scholarly journals Constraining properties of neutron star merger outflows with radio observations

2020 ◽  
Vol 494 (2) ◽  
pp. 2449-2464 ◽  
Author(s):  
Dougal Dobie ◽  
David L Kaplan ◽  
Kenta Hotokezaka ◽  
Tara Murphy ◽  
Adam Deller ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Inclination Angle ◽  
Proper Motion ◽  
Gamma Ray ◽  
Large Fraction ◽  
Opening Angle ◽  
Next Generation ◽  
Vlbi Observations ◽  
Gravitational Wave Detectors

ABSTRACT The jet opening angle and inclination of GW170817 – the first detected binary neutron star merger – were vital to understand its energetics, relation to short gamma-ray bursts, and refinement of the standard siren-based determination of the Hubble constant, H0. These basic quantities were determined through a combination of the radio light curve and Very Long Baseline Interferometry (VLBI) measurements of proper motion. In this paper, we discuss and quantify the prospects for the use of radio VLBI observations and observations of scintillation-induced variability to measure the source size and proper motion of merger afterglows, and thereby infer properties of the merger including inclination angle, opening angle, and energetics. We show that these techniques are complementary as they probe different parts of the circum-merger density/inclination angle parameter space and different periods of the temporal evolution of the afterglow. We also find that while VLBI observations will be limited to the very closest events it will be possible to detect scintillation for a large fraction of events beyond the range of current gravitational wave detectors. Scintillation will also be detectable with next-generation telescopes such as the Square Kilometre Array, 2000 antenna Deep Synoptic Array, and the next-generation Very Large Array, for a large fraction of events detected with third-generation gravitational wave detectors. Finally, we discuss prospects for the measurement of the H0 with VLBI observations of neutron star mergers and compare this technique to other standard siren methods.

scholarly journals 3D magnetized jet break-out from neutron-star binary merger ejecta: afterglow emission from the jet and the ejecta

2021 ◽  
Vol 502 (2) ◽  
pp. 1843-1855
Author(s):  
Antonios Nathanail ◽  
Ramandeep Gill ◽  
Oliver Porth ◽  
Christian M Fromm ◽  
Luciano Rezzolla
Keyword(s):  
Neutron Star ◽  
Thermal Emission ◽  
Opening Angle ◽  
Hollow Core ◽  
Binary Neutron Star ◽  
Vlbi Observations ◽  
Superluminal Motion ◽  
General Relativistic ◽  
Star Binary ◽  
Magnetohydrodynamic Simulations

ABSTRACT We perform 3D general-relativistic magnetohydrodynamic simulations to model the jet break-out from the ejecta expected to be produced in a binary neutron-star merger. The structure of the relativistic outflow from the 3D simulation confirms our previous results from 2D simulations, namely, that a relativistic magnetized outflow breaking out from the merger ejecta exhibits a hollow core of θcore ≈ 4°, an opening angle of θjet ≳ 10°, and is accompanied by a wind of ejected matter that will contribute to the kilonova emission. We also compute the non-thermal afterglow emission of the relativistic outflow and fit it to the panchromatic afterglow from GRB170817A, together with the superluminal motion reported from VLBI observations. In this way, we deduce an observer angle of $\theta _{\rm obs}= 35.7^{\circ \, \, +1.8}_{\phantom{\circ \, \, }-2.2}$. We further compute the afterglow emission from the ejected matter and constrain the parameter space for a scenario in which the matter responsible for the thermal kilonova emission will also lead to a non-thermal emission yet to be observed.

Single-Frequency Fiber Amplifiers for Next-Generation Gravitational Wave Detectors

2018 ◽  
Vol 24 (3) ◽  
pp. 1-13 ◽  
Author(s):  
Michael Steinke ◽  
Henrik Tunnermann ◽  
Vincent Kuhn ◽  
Thomas Theeg ◽  
Malte Karow ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Fiber Amplifiers ◽  
Single Frequency ◽  
Next Generation ◽  
Gravitational Wave Detectors

scholarly journals On the opening angle of magnetized jets from neutron-star mergers: the case of GRB170817A

2020 ◽  
Vol 495 (4) ◽  
pp. 3780-3787 ◽  
Author(s):  
Antonios Nathanail ◽  
Ramandeep Gill ◽  
Oliver Porth ◽  
Christian M Fromm ◽  
Luciano Rezzolla
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Initial Conditions ◽  
Observation Angle ◽  
Opening Angle ◽  
Binary Neutron Star ◽  
Best Fitting ◽  
Standard Picture ◽  
General Relativistic ◽  
Star Binary

ABSTRACT The observations of GW170817/GRB170817A have confirmed that the coalescence of a neutron-star binary is the progenitor of a short gamma-ray burst (GRB). In the standard picture of a short GRB, a collimated highly relativistic outflow is launched after merger and it successfully breaks out from the surrounding ejected matter. Using initial conditions inspired from numerical-relativity binary neutron-star merger simulations, we have performed general-relativistic hydrodynamic (HD) and magnetohydrodynamic (MHD) simulations in which the jet is launched and propagates self-consistently. The complete set of simulations suggests that: (i) MHD jets have an intrinsic energy and velocity polar structure with a ‘hollow core’ subtending an angle θcore ≈ 4°–5° and an opening angle of θjet > ≳ 10°; (ii) MHD jets eject significant amounts of matter and two orders of magnitude more than HD jets; (iii) the energy stratification in MHD jets naturally yields the power-law energy scaling E(> Γβ) ∝ (Γβ)−4.5; (iv) MHD jets provide fits to the afterglow data from GRB170817A that are comparatively better than those of the HD jets and without free parameters; and (v) finally, both of the best-fitting HD/MHD models suggest an observation angle θobs ≃ 21° for GRB170817A.

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.

PULSAR KICKS AND DARK MATTER FROM A STERILE NEUTRINO

2005 ◽  
Vol 20 (06) ◽  
pp. 1148-1154 ◽  
Author(s):  
ALEXANDER KUSENKO
Keyword(s):  
Dark Matter ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Sterile Neutrino ◽  
Supernova Explosion ◽  
Radio Pulsars ◽  
X Ray ◽  
Gravitational Wave Detectors ◽  
Rule Out

The observed velocities of radio pulsars, which range in the hundreds kilometers per second, and many of which exceed 1000 km/s, are not explained by the standard physics of the supernova explosion. However, if a sterile neutrino with mass in the 1–20 keV range exists, it would be emitted asymmetrically from a cooling neutron star, which could give it a sufficient recoil to explain the pulsar motions. The same particle can be the cosmological dark mater. Future observations of X-ray telescopes and gravitational wave detectors can confirm or rule out this explanation.

GRAVITATIONAL WAVEFORMS FOR BINARY BLACK HOLES

2011 ◽  
Vol 20 (10) ◽  
pp. 2081-2086
Author(s):  
BALA R IYER
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Numerical Relativity ◽  
Current Status ◽  
Next Generation ◽  
Binary Black Holes ◽  
Gravitational Wave Detectors ◽  
Body Method

Over the last decade gravitational waveforms of binary black holes have been investigated using a variety of approaches like the Multipolar post-Minkowskian formalism, Numerical Relativity and the Effective-One-Body method. We review these complementary approaches and summarize the current status of these investigations of relevance to construct the best templates for the next generation Advanced gravitational wave detectors.

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