A5035306674- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Geophysics and Sensor Technology
- High-pressure geophysics and materials
- Seismic Waves and Analysis
- Mechanics and Biomechanics Studies
- Statistical and numerical algorithms
- Astro and Planetary Science
- Advanced Frequency and Time Standards
- Radio Astronomy Observations and Technology
- Atomic and Subatomic Physics Research
- Astrophysics and Star Formation Studies
- Relativity and Gravitational Theory
- GNSS positioning and interference
- Seismology and Earthquake Studies
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
Northwestern University
2015-2024
Northwestern University
2019
California Institute of Technology
2011
Cardiff University
2011
Carleton College
2011
Andrews University
2011
Australian National University
2011
Charles Sturt University
2011
LIGO Scientific Collaboration
2011
Center for Astrophysics Harvard & Smithsonian
1998-2010
The Advanced LIGO and Virgo gravitational wave (GW) detectors will begin operation in the coming years, with compact binary coalescence events a likely source for first detections. waveforms emitted directly encode information about sources, including masses spins of objects. Recovering physical parameters sources from GW observations is key analysis task. This work describes LALInference software library Bayesian parameter estimation signals, which builds on several previous methods to...
We present a comprehensive description of the population synthesis code StarTrack. The original has been significantly modified and updated. Special emphasis is placed here on processes leading to formation further evolution compact objects (white dwarfs, neutron stars, black holes). Both single binary star populations are considered. now incorporates detailed calculations all mass-transfer phases, full implementation orbital due tides, as well most recent estimates magnetic braking. This...
A new generation of ground-based interferometric detectors for gravitational waves is currently under construction or has entered the commissioning phase (LIGO, VIRGO, GEO600, TAMA). We study most promising candidate sources these detectors: inspiraling double compact objects. use population synthesis methods to calculate properties and coalescence rates of: neutron stars, black hole-neutron star systems holes. also examine their formation channels. explicitly account evolution low-mass...
We derive the theoretical distribution function of black hole masses by studying formation processes holes. use results recent two-dimensional simulations stellar core collapse to obtain relation between remnant and progenitor fold it with an initial mass for progenitors. Thus, we are able binary distribution. examine how calculated distributions modified (1) strong-wind loss at different evolutionary stages progenitors (2) presence close companions The compact-remnant is dominated neutron...
With the first direct detection of gravitational waves, advanced laser interferometer gravitational-wave observatory (LIGO) has initiated a new field astronomy by providing an alternative means sensing universe. The extreme sensitivity required to make such detections is achieved through exquisite isolation all sensitive components LIGO from non-gravitational-wave disturbances. Nonetheless, still susceptible variety instrumental and environmental sources noise that contaminate data. Of...
Abstract Pair-instability and pulsational pair-instability supernovae (PPISNe) have not been unambiguously observed so far. They are, however, promising candidates for the progenitors of heaviest binary black hole (BBH) mergers detected. If these BBHs are product evolution, then PPISNe could occur in very close binaries. Motivated by this, we discuss implications a PPISN happening with companion what impact events on formation merging through evolution. For computed set models metal-poor ( Z...
Observational identification of black holes as members binary systems requires the knowledge upper limit on gravitational mass a neutron star. We use modern equations state for star matter, fitted to experimental nucleon-nucleon scattering data and properties light nuclei, calculate, within framework Rhoades & Ruffini (1974), minimum mass. Regarding equation valid up twice nuclear matter saturation density, ρnm, we obtain secure bound equal 2.9 M☉. also find that in order reach lowest...
We report on the newly increased event rates due to recent discovery of highly relativistic binary pulsar J0737-3039. Using a rigorous statistical method, we present calculations reported by Burgay et al., which produce coalescence rate for Galactic double neutron star (DNS) systems that is higher factor 6-7 compared estimates made prior new discovery. Our method takes into account known survey selection effects and biases small-number statistics. This increase has dramatic implications...
We present a theoretical study of double compact objects as potential short/hard gamma-ray burst (GRB) progenitors. An updated population synthesis code StarTrack is used to calculate properties neutron stars and black-hole star binaries. obtain their formation rates, estimate merger times finally predict most likely locations afterglow for different types host galaxies. Our results serve direct comparison with the recent HETE-II SWIFT observations several short bursts, which afterglows...
The last century has seen enormous progress in our understanding of the Universe. We know life cycles stars, structure galaxies, remnants big bang, and have a general how Universe evolved. come remarkably far using electromagnetic radiation as tool for observing However, gravity is engine behind many processes Universe, much its action dark. Opening gravitational window on will let us go further than any alternative. Gravity own messenger: Gravitational waves, ripples fabric spacetime. They...
