SN 2012fr: Ultraviolet, Optical, and Near-infrared Light Curves of a Type Ia Supernova Observed within a Day of Explosion
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© 2018. The American Astronomical Society. All rights reserved.. 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 <22 hr before the first detection of the supernova, (ii) the rise time to peak bolometric (λ > 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.
The Astrophysical Journal
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Contreras, Carlos||Phillips, MM||Burns, Christopher R||Piro, Anthony L||Shappee, BJ||Stritzinger, Maximilian D||Baltay, C||Brown, Peter J||Conseil, Emmanuel||Klotz, Alain||Nugent, Peter E||Turpin, Damien||Parker, Stu||Rabinowitz, D||Hsiao, Eric Y||Morrell, Nidia||Campillay, Abdo||Castellón, Sergio||Corco, Carlos||González, Consuelo||Krisciunas, Kevin||Serón, Jacqueline||Tucker, Brad E||Walker, ES||Baron, E||Cain, C||Childress, Michael J||Folatelli, Gastón||Freedman, Wendy L||Hamuy, Mario||Hoeflich, P||Persson, SE||Scalzo, Richard||Schmidt, Brian||Suntzeff, Nicholas B