The Evolution of Late-Time Optical Emission From SN 1979C

Abstract

Optical spectra of the bright Type II-L supernova SN 1979C obtained in April 2008 with the 6.5 m MMT telescope are compared with archival late-time spectra to follow the evolution of its optical emission over the age range of 11 to 29 years. We estimate an Halpha flux decrease of around 35% from 1993 to 2008 but noticeable increases in the strength of blueshifted emission of forbidden oxygen lines. While the maximum expansion of the broad ~6700 km/s Halpha emission appears largely unchanged from 1993, we find a significant narrowing of the double-peaked emission profiles in the [O I] 6300, 6364 and [O II] 7319, 7330 lines. A comparison of late-time optical spectra of a few other Type II supernovae which, like SN 1979C, exhibit bright late-time X-ray, optical, and radio emissions, suggests that blueshifted double-peaked oxygen emission profiles may be a common phenomenon. Finally, detection of a faint, broad emission bump centered around 5800 Angstroms suggests the presence of WC type Wolf-Rayet stars in the supernova's host star cluster.

6 pages, 4 figures, 1 table. Matches version accepted by ApJ

References in corpus (9)

• Asphericity in Supernova Explosions from Late-Time Spectroscopy
• Double-peaked Oxygen Lines Are not Rare in Nebular Spectra of Core-Collapse Supernovae
• Supernova 1996cr: SN 1987A's Wild Cousin?
• X-ray observations of the edge-on star-forming galaxy NGC891 and its supernova SN1986J
• The Massive Star Population in the Giant HII Region Tol89 in NGC5398
• VLT observations of metal-rich extra galactic HII regions. I. Massive star populations and the upper end of the IMF
• Late-time X-Ray, UV and Optical Monitoring of Supernova 1979C
• The Evolution of Late-time Optical Emission from SN 1986J
• Shell revealed in SN 1979C

Cited by in corpus (17)

• Thermal and non-thermal emission from circumstellar interaction
• Late-Time Optical Emission From Core-Collapse Supernovae
• The Massive Progenitor of the Type II-Linear SN 2009kr
• H-alpha Spectral diversity of type II supernovae
• Moderately Luminous type II Supernovae
• Supernova 1998S at 14 years Postmortem: Continuing Circumstellar Interaction and Dust Formation
• Late-time observations of SN2006gy: Still Going Strong
• SN 2008iy: An Unusual Type IIn Supernova with an Enduring 400 Day Rise Time
• Late Spectral Evolution of the Ejecta and Reverse Shock in SN1987A
• Evidence for a pulsar wind nebula in the Type Ib-peculiar supernova SN 2012au
• Stellar Binary Companions to Supernova Progenitors
• Evidence for a Black Hole Remnant in the Type IIL Supernova 1979C
• Dust masses for a large sample of core-collapse supernovae from optical emission line asymmetries: dust formation on 30-year timescales
• The Supernova -- Supernova Remnant Connection
• The Transition of a Type IIL Supernova into a Supernova Remnant: Late-time Observations of SN 2013by
• Evolving into a remnant: optical observations of SN 1978K at three decades
• A Newly Recognized Very Young Supernova Remnant in M83