Maria Okounkova
A5064071927- Pulsars and Gravitational Waves Research
- Black Holes and Theoretical Physics
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Geophysics and Gravity Measurements
- Geophysics and Sensor Technology
- Particle physics theoretical and experimental studies
- Gamma-ray bursts and supernovae
- Advanced Frequency and Time Standards
- Model Reduction and Neural Networks
- Relativity and Gravitational Theory
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Noncommutative and Quantum Gravity Theories
- Gas Dynamics and Kinetic Theory
- Radio Astronomy Observations and Technology
- High-pressure geophysics and materials
- Radiation Therapy and Dosimetry
- Cold Atom Physics and Bose-Einstein Condensates
- Particle Dynamics in Fluid Flows
- Nuclear Physics and Applications
- Modeling, Simulation, and Optimization
- Adaptive optics and wavefront sensing
Pasadena City College
2023-2024
Flatiron Health (United States)
2019-2023
Flatiron Institute
2022
California Institute of Technology
2016-2020
Jet Propulsion Laboratory
2020
Princeton University
2015-2017
We report the first results of DarkSide-50, a direct search for dark matter operating in underground Laboratori Nazionali del Gran Sasso (LNGS) and searching rare nuclear recoils possibly induced by weakly interacting massive particles (WIMPs). The detector is Liquid Argon Time Projection Chamber with (46.4+-0.7) kg active mass, operated inside 30 t organic liquid scintillator neutron veto, which turn installed at center 1 kt water Cherenkov veto residual flux cosmic rays. here null...
The Laser Interferometer Space Antenna (LISA) has the potential to reveal wonders about fundamental theory of nature at play in extreme gravity regime, where gravitational interaction is both strong and dynamical. In this white paper, Fundamental Physics Working Group LISA Consortium summarizes current topics physics observations GWs can be expected provide key input. We briefest reviews then delineate avenues for future research directions discuss connections between working group, other...
Testing general relativity in the non-linear, dynamical, strong-field regime of gravity is one major goals gravitational wave astrophysics. Performing precision tests (GR) requires numerical inspiral, merger, and ringdown waveforms for binary black hole (BBH) systems theories beyond GR. Currently, GR scalar-tensor are only amenable to simulations. In this article, we present a well-posed perturbation scheme numerically integrating beyond-GR that have continuous limit We demonstrate by...
Accurate models of gravitational waves from merging black holes are necessary for detectors to observe as many events possible while extracting the maximum science. Near time merger, can be computed only using numerical relativity. In this paper, we present a major update Simulating eXtreme Spacetimes (SXS) Collaboration catalog simulations holes. The contains 2018 distinct configurations (a factor 11 increase compared 2013 SXS catalog), including 1426 spin-precessing configurations, with...
A present challenge in testing general relativity (GR) with binary black hole gravitational wave detections is the inability to perform model-dependent tests due lack of merger waveforms beyond-GR theories. In this study, we produce first numerical waveform Einstein-dilaton-Gauss-Bonnet (EDGB) gravity, a higher-curvature theory gravity motivations string theory. We evolve system order-reduced EDGB parameters consistent GW150914. focus on portion waveform, presence secular growth inspiral...
We produce the first numerical relativity binary black hole gravitational waveforms in a higher-curvature theory beyond general relativity. In particular, we study head-on collisions of holes order-reduced dynamical Chern-Simons gravity. This is precursor to producing beyond-general-relativity for inspiraling systems that are useful wave detection. Head-on interesting their own right, however, as they cleanly probe quasi-normal mode spectrum final hole. thus compute leading-order...
We produce the first astrophysically-relevant numerical binary black hole gravitational waveform in a higher-curvature theory of gravity beyond general relativity. simulate system with parameters consistent GW150914, LIGO detection, order-reduced dynamical Chern-Simons gravity, motivations string and loop quantum gravity. present results for leading-order corrections to merger ringdown waveforms, as well quasi-normal mode spectrum. estimate that such may be discriminated detections signal...
We perform a new test of general relativity (GR) with signals from GWTC-2, the LIGO and Virgo catalog gravitational wave detections. search for presence amplitude birefringence, in which left versus right circularly polarized modes waves are exponentially enhanced suppressed during propagation. Such an effect is present various beyond-GR theories but absent GR. constrain amount birefringence consistent data through opacity parameter $\kappa$, we bound to be $\kappa \lesssim 0.74 \textrm{...
The final stage of a binary black hole merger is ringdown, in which the system described by Kerr with quasinormal mode perturbations. It far from straightforward to identify time at ringdown begins. Yet determining this important for precision tests general theory relativity that compare an observed signal descriptions such as no-hair theorem. We present algorithmic method analyze choice start waveform. This based on how close strong field (Kerrness). Using numerical simulations, we...
We apply common gravitational wave inference procedures on binary black hole merger waveforms beyond general relativity. consider dynamical Chern-Simons gravity, a modified theory of gravity with origins in string and loop quantum gravity. This introduces an additional parameter $\ensuremath{\ell}$, corresponding to the length-scale below which beyond-general-relativity effects become important. simulate data based numerical relativity produced under approximation this theory, differ from...
