A5038964344- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Neutrino Physics Research
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Geophysics and Sensor Technology
- Advanced Frequency and Time Standards
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Statistical and numerical algorithms
- Particle physics theoretical and experimental studies
- Seismic Waves and Analysis
- Computational Physics and Python Applications
- Semiconductor materials and devices
- Atomic and Subatomic Physics Research
- Astronomical Observations and Instrumentation
- Radio Wave Propagation Studies
- Integrated Circuits and Semiconductor Failure Analysis
- Ion-surface interactions and analysis
- Radio, Podcasts, and Digital Media
- Mechanical and Optical Resonators
Columbia University
2015-2024
Providence College
2024
The University of Texas at Arlington
2024
Lawrence Berkeley National Laboratory
2024
Clark Atlanta University
2024
Southern University and Agricultural and Mechanical College
2024
University of Alaska Anchorage
2024
University of Florida
2021
University of Kansas
2014
California Institute of Technology
2007
The origins of the stellar-mass black hole mergers discovered by LIGO/Virgo are still unknown. Here we show that if migration traps develop in accretion disks active galactic nuclei (AGNs) and promote their captive holes, majority holes within will undergo hierarchical mergers—with one being remnant a previous merger. 40% AGN-assisted detected include with mass ≳50M⊙, limit from stellar core collapse. Hierarchical at AGNs exhibit spins (anti)aligned binary's orbital axis, distinct property...
The characterization of the Advanced LIGO detectors in second and third observing runs has increased sensitivity instruments, allowing for a higher number detectable gravitational-wave signals, provided confirmation all observed events. In this work, we present methods used to characterize curate publicly available datasets, including strain data quality products. We describe essential role these datasets LIGO-Virgo Collaboration analyses gravitational-waves from both transient persistent...
Abstract Accretion disks around supermassive black holes (SMBHs) are promising sites for stellar mass hole (BH) mergers due to segregation and merger acceleration by disk gas torques. Here we show that a gravitational-wave (GW) kick at BH causes ram-pressure stripping of within the Hill sphere. If R H ≥ , height, an off-center UV flare ∼ 10 3 r g emerges t O(2 days)( /10 )( M SMBH 8 ⊙ v 2 km s −1 ) postmerger lasts O( / O(5 ). The with luminosity O(10 42 erg /2days) ( /1 . Active galactic...
Qualitative and quantitative measurements of motor performance are essential for characterizing perturbations systems. Although several methods exist analyzing specific tasks, few behavioral assays readily available to researchers that provide a complete set kinematic parameters in rodents.Here we present MouseWalker, an integrated hardware software system provides comprehensive description features freely walking rodents. Footprints visualized with high spatial temporal resolution by...
The growing number of stellar-mass binary black hole mergers discovered by Advanced LIGO and Virgo are starting to constrain the binaries' origin environment. However, we still lack sufficiently accurate modeling formation channels obtain strong constraints, or identify sub-populations. One promising mechanism that could result in different properties is binaries merging within accretion disks Active Galactic Nuclei (AGN). Here show holes' orbital alignment with AGN preferentially selects...
Abstract The recent discovery of gravitational waves from stellar-mass binary black hole mergers by the Laser Interferometer Gravitational-wave Observatory opened door to alternative probes stellar and galactic evolution, cosmology fundamental physics. Probing origin will be difficult due expected lack electromagnetic emission limited localization accuracy. Associations with rare host galaxy types—such as active nuclei—can nevertheless identified statistically through spatial correlation....
Neutrino events from IceCube have recently been associated with multiple astrophysical sources. Interestingly, these likely detections represent three distinct source types: active galactic nuclei (AGN), blazars, and tidal disruption (TDE). Here we compute the expected contributions of AGNs, blazars TDEs to overall cosmic neutrino flux detected by based on events, IceCube's sensitivity, types' properties. We find that, despite being most commonly identified sources, cannot contribute more...
First measurements of time-dependent second-harmonic generation (SHG) at a $\mathrm{S}\mathrm{i}/({\mathrm{ZrO}}_{2}{)}_{x}({\mathrm{SiO}}_{2}{)}_{1\ensuremath{-}x}$ interface show behavior that is drastically different from similar ${\mathrm{S}\mathrm{i}/\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ interfaces. We suggest in only electron injection important, while both electrons and holes contribute to the dynamics interface. Multiphoton excitation occurs Si for all oxides, involves direct...
Abstract. Knowledge of molecular photolysis cross sections is important for determining atmospheric lifetimes and fates many species. A method laser apparatus measurement these in the near-ultraviolet (UV) region described. The technique based on action spectroscopy, where yield a photodissociation product (in this case OH) measured as function excitation energy. For compounds yielding OH, can be used to measure near-UV section low 10−23 cm2 molecule−1. applied determine methyl hydroperoxide...
Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters gravitational waves (GWs) high-energy neutrinos (HENs). A network GW detectors such as LIGO Virgo can determine direction/time bursts while IceCube ANTARES neutrino telescopes also provide accurate directional information for HEN events. Requiring consistency between both, totally independent, detection channels shall enable new searches cosmic events arriving from common sources, which...
