Ruxandra Bondarescu
A5042892737- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Cosmology and Gravitation Theories
- Advanced Frequency and Time Standards
- Astrophysical Phenomena and Observations
- Geophysics and Sensor Technology
- Atomic and Subatomic Physics Research
- Radio Astronomy Observations and Technology
- High-pressure geophysics and materials
- Cold Atom Physics and Bose-Einstein Condensates
- Dark Matter and Cosmic Phenomena
- Relativity and Gravitational Theory
- Astrophysics and Cosmic Phenomena
- GNSS positioning and interference
- Galaxies: Formation, Evolution, Phenomena
- Black Holes and Theoretical Physics
- Astronomical Observations and Instrumentation
- Quantum Mechanics and Applications
- Seismic Waves and Analysis
- Advanced Data Storage Technologies
- Gender Diversity and Inequality
- Computational Physics and Python Applications
- Radioactive Decay and Measurement Techniques
- Quantum Electrodynamics and Casimir Effect
Universitat de Barcelona
2022-2024
Institut Català de Ciències del Clima
2022-2024
University of Portsmouth
2018-2022
University of Zurich
2012-2017
Pennsylvania State University
2010-2013
Cardiff University
2011
Carleton College
2011
California Institute of Technology
2011
Andrews University
2011
Australian National University
2011
We present an up-to-date, comprehensive summary of the rates for all types compact binary coalescence sources detectable by Initial and Advanced versions ground-based gravitational-wave detectors LIGO Virgo. Astrophysical estimates compact-binary depend on a number assumptions unknown model parameters, are still uncertain. The most confident among these rate predictions coalescing neutron stars which based extrapolations from observed pulsars in our Galaxy. These yield likely 100 per Myr...
The resonant excitation of neutron star (NS) modes by tides is investigated as a source short gamma-ray burst (sGRB) precursors. We find that the driving crust-core interface mode can lead to shattering NS crust, liberating ~10^46-10^47 erg energy seconds before merger NS-NS or NS-black hole binary. Such properties are consistent with Swift/BAT detections sGRB precursors, and we use timing observed precursors place weak constraints on crust equation state. describe how larger sample...
We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009 October 20, 2010. searched signals with total mass 2 25 solar masses; this includes binary neutron stars, black holes, consisting of hole star. The detectors were sensitive to systems up 40 Mpc distant further higher systems. No gravitational-wave detected. upper limits the rate coalescence as function mass, including results previous observations. cumulative...
The theory of general relativity describes macroscopic phenomena driven by the influence gravity while quantum mechanics brilliantly accounts for microscopic effects.Despite their tremendous individual success, a complete unification fundamental interactions is missing and remains one most challenging important quests in modern theoretical physics.The STE-QUEST satellite mission, proposed as medium-size mission within Cosmic Vision program European Space Agency (ESA), aims testing with high...
We present direct upper limits on continuous gravitational wave emission from the Vela pulsar using data Virgo detector's second science run. These have been obtained three independent methods that assume follows radio timing. Two of produce frequentist for an assumed known orientation star's spin axis and value polarization angle of, respectively, $1.9\ee{-24}$ $2.2\ee{-24}$, with 95% confidence. The third method, under same hypothesis, produces a Bayesian limit $2.1\ee{-24}$, degree...
We present results from a search for gravitational-wave bursts in the data collected by LIGO and Virgo detectors between July 7, 2009 October 20, 2010: are analyzed when at least two of three LIGO-Virgo coincident operation, with total observation time 207 days. The analysis searches transients duration < 1 s over frequency band 64-5000 Hz, without other assumptions on signal waveform, polarization, direction or occurrence time. All identified events consistent expected accidental...
Compact binary systems with neutron stars or black holes are one of the most promising sources for ground-based gravitational wave detectors. Gravitational radiation encodes rich information about source physics; thus parameter estimation and model selection crucial analysis steps any detection candidate events. Detailed models anticipated waveforms enable inference on several parameters, such as component masses, spins, sky location distance that essential new astrophysical studies these...
We present a search for periodic gravitational waves from the neutron star in supernova remnant Cassiopeia A. The coherently analyzes data 12 day interval taken fifth science run of Laser Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies 100 to 300 Hz and covers wide range first second frequency derivatives appropriate age different spin-down mechanisms. No signal was detected. Within frequencies, we set 95% confidence upper limits (0.7–1.2) × 10−24 on...
We present results from an all-sky search for unmodeled gravitational-wave bursts in the data collected by LIGO, GEO 600 and Virgo detectors between November 2006 October 2007. The is performed three different analysis algorithms over frequency band 50--6000 Hz. Data are analyzed times with at least two of four LIGO-Virgo coincident operation, a total live time 266 days. No events produced survive selection cuts. set frequentist upper limit on rate impinging our network detectors. When...
We report the results of first search for gravitational waves from compact binary coalescence using data Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months were collected during Observatory's S5 Virgo's VSR1 science runs. The focused on signals mergers with a total mass between 2 $35{M}_{\ensuremath{\bigodot}}$. No are identified. cumulative 90%-confidence upper limits rate calculated nonspinning neutron stars, black hole-neutron star systems, holes to be...
