Related papers: A model for giant flares in soft gamma repeaters

One of a family previously proposed ``central engines'' for cosmic gamma-ray burst sources (Klu\'zniak & Ruderman 1998) is considered in some detail. A steadily accreting $10^6$ Gauss magnetic white dwarf should ultimately collapse to a…

We explore a possibility to explain the phenomenon of the Anomalous X-ray Pulsars (AXP) and Soft Gamma-ray Repeaters (SGR) within the scenario of fall-back magnetic accretion onto a young isolated neutron star. The X-ray emission of the…

We consider the long term evolution of debris following the tidal disruption of compact stars in the context of short gamma ray bursts (SGRBs). The initial encounter impulsively creates a hot, dense, neutrino-cooled disk capable of powering…

The Soft Gamma Repeater SGR 1900+14 entered a remarkable phase of activity during the summer of 1998. This activity peaked on August 27, 1998 when a giant periodic gamma-ray flare resembling the famous March 5, 1979 event from SGR 0526-66…

We discuss the high enegry afterglow emission (including high energy photons, neutrinos and cosmic rays) following the 2004 December 27 Giant Flare from SGR 1806-20. If the initial outflow is relativistic with a bulk Lorentz factor…

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 examined the fall-back disk models, and in general accretion, proposed to explain the properties of anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), and radio pulsars (PSRs). We checked the possibility of some gas remaining…

The giant outburst from SGR 1806-20 was observed on 2004 December 27 by many spacecraft. This extremely rare event exhibits a striking similarity to the two giant outbursts thus far observed, on 1979 March 5 from SGR 0526-66 and 1998 August…

On 2004 December 27, a highly-energetic giant flare was recorded from the magnetar candidate SGR 1806-20. In the months preceding this flare, the persistent X-ray emission from this object began to undergo significant changes. Here, we…

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…

We explore the scenario where the core of a neutron star (having experienced a transition to an up and down quark phase) shrinks into the equilibrated quark object after reaching strange quark matter saturation density (where a composition…

Recent follow-up observations of the December 27 giant flare of SGR 1806-20 have detected a multiple-frequency radio afterglow from 240 MHz to 8.46 GHz, extending in time from a week to about a month after the flare. The angular size of the…

We studied the thermal stability of non-self-gravitating turbulent $\alpha$-discs around supermassive black holes (SMBHs) to test a new type of high-amplitude galactic nucleus flares. By calculating the disc structures, we computed the…

Fast radio bursts (FRBs) last for $\sim $ few milli-seconds and, hence, are likely to arise from the gravitational collapse of supra-massive, spinning neutron stars after they lose the centrifugal support (Falcke \& Rezzolla 2014). In this…

The gravitational wave event GW170817 with a macronova/kilonova shows that a merger of two neutron stars ejects matter with radioactivity including $r$-process nucleosynthesis. A part of the ejecta inevitably falls back to the central…

It is now recognized that long-duration Gamma-Ray Bursts (GRBs) are linked to the collapse of massive stars, based on the association between (low-redshift) GRBs and (type Ic) core-collapse supernovae (SNe). The census of massive stars and…

We present a new model for soft gamma-ray repeaters based on a quark star born with temperatures above the critical value (T_c) for the onset of the colour-flavor locked superconductivity. The quark star then quickly cools below T_c,…

The giant flare of December 27, 2004 from SGR 1806-20 represents one of the most extraordinary events captured in over three decades of monitoring the gamma-ray sky. One measure of the intensity of the main peak is its effect on X- and…

High energy ($> 250$ keV) emission has been detected persisting for several tens of seconds after the initial spike of magnetar giant flares. It has been conjectured that this emission might arise via inverse Compton scattering in a highly…

The brightest giant flare from the soft $\gamma$-ray repeater (SGR) 1806-20 was detected on 2004 December 27. The isotropic-equivalent energy release of this burst is at least one order of magnitude more energetic than those of the two…