SN 2006gy: Discovery of the Most Luminous Supernova Ever Recorded, Powered by the Death of an Extremely Massive Star like η Carinae

By N. Smith, Weidong Li, R. Foley, J. C. Wheeler, D. Pooley, Ryan Chornock, A. Filippenko, J. Silverman, R. Quimby, Joshua S. Bloom and 1 more. 2006

461 citations recorded by the source corpus.

We report the discovery and early observations of the peculiar Type IIn supernova (SN) 2006gy in NGC 1260. With a peak visual magnitude of about -22, it is the most luminous supernova ever recorded. Its very slow rise to maximum took ~70 days, and it stayed brighter than -21 mag for about 100 days. It is not yet clear what powers the enormous luminosity and the total radiated energy of ~1051 erg, but we argue that any known mechanism—thermal emission, circumstellar interaction, or 56Ni decay—requires a very massive progenitor star. The circumstellar interaction hypothesis would require truly exceptional conditions around the star, which, in the decades before its death, must have experienced a luminous blue variable (LBV) eruption like the 19th century eruption of η Carinae. However, this scenario fails to explain the weak and unabsorbed soft X-rays detected by Chandra. Radioactive decay of 56Ni may be a less objectionable hypothesis, but it would imply a large Ni mass of ~22 M☉, requiring SN 2006gy to have been a pair-instability supernova where the star's core was obliterated. While this is still uncertain, SN 2006gy is the first supernova for which we have good reason to suspect a pair-instability explosion. Based on a number of lines of evidence, we eliminate the hypothesis that SN 2006gy was a ``Type IIa'' event, that is, a white dwarf exploding inside a hydrogen envelope. Instead, we propose that the progenitor was a very massive evolved object like η Carinae that, contrary to expectations, failed to shed its hydrogen envelope. SN 2006gy implies that some of the most massive stars can explode prematurely during the LBV phase, never becoming Wolf-Rayet stars. SN 2006gy also suggests that they can create brilliant supernovae instead of experiencing ignominious deaths through direct collapse to a black hole. If such a fate is common among the most massive stars, then observable supernovae from Population III stars in the early universe will be more numerous than previously believed.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/de2c4272364f2b0a3d9af9f1c895753cc4c093ef

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In Astronomy and Astrophysics

