 2012fr also adds to a growing number of Type Ia supernovae that are hosted by galaxies with direct Cepheid distance measurements.