[PDF] Probing The Dark Universe With Gravitational Waves From Subsolar Mass Compact Objects eBook

Author : Ryan Magee
Publisher :
Page : pages
File Size : 10,57 MB
Release : 2021
Category :
ISBN :

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The detection of gravitational waves by Advanced LIGO in 2015 marked the start of a new era in astrophysics. These small ripples in space-time - first predicted in the early 20th century by Albert Einstein - encode properties of the progenitor system and provide a powerful new way to probe distant and extreme astrophysical environments. My dissertation focuses on contributions I have made in facilitating the multi-messenger detection of electromagnetically bright sources and using LIGO's observations (or lack thereof) to constrain models of the dark matter. I describe the motivation for Advanced LIGO searches for sub-solar mass ultracompact binaries, as well as two recent searches I carried out with the LIGO-Virgo Scientific Collaboration. No confident detections were made in these searches, but the null result allowed us to place the tightest contraint to date on a particular model of the dark matter. I also discuss my contributions to efforts to detect binary neutron stars. Although the first BNS detection, GW170817, was a model multi-messenger discovery, there remains much to be learned about the extreme environment of the coalescence that can only be resolved by additional, prompt observations. I describe a subthreshold search for BNS that aims to increase our catalog of joint discoveries by facilitating searches for temporal or spatial coincidence, as well as recent attempts to detect BNS prior to merger to enable prompt electromagnetic followup.

Author : Phoebe Katherine McClincy
Publisher :
Page : pages
File Size : 41,61 MB
Release : 2021
Category :
ISBN :

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There is increasing interest in sub-solar mass (SSM) black holes (BHs) regarding the possibility that they are a component of dark matter (DM), due to the limited knowledge regarding its composition. Dark matter is a mysterious type of matter that composes 85 percent of the matter in the universe. Little is known about the actual makeup of dark matter. Thus, it is hypothesized that black holes could account for a portion of the DM. Specifically, it is theorized that primordial black holes (PBHs) could account for DM. PBHs, which are BHs born in the Big Bang, have yet to be detected. The primordial black hole theory of dark matter may be tested by running a targeted search for SSM ultracompact objects using data collected by the Laser Interferometer Gravitational-wave Observatory (LIGO). LIGO uses gravitational waves (GW), ripples in the fabric of spacetime caused by energetic events in space, to discern information about systems of black holes and neutron stars in space. We define parameters that produce a search which simultaneously maximizes relative search sensitivity and minimizes computational cost. The dependence of template bank size on several parameter sets was tested, including the frequency range of the search, minimum mass, and spin. We determined that larger magnitudes of spin, wider frequency ranges, and smaller masses produce a larger template bank, and subsequently a higher computational cost. From this, we derived ideal parameters with which to conduct an Advanced LIGO search on O1 and O2 data for SSM binaries. A null result was produced from all searches; however, from our searches we are able to place constraints on the event rate and fraction of DM composed of SSM BHs, for BHs in the 0.2-1.0 solar masses range.

Author : Mario Livio
Publisher : Cambridge University Press
Page : 207 pages
File Size : 47,70 MB
Release : 2004-02-26
Category : Science
ISBN : 113944980X

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This volume presents especially written articles by a host of world experts working on all aspects of dark matter and theories of gravity. This is an indispensable collection of review articles for researchers and graduate students.

Author : Arun Kenath
Publisher : Springer
Page : 0 pages
File Size : 45,94 MB
Release : 2023-05-26
Category : Science
ISBN : 9783031304620

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This book provides a concise introduction to the physics of gravitational waves. It is aimed at graduate-level students and PhD scholars. Ever since the discovery of gravitational waves in 2016, gravitational wave astronomy has been adding to our understanding of the universe. 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 will 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 and close planetary stellar entities. This book discusses 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 discussed are the high-frequency thermal background gravitational radiation from hot stellar interiors and newly formed compact objects. The reader will also learn how gravitational waves provide a testing tool for various theories of gravity, i.e. general relativity and extended theories of gravity, and will be the definitive test for general relativity.

Author : Larry J Chamber
Publisher : Tredition Gmbh
Page : 0 pages
File Size : 13,8 MB
Release : 2024-05-04
Category : Science
ISBN : 9783384218339

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The growing catalog of gravitational-wave signals from compact object mergers has allowed us to study the properties of black holes and neutron stars more precisely than ever before and has opened a new window through which to probe the earliest moments in our universe's history. Population-level measurements of the masses and spins of compact objects can reveal how these systems form and evolve. Multimessenger observations of compact object mergers can shed light on the properties of the electromagnetic counterparts of these systems, such as short gamma-ray bursts and kilonovae. Finally, observations of the stochastic gravitational-wave background can constrain early-universe physics inaccessible with other means.

