scholarly journals Relativistic outflows from remnants of compact object mergers and their viability for short gamma-ray bursts

2005 ◽  
Vol 436 (1) ◽  
pp. 273-311 ◽  
Author(s):  
M. A. Aloy ◽  
H.-T. Janka ◽  
E. Müller
Keyword(s):  
Gamma Ray ◽  
Compact Object ◽  
Gamma Ray Bursts ◽  
Relativistic Outflows

scholarly journals Diffusive photospheres in gamma-ray bursts

2020 ◽  
Vol 494 (1) ◽  
pp. 1463-1469
Author(s):  
G V Vereshchagin ◽  
I A Siutsou
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Total Flux ◽  
Thermal Component ◽  
Radiative Diffusion ◽  
Relativistic Outflows ◽  
Photospheric Radius

ABSTRACT Photospheric emission may originate from relativistic outflows in two qualitatively different regimes: last scattering of photons inside the outflow at the photospheric radius or radiative diffusion to the boundary of the outflow. In this work, the measurement of temperature and flux of the thermal component in the early afterglows of several gamma-ray bursts along with the total flux in the prompt phase is used to determine initial radii of the outflow as well as its Lorentz factors. Results indicate that in some cases the outflow has relatively low Lorentz factors (Γ < 10), favouring cocoon interpretation, while in other cases Lorentz factors are larger (Γ > 10), indicating diffusive photospheric origin of the thermal component, associated with an ultrarelativistic outflow.

scholarly journals Radio studies of relativistic SN 2009bb

2013 ◽  
Vol 9 (S296) ◽  
pp. 395-396
Author(s):  
Alak Ray ◽  
Naveen Yadav ◽  
Sayan Chakraborti ◽  
Alicia Soderberg ◽  
Poonam Chandra
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Radio Observations ◽  
X Ray ◽  
Radio Studies ◽  
Relativistic Outflows

AbstractA local sub-population of type Ib/c supernovae (stripped envelope SNe) with mildly relativistic outflows have been detected as sub-energetic Gamma Ray Bursts (GRBs) or X-ray Flashes (XRFs) and as radio afterglows without detected GRB counterpart. SN 2009bb belongs to the last class of objects. The long term radio observations with (J)VLA and GMRT of this SN map the dynamics of the relativistic ejecta characteristic of Central Engines associated with GRBs. We present here GMRT observations of this SN from October 2009 onwards.

scholarly journals First spectroscopy of a short-hard GRB: the environment of a compact object merger

2014 ◽  
Vol 10 (S313) ◽  
pp. 398-399
Author(s):  
Antonio de Ugarte Postigo ◽  
Christina C. Thöne ◽  
Antonia Rowllinson ◽  
Rubén García Benito ◽  
Andrew J. Levan ◽  
...  
Keyword(s):  
Black Holes ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Compact Object ◽  
Gamma Ray Bursts ◽  
Compact Objects ◽  
Spectroscopic Observations ◽  
Cosmic Explosions

AbstractShort gamma-ray bursts (GRBs) are an extremely elusive family of cosmic explosions. They are thought to be related to the violent merger of compact objects (such as a neutron stars or black holes). Their optical counterparts were not discovered until 2005, and since then, there had been no successful spectroscopic observations. Here we present the first spectra of a short GRB, which we use to study the environment and derive implications on the progenitors of these cosmic explosions. This poster is based on the work by de Ugarte Postigoet al. (2014).

scholarly journals Observational Features of Cosmic Gamma-Ray Bursts: Evidence for Galactic Versus Extragalactic Origin

1994 ◽  
Vol 142 ◽  
pp. 857-861
Author(s):  
Kevin Hurley
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Compact Object ◽  
Current Data ◽  
Gamma Ray Bursts ◽  
Spectral Evolution ◽  
Characteristic Distance ◽  
Time Histories ◽  
Burst Time ◽  
Galactic Distribution

AbstractThe recent observational data on gamma-ray bursts are reviewed. Burst time histories display features at the millisecond level which suggest a compact object origin. Lines in the energy spectra and spectral evolution point toward a Galactic neutron star origin, even though line features have not yet been confirmed in recent data. The Galactic distribution of burst sources, however, is both isotropic and sampled to its characteristic distance, making it unlikely that the sources are related to populations of Galactic neutrons stars we are familiar with. Counterpart searches, previously carried out years after the gamma-ray bursts, are now proceeding days after the events. Based on the current data, it is impossible to conclude whether bursters are Galactic, extragalactic, or both. Data being returned from current experiments, as well as data from new experiments to be launched in the next few years, may yet provide the answer.Subject heading: gamma rays: bursts