We investigate the characteristics of young (< 20 Myr) and bright (Lx > 1e36 erg/s) High-Mass X-ray Binaries (HMXBs) find population to be strongly metallicity-dependent. separate model populations among two distinct formation pathways: (1) systems undergoing active Roche Lobe Overflow (RLO), (2) wind accretion with donors in (super)giant (SG) stage, which we dominate HMXB population. metallicity primarily affect number move through each pathway, rather than observable parameters individual...
Double black hole binaries are among the most important sources of gravitational radiation for ground-based detectors such as LIGO or VIRGO. Even if formed with lower efficiency than double neutron star binaries, they could dominate predicted detection rates, since holes more massive stars and therefore be detected at greater distances. Here we discuss an evolutionary process that can very significantly limit formation close binaries: vast majority their potential progenitors undergo a...
It is firmly established that the stellar mass distribution smooth, covering range 0.1–100 M☉. to be expected masses of ensuing compact remnants correlate with their progenitor stars, and thus it generally thought remnant should smoothly distributed from lightest white dwarfs heaviest black holes (BHs). However, this intuitive prediction not borne out by observed data. In rapidly growing population observationally determined masses, a striking gap has emerged at boundary between neutron...
Abstract Gravitational waves (GWs) from binary black hole (BBH) mergers provide a new probe of massive-star evolution and the formation channels compact objects. By coupling growing sample BBH systems with population synthesis models, we can begin to constrain parameters such models glean unprecedented knowledge about inherent physical processes that underpin stellar evolution. In this study, apply hierarchical Bayesian model mass measurements synthetic GW prescriptions in relative fraction...
High redshift galaxies permit the study of formation and evolution X-ray binary populations on cosmological timescales, probing a wide range metallicities star-formation rates. In this paper, we present results from large scale population synthesis that models first universe until today. We use as input to our modeling Millennium II Cosmological Simulation updated semi-analytic galaxy catalog by Guo et al. (2011) self-consistently account for star history metallicity universe. Our modeling,...
The recent detections of GW150914 and GW151226 imply an abundance stellar-mass binary-black-hole mergers in the local universe. While ground-based gravitational-wave detectors are limited to observing final moments before a binary merges, space-based detectors, such as Laser Interferometer Space Antenna (LISA), can observe binaries at lower orbital frequencies where systems may still encode information about their formation histories. In particular, eccentricity mass black holes LISA...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
Understanding the noise in gravitational-wave detectors is central to detecting and interpreting signals. Glitches are transient, non-Gaussian features that can have a range of environmental instrumental origins. The Gravity Spy project uses machine-learning algorithm classify glitches based upon their time-frequency morphology. resulting set classified be used as input detector-characterisation investigations how mitigate glitches, or data-analysis studies ameliorate impact glitches. Here...
Spin-orbit misalignment in coalescing compact binaries affects their gravitational radiation waveforms. When the angles are large (≳30°), detection efficiency of coalescence events can decrease significantly if effects not modeled. In this paper, we consider formation close and calculate expected after second core collapse event. Depending on progenitor parameters assumptions made about supernova kicks, find that 30%-80% containing a black hole neutron star coalesce within 1010 yr have...
We present an analytical method for studying the changes of orbital characteristics binary systems with circular orbits due to a kick velocity imparted newborn neutron star during supernova (SN) explosion. Assuming Maxwellian distribution velocities we derive expressions functions separations and eccentricities immediately after explosion, circularization post-SN orbits, systemic binaries that remain bound These distributions can be used perform population synthesis calculations various...
The study of how stars distribute themselves around a massive black hole (MBH) in the center galaxy is an important prerequisite for understanding many galactic-center processes. These include observed overabundance point X-ray sources at Galactic and prediction rates characteristics tidal disruptions extended by MBH inspirals compact into MBH, latter being events high importance future space-borne gravitational wave interferometer LISA. In relatively small galactic nuclei hosting MBHs with...
We investigate the existence and properties of equipotential surfaces Lagrangian points in nonsynchronous, eccentric binary star planetary systems under assumption quasi-static equilibrium. adopt a potential that accounts for nonsynchronous rotation orbits calculate positions as functions mass ratio, degree asynchronism, orbital eccentricity, position stars or planets their relative orbit. find geometry may facilitate nonconservative transfer systems, especially if component are rotating...