Fourteen months of observations of the possible super-Chandrasekhar mass Type Ia Supernova 2009dc

By J. Silverman, M. Ganeshalingam, Weidong Li, A. Filippenko, Adam A. Miller, D. P. D. O. Astronomy, U. California, Berkeley, Ca. 2010

174 citations recorded by the source corpus.

In this paper, we present and analyse optical photometry and spectra of the extremely luminous and slowly evolving Type Ia supernova (SN Ia) 2009dc, and offer evidence that it is a super-Chandrasekhar mass (SC) SN Ia and thus has a SC white dwarf (WD) progenitor. Optical spectra of SN 2007if, a similar object, are also shown. SN 2009dc had one of the most slowly evolving light curves ever observed for a SN Ia, with a rise time of ~23 d and Δm 15 (B) = 0.72 mag. We calculate a lower limit to the peak bolometric luminosity of ~2.4 x 10 43 erg s -1 , though the actual value is likely almost 40 per cent larger. Optical spectra of SN 2009dc and SN 2007if obtained near maximum brightness exhibit strong C II features (indicative of a significant amount of unburned material), and the post-maximum spectra are dominated by iron-group elements (IGEs). All of our spectra of SN 2009dc and SN 2007if also show low expansion velocities. However, we see no strong evidence in SN 2009dc for a velocity 'plateau' near maximum light like the one seen in SN 2007if. The high luminosity and low expansion velocities of SN 2009dc lead us to derive a possible WD progenitor mass of more than 2 M ⊙ and a 56 Ni mass of about 1.4-1.7 M ⊙ . We propose that the host galaxy of SN 2009dc underwent a gravitational interaction with a neighbouring galaxy in the relatively recent past. This may have led to a sudden burst of star formation which could have produced the SC WD progenitor of SN 2009dc and likely turned the neighbouring galaxy into a 'post-starburst galaxy'. No published model seems to match the extreme values observed in SN 2009dc, but simulations do show that such massive progenitors can exist (likely as a result of the merger of two WDs) and can possibly explode as SC SNe Ia.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/6f1ebf9c1140715ef4d7f0c638b9bedff8fe6a79

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In Astronomy and Astrophysics

1. A. Filippenko
2. N. Smith
3. D. Maoz
4. S. Smartt
5. F. Mannucci
6. R. Kirshner
7. Ryan Chornock
8. Weidong Li

In Nuclear and High Energy Physics

1. D. Maoz
2. F. Mannucci
3. A. Gal-yam
4. G. Nelemans
5. A. Filippenko
6. N. Smith
7. R. Kirshner
8. M. Kromer

Citations in the corpus

• High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios (2010, methodology): “These numbers are consistent with those obtained by Yamanaka et al. (2009) and Silverman et al. (2011) using Arnett’s law and assuming a similar host reddening, i.e. M0Ni = 1.8 ± 0.5 M [for E(B − V)host = 0.14 mag and tmax = 20 d] and 1.7 ± 0.4 M [for E(B − V)host = 0.10 mag and tmax = 23 d],…”
• Stellar structure models in modified theories of gravity: Lessons and challenges (2019, background): “8M⊙ [486, 487, 488, 489, 490], offering further avenues to test EiBI gravity (and other modified theories of gravity).”
• TYPE Ia SUPERNOVAE STRONGLY INTERACTING WITH THEIR CIRCUMSTELLAR MEDIUM (2013, background): “Longer rise times have been seen in more exotic SN Ia subtypes, with possible superChandrasekhar mass SNe Ia having rise times of ∼24 d (e.g., Scalzo et al. 2010; Silverman et al. 2011).”
• CfA4: LIGHT CURVES FOR 94 TYPE Ia SUPERNOVAE (2012, background): “Twelve CfA4 SN Ia light curves overlap with recent LOSS photometry (Ganeshalingam et al. 2010; Silverman et al. 2011), and eight overlap with CSP2.”
• TYPE Iax SUPERNOVAE: A NEW CLASS OF STELLAR EXPLOSION (2012, background): “However, Silverman et al. (2011a) later classified SN 2011ay as a SN Iax.”
• Observational Clues to the Progenitors of Type Ia Supernovae (2013, background): “At the other extreme, the nickel mass deduced for some very bright SN Ia explosions is suggestive of a super-Chandrasekhar-mass progenitor, with mass ∼> 2M (e.g. Howell et al. 2006, Kamiya et al. 2012, Scalzo et al. 2012, 2010, Silverman et al. 2011, Taubenberger et al. 2011, 2013a).”