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University of Texas Rio Grande Valley

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Articles 211 - 240 of 832

Full-Text Articles in Astrophysics and Astronomy

Reducing Leakage Current And Enhancing Polarization In Multiferroic 3d Super-Nanocomposites By Microstructure Engineering, Erik Enriquez, Ping Lu, Leigang Li, Bruce Zhang, Haiyan Wang, Quanxi Jia, Aiping Chen Jul 2022

Reducing Leakage Current And Enhancing Polarization In Multiferroic 3d Super-Nanocomposites By Microstructure Engineering, Erik Enriquez, Ping Lu, Leigang Li, Bruce Zhang, Haiyan Wang, Quanxi Jia, Aiping Chen

Physics & Astronomy Faculty Publications

Multiferroic materials have generated great interest due to their potential as functional device materials. Nanocomposites have been increasingly used to design and generate new functionalities by pairing dissimilar ferroic materials, though the combination often introduces new complexity and challenges unforeseeable in single-phase counterparts. The recently developed approaches to fabricate 3D super-nanocomposites (3D‐sNC) open new avenues to control and enhance functional properties. In this work, we develop a new 3D‐sNC with CoFe2O4 (CFO) short nanopillar arrays embedded in BaTiO3 (BTO) film matrix via microstructure engineering by alternatively depositing BTO:CFO vertically-aligned nanocomposite layers and single-phase BTO layers. This microstructure engineering method allows …

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Asymmetric Localization Of Light By Second-Harmonic Generation, Hamed Ghaemi-Dizicheh, Amir Targholizadeh, Bao-Feng Feng, Hamidreza Ramezani Jul 2022

Asymmetric Localization Of Light By Second-Harmonic Generation, Hamed Ghaemi-Dizicheh, Amir Targholizadeh, Bao-Feng Feng, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

We introduce a nonlinear photonic system that enables asymmetric localization and unidirectional transfer of an electromagnetic wave through the second-harmonic generation process. Our proposed scattering setup consists of a noncentrosymmetric nonlinear slab with nonlinear susceptibility χ(2) placed to the left side of a one-dimensional periodic linear photonic crystal with an embedded defect. We engineered the linear lattice to allow the localization of a selected frequency 2ω⋆ while frequency ω⋆ is in the gap. Thus in our proposed scattering setup, a left-incident coherent transverse electric wave with frequency ω⋆ partially converts to frequency 2ω⋆ and becomes localized at the defect layer …

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Coexistence Of Extended And Localized States In The One-Dimensional Non-Hermitian Anderson Model, Cem Yuce, Hamidreza Ramezani Jul 2022

Coexistence Of Extended And Localized States In The One-Dimensional Non-Hermitian Anderson Model, Cem Yuce, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

In one-dimensional Hermitian tight-binding models, mobility edges separating extended and localized states can appear in the presence of properly engineered quasiperiodical potentials and coupling constants. On the other hand, mobility edges do not exist in a one-dimensional Anderson lattice since localization occurs whenever a diagonal disorder through random numbers is introduced. Here we consider a nonreciprocal non-Hermitian lattice and show that the coexistence of extended and localized states appears with or without diagonal disorder in the topologically nontrivial region. We discuss that the mobility edges appear basically due to the boundary condition sensitivity of the nonreciprocal non-Hermitian lattice.

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Narrowband Searches For Continuous And Long-Duration Transient Gravitational Waves From Known Pulsars In The Ligo-Virgo Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Jun 2022

Narrowband Searches For Continuous And Long-Duration Transient Gravitational Waves From Known Pulsars In The Ligo-Virgo Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those …

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All-Sky, All-Frequency Directional Search For Persistent Gravitational-Waves From Advanced Ligo's And Advanced Virgo's First Three Observing Runs, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Jun 2022

All-Sky, All-Frequency Directional Search For Persistent Gravitational-Waves From Advanced Ligo's And Advanced Virgo's First Three Observing Runs, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present the first results from an all-sky all-frequency (ASAF) search for an anisotropic stochastic gravitational-wave background using the data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. Upper limit maps on broadband anisotropies of a persistent stochastic background were published for all observing runs of the LIGO-Virgo detectors. However, a broadband analysis is likely to miss narrowband signals as the signal-to-noise ratio of a narrowband signal can be significantly reduced when combined with detector output from other frequencies. Data folding and the computationally efficient analysis pipeline, PyStoch, enable us to perform the radiometer …

