Critical Angular Momentum Distributions in Collapsars: Quiescent Periods From Accretion State Transitions in Long Gamma-Ray Bursts

López-Cámara, Diego; Lee, W.H.; Ramírez-Ruiz, E.

doi:10.1088/0004-637x/716/2/1308

Cited by 21 publications

(16 citation statements)

References 42 publications

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“…The indications we have seem to point towards a prolonged activity of the central engine, similar to the one producing the prompt emission. As discussed in the literature (Proga & Begelman 2003; King et al 2005; Perna, Armitage & Zhang 2006; Proga & Zhang 2006; Kumar, Narayan & Johnson 2008; López‐Cámara, Lee & Ramirez‐Ruiz 2010), there are several mechanisms that could keep the central engine active for a long time or reactivate it in a pseudo‐random way. After the formation of a black hole and accretion disc, accretion of the progenitor material left over by the collapse or disc instabilities could generate the activity we observe (in some cases the instability can be strong enough to generate gravitationally bound clumps within the disc and determine disc fragmentation, see Lodato 2007).…”

Section: Discussionmentioning

confidence: 99%

Unveiling the origin of X-ray flares in gamma-ray bursts

Chincarini¹,

Mao²,

Margutti³

et al. 2010

Monthly Notices of the Royal Astronomical Society

178

280

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We present an updated catalogue of 113 X-ray flares detected by Swift in the ~33 per cent of the X-ray afterglows of gamma-ray burst (GRB). 43 flares have a measured redshift. For the first time the analysis is performed in four different X-ray energy bands, allowing us to constrain the evolution of the flare temporal properties with energy. We find that flares are narrower at higher energies: their width follows a power-law relation w ~ E^(-0.5) reminiscent of the prompt emission. Flares are asymmetric structures, with a decay time which is twice the rise time on average. Both time-scales linearly evolve with time, giving rise to a constant rise-to-decay ratio: this implies that both time-scales are stretched by the same factor. As a consequence, the flare width linearly evolves with time to larger values: this is a key point that clearly distinguishes the flare from the GRB prompt emission. The flare 0.3-10 keV peak luminosity decreases with time, following a power-law behaviour with large scatter: Lpk ~ t^(-2.7+/-0.5). When multiple flares are present, a global softening trend is established: each flare is on average softer than the previous one. The 0.3-10 keV isotropic energy distribution is a lognormal peaked at 10^51 erg, with a possible excess at low energies. The flare average spectral energy distribution is found to be a power law with spectral energy index β ~ 1.1. These results confirmed that the flares are tightly linked to the prompt emission. However, after considering various models we conclude that no model is currently able to account for the entire set of observations

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Section: Discussionmentioning

confidence: 99%

Unveiling the origin of X-ray flares in gamma-ray bursts

Chincarini¹,

Mao²,

Margutti³

et al. 2010

Monthly Notices of the Royal Astronomical Society

178

280

View full text Add to dashboard Cite

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“…If this is not the case, then the nonmonotonicity (see, e.g., Heger et al 2000Heger et al , 2005Petrovic et al 2005) might have interesting consequences for the evolution of the accretion rate. For example, the accretion rate may surge if the average specific angular momentum in the shocked region drops below the critical value for rotational support near ISCO, and this might result in a "flaring" in the LGRB X-ray light curve (see, e.g., López-Cámara et al 2010;Perna & MacFadyen 2010).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Supernovae Powered by Collapsar Accretion in Gamma-Ray Burst Sources

Milosavljević¹,

Lindner

Shen

et al. 2011

ApJ

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The association of long-duration gamma-ray bursts (LGRBs) with Type Ic supernovae presents a challenge to supernova explosion models. In the collapsar model for LGRBs, gamma rays are produced in an ultrarelativistic jet launching from the magnetosphere of the black hole that forms in the aftermath of the collapse of a rotating progenitor star. The jet is collimated along the star's rotation axis, but the concomitant luminous supernova should be relatively-though certainly not entirely-spherical, and should synthesize a substantial mass of 56 Ni. Our goal is to provide a qualitative assessment of the possibility that accretion of the progenitor envelope onto the black hole, which powers the LGRB, could also deposit sufficient energy and nickel mass in the envelope to produce a luminous supernova. For this, the energy dissipated near the black hole during accretion must be transported outward, where it can drive a supernova-like shockwave. Here we suggest that the energy is transported by convection and develop an analytical toy model, relying on global mass and energy conservation, for the dynamics of stellar collapse. The model suggests that a ∼ 10, 000 km s −1 shock can be driven into the envelope and that ∼ 10 51 erg explosions are possible. The efficiency with which the accretion energy is being transferred to the envelope is governed by the competition of advection and convection at distances ∼ 100 − 1, 000 km from the black hole and is sensitive to the values of the convective mixing length, the magnitude of the effective viscous stress, and the specific angular momentum of the infalling envelope. Substantial masses of 56 Ni may be synthesized in the convective accretion flow over the course of tens of seconds from the initial circularization of the infalling envelope around the black hole. The synthesized nickel is convectively mixed with a much larger mass of unburned ejecta.

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“…More dramatic time varying conditions will be found for jets launched during a common-envelope phase as studied by López-Cámara et al (2019), or for long GRBs as studied by e.g. López-Cámara et al (2010); Taylor et al (2011).…”

Section: Applicability In Astrophysicsmentioning

confidence: 97%

Choked Accretion onto a Schwarzschild Black Hole: A Hydrodynamical Jet-launching Mechanism

Tejeda

Aguayo-Ortiz

Hernández

2020

ApJ

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We present a novel, relativistic accretion model onto a Schwarzschild black hole. This consists of a purely hydrodynamical mechanism in which, by breaking spherical symmetry, a radially accreting flow transitions into an inflow-outflow configuration. The spherical symmetry is broken by considering that the accreted material is more concentrated on an equatorial belt, leaving the polar regions relatively under-dense. What we have found is a flux-limited accretion regime in which, for a sufficiently large accretion rate, the incoming material chokes at a gravitational bottleneck and the excess flux is redirected by the density gradient as a bipolar outflow. The threshold value at which the accreting material chokes is of the order of the mass accretion rate found in the spherically symmetric case studied by Bondi and Michel. We describe the choked accretion mechanism first in terms of a general relativistic, analytic toy model based on the assumption of an ultrarelativistic stiff fluid. We then relax this approximation and, by means of numerical simulations show that this mechanism can operate also for general polytropic fluids. Interestingly, the qualitative inflow-outflow morphology obtained appears as a generic result of the proposed symmetry break, across analytic and numeric results covering both the Newtonian and relativistic regimes. Finally, we discuss the applicability of this model as a jet-launching mechanism in different astrophysical settings.

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Critical Angular Momentum Distributions in Collapsars: Quiescent Periods From Accretion State Transitions in Long Gamma-Ray Bursts

Cited by 21 publications

References 42 publications

Unveiling the origin of X-ray flares in gamma-ray bursts

Unveiling the origin of X-ray flares in gamma-ray bursts

Supernovae Powered by Collapsar Accretion in Gamma-Ray Burst Sources

Choked Accretion onto a Schwarzschild Black Hole: A Hydrodynamical Jet-launching Mechanism

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