Shell-shocked Diffusion Model for the Light Curve of SN 2006gy

By N. Smith, R. McCray. 2007

184 citations recorded by the source corpus.

We explore a simple model for the high luminosity of SN 2006gy involving photon diffusion of shock-deposited thermal energy. The distinguishing property of the model is that the large "stellar" radius of ~160 AU required to prevent adiabatic losses is not the true stellar radius, but rather, it is the radius of an opaque, unbound circumstellar envelope, created when ~10 M☉ was ejected in the decade before the supernova in an eruption analogous to that of η Carinae. The supernova light is produced primarily by diffusion of thermal energy following the passage of the blast wave through this shell. This model differs from traditional models of supernova debris interacting with an external circumstellar medium (CSM) in that here the shell is optically thick and the escape of radiation is delayed. We show that any model attempting to account for SN 2006gy's huge luminosity with radiation emitted by ongoing CSM interaction fails for the following basic reason: the CSM density required to achieve the observed luminosity makes the same circumstellar envelope opaque (τ ≳ 300), forcing a thermal diffusion solution. In our model, the weaker CSM interaction giving rise to SN 2006gy's characteristic Type IIn spectrum and soft X-rays is not linked to the power source of the visual continuum; instead, it arises after the blast wave breaks free from the opaque shell into the surrounding wind. While a simple diffusion model can explain the gross properties of the early light curve of SN 2006gy, it predicts that the light curve must plummet rapidly at late times, unless an additional power source is present.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/16872c55312edb83e3f6d06563ec489ef55f60a1

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In Astronomy and Astrophysics

