Details

Autor(en) / Beteiligte

• Childress, M J
• Scalzo, R A
• Sim, S A
• Tucker, B E
• Yuan, F
• Schmidt, B P
• Cenko, S B
• Silverman, J M
• Contreras, C
• Hsiao, E Y

Titel

SPECTROSCOPIC OBSERVATIONS OF SN 2012fr: A LUMINOUS, NORMAL TYPE Ia SUPERNOVA WITH EARLY HIGH-VELOCITY FEATURES AND A LATE VELOCITY PLATEAU

Ist Teil von

• The Astrophysical journal, 2013-06, Vol.770 (1), p.1-20

Ort / Verlag

United States

Erscheinungsjahr

2013

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present 65 optical spectra of the Type Ia SN 2012fr, 33 of which were obtained before maximum light. At early times, SN 2012fr shows clear evidence of a high-velocity feature (HVF) in the Si II [lambda]6355 line that can be cleanly decoupled from the lower velocity "photospheric" component. This Si II [lambda]6355 HVF fades by phase -5; subsequently, the photospheric component exhibits a very narrow velocity width and remains at a nearly constant velocity of ~12,000 km s super(-1) until at least five weeks after maximum brightness. The Ca II infrared triplet exhibits similar evidence for both a photospheric component at [upsilon] [asymptotically =] 12,000 km s super(-1) with narrow line width and long velocity plateau, as well as an HVF beginning at [upsilon] [asymptotically =] 31,000 km s super(-1) two weeks before maximum. SN 2012fr resides on the border between the "shallow silicon" and "core-normal" subclasses in the Branch et al. classification scheme, and on the border between normal and high-velocity Type Ia supernovae (SNe Ia) in the Wang et al. system. Though it is a clear member of the "low velocity gradient" group of SNe Ia and exhibits a very slow light-curve decline, it shows key dissimilarities with the overluminous SN 1991T or SN 1999aa subclasses of SNe Ia. SN 2012fr represents a well-observed SN Ia at the luminous end of the normal SN Ia distribution and a key transitional event between nominal spectroscopic subclasses of SNe Ia.