scholarly journals GRANDMA: A NETWORK TO COORDINATE THEM ALL

2021 ◽  
Vol 53 ◽  
pp. 198-205
Author(s):  
S. Agayeva ◽  
S. Alishov ◽  
S. Antier ◽  
V. R. Ayvazian ◽  
J. M. Bai ◽  
...  
Keyword(s):  
Organizational Structure ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
International Project ◽  
Optical Counterpart ◽  
Transient Source ◽  
Transient Sources ◽  
Imaging Strategy ◽  
Initial Results

GRANDMA is an international project that coordinates telescope observations of transient sources with large localization uncertainties. Such sources include gravitational wave events, gamma-ray bursts and neutrino events. GRANDMA currently coordinates 25 telescopes (70 scientists), with the aim of optimizing the imaging strategy to maximize the probability of identifying an optical counterpart of a transient source. This paper describes the motivation for the project, organizational structure, methodology and initial results.

scholarly journals Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Dipole Radiation ◽  
X Ray ◽  
Radiative Efficiency ◽  
Central Engine ◽  
Radiative Losses ◽  
Wave Emission ◽  
Prompt Emission

ABSTRACT The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.

scholarly journals A comparison between short GRB afterglows and kilonova AT2017gfo: shedding light on kilonovae properties

2020 ◽  
Vol 493 (3) ◽  
pp. 3379-3397 ◽  
Author(s):  
A Rossi ◽  
G Stratta ◽  
E Maiorano ◽  
D Spighi ◽  
N Masetti ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Light Curves ◽  
Optical Counterpart ◽  
Wave Source ◽  
Gamma Ray Burst ◽  
Nir Light ◽  
First Time ◽  
Short Grbs

ABSTRACT Multimessenger astronomy received a great boost following the discovery of kilonova (KN) AT2017gfo, the optical counterpart of the gravitational wave source GW170817 associated with the short gamma-ray burst GRB 170817A. AT2017gfo was the first KN that could be extensively monitored in time using both photometry and spectroscopy. Previously, only few candidates have been observed against the glare of short GRB afterglows. In this work, we aim to search the fingerprints of AT2017gfo-like KN emissions in the optical/NIR light curves of 39 short GRBs with known redshift. For the first time, our results allow us to study separately the range of luminosity of the blue and red components of AT2017gfo-like kilonovae in short GRBs. In particular, the red component is similar in luminosity to AT2017gfo, while the blue KN can be more than 10 times brighter. Finally, we exclude a KN as luminous as AT2017gfo in GRBs 050509B and 061201.

Gravitational-wave astrophysics from neutron star inspiral and coalescence

2018 ◽  
Vol 27 (11) ◽  
pp. 1843018 ◽  
Author(s):  
John L. Friedman
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
Hubble Constant ◽  
Gamma Ray Bursts ◽  
Nuclear Density ◽  
Independent Measurement ◽  
Process Elements ◽  
Heaviest Elements ◽  
Cold Matter

Prior to the observation of a double neutron star inspiral and merger, its possible implications were striking. Events whose light and gravitational waves are simultaneously detected could resolve the 50-year mystery of the origin of short gamma-ray bursts; they might provide strong evidence for (or against) mergers as the main source of half the heaviest elements (the [Formula: see text]-process elements); and they could give an independent measurement of the Hubble constant. The closest events can also address a primary goal of gravitational-wave astrophysics: From the imprint of tides on inspiral waveforms, one can find the radius and tidal distortion of the inspiraling stars and infer the behavior of cold matter above nuclear density. Remarkably, the first observation of the inspiral and coalescence of a double neutron star system was accompanied by a gamma-ray burst and then an array of electromagnetic counterparts, and the combined effort of the gravitational-wave and astronomy communities has led to dramatic advances along all of these anticipated avenues of multimessenger astrophysics.

scholarly journals Search for Gravitational-wave Signals Associated with Gamma-Ray Bursts during the Second Observing Run of Advanced LIGO and Advanced Virgo

2019 ◽  
Vol 886 (1) ◽  
pp. 75 ◽  
Author(s):  
B. P. Abbott ◽  
R. Abbott ◽  
T. D. Abbott ◽  
S. Abraham ◽  
F. Acernese ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts

scholarly journals Towards Improving the Prospects for Coordinated Gravitational-Wave and Electromagnetic Observations

2011 ◽  
Vol 7 (S285) ◽  
pp. 358-360 ◽  
Author(s):  
Ilya Mandel ◽  
Luke Z. Kelley ◽  
Enrico Ramirez-Ruiz
Keyword(s):  
Gravitational Wave ◽  
Prior Information ◽  
Gamma Ray ◽  
Optimal Parameter ◽  
Gamma Ray Bursts ◽  
Binary Neutron Star ◽  
Quantitative Estimates ◽  
Optimal Parameter Estimation ◽  
Parameter Estimation Techniques

AbstractWe discuss two approaches to searches for gravitational-wave (GW) and electromagnetic (EM) counterparts of binary neutron-star mergers. The first approach relies on triggering archival searches of GW detector data based on detections of EM transients. Quantitative estimates of the improvement to GW detector reach due to the increased confidence in the presence and parameters of a signal from a binary merger gained from the EM transient suggest utilizing other transients in addition to short gamma-ray bursts. The second approach involves following up GW candidates with targeted EM observations. We argue for the use of slower but optimal parameter-estimation techniques and for a more sophisticated use of astrophysical prior information, including galaxy catalogues to find preferred follow-up locations.

scholarly journals Gravitational waves and gamma-ray bursts

2011 ◽  
Vol 7 (S279) ◽  
pp. 142-149 ◽  
Author(s):  
Alessandra Corsi ◽  
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Energy Release ◽  
Gamma Ray ◽  
Stellar Mass ◽  
Gamma Ray Bursts ◽  
The Other ◽  
Direct Information ◽  
Central Source ◽  
Indirect Information

AbstractGamma-Ray Bursts are likely associated with a catastrophic energy release in stellar mass objects. Electromagnetic observations provide important, but indirect information on the progenitor. On the other hand, gravitational waves emitted from the central source, carry direct information on its nature. In this context, I give an overview of the multi-messenger study of gamma-ray bursts that can be carried out by using electromagnetic and gravitational wave observations. I also underline the importance of joint electromagnetic and gravitational wave searches, in the absence of a gamma-ray trigger. Finally, I discuss how multi-messenger observations may probe alternative gamma-ray burst progenitor models, such as the magnetar scenario.

scholarly journals SEARCH FOR GRAVITATIONAL-WAVE INSPIRAL SIGNALS ASSOCIATED WITH SHORT GAMMA-RAY BURSTS DURING LIGO'S FIFTH AND VIRGO'S FIRST SCIENCE RUN

2010 ◽  
Vol 715 (2) ◽  
pp. 1453-1461 ◽  
Author(s):  
J. Abadie ◽  
B. P. Abbott ◽  
R. Abbott ◽  
T. Accadia ◽  
F. Acernese ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts
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