Related papers: Nature and Nurture: a model for soft gamma-ray rep…
There are several phenomenological similarities between Soft Gamma Repeaters and Fast Radio Bursts, including duty factors, time scales and probable repetition. The sudden release of magnetic energy in a neutron star magnetosphere, as in…
We present a scenario of formation of strange stars due to spin-down of {\it rapidly rotating} neutron stars left after supernova explosions . By assuming a process where the total baryon mass is conserved but the angular momentum is lost…
Precessing Gamma Jets, originated by Neutron Stars or Black Holes, may blaze to the observer leading to Gamma Bursts (GRBs) and Soft Gamma repeaters (SGRs). The thin gamma jet is born either at Supernova (SN) like events mostly at the…
I consider the state of play regarding associations of supernova remnants (SNRs) with anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs). The three AXP/SNR associations are convincing, and are consistent with AXPs being…
The optical afterglow of the gamma-ray burst GRB 970508 (z = 0.835) was a few hundred times more luminous than any supernova. Therefore, a name `hypernova' is proposed for the whole GRB/afterglow event. There is tentative evidence that the…
Strange stars (SSs) are compact objects made of deconfined quarks. It is hard to distinguish SSs from neutron stars as a thin crust composed of normal hadronic matter may exist and obscure the whole surface of the SS. Here we suggest that…
When a spinning-down neutron star undergoes a phase transition that produces quark matter in its core, a Super-Giant Glitch of the order ${\Delta} \Omega/\Omega\sim 0.3$ occurs on time scales from 0.05 seconds to a few minutes. The energy…
The physical nature of Fast Radio Bursts (FRBs), a new type of cosmological transients discovered recently, is not known. It has been suggested that FRBs can be produced when a spinning supra-massive neutron star loses centrifugal support…
Soft gamma repeaters (SGRs) have unique properties that make them intriguing targets for gravitational wave (GW) searches. They are nearby, their burst emission mechanism may involve neutron star crust fractures and excitation of…
A clear gamma polarization in the gamma signals from GRB021206 probes the presence of a very thin collimated jet (opening angle Delta\theta < 0.6^o, (Delta\Omega)\Omega< 2.5 10^-5) in Gamma Ray Burst, GRBs. The last and well proved…
There are about 2000 gamma ray burst (GRB) events known to us with data pouring in at the rate of one per day. While the afterglows of GRBs in radio, optical and X-ray bands are successfully explained by the fireball model, a significant…
Gamma Ray Bursts as recent GRB990123 and GRB990510 are observed to occur in cosmic volumes with a corresponding output reaching, for isotropic explosions, energies as large as two solar masses annihilation. These energies are underestimated…
Long duration gamma ray bursts (GRBs) and X-ray flashes (XRFs) are produced by highly- relativistic jets ejected in core-collapse supernova explosions. The origin of short hard gamma-ray bursts (SHBs) has not been established. They may be…
Strange stars are one of the hypothetical compact stellar objects that can be formed after a supernova explosion. The existence of these objects relies on the absolute stability of strange {\it collapsed} quark matter with respect to…
Four Soft Gamma Repeaters (SGRs) have now been identified with certainty, and a fifth has possibly been detected. I will review their X-ray and gamma-ray properties in both outburst and quiescence. The magnetar model accounts fairly well…
Quiescence and burst emission and relativistic particle winds of soft gamma-ray repeaters (SGRs) have been widely interpreted to result from ultrastrongly magnetized neutron stars. In this magnetar model, the magnetic energy and…
A list of questions regarding Gamma Ray Bursts (GRBs) and Soft Gamma Repeaters (SGRs) remain unanswered within the Fireball-cone and Magnetar explosive scenarios. A persistent, thin (less than micron-sr solid angle) precessing and spinning…
The probability of observing "supernova - gamma-ray burst" (GRB) pair events and recurrent GRBs from one galaxy in a time interval of several years has been estimated. Supernova explosions in binary systems accompanied by the formation of a…
We present a new model for gamma-ray bursts (GRBs) that are not only associated with supernovae but also have small baryon contamination. In this model, we assume a newborn neutron star to move outward at a kick velocity of $\sim 10^3 {\rm…
The fraction of long duration gamma ray bursts (GRBs) without an associated bright supernovae (SNe) at small redshifts $(z<0.15)$ is comparable to that of GRBs associated with SNe. We show, that their X-ray afterglow and the X-ray afterglow…