scholarly journals Multifrequency Gravitational Wave Background From Continuous Sources

2021 ◽  
Author(s):  
C Sivaram ◽  
Arun Kenath
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Mass Range ◽  
Compact Objects ◽  
Compact Binary ◽  
Transient Events ◽  
Stellar Interiors ◽  
Gravitational Wave Background ◽  
Hubble Time ◽  
Thermal Background

Gravitational waves have been detected in the past few years from several transient events such as merging stellar mass black holes, binary neutron stars, etc. These waves have frequencies in a band ranging from a few hundred hertz to around a kilohertz to which LIGO type instruments are sensitive. LISA would be sensitive to much lower range of frequencies from SMBH mergers. Apart from these cataclysmic burst events, there are innumerable sources of radiation which are continuously emitting gravitational waves of all frequencies. These include a whole mass range of compact binary and isolated compact objects as well as close planetary stellar entities. In this work, quantitative estimates are made of the gravitational wave background produced in typical frequency ranges from such sources emitting over a Hubble time and the fluctuations in the h values measured in the usual devices. Also estimates are made of the high frequency thermal background gravitational radiation from hot stellar interiors and newly formed compact objects.

scholarly journals Modern Topics in Scalar Field Cosmology

2020 ◽  
Author(s):  
◽  
Cari Powell
Keyword(s):  
Dark Matter ◽  
Scalar Field ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Mass Range ◽  
Distant Future ◽  
Field System ◽  
Stochastic Background ◽  
Scalar Field Cosmology

The aim of this research is to use modern techniques in scalar field Cosmol-ogy to produce methods of detecting gravitational waves and apply them to current gravitational waves experiments and those that will be producing results in the not too distant future. In the first chapter we discuss dark matter and some of its candidates, specifically, the axion. We then address its relationship with gravitational waves. We also discuss inflation and how it can be used to detect gravitational waves. Chapter 2 concentrates on constructing a multi field system of axions in order to increase the mass range of the ultralight axion, putting it into the observation range of pul-sar timing arrays. Chapter 3 discusses non-attractor inflation which is able to enhance stochastic background gravitational waves at scales that allows them to be measured by gravitational wave experiments. Chapter 4 uses a similar method to chapter 3 and applies it to 3-point overlap functions for tensor, scalar and a combination of the two polarisations.

scholarly journals The gravitational-wave physics

2017 ◽  
Vol 4 (5) ◽  
pp. 687-706 ◽  
Author(s):  
Rong-Gen Cai ◽  
Zhoujian Cao ◽  
Zong-Kuan Guo ◽  
Shao-Jiang Wang ◽  
Tao Yang
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Laser Interferometer ◽  
Direct Detection ◽  
Fundamental Physics ◽  
First Order ◽  
Compact Binary ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
The Universe

Abstract The direct detection of gravitational wave by Laser Interferometer Gravitational-Wave Observatory indicates the coming of the era of gravitational-wave astronomy and gravitational-wave cosmology. It is expected that more and more gravitational-wave events will be detected by currently existing and planned gravitational-wave detectors. The gravitational waves open a new window to explore the Universe and various mysteries will be disclosed through the gravitational-wave detection, combined with other cosmological probes. The gravitational-wave physics is not only related to gravitation theory, but also is closely tied to fundamental physics, cosmology and astrophysics. In this review article, three kinds of sources of gravitational waves and relevant physics will be discussed, namely gravitational waves produced during the inflation and preheating phases of the Universe, the gravitational waves produced during the first-order phase transition as the Universe cools down and the gravitational waves from the three phases: inspiral, merger and ringdown of a compact binary system, respectively. We will also discuss the gravitational waves as a standard siren to explore the evolution of the Universe.

scholarly journals Dependence of gravitational wave transient rates on cosmic star formation and metallicity evolution history

2020 ◽  
Vol 493 (1) ◽  
pp. L6-L10 ◽  
Author(s):  
Petra N Tang ◽  
J J Eldridge ◽  
Elizabeth R Stanway ◽  
J C Bray
Keyword(s):  
Star Formation ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Formation Rate ◽  
Compact Objects ◽  
Star Formation History ◽  
Compact Binary ◽  
Formation History ◽  
Order Of Magnitude ◽  
History Of

ABSTRACT We compare the impacts of uncertainties in both binary population synthesis models and the cosmic star formation history on the predicted rates of gravitational wave (GW) compact binary merger events. These uncertainties cause the predicted rates of GW events to vary by up to an order of magnitude. Varying the volume-averaged star formation rate density history of the Universe causes the weakest change to our predictions, while varying the metallicity evolution has the strongest effect. Double neutron star merger rates are more sensitive to assumed neutron star kick velocity than the cosmic star formation history. Varying certain parameters affects merger rates in different ways depending on the mass of the merging compact objects; thus some of the degeneracy may be broken by looking at all the event rates rather than restricting ourselves to one class of mergers.