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First Joint Observation By The Underground Gravitational-Wave Detector Kagra With Geo 600, R. Abbott, H. Abe, Fausto Acernese, K. Ackley, N. Adhikari, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang Jun 2022

First Joint Observation By The Underground Gravitational-Wave Detector Kagra With Geo 600, R. Abbott, H. Abe, Fausto Acernese, K. Ackley, N. Adhikari, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We report the results of the first joint observation of the KAGRA detector with GEO 600. KAGRA is a cryogenic and underground gravitational-wave detector consisting of a laser interferometer with 3 km arms, located in Kamioka, Gifu, Japan. GEO 600 is a British–German laser interferometer with 600 m arms, located near Hannover, Germany. GEO 600 and KAGRA performed a joint observing run from April 7 to 20, 2020. We present the results of the joint analysis of the GEO–KAGRA data for transient gravitational-wave signals, including the coalescence of neutron-star binaries and generic unmodeled transients. We also perform dedicated searches for …

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Searches For Gravitational Waves From Known Pulsars At Two Harmonics In The Second And Third Ligo-Virgo Observing Runs, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, M. G. Benjamin, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang May 2022

Searches For Gravitational Waves From Known Pulsars At Two Harmonics In The Second And Third Ligo-Virgo Observing Runs, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, M. G. Benjamin, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the l = m = 2 mass quadrupole mode with a frequency at only twice the pulsar rotation frequency (single harmonic) and the l = 2, m = 1, 2 modes with a frequency of both once and twice the rotation frequency (dual harmonic). No evidence of GWs was found, so we present 95% credible upper limits on the strain amplitudes …

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X-Ray Observation Of The Roche-Lobe-Filling White Dwarf Plus Hot Subdwarf System Ztf J213056.71+442046.5, S. Mereghetti, N. La Palombara, T. Kupfer, T. R. Marsh, C. M. Copperwheat, K. Deshmukh, P. Esposito, T. Maccarone, F. Pintore, Liliana Rivera Sandoval May 2022

X-Ray Observation Of The Roche-Lobe-Filling White Dwarf Plus Hot Subdwarf System Ztf J213056.71+442046.5, S. Mereghetti, N. La Palombara, T. Kupfer, T. R. Marsh, C. M. Copperwheat, K. Deshmukh, P. Esposito, T. Maccarone, F. Pintore, Liliana Rivera Sandoval

Physics & Astronomy Faculty Publications

ZTF J213056.71+442046.5 is the prototype of a small class of recently discovered compact binaries composed of a white dwarf and a hot subdwarf that fills its Roche lobe. Its orbital period of only 39 minutes is the shortest known for the objects in this class. Evidence for a high orbital inclination (i = 86°) and for the presence of an accretion disk has been inferred from a detailed modeling of its optical photometric and spectroscopic data. We report the results of an XMM-Newton observation carried out on 2021 January 7. ZTF J213056.71+442046.5 was clearly detected by the Optical Monitor, …

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All-Sky Search For Gravitational Wave Emission From Scalar Boson Clouds Around Spinning Black Holes In Ligo O3 Data, R. Abbott, H. Abe, F. Acernese, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang May 2022

All-Sky Search For Gravitational Wave Emission From Scalar Boson Clouds Around Spinning Black Holes In Ligo O3 Data, R. Abbott, H. Abe, F. Acernese, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

This paper describes the first all-sky search for long-duration, quasimonochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of Advanced LIGO. We analyze the frequency range from 20 to 610 Hz, over a small frequency derivative range around zero, and use multiple frequency resolutions to be robust towards possible signal frequency wanderings. Outliers from this search are followed up using two different methods, one more suitable for nearly monochromatic signals, and the other more robust towards frequency fluctuations. We do not find any evidence for such signals and set …

