Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userDistortion of Gravitational-wave Signals by Astrophysical Environments
65
0
0.0
(
0
)
Authors
Xian Chen
Ask ChatGPT about the research
No Arabic abstract
Many objects discovered by LIGO and Virgo are peculiar because they fall in a mass range which in the past was considered unpopulated by compact object. Given the significance of the astrophysical implications, it is important to first understand how their masses are measured from gravitational-wave signals. How accurate is the measurement? Are there elements missing in our current model which may result in a bias? This chapter is dedicated to these questions. In particular, we will highlight several astrophysical factors which are not included in the standard model of GW sources but could result in a significant bias in the estimation of the mass. These factors include strong gravitational lensing, the relative motion of the source, a nearby massive object, and a gaseous background.
rate research
Read More
The detection of electromagnetic counterparts to gravitational waves has great promise for the investigation of many scientific questions. It has long been hoped that in addition to providing extra, non-gravitational information about the sources of these signals, the detection of an electromagnetic signal in conjunction with a gravitational wave could aid in the analysis of the gravitational signal itself. That is, knowledge of the sky location, inclination, and redshift of a binary could break degeneracies between these extrinsic, coordinate-dependent parameters and the physical parameters, such as mass and spin, that are intrinsic to the binary. In this paper, we investigate this issue by assuming a perfect knowledge of extrinsic parameters, and assessing the maximal impact of this knowledge on our ability to extract intrinsic parameters. However, we find only modest improvements in a few parameters --- namely the primary components spin --- and conclude that, even in the best case, the use of additional information from electromagnetic observations does not improve the measurement of the intrinsic parameters significantly.
The second generation of gravitational-wave detectors are being built and tuned all over the world. The detection of signals from binary black holes is beginning to fulfill the promise of gravitational-wave astronomy. In this work, we examine several possible configurations for third-generation laser interferometers in existing km-scale facilities. We propose a set of astrophysically motivated metrics to evaluate detector performance. We measure the impact of detector design choices against these metrics, providing a quantitative cost-benefit analyses of the resulting scientific payoffs.
Certain classes of astrophysical objects, namely magnetars and central engines of supernovae and gamma-ray bursts (GRBs), are characterized by extreme physical conditions not encountered elsewhere in the Universe. In particular, they possess magnetic fields that exceed the critical quantum field of 44 teragauss. Figuring out how these complex ultra-magnetized systems work requires understanding various plasma processes, both small-scale kinetic and large-scale magnetohydrodynamic (MHD). However, an ultra-strong magnetic field modifies the underlying physics to such an extent that many relevant plasma-physical problems call for building QED-based relativistic quantum plasma physics. In this review, after describing the extreme astrophysical systems of interest and identifying the key relevant plasma-physical problems, we survey the recent progress in the development of such a theory. We discuss how a super-critical field modifies the properties of vacuum and matter and outline the basic theoretical framework for describing both non-relativistic and relativistic quantum plasmas. We then turn to astrophysical applications of relativistic QED plasma physics relevant to magnetar magnetospheres and central engines of supernovae and long GRBs. Specifically, we discuss propagation of light through a magnetar magnetosphere; large-scale MHD processes driving magnetar activity and GRB jet launching and propagation; energy-transport processes governing the thermodynamics of extreme plasma environments; micro-scale kinetic plasma processes important in the interaction of intense magnetospheric electric currents with a magnetars surface; and magnetic reconnection of ultra-strong magnetic fields. Finally, we point out that future progress will require the development of numerical modeling capabilities.
The dynamics of coalescing compact binaries can be affected by the environment in which the systems evolve, leaving detectable signatures into the emitted gravitational signal. In this paper we investigate the ability of gravitational-wave detectors to constrain the nature of the environment in which compact binaries merge. We parametrize a variety of environmental effects by modifying the phase of the gravitational signal emitted by black hole and neutron star binaries. We infer the bounds on such effects by current and future generation of interferometers, studying their dependence on the binarys parameters. We show that the strong dephasing induced by accretion and dynamical friction can constraint the density of the surrounding medium to orders of magnitude below that of accretion disks. Planned detectors, such as LISA or DECIGO, will be able to probe densities typical of those of dark matter.
A gravitational wave stochastic background of astrophysical origin may have resulted from the superposition of a large number of unresolved sources since the beginning of stellar activity. Its detection would put very strong constrains on the physical properties of compact objects, the initial mass function or the star formation history. On the other hand, it could be a noise that would mask the stochastic background of cosmological origin. We review the main astrophysical processes able to produce a stochastic background and discuss how it may differ from the primordial contribution by its statistical properties. Current detection methods are also presented.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
