Black Hole Hyperaccretion Inflow–Outflow Model. I. Long and Ultra-long Gamma-Ray Bursts

Abstract

Long-duration gamma-ray bursts (LGRBs) and ultra-LGRBs (ULGRBs) originate from collapsars, in the center of which a newborn rotating stellar-mass black hole (BH) surrounded by a massive accretion disk may form. In the scenario of BH hyperaccretion inflow-outflow model and BlandfordZnajek (BZ) mechanism to trigger gamma-ray bursts (GRBs), the real accretion rate to power a BZ jet is far lower than the mass supply rate from the progenitor star. The characteristics of the progenitor stars can be constrained by GRB luminosity observations, and the results exceed usual expectations.LGRBs lasting from several seconds to tens of seconds in the rest frame may originate from solar-metallicity (Z ∼ 1 Z ⊙ , where Z and Z ⊙ are the metallicities of progenitor stars and the Sun), massive (M 34 M ⊙ , where M and M ⊙ are the masses of progenitor stars and the Sun) stars or some zero-metallicity (Z ∼ 0) stars. A fraction of low-metallicity (Z 10 −2 Z ⊙ ) stars, including Population III stars, can produce ULGRBs such as GRB 111209A. The fraction of LGRBs lasting less than tens of seconds in the rest frame is more than 40%, which cannot conform to the fraction of the demanded type of progenitor star. It possibly implies that the activity timescale of central engine may be much longer than the observed timescale of prompt emission phase, as indicated by X-ray late-time activities. Alternatively, LGRBs and ULGRBs may be powered by a millisecond magnetar central engine.

An Embedded X-Ray Source Shines through the Aspherical AT 2018cow: Revealing the Inner Workings of the Most Luminous Fast-evolving Optical Transients

“…Panchromatic studies of future FBOTs will clarify if AT 2018cow is a representative member of its class and will reveal the connection (or lack thereof) of FBOTs to other classes of explosive transients, like GRBs or TDEs (the only two types of transients that are known to show persistent and rapid X-ray variability so far). In this respect it is interesting to mention that hints for hard X-ray excesses have been reported in long GRBs Margutti et al 2008), which are central-engine powered explosions, and in ultra-long GRBs Bellm et al 2014), for which the connection to blue supergiant progenitors has already been suggested (e.g., Quataert & Kasen 2012;Gendre et al 2013;Nakauchi et al 2013;Wu et al 2013;Liu et al 2018).…”

Highly luminous supernovae associated with gamma-ray bursts

“…This model therefore represents one of the best solutions for GRB 111209A/SN 2011kl presented so far. Liu et al (2018b) used prompt emission data to constrain the possible progenitor stars of GRBs of different duration within the framework of a BH hyper-accretion model. They found that ULGRBs such as GRB 111209A can only have progenitors of high mass and low metallicity, up to metal-free Pop III stars.…”

Ultra-long gamma-ray bursts and ultra-soft gamma-ray bursts

“…超长暴的前身星模型主要分为以下三种类型: 超 大质量恒星, 类似于Pop III Stars(蓝超巨星) [20,45,48,49] ; 白矮星的潮汐瓦解 [50,51] ; 特殊的中心引擎, 如新诞生的 磁星 [40] 、夸克星 [26] , 黑洞的超吸积 [52] 以及黑洞自旋衰 减提供能量 [53] 等. 我们将在下面的叙述中举例说明.…”