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Fabrication And Characterization Of Superparamagnetic Nickel Ferrite Ferrofluid, D. Karthickraja, S. Karthi, G. Ajith Kumar, D. K. Sardar, Gamage Chamath Dannangoda, Karen S. Martirosyan, Niroj Kumar Sahu, M. Prasath, R. Arunima, E. L. Girija May 2022

Fabrication And Characterization Of Superparamagnetic Nickel Ferrite Ferrofluid, D. Karthickraja, S. Karthi, G. Ajith Kumar, D. K. Sardar, Gamage Chamath Dannangoda, Karen S. Martirosyan, Niroj Kumar Sahu, M. Prasath, R. Arunima, E. L. Girija

Physics & Astronomy Faculty Publications

Because of their unique magnetic characteristics, magnetic nanoparticles are being used in various applications. We used a two-step method to create nickel ferrite ferrofluid in this study. The first step included hydrothermal preparation of oleic acid-capped nickel ferrite nanoparticles, followed by surface functionalization of the particles with citric acid, which made the nanoparticles hydrophilic. The materials' phase purity, functional groups, and magnetic behaviour were investigated. The production of mono-dispersed spherical nanoparticles with an average diameter of 9 ± 3.6 nm was shown by TEM images. With a blocking temperature of 53 K, ZFC-FC measurements verified the sample's …

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Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, R. Abbott, T. Abbott, K. Ackley, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Apr 2022

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, R. Abbott, T. Abbott, K. Ackley, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …

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Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin Apr 2022

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics & Astronomy Faculty Publications

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

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Dry And Hydrated Defective Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain For Hydrogen Evolution From Water Splitting: A First-Principle Study, Nicholas Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti Apr 2022

Dry And Hydrated Defective Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain For Hydrogen Evolution From Water Splitting: A First-Principle Study, Nicholas Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti

Physics & Astronomy Faculty Publications

In search of exploiting cost-effective, highly stable, efficient, and greatly active electrocatalysts for hydrogen evolution reaction (HER), molybdenum disulfide-graphene heterostructures (MoS2/graphene) are promising, in contrast to noble metals. We used density functional theory (DFT) to examine the changes in the electronic structure of MoS2/graphene under compressive strain for structural defects in the MoS2 and graphene layers, as well as from hydration of the MoS2 layer. In the pristine MoS2/graphene heterostructure, a small bandgap (minigap) is opened at the graphene Dirac point, which is located above the Fermi energy, for dry and hydrated configurations. The presence of sulfur and carbon vacancies …

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Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Apr 2022

Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence …

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Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Mar 2022

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

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Hadron-Quark Phase Transition At Finite Density In The Presence Of A Magnetic Field: Anisotropic Approach, Efrain J. Ferrer, Aric Hackebill Mar 2022

Hadron-Quark Phase Transition At Finite Density In The Presence Of A Magnetic Field: Anisotropic Approach, Efrain J. Ferrer, Aric Hackebill

Physics & Astronomy Faculty Publications

We investigate the hadron-quark phase transition at finite density in the presence of a magnetic field taking into account the anisotropy created by a uniform magnetic field in the system’s equations of state. We find a new anisotropic equilibrium condition that will drive the first-order phase transition along the boundary between the two phases. Fixing the magnetic field in the hadronic phase, the phase transition is realized by increasing the baryonic chemical potential at zero-temperature. It is shown that the magnetic field is mildly boosted after the system transitions from the hadronic to the quark phase. The magnetic-field discontinuity between …

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Computational Data Of Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain, Nicholas Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti Mar 2022

Computational Data Of Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain, Nicholas Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti

Physics & Astronomy Faculty Publications

The data presented in this paper refer to the research article "Dry and Hydrated Defective Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain for Hydrogen Evolution from Water Splitting: A First-principle Study". Here, we present the Density Functional Theory (DFT) data used to generate optimal geometries and electronic structure for the MoS2/graphene heterostructure under strain, for dry and hydrated pristine and defect configurations. We also report DFT data used to obtain hydrogen Gibbs free energies for adsorption on the MoS2 monolayer and on graphene of the heterostructure. The DFT data were calculated using the periodic DFT code CRYSTAL17, which employs Gaussian basis …

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The Arecibo Observatory As An Instrument For Investigating Orbital Debris: Legacy And Next Generation Performance, James Murray, Fredrick A. Jenet Mar 2022