Author : Jean-François Coupechoux
Publisher :
Page : 0 pages
File Size : 17,43 MB
Release : 2021
Category :
ISBN :

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Motivated by the recent gravitational wave detections, we consider primordial black holes as a valid alternative to a significant fraction of dark matter. At the moment, there is no experimental evidence of such an object, but the event called GW190814 has detected a compact object of 2.6 times the sun mass. It is therefore either the most massive neutron star or the lightest black hole ever detected. But it could also be a primordial black hole and we will consider different aspects of gravitational waves related to primordial black holes. First, we used the code developed by the Einstein Toolkit community to solve numerically the Einstein equations and calculate the gravitational wave-forms emitted by a binary black hole merger. These wave-forms are valid for any mass of the system thanks to the scaling relations for black holes described by the Kerr metric. We can thus easily have the wave-form for black holes having a mass of the order of a gram up to millions of solar masses. These scaling relations are also valid for charged black holes but there are more exotic black holes that break the scaling relations. We will also study the physical limits of these relations by considering the expansion of the Universe and Hawking radiation, which can become non-negligible for primordial black holes. When a gravitational wave signal is detected by the LIGO/Virgo collaboration, the detected objects are classified as neutron stars if their mass is lower than 2.2 times the sun mass and as black holes if their mass is higher than 5 times the sun mass. But if we do not want to use this distinction, we must be able to distinguish the effect of baryonic matter describing a neutron star through the tidal deformability. We will study the necessary conditions to determine the nature of compact objects by injecting wave-forms into a realistic detector noise. There are many candidates to describe dark matter and primordial black holes are one of them. The Fuzzy Dark Matter model based on a scalar field is another one and it is possible to extend this model to also mimic the behavior of dark energy. We will study the potential of such a model to give the most general form. At low energy, the two basic ingredients are: an extremely low mass term and a constant dominating the recent evolution of the Universe to replace dark energy. However, the shape of the potential remains an open issue because it is not very constrained in the primordial Universe. On the other hand, it is possible to give limits on the energy density of a generic scalar field during Big-Bang nucleosynthesis by the observed abundance of the elements. These limits are given: for a stable scalar field and for a scalar field decaying into radiation. There are many models using scalar fields in cosmology, to reduce their number, a solution is to consider them as non-independent. For this, we will introduce a triple unification model unifying: inflation, dark matter and dark energy with a single scalar field with a non-minimal coupling to gravity.

Author : Mansour Karami
Publisher :
Page : 219 pages
File Size : 23,11 MB
Release : 2018
Category : Black holes (Astronomy)
ISBN :

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Since its early success as an experimental test of the theory of general relativity in 1919, gravitational lensing has come a long way and is firmly established as an indispensable element for many astrophysical applications. In this thesis, we explore novel applications of gravitational lensing that further our understanding of the dark sectors of the cosmos and other astrophysical objects, namely dark matter nanostructure, black holes and the Galactic disk. We pay particular attention to developing concrete and optimal statistical methodologies and numerical implemen- tations for these novel probes. We start by developing a statistical framework to measure the dark matter power spectrum in the deep nonlinear regime, using transient weak lensing, and simultaneously measure the time delays for strongly lensed quasars. We then outline how observations of microlensing in optical and radio can unravel the structure, dynamics, and content of the Galactic disk, and in particular, be used to detect stellar mass black holes. Lastly, using the shadow images of the super-massive black holes caused by extreme lensing effect, we can learn about the structure of space-time, accretion flows and astrophysical jets. We present a Bayesian framework for analyzing the data from the Event Horizon Telescope Collaboration.

Author : Boyuan Liu (Ph. D. in astronomy)
Publisher :
Page : 0 pages
File Size : 12,46 MB
Release : 2022
Category :
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We use semi-analytical models and cosmological hydrodynamic simulations to derive the imprints of dark matter physics on the first generation of stars, black holes and galaxies, which, combined with observational data, place constraints on the properties of dark matter. Inspired by the recent detection of gravitational waves, we further investigate the gravitational waves of the first star remnants as a promising probe for early star/structure formation and dark matter physics. Our results indicate that although the first stars only make up a tiny fraction (~ 10−5) of all stars (ever formed) in the Universe, a much higher fraction (~ 10−3 -0.1) of massive compact object mergers can originate from the first stars, which carry valuable information of the early Universe. Finally, we explore the effects of primordial black holes, which can make up all or part of dark matter, on first star formation, and discuss their implications on using gravitational waves as a direct probe of dark matter

Author : Eleftherios Papantonopoulos
Publisher : Springer
Page : 0 pages
File Size : 40,56 MB
Release : 2024-08-11
Category : Science
ISBN : 9783031550973

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The main objective of this volume is to discuss the physical properties, observational signals and various probes of compact objects in the Universe. These include black holes, neutron stars, and exotic objects studied in alternative theories of gravity. The text is mainly addressed to postgraduate students and young researchers with the aim of introducing them to these very challenging topics.

Author : Manuel Arca Sedda
Publisher : Elsevier
Page : 510 pages
File Size : 44,32 MB
Release : 2024-06-03
Category : Science
ISBN : 0323956378

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Black Holes in the Era of Gravitational-Wave Astronomy provides a multidisciplinary, up-to-date view of the physics of black holes, along with an exhaustive overview of crucial open questions and recent advancements in the astrophysics of black holes in the wake of incredible advancements made in the last decade. It includes discussions on improvements in theoretical modeling and observational perspectives for black holes of all sizes, along with associated challenges. The book's structure and themes will enable an entwined understanding of black hole physics at all scales, thus avoiding the compartmentalized view that is typical of more specialized manuscripts and reviews.This book is a complete reference for scientists interested in a multidirectional approach to the study of black holes. It provides substantial discussions about the interplay of different types of black holes and gives professionals a heterogeneous and comprehensive overview of the astrophysics of black holes of all masses. Focuses on recent advances and future perspectives surrounding black holes, providing researchers with a clear view of cutting-edge research Offers readers a multidisciplinary, fresh view on black holes, discussing and reviewing the most recent advancements in theoretical, numerical and observational techniques put in place to detect black holes Provides a bridge among different black hole areas, fostering new collaborations among professionals working in different, but intrinsically interconnected fields