A detailed experimental investigation of classical and quantum noises in the LIGO gravitational-wave detector is performed. As a result, an estimate radiation pressure noise given sensitivity for next run astrophysical experiments established.
We report first band-offset measurements obtained by multiphoton internal-photoemission induced second-harmonic generation. Our two-color contactless laser technique involves (1) optically pumping electrons into the oxide and (2) probing resulting interface electric field using time-dependent One- two-photon thresholds for ${\mathrm{S}\mathrm{i}/\mathrm{S}\mathrm{i}\mathrm{O}}_{2}$ were measured to be 4.5 2.25 eV, respectively. This method promises become a valuable experimental tool in...
We present an approach to experimentally evaluate gravity gradient noise, a potentially limiting noise source in advanced interferometric gravitational-wave detectors. In addition, the method can be used provide sub-percent calibration phase and amplitude. Knowledge of such certainties shall enhance scientific output instruments case eventual detection gravitational waves. The relies on rotating symmetrical two-body mass, dynamic field generator (DFG). placement DFG proximity one...
The observation of the electromagnetic counterpart gravitational-wave (GW) transient GW170817 demonstrated potential in extracting astrophysical information from multimessenger discoveries. forthcoming deployment first telescopes Cherenkov Telescope Array (CTA) observatory will coincide with Advanced LIGO/Virgo's next observing run, O3, enabling monitoring gamma-ray emission at E > 20 GeV, and thus particle acceleration, GW sources. CTA not be greatly limited by precision localization as it...
The multi-messenger observation of gamma-ray burst (GRB)\,170817A from the nearby binary neutron-star merger GW170817 demonstrated that low-energy $γ$-ray emission can be observed at relatively large angles GRB jet axes. If such structured is typical, then currently known sample short GRBs with no distance measurements may contain multiple off-axis events whose delayed afterglows could have gone undetected. These neutron star mergers produce telltale radio flares peaking years after prompt...
ABSTRACT The recent discovery of TeV emission from gamma-ray bursts (GRBs) by the MAGIC and H.E.S.S. Cherenkov telescopes confirmed that these transients can extend to very high energies. energy domain reaches most sensitive band Telescope Array (CTA). This newly anticipated, improved sensitivity will enhance prospects gravitational-wave follow-up observations CTA probe particle acceleration high-energy binary black hole neutron star mergers, stellar core-collapse events. Here we discuss...
We report the first application of second-harmonic generation (SHG) measurements for characterization X-ray radiation damage in Si/SiO/sub 2/ structures. The main advantage this experimental technique is that it noninvasive, contactless, and sensitive to electric field at interface. Interaction intense 800 nm femtosecond laser pulses with structures results electron-hole pair creation Si, multiphoton carrier injection generation. time-dependent (doubled frequency) signal a measure dynamic...
One of the ongoing searches performed using LIGO-Virgo network gravitational-wave interferometers is search for burst (GWB) counterparts to gamma-ray bursts (GRBs).This type analysis makes use GRB time and position information from satellite detectors trigger GWB search, detection rates possible such an thus strongly depend on efficiencies detectors.Using local rate densities inferred observations which are found in science literature, we calculate estimates different configurations this analysis.
Abstract The multimessenger detection of GW170817 showed that binary neutron star (BNS) mergers are progenitors (at least some) short gamma-ray bursts (GRBs), and GRB jets (and their afterglows) can have structures observational properties) more complex than predicted by the standard top-hat jet scenario. Indeed, emission from structured launched in peaked radio band (centimeter wavelengths) at ≈100 days since merger—a timescale much longer typical time span follow-up observations GRBs....
This paper presents an analysis of the transient behavior Advanced LIGO suspensions used to seismically isolate optics. We have characterized transients in longitudinal motion quadruple during LIGO's first observing run. Propagation between stages is consistent with modelled transfer functions, such that originating at top suspension chain significantly reduced amplitude test mass. find there are seen by monitors suspensions, but they not correlated above noise floor gravitational wave...
Abstract The multi-messenger discovery of gravitational waves (GWs) and light from the binary neutron star (NS) merger GW170817, associated with gamma-ray burst (GRB) 170817A kilonova AT2017gfo, has marked start a new era in astrophysics. GW170817 confirmed that NS mergers are progenitors at least some short GRBs. peculiar properties GRB radio afterglow, characterized by delayed onset related to off-axis geometry, have also demonstrated how nearby GRBs may not be identified as such standard...
LIGO's mission critical timing system has enabled gravitational wave and multi-messenger astrophysical discoveries as well the rich science extracted. Achieving optimal detector sensitivity, detecting transient waves, especially localizing sources, underpinning of astrophysics, all require proper data time-stamping. Measurements relative arrival times waves between different detectors allow for coherent detections, localization creation skymaps. The carefully designed achieves these goals by...
Damage enhanced electron transport, across thin oxides in x-ray irradiated Si/SiO2 samples, was measured via a contactless two-color laser technique. This method involves two steps: (1) optically stimulated injection into the oxide and (2) detection of trapping, recombination rates using time-dependent electric-field-induced second-harmonic generation arising from charge separation at interface. Measured transport an are found to be substantially higher comparison unirradiated oxides. effect...