scholarly journals STATISTICAL PROPERTIES OF MULTIPLE OPTICAL EMISSION COMPONENTS IN GAMMA-RAY BURSTS AND IMPLICATIONS

2013 ◽  
Vol 23 ◽  
pp. 228-237
Author(s):  
EN-WEI LIANG ◽  
LIANG LI ◽  
QING-WEN TANG ◽  
JIE-MIN CHEN ◽  
BING ZHANG
Keyword(s):  
Gamma Ray ◽  
Compact Object ◽  
Optical Emission ◽  
Gamma Ray Bursts ◽  
Statistical Properties ◽  
Clear Correlation ◽  
Prompt Gamma ◽  
Peak Time ◽  
Gamma Ray Emission ◽  
Peak Luminosity

Well-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are complied from the literature. Multiple optical emission components are extracted with power-law function fits to these lightcurves. We present a systematical analysis for statistical properties and their relations to prompt gamma-ray emission and X-ray afterglow for each component. We show that peak luminosity in the prompt and late flares are correlated and the evolution of the peak luminosity may signal the evolution of the accretion rate. No tight correlation between the shallow decay phase/plateau and prompt gamma-ray emission is found. Assuming that they are due to a long-lasting wind injected by a compact object, we show that the injected behavior favors the scenarios of a long-lasting wind powered by a Poynting flux from a black hole via the Blandford-Znajek mechanism fed by fall-back mass or by the spin-down energy release of a magnetar after the main burst episode. The peak luminosity of the afterglow onset is tightly correlated with Eγ, iso , and it is dimmer as peaking later. Assuming that the onset bump is due to the fireball deceleration by the external medium, we examine the Γ0 – Eγ,iso relation and find that it is confirmed with the current sample. Optical re-brightening is observed in 30 GRBs in our sample. It shares the same relation between the width and the peak time as found in the onset bump, but no clear correlation between LR,p and Eγ,iso similar to that observed for the onset bumps is found. Although its peak luminosity also decays with time, the slope is much shallower than that of the onset peak, as is the case for the onset bumps. We get [Formula: see text], being consistent with off-axis observations to an expanding external fireball in a wind-like circum medium. Therefore, the late re-brightening may signal another jet component. Mixing of different emission components may be the reason for the observed chromatic breaks of the shallow decay segment in different energy bands.

scholarly journals Revealing Short GRB Jet Structure and Dynamics with Gravitational Wave Electromagnetic Counterparts

2017 ◽  
Vol 13 (S338) ◽  
pp. 1-8
Author(s):  
Gavin P. Lamb ◽  
Shiho Kobayashi
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Compact Object ◽  
Gamma Ray Bursts ◽  
Viewing Angle ◽  
Hidden Population ◽  
Structure And Dynamics ◽  
Optical Transients ◽  
Jet Structure

AbstractCompact object mergers are promising candidates for the progenitor system of short gamma-ray bursts (GRBs). Using gravitational wave (GW) triggers to identify a merger, any electromagnetic (EM) counterparts from the jet can be used to constrain the dynamics and structure of short GRB jets. GW triggered searches could reveal a hidden population of optical transients associated with the short-lived jets from the merger object. If the population of merger-jets is dominated by low-Lorentz-factors, then a GW triggered search will reveal the on-axis orphan afterglows from these failed GRBs. By considering the EM counterparts from a jet, with or without the prompt GRB, the jet structure and dynamics can be constrained. By modelling the afterglow of various jet structures with viewing angle, we provide observable predictions for the on- and off- axis EM jet counterparts. The predictions provide an indication for the various features expected from the proposed jet structure models.

scholarly journals One Dimensional Hydrodynamics of Asteroid-Neutron Star Collisions

1980 ◽  
Vol 58 ◽  
pp. 591-594
Author(s):  
Michael J. Newman ◽  
Arthur N. Cox
Keyword(s):  
Neutron Star ◽  
Solid Body ◽  
Gamma Ray ◽  
Compact Object ◽  
Gamma Ray Bursts ◽  
Radiation Diffusion ◽  
Gamma Ray Burst ◽  
One Dimensional

It has been suggested by several authors (e.g., Harwit and Salpeter, 1973) that the observed cosmic gamma-ray bursts might be produced by the collision of comet or asteroid-sized bodies with a compact object. Colgate and Petschek (1980) have discussed the tidal breakup of a solid body approaching a neutron star in central impact, with particular application to the cosmic gamma-ray burst of March 5, 1979. In this work we present the results of simplified one-dimensional hydrodynamic-radiation diffusion calculations of such an occurence.

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