Related papers: Identifying Black Hole Central Engines in Gamma-Ra…
Presently there are several classes of detected gamma-ray extragalatic sources. They are mostly associated to active galactic nuclei (AGN) and (at soft gamma rays) to gamma-ray bursts (GRB), but not only. Active galactic nuclei consist of…
Data from the Fermi Gamma-ray Burst Monitor satellite observatory suggested that the recently discovered gravitational wave source, a pair of two coalescing black holes, was related to a gamma-ray burst. The observed high-energy…
Various authors have suggested that the gamma-ray burst (GRB) central engine is a rapidly rotating, strongly magnetized, $(\sim 10^{15}-10^{16}$ G) compact object. The strong magnetic field can accelerate and collimate the relativistic flow…
We here propose a two-step model for gamma-ray bursts (GRBs) associated with supernovae. In the first step, the core collapse of a star with mass $\ge 19M_\odot$ leads to a massive neutron star and a normal supernova, and subsequently…
We note that if the GRB phenomenon follows from the collapse of a massive object forming a black hole and a torus accreting into it, the resulting ejecta can be only related to the mass and angular momentum that characterize the black hole.…
Relativistic jets originating from protomagnetar central engines can lead to long duration gamma-ray bursts (GRBs) and are considered potential sources of ultrahigh-energy cosmic rays and secondary neutrinos. We explore the propagation of…
Extragalactic relativistic jets are engines able to carry out to large distances a huge amount of power, not only in the form of radiation, but especially in the form of kinetic energy of matter and fields. As such, they can be thought as…
A multi-decade theoretical effort has been devoted to finding an efficient mechanism to use the rotational and electrodynamical extractable energy of a Kerr-Newman black hole (BH), to power the most energetic astrophysical sources such as…
It is widely believed that relativistic jets in X-ray binaries and active-galactic nuclei are powered by the rotational energy of black holes. This idea is supported by general-relativistic magnetohydrodynamic (GRMHD) simulations of…
Gamma-ray bursts (GRBs) are the most electromagnetically luminous cosmic explosions. They are powered by collimated streams of plasma (jets) ejected by a newborn stellar-mass black hole or neutron star at relativistic velocities (near the…
Last and nearest GRB-XRF 080109 has been an exceptional lesson on GRB nature. After a decade (since 25 April 08) we know that Supernovae may often contain a Jet. Its persistent activity may shine on axis as a GRBs. Such a persistent, thin…
Long duration gamma-ray bursts (GRB) are at cosmological distance, they appear to be located near star forming regions, and are likely associated with some type of supernovae. They are also likely to be strongly beamed, which lowers their…
The most energetic gamma-ray bursts (GRBs) are remarkable sources releasing huge amounts of energy on short timescales. Their prompt emission, which usually lasts few seconds, is so bright that it is visible across the whole observable…
In a companion theory paper, we presented a unified model of jet formation. We suggested that primarily two types of relativistic jets form near accreting black holes: a potentially ultrarelativistic Poynting-dominated jet and a…
In order to investigate formation of relativistic jets at the center of a progenitor of a long gamma-ray burst (GRB), we develop a two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. We show the code passes many,…
The aim of this short paper is to motivate and encourage research in the field of Active Galactic Nuclei (AGN). Here we summarize the main open questions concerning the central engine. Is the central black hole rapidly spinning and can we…
The possible short gamma-ray burst (GRB) observed by {\it Fermi}/GBM in coincidence with the first gravitational wave (GW) detection, offers new ways to test GRB prompt emission models. Gravitational wave observations provide previously…
We present a mechanism for long bursts of gravitational radiation from Kerr black holes surrounded by a torus. These systems are believed to form in core-collapse of massive stars in association with gamma-ray bursts. The torus catalyzes…
Recent observations suggest that gamma ray bursts (GRBs) and their afterglows are produced by highly relativistic jets emitted in supernova explosions. We have proposed that the result of the event is not just a compact object plus the…
Recent gamma-ray burst observations have revealed late-time, highly energetic events which deviate from the simplest expectations of the standard fireball picture. Instead they may indicate that the central engine is active or restarted at…