We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based experiments in 2009–2010, during sixth LIGO science run and second third Virgo runs. perform two distinct searches: modeled coalescences either neutron stars or star black hole, generic, unmodeled gravitational-wave bursts. find no evidence counterparts, any individual GRB this sample population as whole. For all GRBs we place lower bounds on distance...
We report a search for gravitational waves from the inspiral, merger and ringdown of binary black holes (BBH) with total mass between 25 100 solar masses, in data taken at LIGO Virgo observatories July 7, 2009 October 20, 2010. The maximum sensitive distance detectors over this period $(20,20){\mathrm{M}}_{\ensuremath{\bigodot}}$ coalescence was 300 Mpc. No wave signals were found. thus upper limits on astrophysical rates BBH as function component masses nonspinning components, also evaluate...
This paper presents results of an all-sky searches for periodic gravitational waves in the frequency range [50, 1190] Hz and with derivative ranges [-2 x 10^-9, 1.1 10^-10] Hz/s fifth LIGO science run (S5). The novelty search lies use a non-coherent technique based on Hough-transform to combine information from coherent timescales about one day. Because these are very computationally intensive, they have been deployed Einstein@Home distributed computing project infrastructure. presented here...
Soft gamma repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are thought to be magnetars: neutron stars powered by extreme magnetic fields. These rare objects characterized repeated sometimes spectacular gamma-ray bursts. The burst mechanism might involve crustal fractures excitation of non-radial modes which would emit gravitational waves (GWs). We present the results a search for GW bursts from six galactic magnetars that is sensitive star f-modes, most efficient emitting oscillatory in...
The gravitational-wave (GW) sky may include nearby pointlike sources as well stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized and arbitrary extended sources. Finding no evidence to support detection of GWs, we present 90% confidence level (C.L.) upper-limit maps GW strain power with typical values between $2\ensuremath{-}20\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}50}\text{ }\text{...
Progenitor scenarios for short gamma-ray bursts (short GRBs) include coalescenses of two neutron stars or a star and black hole, which would necessarily be accompanied by the emission strong gravitational waves. We present search these known gravitational-wave signatures in temporal directional coincidence with 22 GRBs that had sufficient data available multiple instruments during LIGO's fifth science run, S5, Virgo's first VSR1. find no statistically significant candidates within [-5, +1) s...
Aims. A transient astrophysical event observed in both gravitational wave (GW) and electromagnetic (EM) channels would yield rich scientific rewards. first program initiating EM follow-ups to possible GW events has been developed exercised by the LIGO Virgo community association with several partners. In this paper, we describe evaluate methods used promptly identify localize candidates request images of targeted sky locations. Methods. During two observing periods (Dec 17 2009 Jan 8 2010...
We model the nonlinear saturation of $r$-mode instability via three-mode couplings and effects on spin evolution young neutron stars. include one mode triplet consisting two near-resonant inertial modes that couple to it. find spectrum evolutions is more diverse than previously thought. start our with a star temperature $\ensuremath{\sim}{10}^{10}\text{ }\text{ }\mathrm{K}$ frequency close Kepler break-up frequency. assume hyperon bulk viscosity dominates at high temperatures...
Aims. The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting at frequencies that span the most sensitive bands LIGO Virgo detectors, these sources are also amongst likely produce electromagnetic counterpart emission. A joint signals would provide a powerful new probe astronomy. Methods. During period between September 19 October 20, 2010, first...
Between 2007 and 2010 Virgo collected data in coincidence with the LIGO GEO gravitational-wave (GW) detectors. These have been searched for GWs emitted by cataclysmic phenomena universe, non-axisymmetric rotating neutron stars or from a stochastic background frequency band of The sensitivity GW searches is limited noise produced detector its environment. It therefore crucial to characterize various sources detector. This paper reviews sources, propagation, conversion mechanisms which were...
We report on an all-sky search for periodic gravitational waves in the frequency band 50--800 Hz and with time derivative range of 0 through $\ensuremath{-}6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}\text{ }\text{ }\mathrm{Hz}/\mathrm{s}$. Such a signal could be produced by nearby spinning slightly nonaxisymmetric isolated neutron star our Galaxy. After recent improvements program that yielded $10\ifmmode\times\else\texttimes\fi{}$ increase computational efficiency, we have...
The nonlinear saturation of the $r$-mode instability and its effects on spin evolution low mass x-ray binaries (LMXBs) are modeled using triplet modes at lowest parametric threshold. We solve numerically coupled equations for three in conjunction with temperature equations. observe that very quickly mode amplitudes settle into quasistationary states change slowly as star evolve. Once these reached, can be found algebraically system is reduced from eight to two equations: evolution. neutron...
We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident spiral galaxy M81, which 3.6 Mpc from Earth. Possible progenitors short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce characteristic GW signal that should be detectable at distance while emission an SGR not...