SN 2012au: A GOLDEN LINK BETWEEN SUPERLUMINOUS SUPERNOVAE AND THEIR LOWER-LUMINOSITY COUNTERPARTS

Journal Article · Thu Jun 20 00:00:00 EDT 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/770/2/L38· OSTI ID:22118740

Milisavljevic, Dan; Soderberg, Alicia M.; Margutti, Raffaella; Drout, Maria R.; Marion, G. Howie; Sanders, Nathan E.; Lunnan, Ragnhild; Chornock, Ryan; Berger, Edo; Foley, Ryan J.; Challis, Pete; Kirshner, Robert P.; Dittmann, Jason; Bieryla, Allyson; Kamble, Atish; Chakraborti, Sayan ^[1]; Hsiao, Eric Y. ^[2]; Fesen, Robert A.; Parrent, Jerod T. ^[3]; others, and

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile)
3. 6127 Wilder Lab, Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States)

We present optical and near-infrared observations of SN 2012au, a slow-evolving supernova (SN) with properties that suggest a link between subsets of energetic and H-poor SNe and superluminous SNe. SN 2012au exhibited conspicuous Type-Ib-like He I lines and other absorption features at velocities reaching Almost-Equal-To 2 Multiplication-Sign 10{sup 4} km s{sup -1} in its early spectra, and a broad light curve that peaked at M{sub B} = -18.1 mag. Models of these data indicate a large explosion kinetic energy of {approx}10{sup 52} erg and {sup 56}Ni mass ejection of M{sub Ni} Almost-Equal-To 0.3 M{sub Sun} on par with SN 1998bw. SN 2012au's spectra almost one year after explosion show a blend of persistent Fe II P-Cyg absorptions and nebular emissions originating from two distinct velocity regions. These late-time emissions include strong [Fe II], [Ca II], [O I], Mg I], and Na I lines at velocities {approx}> 4500 km s{sup -1}, as well as O I and Mg I lines at noticeably smaller velocities {approx}< 2000 km s{sup -1}. Many of the late-time properties of SN 2012au are similar to the slow-evolving hypernovae SN 1997dq and SN 1997ef, and the superluminous SN 2007bi. Our observations suggest that a single explosion mechanism may unify all of these events that span -21 {approx}< M{sub B} {approx}< -17 mag. The aspherical and possibly jetted explosion was most likely initiated by the core collapse of a massive progenitor star and created substantial high-density, low-velocity Ni-rich material.

• OSTI ID: 22118740
• Journal Information: Astrophysical Journal Letters, Vol. 770, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION
ABSORPTION SPECTRA
ASTRONOMY
ASTROPHYSICS
CALCIUM IONS
DENSITY
DIAGRAMS
EMISSION
GRAVITATIONAL COLLAPSE
IRON IONS
KINETIC ENERGY
LUMINOSITY
MAGNESIUM IONS
MASS
NEAR INFRARED RADIATION
NICKEL 56
OXYGEN IONS
SUPERNOVAE
VELOCITY
VISIBLE RADIATION