1. S. Smartt
2. E. Berger
3. N. Smith
4. Bing Zhang
5. B. Metzger
6. A. Filippenko
7. Stan Woosley
8. Ryan Chornock

Citations in the corpus

• Progenitors of Core-Collapse Supernovae (2009, methodology): “At the distance limits of 28-30 Mpc (µ ≃ 32.3) one might naively think that the samples of Smartt et al. (2009) and Li et al. (2007) do not suffer serious bias from missing known classes of SNe, as the limiting magnitude of LOSS and other well equipped amateur searches is around mCCD ∼ 19.”
• Massive stars exploding in a He-rich circumstellar medium. I. Type Ibn (SN 2006jc-like) events (2008, background): “Recently, Smith et al. (2007) and Langer et al. (2007) proposed that the bright type IIn SN 2006gy (see also Ofek et al. 2007) might be a pair-creation SN (PCSN), an exotic event produced by the explosion of a very massive star (more than 100M⊙ , Heger & Woosley 2002).”
• Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete Sample (2010, background): “Recently, several extremely luminous CC SNe have been reported, including SN 2003ma (Rest et al. 2009), SN 2005ap (Quimby et al. 2007), SN 2006gy (Smith et al. 2007; Ofek et al. 2007), SN 2006tf (Smith et al. 2008), SN 2008es (Miller et al. 2009; Gezari et al. 2009), and SN 2008fz (Drake et al.…”
• The Magnetar Model for Type I Superluminous Supernovae. I. Bayesian Analysis of the Full Multicolor Light-curve Sample with MOSFiT (2017, background): “Type II SLSNe do exhibit hydrogen in their spectra, usually in the form of relatively low-velocity emission lines with broad bases (e.g., Smith et al. 2007), and appear to be an extension of the lower-luminosity SN IIn population.”
• How Much 56Ni Can Be Produced in Core-Collapse Supernovae? Evolution and Explosions of 30-100 M☉ Stars (2007, background): “In the present days, however, there are very interesting peculiar SNe, SN1999as (Knop, R., et al. 1999) and SN2006gy (Foley et al. 2006; Ofek et al. 2007; Smith et al. 2007).”
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 M⊙ stellar mass limit (2010, background): “…demonstrated that local pair-instability SNe could be produced either by slow rotating moderately metalpoor (≤1/3 Z ) yellow hypergiants with thick hydrogen-rich envelopes – resembling SN 2006gy (Ofek et al. 2007; Smith et al. 2007) – or rapidly rotating very metal-deficient (≤10−3 Z ) WR stars.”
• SPECTRAL EVOLUTION OF THE EXTRAORDINARY TYPE IIn SUPERNOVA 2006gy (2009, background): “Although SN 2006gy had the hghest peak luminosity of any known SN when it was discovered (Ofek et al. 2007; Smith et al. 2007), subsequent discoveries of SN 2005ap5 5 Although the explosion of SN 2005ap obviously occurred before SN 2006gy, its distance and high luminosity were recognized later…”
• ANALYTICAL LIGHT CURVE MODELS OF SUPERLUMINOUS SUPERNOVAE: χ2-MINIMIZATION OF PARAMETER FITS (2013, methodology): “Other potential mass-loss mechanisms are LBV-type mass loss reminiscent to η-Carina (Smith et al. 2007), or shell ejection in the context of PPISN (Woosley, Blinnikov & Heger 2007; Chatzopoulos & Wheeler 2012b).”
• Shell-shocked Diffusion Model for the Light Curve of SN 2006gy (2007, methodology): “To account for the luminosity with CSM interaction, Smith et al. (2007) proposed that the star suffered a tremendous explosive but nonterminal mass-loss event in the decade preceding the SN, analogous to the 19th century eruption of η Carinae.”
• SN 2008S: An electron-capture SN from a super-AGB progenitor? (2009, background): “However, the simplicity of the emergingpicture is compromised by the growing number of peculiar events(e.g. Kulkarni et al. 2007; Smith et al. 2007; Quimby et al. 2007).”
• CALTECH CORE-COLLAPSE PROJECT (CCCP) OBSERVATIONS OF TYPE IIn SUPERNOVAE: TYPICAL PROPERTIES AND IMPLICATIONS FOR THEIR PROGENITOR STARS (2010, background): “Early results were reported by Ofek et al. (2007), estimating a mass-loss rate of 0.1M⊙ y −1, and Smith et al. (2007), who were more ambiguous about such high mass-loss values.”
• OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES (2010, background): “We note that the unusual SN 2006gy, which occurred at about 350 pc from the center of its host (Smith et al. 2007), could be an example of a “galatic nucleus SN”, but a larger sample of requirement were not imposed can be estimated by integrating the fit to the d-distribution (Fig.”
• Luminous blue variable eruptions and related transients: diversity of progenitors and outburst properties (2010, background): “Woosley et al. (2007) and Smith et al. (2007, 2010b) have mentioned the PPI as an attractive explanation for the precursor LBVlike mass ejections that precede some very luminous SNe IIn like SN 2006gy.”
• INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END? (2012, methodology): “Based on analysis of SN data, a link between some LBVs and SNe IIn has been proposed (see e.g. Kotak & Vink 2006; Smith & Owocki 2006; Smith et al. 2007; Trundle et al. 2008, 2009).”
• Observed Fractions of Core-Collapse Supernova Types and Initial Masses of their Single and Binary Progenitor Stars (2010, background): “…interaction in SNe IIn indicate that heavy mass-loss sometimes occurs shortly before core collapse (e.g. Chugai et al. 2004; Smith & McCray 2007; Smith et al. 2007, 2008b, 2010); if heavy mass-loss is concentrated in brief events during the last few thousand years before core collapse, then the…”
• Pan-STARRS1 DISCOVERY OF TWO ULTRALUMINOUS SUPERNOVAE AT z ≈ 0.9 (2011, background): “…be a pair-instability explosion (Gal-Yam et al. 2009; Young et al. 2010), to the Type IIn SN 2006gy, with strong signs of circumstellar interaction (Smith et al. 2007; Smith & McCray 2007; lchomiuk@cfa.harvard.edu 1 National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 USA 2…”