Trans-Relativistic Blast Waves in Supernovae as Gamma-Ray Burst Progenitors

By Jonathan C. Tan, C. Matzner, C. McKee. 2000

157 citations recorded by the source corpus.

We investigate the acceleration of shock waves to relativistic velocities in the outer layers of exploding stars. By concentrating the energy of the explosion in the outermost ejecta, such trans-relativistic blast waves can serve as the progenitors of gamma-ray bursts (GRBs); in particular, the "baryon-loading" problem that plagues many models of GRBs is circumvented. Postshock acceleration is effective in boosting the kinetic energy in relativistic ejecta. We present physically motivated analytic expressions to describe trans-relativistic blast waves in supernovae, and we validate these expressions against numerical simulations of test problems. Investigating the effect of stellar structure on mass ejection, we find that relativistic ejecta are enhanced in more centrally condensed envelopes, e.g., for radiative envelopes, when the luminosity approaches the Eddington limit. Convenient formulae are presented with which to estimate the production of relativistic ejecta from a given progenitor. We apply our analytic and numerical methods to a model of SN 1998bw, finding significantly enhanced relativistic ejecta compared to previous studies. We propose that GRB 980425 is associated with SN 1998bw and may have resulted from an approximately spherical explosion producing ~10-6 M☉ of mildly relativistic ejecta with mean Lorentz factor ~ 2, which then interacted with a dense circumstellar wind with a mass-loss rate of approximately a few times 10-4 M☉ yr-1. A highly asymmetric explosion is not required. An extreme model of "hypernova" explosions in massive stars is able to account for the energetics and relativistic ejecta velocities required by many of the observed cosmological GRBs. However, the most energetic bursts require asymmetric expulsion of ejecta, perhaps caused by rotationally flattened progenitors. We present simplified models and simulations of explosions resulting from accretion-induced collapse of white dwarfs and phase transitions of neutron stars. While we find increased energies in relativistic ejecta compared to previous studies, these explosions are unlikely to be observed at cosmological distances with current detectors, unless extreme explosion energies and asymmetries are invoked.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d835bb2e25a3d206b8d88767581f5acb0329c2ce

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In Astronomy and Astrophysics

1. Bing Zhang
2. Stan Woosley
3. E. Nakar
4. T. Piran
5. B. Metzger
6. Alexander Heger
7. A. Tchekhovskoy
8. O. Bromberg

Citations in the corpus

• The Supernova Gamma-Ray Burst Connection (2006, background): “…blast wave interacting with a circumstellar medium might be a reasonable model for some events (Woosley et al., 1999; Matzner and McKee, 1999; Tan et al., 2001), especially if the ejecta are beamed. length scales spanning parsecs (“circumburst”), to galaxies, to cosmic distances, GRBs…”
• Modules for Experiments in Stellar Astrophysics ( ): Convective Boundaries, Element Diffusion, and Massive Star Explosions (2017, methodology): “For a radiationdominated strong shock, a simple analytic expression for the shock velocity is provided by Matzner & McKee (1999), v E m M m M r , 32sh center 1 2 center 3 0.19 a r = - -⎛ ⎝⎜ ⎞ ⎠⎟ ⎡ ⎣⎢ ⎤ ⎦⎥ ( ) where we adopt 0.736a = as suggested by Tan et al. (2001).”
• Supernova hosts for gamma-ray burst jets: dynamical constraints (2002, methodology): “Once x and βh(x) or h(x) have been identified, the production of fast ejecta follows from Tan et al. (2001)’s theory (their equation 54) if one matches the shock four-velocity γ sβs with the head four-velocity hβh at depth x.”
• Circumstellar Emission from Type Ib and Ic Supernovae (2006, background): “Tan et al. (2001) have discussed the supernova structure for the case in which the accelerating shock at the outer edge of the star becomes relativistic.”
• THE OBSERVABLE SIGNATURES OF GRB COCOONS (2016, background): “Various authors (Kulkarni et al. 1998; Tan et al. 2001; MacFadyen et al. 2001; Campana et al. 2006; Wang et al. 2007; Katz et al. 2010; Nakar & Sari 2010; Bromberg et al. 2011a) suggested that the emission from the shock breakout of chocked jets’ cocoons produce the low luminosity GRBs (llGRBs).”
• The Observer's Guide to the Gamma-Ray Burst-Supernova Connection (2016, background): “2 [57, 82, 83]; explosions powered by a shortlived central engine (blue/purple dashed), SBO-GRBs and relativistic IcBL SNe 2009bb and 2012ap: EK ∝ (Γβ) ; and those arising from a long-lived central engine (red), that is, jetted-GRBs: EK ∝ (Γβ) −0.”
• The Propagation and Eruption of Relativistic Jets from the Stellar Progenitors of Gamma-Ray Bursts (2003, background): “Tan et al. (2001) present arguments, however, that, by external shock interaction with the progenitor wind, a hard transient of some sort should result. a Angle between the axis of the injected jet and the z-axis. b Period of precession in models 3P3, 3P5, and 3P10. c Models 3BL and 3BS were like…”
• Relativistic MHD simulations of core-collapse GRB jets: 3D instabilities and magnetic dissipation (2015, background): “…the cocoon breaks out of the star, and feasibly leads to a different type of burst, which may resemble a low-luminosity GRB (Kulkarni et al. 1998; MacFadyen et al. 2001; Tan et al. 2001; Wang et al. 2007; Waxman et al. 2007; Katz et al. 2010; Bromberg et al. 2011; Nakar & Sari 2012; Nakar 2015).”