NEARBY SUPERNOVA FACTORY OBSERVATIONS OF SN 2007if: FIRST TOTAL MASS MEASUREMENT OF A SUPER-CHANDRASEKHAR-MASS PROGENITOR

By R. Scalzo, G. Aldering, P. Antilogus, C. Aragon, S. Bailey, C. Baltay, S. Bongard, C. Buton, M. Childress, N. Chotard and 21 more. 2010

255 citations recorded by the source corpus.

We present photometric and spectroscopic observations of SN 2007if, an overluminous (MV = −20.4), red (B − V = 0.16 at B-band maximum), slow-rising (trise = 24 days) type Ia supernova (SN Ia) in a very faint (Mg = −14.10) host galaxy. A spectrum at 5 days past B-band maximum light is a direct match to the super-Chandrasekhar-mass candidate SN Ia 2003fg, showing Si ii and C ii at ∼9000 km s−1. A high signal-to-noise co-addition of the SN spectral time series reveals no Na i D absorption, suggesting negligible reddening in the host galaxy, and the late-time color evolution has the same slope as the Lira relation for normal SNe Ia. The ejecta appear to be well mixed, with no strong maximum in I band and a diversity of iron-peak lines appearing in near-maximum-light spectra. SN 2007if also displays a plateau in the Si ii velocity extending as late as +10 days, which we interpret as evidence for an overdense shell in the SN ejecta. We calculate the bolometric light curve of the SN and use it and the Si ii velocity evolution to constrain the mass of the shell and the underlying SN ejecta, and demonstrate that SN 2007if is strongly inconsistent with a Chandrasekhar-mass scenario. Within the context of a “tamped detonation” model appropriate for double-degenerate mergers, and assuming no host extinction, we estimate the total mass of the system to be 2.4 ± 0.2 M☉, with 1.6 ± 0.1 M☉ of 56Ni and with 0.3–0.5 M☉ in the form of an envelope of unburned carbon/oxygen. Our modeling demonstrates that the kinematics of shell entrainment provide a more efficient mechanism than incomplete nuclear burning for producing the low velocities typical of super-Chandrasekhar-mass SNe Ia.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/48dee1ec5658e84564a832e61a8eea83d1ab902b

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In Astronomy and Astrophysics

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

In Nuclear and High Energy Physics

1. D. Maoz
2. F. Mannucci
3. R. Kirshner
4. A. Filippenko
5. S. Jha
6. A. Gal-yam
7. M. Kromer
8. J. C. Wheeler

Citations in the corpus

• THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE (2000, background): “…al. 1992a; Leibundgut et al. 1993; Garnavich et al. 2004; Taubenberger et al. 2008), peculiar 2002cx-like events (e.g., Li et al. 2003; Phillips et al. 2007), and high-luminosity SN Ia speculated to originate from super-Chandrasekhar-mass progenitors (e.g., Howell et al. 2006; Scalzo et al. 2010).”
• Rates of superluminous supernovae at z ∼ 0.2 (2013, background): “The highest luminosity Type Ia found in our survey is SN2007if at about Mr = −20.4mag (Scalzo et al. 2010; Yuan et al. 2010).”
• 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).”
• SUB-CHANDRASEKHAR WHITE DWARF MERGERS AS THE PROGENITORS OF TYPE Ia SUPERNOVAE (2010, background): “This range could account for “superChandrasekhar” SN Ia (e.g., Howell et al. 2006; Scalzo et al. 2010).”
• Evidence of Environmental Dependencies of Type Ia Supernovae from the Nearby Supernova Factory indicated by Local H$\alpha$ (2013, unknown): “2.1 of Scalzo et al. (2010).”
• On the Progenitors of Type Ia Supernovae (2018, unknown): “Following the first such event (Howell et al. 2006), a few other caes have been found, with SN 2007if (Yuan et al. 2010; Scalzo et al. 2010; Childress et al. 2011) and SN 2009dc (Taubenberger et al. 2011) being among the best observed.”
• Fourteen months of observations of the possible super-Chandrasekhar mass Type Ia Supernova 2009dc (2010, methodology): “Therefore, we concur with Howell et al. (2006) and Scalzo et al. (2010) that both SN 2003fg and SN 2007if (respectively) are also probably SC SNe Ia.”
• Type-Ia Supernova Rates and the Progenitor Problem: A Review (2011, background): “Conversely, the Ni mass deduced for some SN Ia explosions is strongly suggestive of a super-Chandrasekhar-mass progenitor (e.g. Tanaka et al. 2010; Silverman et al. 2010; Scalzo et al. 2010).”
• Violent mergers of nearly equal-mass white dwarf as progenitors of subluminous Type Ia supernovae (2011, background): “There is, however, a number of subclasses of SNe Ia consisting of very dim (e.g. SN 1991bg, Leibundgut et al. 1993), normal, bright (e.g. SN 1991T, Filippenko et al. 1992) and very bright supernovae (e.g. SN 2007if, Scalzo et al. 2010).”
• Spectrophotometric time series of SN 2011fe from the Nearby Supernova Factory (2013, methodology): “We will thus elaborate on the data reduction discussion given in Scalzo et al. (2010) and on modifications needed in order to flux calibrate the observations presented here.”
• High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios (2010, background): “This decline rate is among the lowest ever measured for SNe Ia, similar to those of SNe 2006gz (0.69; Hicken et al. 2007) and 2007if (0.71; Scalzo et al. 2010).”
• Observational and Physical Classification of Supernovae (2016, unknown): “A few additional examples of such objects have been published since, including SN 2006gz (Hicken et al. 2007), SN 2009dc (Tanaka et al. 2010), and SN 2007if (Scalzo et al. 2010).”
• Stellar structure models in modified theories of gravity: Lessons and challenges (2019, background): “8M⊙ [518, 519, 520, 521, 522], offering further avenues to test EiBI gravity (and other modified theories of gravity).”