The Arecibo Observatory As An Instrument For Investigating Orbital Debris: Legacy And Next Generation Performance, James Murray, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

In this paper, we investigate the ability of the Arecibo Observatory to characterize the orbital debris environment and compare it to the primary instrument used by NASA's Orbital Debris Program Office, the Haystack Ultra-Wideband Satellite Imaging Radar (HUSIR). Arecibo's location (183 N) increases the percentage of observable orbits (relative to HUSIR) by 27%, which gives Arecibo access to a much larger and previously unmeasured portion of the environment. Due to the recent collapse of the Arecibo dish, in addition to exploring historic capabilities of the Legacy Arecibo Telescope, estimates of the performance of the proposed Next Generation Arecibo Telescope (NGAT) …

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Search For Intermediate-Mass Black Hole Binaries In The Third Observing Run Of Advanced Ligo And Advanced Virgo, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Mar 2022

Search For Intermediate-Mass Black Hole Binaries In The Third Observing Run Of Advanced Ligo And Advanced Virgo, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Intermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of …

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A Skateboarding Experiential Learning Activity For Introductory Physics, Liang Zeng, Guang Zeng, Oscar Guerrero, George Garcia Feb 2022

A Skateboarding Experiential Learning Activity For Introductory Physics, Liang Zeng, Guang Zeng, Oscar Guerrero, George Garcia

Physics & Astronomy Faculty Publications

Instructors of introductory college physics courses are in a unique position to explain the physics of skateboarding and its associated risks. A field trip to a skate park to explore the law of conservation of energy and measure the impact forces can enhance student analytical thinking skills and their appreciation of physics in everyday life. Through the measurement of the impact forces and student discussions of their own skateboarding experiences, students are better prepared to protect themselves from skateboarding-related physical injuries. Due to its flexible and creative nature, skateboarding has become a popular action sport worldwide. In the United States, …

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Wallaby Pilot Survey: H I Gas Disc Truncation And Star Formation Of Galaxies Falling Into The Hydra I Cluster, T. N. Reynolds, B. Catinella, L. Cortese, Tobias Westmeier, G. R. Meurer, L. Shao, D. Obreschkow, J. Román, L. Verdes-Montenegro, Juan P. Madrid Feb 2022

Wallaby Pilot Survey: H I Gas Disc Truncation And Star Formation Of Galaxies Falling Into The Hydra I Cluster, T. N. Reynolds, B. Catinella, L. Cortese, Tobias Westmeier, G. R. Meurer, L. Shao, D. Obreschkow, J. Román, L. Verdes-Montenegro, Juan P. Madrid

Physics & Astronomy Faculty Publications

We present results from our analysis of the Hydra I cluster observed in neutral atomic hydrogen (HI) as part of the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). These WALLABY observations cover a 60-square-degree field of view with uniform sensitivity and a spatial resolution of 30 arcsec. We use these wide-field observations to investigate the effect of galaxy environment on HI gas removal and star formation quenching by comparing the properties of cluster, infall and field galaxies extending up to ∼5R200 from the cluster centre. We find a sharp decrease in the HI-detected fraction of infalling galaxies at a …

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Search For Continuous Gravitational Waves From 20 Accreting Millisecond X-Ray Pulsars In O3 Ligo Data, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Jan 2022

Search For Continuous Gravitational Waves From 20 Accreting Millisecond X-Ray Pulsars In O3 Ligo Data, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Results are presented of searches for continuous gravitational waves from 20 accreting millisecond x-ray pulsars with accurately measured spin frequencies and orbital parameters, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. The search algorithm uses a hidden Markov model, where the transition probabilities allow the frequency to wander according to an unbiased random walk, while the J-statistic maximum-likelihood matched filter tracks the binary orbital phase. Three narrow subbands are searched for each target, centered on harmonics of the measured spin frequency. The search yields 16 candidates, consistent with a false alarm probability of …

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Comparison Of Maximum-Likelihood Mapping Methods For Gravitational-Wave Backgrounds, Arianna I. Renzini, Joseph D. Romano, Carlo R. Contaldi, Neil Cornish Jan 2022

