SN 2012fr in NGC 1365Mark 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 CurveUVOIR Bolometric Light Curve Fit to Rise Time (L t∝ 2)

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 IISi II λ6355 Ca II triplet

Velocity Evolution of Si II and Ca II

Velocity Evolution of Si II:Comparison with Other SNe Ia

Spectropolarimetry

• 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?

[Maund et al. (2013)]

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

HV Ca II

HV Ca IIHV + LV Si II

Mg II

Fe III?

No HV components in the near-IR?

Look-Alikes:2009ig and 2012fr

From Blondin et al.(2012)

(2012)

Branch Classification Systems

(2012)

Data from Swift satellite:

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