scholarly journals GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

2018 ◽  
Vol 120 (9) ◽  
Author(s):  
B. P. Abbott ◽  
R. Abbott ◽  
T. D. Abbott ◽  
F. Acernese ◽  
K. Ackley ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Compact Binary ◽  
Gravitational Wave Background

scholarly journals Multimessenger Probes of High-energy Sources

2019 ◽  
Vol 209 ◽  
pp. 01036
Author(s):  
Dafne Guetta
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Large Scale ◽  
High Energy ◽  
Compact Objects ◽  
Binary Black Holes ◽  
Comprehensive Picture ◽  
Electromagnetic Signals ◽  
Combine Information ◽  
Open Question

Multimessenger observations may hold the key to learn about the most energetic sources in the universe. The recent construction of large scale observatories opened new possibilities in testing non thermal cosmic processes with alternative probes, such as high energy neutrinos and gravitational waves. We propose to combine information from gravitational wave detections, neutrino observations and electromagnetic signals to obtain a comprehensive picture of some of the most extreme cosmic processes. Gravitational waves are indicative of source dynamics, such as the formation, evolution and interaction of compact objects. These compact objects can play an important role in astrophysical particle acceleration, and are interesting candidates for neutrino and in general high-energy astroparticle studies. In particular we will concentrate on the most promising gravitational wave emitter sources: compact stellar remnants. The merger of binary black holes, binary neutron stars or black hole-neutron star binaries are abundant gravitational wave sources and will likely make up the majority of detections. However, stellar core collapse with rapidly rotating core may also be significant gravitational wave emitter, while slower rotating cores may be detectable only at closer distances. The joint detection of gravitational waves and neutrinos from these sources will probe the physics of the sources and will be a smoking gun of the presence of hadrons in these objects which is still an open question. Conversely, the non-detection of neutrinos or gravitational waves from these sources will be fundamental to constrain the hadronic content.

scholarly journals Synthetic model of the gravitational wave background from evolving binary compact objects

2016 ◽  
Vol 94 (10) ◽  
Author(s):  
Irina Dvorkin ◽  
Jean-Philippe Uzan ◽  
Elisabeth Vangioni ◽  
Joseph Silk
Keyword(s):  
Gravitational Wave ◽  
Compact Objects ◽  
Synthetic Model ◽  
Gravitational Wave Background

scholarly journals PULSAR TIMING ARRAYS

2013 ◽  
Vol 22 (01) ◽  
pp. 1341008 ◽  
Author(s):  
BHAL CHANDRA JOSHI
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Low Frequency ◽  
Radio Pulsars ◽  
Very Low Frequency ◽  
Pulsar Timing ◽  
Gravitational Wave Background ◽  
Pulsar Timing Array ◽  
Current Operating

In the last decade, the use of an ensemble of radio pulsars to constrain the characteristic strain caused by a stochastic gravitational wave background has advanced the cause of detection of very low frequency gravitational waves (GWs) significantly. This electromagnetic means of GW detection, called Pulsar Timing Array (PTA), is reviewed in this paper. The principle of operation of PTA, the current operating PTAs and their status are presented along with a discussion of the main challenges in the detection of GWs using PTA.

Review of the possible role of self-ordering scalar fields in production of a stochastic background of gravitational waves

2015 ◽  
Vol 24 (04) ◽  
pp. 1541005
Author(s):  
James B. Dent
Keyword(s):  
Phase Transition ◽  
Scalar Field ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Scalar Fields ◽  
Inflationary Cosmology ◽  
Tensor Power ◽  
Stochastic Background ◽  
Gravitational Wave Background

A primordial gravitational wave background is a hallmark of inflationary cosmology. The recent announcement made by the BICEP2 collaboration of a possible measurement of B-mode polarization of the CMB on degree scales has produced an abundance of ideas and speculations on how such a signal constrains the inflationary paradigm, or possible alternative mechanisms of gravitational wave production. Here the possibility of a contribution to the gravitational wave background from the relaxation of a scalar field after a global phase transition is reviewed. The general contribution to the overall power is shown, and it is then demonstrated that if the BICEP2 result were to hold, this mechanism could at best produce a very small fraction of the measured tensor power.

scholarly journals MULTIPLE IMAGING BY GRAVITATIONAL WAVES

1998 ◽  
Vol 07 (03) ◽  
pp. 409-429 ◽  
Author(s):  
VALERIO FARAONI
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Gravitational Lenses ◽  
Multiple Imaging ◽  
Gravitational Wave Background

Gravitational waves act like lenses for the light propagating through them. This phenomenon is described using the vector formalism employed for ordinary gravitational lenses, which was proved to be applicable also to a nonstationary spacetime, with the appropriate modifications. In order to have multiple imaging an approximate condition analogous to that for ordinary gravitational lenses must be satisfied. Certain astrophysical sources of gravitational waves satisfy this condition, while the gravitational wave background, on average, does not. Multiple imaging by gravitational waves is, in principle, possible, but the probability of observing such a phenomenon is extremely low.

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