Comparison Of Maximum-Likelihood Mapping Methods For Gravitational-Wave Backgrounds, Arianna I. Renzini, Joseph D. Romano, Carlo R. Contaldi, Neil Cornish

Physics & Astronomy Faculty Publications

Detection of a stochastic background of gravitational waves is likely to occur in the next few years. Beyond searches for the isotropic component of a stochastic gravitational-wave background, there have been various mapping methods proposed to target anisotropic backgrounds. Some of these methods have been applied to data taken by the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo. Specifically, these directional searches have focused on mapping the intensity of the signal on the sky via maximum-likelihood solutions. We compare this intensity mapping approach to a previously proposed, but never employed, amplitude-phase mapping method to understand whether this latter approach may …

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Individual Element Sensitivity For Stellar Evolutionary Isochrones, Guy Worthey, Xiang Shi, Tathagata Pal, Hyun-Chul Lee, Baitian Tang Jan 2022

Individual Element Sensitivity For Stellar Evolutionary Isochrones, Guy Worthey, Xiang Shi, Tathagata Pal, Hyun-Chul Lee, Baitian Tang

Physics & Astronomy Faculty Publications

Stellar evolution calculations with variable abundance ratios were used to gauge the effects on temperatures, luminosities, and lifetimes in various phases. The individual elements C, N, O, Mg, Si, and Fe were included. Most of the effect relevant to integrated light models is contained in the temperature variable, as opposed to the time-scale or luminosity. We derive a recipe for including abundance-sensitive temperature effects that is applicable to existing isochrone grids. The resultant enhanced isochrones are incorporated into composite stellar population models and compared with galaxy data from the Sloan Digital Sky Survey. A severe oxygen–age degeneracy is apparent, 2–3 …

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Exceptional Point Generated Robust Asymmetric High-Order Harmonics, Hamidreza Ramezani, Amir Targholizadeh, Gui-Lei Zhu, Xin-You Lü, Cem Yuce Jan 2022

Exceptional Point Generated Robust Asymmetric High-Order Harmonics, Hamidreza Ramezani, Amir Targholizadeh, Gui-Lei Zhu, Xin-You Lü, Cem Yuce

Physics & Astronomy Faculty Publications

Using exceptional point dynamics in time and space modulated lattices we propose a new mechanism for generation of asymmetric robust higher harmonics. Specifically we design a metallic-silicon system with a complex optical potential spatiotemporally modulated along the length of the waveguide for this robust higher harmonic generation. In our system the dynamical equations associated with modal field amplitudes are described by a Jordan form Hamiltonian. This ultimately will allow for a unidirectional higher frequency generation which always has a maximum value for a specific length of the waveguide irrespective of the geometrical imperfections in the design of the waveguide. Furthermore, …

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All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Dec 2021

All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

This paper presents the results of a search for generic short-duration gravitational-wave transients in data from the third observing run of Advanced LIGO and Advanced Virgo. Transients with durations of milliseconds to a few seconds in the 24–4096 Hz frequency band are targeted by the search, with no assumptions made regarding the incoming signal direction, polarization, or morphology. Gravitational waves from compact binary coalescences that have been identified by other targeted analyses are detected, but no statistically significant evidence for other gravitational wave bursts is found. Sensitivities to a variety of signals are presented. These include updated upper limits on …

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Search For Lensing Signatures In The Gravitational-Wave Observations From The First Half Of Ligo–Virgo's Third Observing Run, Richard Abbott, Thomas D. Abbott, S. Abraham, Fausto Acernese, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang Dec 2021

Search For Lensing Signatures In The Gravitational-Wave Observations From The First Half Of Ligo–Virgo's Third Observing Run, Richard Abbott, Thomas D. Abbott, S. Abraham, Fausto Acernese, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang

Physics & Astronomy Faculty Publications

We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) and Advanced Virgo during O3a, the first half of their third observing run. We study: (1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; (2) how the interpretation of individual high-mass events would change if they were found to be lensed; (3) the possibility of multiple images due to strong lensing by galaxies or galaxy …