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

Citations in the corpus

• Pan-STARRS1 DISCOVERY OF TWO ULTRALUMINOUS SUPERNOVAE AT z ≈ 0.9 (2011, background): “The general idea is that interaction with CSM transforms much of the SN’s kinetic energy into radiation before it can be lost to adiabatic expansion (e.g., Smith & McCray 2007; Chevalier & Irwin 2011).”
• HIGH-DENSITY CIRCUMSTELLAR INTERACTION IN THE LUMINOUS TYPE IIn SN 2010jl: THE FIRST 1100 DAYS (2013, background): “Republica 252, Santiago, Chile 7 Tuorla Observatory, University of Turku, Väisäläntie 20 FI21500 Piikkiö, Finland 8 Nordic Optical Telescope (NOT), Apartado 474, E-38700 Santa Cruz de La Palma, Spain 9 KTH, Department of Physics, and the Oskar Klein Centre, AlbaNova, SE-106 91 Stockholm, Sweden ”
• PAIR INSTABILITY SUPERNOVAE: LIGHT CURVES, SPECTRA, AND SHOCK BREAKOUT (2011, background): “In some cases, the high luminosity can be attributed to an interaction of the supernova ejecta with a surrounding circumstellar medium (Smith & McCray 2007).”
• GENERALIZED SEMI-ANALYTICAL MODELS OF SUPERNOVA LIGHT CURVES (2011, methodology): “Smith & McCray (2007) adopted a L∝ r2 rise for their model of SN 2006gy based on the early portion of the diffusion models of A82.”
• SUPER-LUMINOUS TYPE Ic SUPERNOVAE: CATCHING A MAGNETAR BY THE TAIL (2013, background): “The first group which was recognised was the luminous Type IIn SNe epitomised by SN 2006gy (Smith et al. 2007; Smith & McCray 2007; Ofek et al. 2007; Agnoletto et al. 2009) which show signs of strong circumstellar interaction.”
• Observed Fractions of Core-Collapse Supernova Types and Initial Masses of their Single and Binary Progenitor Stars (2010, background): “…clues from CSM 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…”
• Unifying Type II Supernova Light Curves with Dense Circumstellar Material (2016, background): “In the most extreme cases, there are the super-luminous SNe and SNe IIn events that can require ∼ 10M or more ejected in the last few years of a massive star’s life (Smith et al. 2007; Smith & McCray 2007; Woosley et al. 2007; van Marle et al. 2010; Smith et al. 2011; Ofek et al. 2013).”
• SN 2006tf: Precursor Eruptions and the Optically Thick Regime of Extremely Luminous Type IIn Supernovae (2008, methodology): “As we have noted elsewhere for SN 2006gy (Smith et al. 2007, 2008b; Smith & McCray 2007), the only stars known to be capable of producing such extreme mass-loss rates of this order are LBVs during their giant eruptions (Smith & Owocki 2006), like the 19th-century eruption of η Carinae when the star…”
• SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION (2012, background): “…IIn SNe with narrow hydrogen absorption lines are thought to be powered, at least in part, by the interaction of the supernova ejecta with circumstellar material, effectively re-thermalizing the supernova shock energy (Smith & McCray 2007; Chevalier & Irwin 2011; Moriya et al. 2012; Gal-Yam 2012).”
• Wave‐driven mass loss in the last year of stellar evolution: setting the stage for the most luminous core‐collapse supernovae (2012, background): “…the interaction between an outgoing supernova shock and such ejecta can explain some of the most optically luminous SNe yet detected (e.g., Smith & McCray 2007), including, e.g., SN 2006gy (Smith et al. 2007; Ofek et al. 2007) and perhaps the emerging class of hydrogen-poor ultraluminous…”
• Light-curve modelling of superluminous supernova 2006gy: collision between supernova ejecta and a dense circumstellar medium (2012, background): “Smith & McCray (2007) suggest that the declining phase of the light curve (LC) of SN 2006gy can be explained by emission from a shocked ∼10 M CSM shell.”
• ANALYTICAL LIGHT CURVE MODELS OF SUPERLUMINOUS SUPERNOVAE: χ2-MINIMIZATION OF PARAMETER FITS (2013, unknown): “It has been suggested (Smith et al. 2007; Smith & McCray 2007, Smith et al. 2010) that the progenitor of SN 2006gy was most likely an LBVtype star that suffered extreme mass-loss prior to its death.”
• SHOCK BREAKOUT IN DENSE MASS LOSS: LUMINOUS SUPERNOVAE (2011, methodology): “The dense mass loss is typically attributed to LBV (luminous blue variable) eruptions (Smith & McCray 2007), although such eruptions are not understood in the context of stellar evolution.”
• The Destruction of Cosmological Minihalos by Primordial Supernovae (2008, background): “Peculiar features in a supernova light curve can be exploited to infer the properties of circumstellar gas (Smith & McCray 2007).”
• PREPARING FOR AN EXPLOSION: HYDRODYNAMIC INSTABILITIES AND TURBULENCE IN PRESUPERNOVAE (2013, background): “…2003ma, etc.) where the bolometric luminosity of the CSM interaction demands very large masses up to 20 M⊙ ejected a few years7 before core collapse (Smith & McCray 2007; Smith et al. 2007, 2008, 2010a; Woosley et al. 2007; Rest et al. 7 In a 25 M⊙ star, the neutrino-cooled stage takes about 300…”
• Rates of superluminous supernovae at z ∼ 0.2 (2013, background): “Interaction with circum-stellar media clearly plays an important role in these events and may be responsible for their extreme luminosities (e.g. Smith & McCray 2007; Smith et al. 2008b; Chevalier & Irwin 2011).”
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars (2014, background): “…with Type IIn spectra represent the most extreme cases of eruptive pre-SN mass loss, with luminosities ∼10 times higher than a normal bright SN Ia. Smith & McCray (2007) proposed that these extremely high luminosities could be achieved wth normal energy core-collapse SNe (a few 1051 ergs) if…”
• Progenitors of Core-Collapse Supernovae (2009, background): “The collisions between the massive shells produces radiative energies in a similar manner to that discussed in Smith & McCray (2007) The radio lightcurve modulations seen in some SNe have been suggested to be due to the interaction of the ejecta with the progenitor stars’ surrounding gas shells…”
• SPECTRAL EVOLUTION OF THE EXTRAORDINARY TYPE IIn SUPERNOVA 2006gy (2009, methodology): “This radiation cannot escape directly from the post-shock zone, but must diffuse out through the opaque envelope, as suggested by Smith & McCray (2007) to explain the slow rise to maximum of SN 2006gy.”