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SN 2012fr in NGC 1365. Mark M. Phillips, Carlos Contreras, Eric Hsiao, Nidia Morrell, Kevin Krisciunas, Peter Brown, and Max Stritzinger. The Type Ia SN 2012fr in NGC 1365. Optical Spectroscopy: Childress et al. (2013; arXiv:1302.2926)
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SN 2012fr in NGC 1365 Mark M. Phillips, Carlos Contreras, Eric Hsiao, Nidia Morrell, Kevin Krisciunas, Peter Brown, and Max Stritzinger
The Type Ia SN 2012fr in NGC 1365 Optical Spectroscopy: Childress et al. (2013; arXiv:1302.2926) Optical Spectropolarimetry: Maund et al. (2013; arXiv:1302.0166) Optical/NIR Imaging: Contreras et al. (2013; in preparation) NIR Spectroscopy: Hsiao et al. (2013; in preparation)
SN 2012fr • Discovered by TAROT on images taken by its robotic telescope at La Silla observatory, Chile, on 2012 Oct 27.05 (~6-12 hours after explosion) • Hosted by the nearby galaxy NGC1365, a barred spiral ~18 Mpc distant in the Fornax cluster (has a Cepheid distance) • The first optical spectrum obtained with the ANU 2.3 m/WiFeS on 2012 Oct 28.53 showed that the supernova was a very young type Ia with high-velocity Si II and Ca II • The CSP started optical imaging on Oct 30.16, and near-IR imaging and spectroscopy on Oct 31.16
Optical Light Curves Δm15(B) = 0.84 ± 0.03
Near-IR Light Curves S-corrected Uncorrected
Low Host Dust Reddening Lira Relation Keck HIRES Spectrum
UVOIR Bolometric Light Curve UVOIR Bolometric Light Curve Fit to Rise Time (L∝ t2) Rise time of ~16 days from explosion to maximum. In left Fig, others from top down: 91T, 92A, 94ae 91bg.
Optical Spectroscopic Coverage 69 spectra obtained between t(Bmax) = -14.5 to +98 days
High-Velocity Si II and Ca II Si II λ6355 Ca II triplet
Velocity Evolution of Si II: Comparison with Other SNeIa
Spectropolarimetry [Maund et al. (2013)] • Low (< 0.1%) continuum polarization • HV components of Si II and Ca II are highly polarized at earliest epoch; polarization decreases as these features weaken • At +2 days, the polarization angles of the LV components of Si II and Ca II are identical and oriented at 90° relative to the HV Ca II component, meaning they have orthogonal distributions in the plane of the sky • Observations are perhaps more consistent with the pulsating delayed detonation model?
Near-IR Spectroscopic Coverage of SN 2012fr 31 spectra obtained between t(Bmax) = -11.5 to +108 days
SN 2012fr: Optical + Near-IR, -7 days No HV components in the near-IR? HV Ca II HV + LV Si II HV Ca II Mg II Fe III?
Look-Alikes: 2009ig and 2012fr
From Blondin et al. (2012)
Data from Swift satellite: (2012)
Summary of Observational Characteristics of SN 2012fr • Fast rise to max; slow decline after max • Strong HV components of Si II and Ca II absorption at early epochs • Nearly flat evolution of LV Si II λ6355 expansion velocity • “Normal” luminosity