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Point Absorber Limits To Future Gravitational-Wave Detectors, Wenxuan Jia, Hiroaki Yamamoto, Kevin Kuns, Anamaria Effler, Matthew Evans, Peter Fritschel, R. Abbott, C. Adams, R. Adhikari, Karla E. Ramirez Dec 2021

Point Absorber Limits To Future Gravitational-Wave Detectors, Wenxuan Jia, Hiroaki Yamamoto, Kevin Kuns, Anamaria Effler, Matthew Evans, Peter Fritschel, R. Abbott, C. Adams, R. Adhikari, Karla E. Ramirez

Physics & Astronomy Faculty Publications

High-quality optical resonant cavities require low optical loss, typically on the scale of parts per million. However, unintended micron-scale contaminants on the resonator mirrors that absorb the light circulating in the cavity can deform the surface thermoelastically, and thus increase losses by scattering light out of the resonant mode. The point absorber effect is a limiting factor in some highpower cavity experiments, for example, the Advanced LIGO gravitational wave detector. In this Letter, we present a general approach to the point absorber effect from first principles and simulate its contribution to the increased scattering. The achievable circulating power in current …

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Identification And Characterization Of Bisbenzimide Compounds That Inhibit Human Cytomegalovirus Replication, Nicole Falci Finardi, Hyeongjun Kim, Lee Z. Hernandez, Matthew R. G. Russell, Catherine M-K Ho, Vattipally B. Sreenu, Hannah A. Wenham, Andy Merritt, Blair L. Strang Dec 2021

Identification And Characterization Of Bisbenzimide Compounds That Inhibit Human Cytomegalovirus Replication, Nicole Falci Finardi, Hyeongjun Kim, Lee Z. Hernandez, Matthew R. G. Russell, Catherine M-K Ho, Vattipally B. Sreenu, Hannah A. Wenham, Andy Merritt, Blair L. Strang

Physics & Astronomy Faculty Publications

The shortcomings of current anti-human cytomegalovirus (HCMV) drugs has stimulated a search for anti-HCMV compounds with novel targets. We screened collections of bioactive compounds and identified a range of compounds with the potential to inhibit HCMV replication. Of these compounds, we selected bisbenzimide compound RO-90-7501 for further study. We generated analogues of RO-90-7501 and found that one compound, MRT00210423, had increased anti-HCMV activity compared to RO-90-7501. Using a combination of compound analogues, microscopy and biochemical assays we found RO-90-7501 and MRT00210423 interacted with DNA. In single molecule microscopy experiments we found RO-90-7501, but not MRT00210423, was able to compact DNA, …

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Upconversion, Mri Imaging And Optical Trapping Studies Of Silver Nanoparticle Decorated Multifunctional Nagdf4:Yb,Er Nanocomposite, S. Yamini, M. Gunaseelan, Ajithkumar Gangadharan, Silverio A. Lopez, Karen S. Martirosyan, Agnishwar Girigoswami, Basudev Roy, J. Manonmani, Senthilselvan Jayaraman Nov 2021

Upconversion, Mri Imaging And Optical Trapping Studies Of Silver Nanoparticle Decorated Multifunctional Nagdf4:Yb,Er Nanocomposite, S. Yamini, M. Gunaseelan, Ajithkumar Gangadharan, Silverio A. Lopez, Karen S. Martirosyan, Agnishwar Girigoswami, Basudev Roy, J. Manonmani, Senthilselvan Jayaraman

Physics & Astronomy Faculty Publications

The multifunctional upconversion nanoparticles (UCNPs) are fascinating tool for biological applications. In the present work, photon upconverting NaGdF4:Yb,Er and Ag nanoparticles decorated NaGdF4:Yb,Er (NaGdF4:Yb,Er@Ag) nanoparticles were prepared using a simple polyol process. Rietveld refinement was performed for detailed crystal structural and phase fraction analysis. The morphology of the NaGdF4:Yb,Er@Ag was examined using high-resolution transmission electron microscope, which reveals silver nanoparticles of 8 nm in size were decorated over spherical shaped NaGdF4:Yb,Er nanoparticles with a mean particle size of 90 nm. The chemical compositions were confirmed by EDAX and inductively coupled plasma-optical emission spectrometry analyses. The upconversion luminescence (UCL) of NaGdF4:Yb,Er …

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