scholarly journals Distinguishing Binary Neutron Star from Neutron Star–Black Hole Mergers with Gravitational Waves

2020 ◽  
Vol 893 (2) ◽  
pp. L41 ◽  
Author(s):  
Hsin-Yu Chen ◽  
Katerina Chatziioannou
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Waves ◽  
Binary Neutron Star

scholarly journals Recent searches for continuous gravitational waves

2017 ◽  
Vol 32 (39) ◽  
pp. 1730035 ◽  
Author(s):  
Keith Riles
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Star ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Continuous Wave ◽  
New Era ◽  
Binary Neutron Star ◽  
Binary Black Hole ◽  
Bose Einstein

Gravitational wave astronomy opened dramatically in September 2015 with the LIGO discovery of a distant and massive binary black hole coalescence. The more recent discovery of a binary neutron star merger, followed by a gamma ray burst (GRB) and a kilonova, reinforces the excitement of this new era, in which we may soon see other sources of gravitational waves, including continuous, nearly monochromatic signals. Potential continuous wave (CW) sources include rapidly spinning galactic neutron stars and more exotic possibilities, such as emission from axion Bose Einstein “clouds” surrounding black holes. Recent searches in Advanced LIGO data are presented, and prospects for more sensitive future searches are discussed.

scholarly journals Spectral analysis of gravitational waves from binary neutron star merger remnants

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Francesco Maione ◽  
Roberto De Pietri ◽  
Alessandra Feo ◽  
Frank Löffler
Keyword(s):  
Spectral Analysis ◽  
Neutron Star ◽  
Gravitational Waves ◽  
Binary Neutron Star

scholarly journals Gravitational waves, neutrino emissions and effects of hyperons in binary neutron star mergers

2012 ◽  
Vol 29 (12) ◽  
pp. 124003 ◽  
Author(s):  
Kenta Kiuchi ◽  
Yuichiro Sekiguchi ◽  
Koutarou Kyutoku ◽  
Masaru Shibata
Keyword(s):  
Neutron Star ◽  
Gravitational Waves ◽  
Binary Neutron Star

scholarly journals Binary Neutron Star (BNS) Merger: What We Learned from Relativistic Ejecta of GW/GRB 170817A

Physics ◽  
2019 ◽  
Vol 1 (2) ◽  
pp. 194-228 ◽  
Author(s):  
Houri Ziaeepour
Keyword(s):  
Neutron Star ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Lorentz Factor ◽  
Prompt Gamma ◽  
External Shocks ◽  
Binary Neutron Star ◽  
Tidal Forces ◽  
Relativistic Jet ◽  
Short Grbs

Gravitational Waves (GW) from coalescence of a Binary Neutron Star (BNS) and its accompanying short Gamma-Ray Burst (GRB) GW/GRB 170817A confirmed the presumed origin of these puzzling transients and opened up the way for relating properties of short GRBs to those of their progenitor stars and their surroundings. Here we review an extensive analysis of the prompt gamma-ray and late afterglows of this event. We show that a fraction of polar ejecta from the merger had been accelerated to ultra-relativistic speeds. This structured jet had an initial Lorentz factor of about 260 in our direction, which was O ( 10 ∘ ) from the jet’s axis, and was a few orders of magnitude less dense than in typical short GRBs. At the time of arrival to circum-burst material the ultra-relativistic jet had a close to Gaussian profile and a Lorentz factor ≳ 130 in its core. It had retained in some extent its internal collimation and coherence, but had extended laterally to create mildly relativistic lobes—a cocoon. Its external shocks on the far from center inhomogeneous circum-burst material and low density of colliding shells generated slowly rising afterglows, which peaked more than 100 days after the prompt gamma-ray. The circum-burst material was somehow correlated with the merger. As non-relativistic outflows or tidally ejected material during BNS merger could not have been arrived to the location of the external shocks before the relativistic jet, circum-burst material might have contained recently ejected materials from resumption of internal activities, faulting and mass loss due to deformation and breaking of stars crusts by tidal forces during latest stages of their inspiral but well before their merger. By comparing these findings with the results of relativistic Magneto-Hydro-Dynamics (MHD) simulations and observed gravitational waves we conclude that progenitor neutron stars were most probably old, had close masses and highly reduced magnetic fields.

scholarly journals Collimated outflows from long-lived binary neutron star merger remnants

2020 ◽  
Vol 495 (1) ◽  
pp. L66-L70 ◽  
Author(s):  
Riccardo Ciolfi
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spin Axis ◽  
Binary Neutron Star ◽  
Physical Conditions ◽  
Massive Neutron Star ◽  
Merger Event ◽  
First Time

ABSTRACT The connection between short gamma-ray bursts (SGRBs) and binary neutron star (BNS) mergers was recently confirmed by the association of GRB 170817A with the merger event GW170817. However, no conclusive indications were obtained on whether the merger remnant that powered the SGRB jet was an accreting black hole (BH) or a long-lived massive neutron star (NS). Here, we explore the latter case via BNS merger simulations covering up to 250 ms after merger. We report, for the first time in a full merger simulation, the formation of a magnetically driven collimated outflow along the spin axis of the NS remnant. For the system at hand, the properties of such an outflow are found largely incompatible with an SGRB jet. With due consideration of the limitations and caveats of our present investigation, our results favour a BH origin for GRB 170817A and SGRBs in general. Even though this conclusion needs to be confirmed by exploring a larger variety of physical conditions, we briefly discuss possible consequences of all SGRB jets being powered by accreting BHs.

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