LISA, the Laser Interferometer Space Antenna, will usher in a new era gravitational-wave astronomy. As first anticipated space-based detector, it expand our view to millihertz sky, where spectacular variety of interesting sources abound: from millions ultra-compact binaries Galaxy, mergers massive black holes at cosmological distances; beginnings inspirals that venture into ground-based detectors' death spiral compact objects holes, and many between. Central realising LISA's discovery...
The second generation of gravitational-wave (GW) detectors are being built and tuned all over the world. detection signals from binary black holes is beginning to fulfil promise GW astronomy. In this work, we examine several possible configurations for third-generation laser interferometers in existing km-scale facilities. We propose a set astrophysically motivated metrics evaluate detector performance. measure impact design choices against these metrics, providing quantitative cost-benefit...
The stability of rotating black holes in dynamical Chern-Simons gravity (dCS) is an open question. To study this issue, we evolve the leading-order metric perturbation order-reduced gravity. source dCS scalar field coupled to spacetime curvature a hole background. We use well-posed, constraint-preserving scheme. find that numerically exhibits linear growth, but level growth converges zero with numerical resolution. This analysis shows spinning are stable perturbations metric.
In order to perform model-dependent tests of general relativity with gravitational wave observations, we must have access numerical binary black hole waveforms in theories beyond (GR). this study, focus on order-reduced Einstein dilaton Gauss-Bonnet gravity (EDGB), a higher curvature beyond-GR theory motivations string theory. The stability single, rotating holes EDGB is unknown, but necessary condition for being able simulate systems (especially the early-inspiral and late ringdown stages)...
We numerically investigate the imprints of gravitational radiation-reaction driven changes to a black hole's mass and spin on corresponding ringdown waveform. do so by comparing dynamics perturbed hole evolved with full (nonlinear) versus linearized Einstein equations. As expected, we find that quasinormal mode amplitudes extracted from nonlinear evolution deviate their linear counterparts at third order in initial perturbation amplitude. For perturbations leading change $\sim 5\%$, which is...
Recently, it has been shown that with the inclusion of overtones, post-merger gravitational waveform at infinity a binary black hole system is well-modelled using pure linear theory. However, given merger expected to be highly non-linear, where do these non-linearities, which not make out infinity, go? We visualize quantities measuring non-linearity in strong-field region numerical relativity order begin answer this question.
DarkSide-50 is a two phase argon TPC for direct dark matter detection which installed at the Gran Sasso underground laboratory, Italy. has 50-kg active volume and will make use of low in 39Ar. The inside an neutron veto made with boron-loaded high radiopurity liquid scintillator. 1000 m3 water Cherenkov muon veto. cryostat are assembled radon-free clean rooms to reduce radioactive contaminants. overall design aims background free exposure after selection cuts applied. expected sensitivity...
We present a scheme for generating first-order metric perturbation initial data an arbitrary background and source. then apply this to derive perturbations in order-reduced dynamical Chern-Simons gravity (dCS). In particular, we solve on black hole that are sourced by dCS scalar field. This gives us the leading-order spacetime gravity. use these solutions compute shadows linearly perturbed evolving null geodesics. novel decompose shape of shadow into multipoles parametrized spin parameter...
The DarkSide experiment is designed for the direct detection of Dark Matter with a double phase liquid Argon TPC operating underground at Laboratori Nazionali del Gran Sasso. placed inside 30 tons organic scintillator sphere, acting as neutron veto, which in turn installed 1 kt water Cherenkov detector. current detector running since November 2013 50 kg atmospheric fill and we report here first null results search (1422 ± 67) kg.d exposure. This result correspond to 90% CL upper limit on...
DarkSide-50 is a dark matter direct search experiment at LNGS, searching for rare nuclear recoils possibly induced by WIMPs. It has two nested vetoes and dual phase liquid argon TPC as detector. Key features of this are the use underground radio-pure target muon neutron active to suppress background. The first data-taking campaign was running from November 2013 April 2015 with an atmospheric reduced efficiency veto due internal contamination. However, upper limit on WIMP-nucleon cross...
We perform a new test of general relativity (GR) with signals from GWTC-2, the LIGO and Virgo catalog gravitational wave detections. search for presence amplitude birefringence, in which left versus right circularly polarized modes waves are exponentially enhanced suppressed during propagation. Such an effect is present various beyond-GR theories but absent GR. constrain amount birefringence consistent data through opacity parameter $κ$, we bound to be $κ\lesssim 0.74 \textrm{ Gpc}^{-1}$....
We apply common gravitational wave inference procedures on binary black hole merger waveforms beyond general relativity. consider dynamical Chern-Simons gravity, a modified theory of gravity with origins in string and loop quantum gravity. This introduces an additional parameter $\ell$, corresponding to the length-scale below which beyond-general-relativity effects become important. simulate data based numerical relativity produced under approximation this theory, differ from those strongly...
The existence of dark matter is known because its gravitational effects, and although nature remains undisclosed, there a growing indication that the galactic halo could be permeated by weakly interactive massive particles (WIMPs) with mass order 100 GeV. Direct observation WIMP-nuclear collisions in laboratory detector plays key role searches. However, it also poses significant challenges, as expected signals are low energy very rare. DarkSide project for direct WIMPs liquid argon...