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Articles 1 - 30 of 73
Full-Text Articles in Physical Sciences and Mathematics
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, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
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, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
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 …
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, K. Ackley, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
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, K. Ackley, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
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 …
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
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 and Astronomy Faculty Publications and Presentations
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 …
Conceptual Insight Into The Application Of Innovative Educational Methods In Astronomy, Wahltyn A. Rattray
Conceptual Insight Into The Application Of Innovative Educational Methods In Astronomy, Wahltyn A. Rattray
Theses and Dissertations
University students taking introductory astronomy courses were studied with a control group enrolled in a class with standard curriculum and an experimental group enrolled in a class with a curriculum using innovative instructional methods. Using multiple assessments, I analyzed the students’ astronomy knowledge and overall class experience to determine which curriculum was more instructionally effective. The innovative methods were developed with the ADDIE method and were based on the Karplus learning cycle which provided the framework for the astronomy curriculum. The end goal of the innovative curriculum is to produce graduates with better conceptual understanding of astronomy than with the …
Dynamical Casimir Effect In A Superconducting Circuit Periodic Lattice, Andres Cuellar Vega
Dynamical Casimir Effect In A Superconducting Circuit Periodic Lattice, Andres Cuellar Vega
Theses and Dissertations
The dynamical Casimir effect (DCE) is the generation of real photons out of the quantum vacuum due to a rapid modulation of boundary conditions for the electromagnetic field, such as a mirror oscillating at speeds comparable to the speed of light. Previous work demonstrated experimentally that DCE radiation can be generated in electrical circuits based on superconducting microfabricated waveguides, where a rapid modulation of boundary conditions corresponding to semi-transparent mirrors is realized by tuning the applied magnetic flux through superconducting quantum-interference devices (SQUIDs) that are embedded in the waveguide circuits. We propose a novel SQUID periodic lattice architecture, in which …
Contributions To The Heat Capacity Of Neutron Stars, Pedro Paulo Barboza Sanson
Contributions To The Heat Capacity Of Neutron Stars, Pedro Paulo Barboza Sanson
Theses and Dissertations
In this thesis, we review the contribution to the heat capacity of different matter phases that can appear inside a Neutron Star's core, paying special attention to the magnetic dual chiral density wave (MDCDW) phase, which is characterized by an inhomogeneous chiral condensate in the presence of a magnetic field and that is expected to be favored at intermediate densities and low temperatures. Furthermore, we compare our results with the observational lower limit of the core heat capacity established from observations of transiently accreting neutron stars which give us crucial information whether certain phases are feasible to appear in the …
Effects Of Collaborative Group Activities On Students’ Interest, Course Participation, And Performance In An Online Physics Course, Airik R. Sanchez
Effects Of Collaborative Group Activities On Students’ Interest, Course Participation, And Performance In An Online Physics Course, Airik R. Sanchez
Theses and Dissertations
The purpose of this study was to investigate the impact of the use of collaborative work activities in online physics courses as perceived by students. Nearly identical surveys were administered at the beginning and end of two semesters to ascertain student perception on the impact of the utilization on their level of interest, participation, performance as well as teamwork skills. The results show that the majority of the population tested strongly agree that collaborative work had significant effect on all core areas tested, and they support the notion that it should be further utilized in both lecture and lab portions …
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
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 and Astronomy Faculty Publications and Presentations
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, …
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
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 and Astronomy Faculty Publications and Presentations
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 …
Magnetic Dual Chiral Density Wave: A Candidate Quark Matter Phase For The Interior Of Neutron Stars, Efrain J. Ferrer, Vivian De La Incera
Magnetic Dual Chiral Density Wave: A Candidate Quark Matter Phase For The Interior Of Neutron Stars, Efrain J. Ferrer, Vivian De La Incera
Physics and Astronomy Faculty Publications and Presentations
n this review, we discuss the physical characteristics of the magnetic dual chiral density wave (MDCDW) phase of dense quark matter and argue why it is a promising candidate for the interior matter phase of neutron stars. The MDCDW condensate occurs in the presence of a magnetic field. It is a single-modulated chiral density wave characterized by two dynamically generated parameters: the fermion quasiparticle mass m and the condensate spatial modulation q. The lowest-Landau-level quasiparticle modes in the MDCDW system are asymmetric about the zero energy, a fact that leads to the topological properties and anomalous electric transport exhibited by …
Twisted Laminar Superconducting Composite: Mgb2 Embedded Carbon Nanotube Yarns, Ujjal Lamichhane, Gamage C. Dannangoda, Mkhitar Hobosyan, R. A. Shohan, A. Zakhidov, Karen S. Martirosyan
Twisted Laminar Superconducting Composite: Mgb2 Embedded Carbon Nanotube Yarns, Ujjal Lamichhane, Gamage C. Dannangoda, Mkhitar Hobosyan, R. A. Shohan, A. Zakhidov, Karen S. Martirosyan
Physics and Astronomy Faculty Publications and Presentations
Twisted laminar superconducting composite structures based on multi-wall carbon nanotube (MWCNT) yarns were crafted by integrating magnesium and boron homogeneous mixture into the carbon nanotube (CNT) aerogel sheets. After the ignition of the Mg–B–MWCNT system, under the controlled argon environment, the high exothermic reaction between magnesium (Mg) and boron (B) with stoichiometric ratio produced the MgB2@MWCNT superconducting composite yarns. The process was conducted under the controlled argon environment and uniform heating rate in the differential scanning calorimetry and thermogravimetric analyzer. The XRD analysis confirmed that the produced composite yarns contain nano and microscale inclusions of superconducting phase of MgB2. The …
Enhancing Student Learning Of Global Warming Through Reflective Writing, Liang Zeng, Guang Zeng
Enhancing Student Learning Of Global Warming Through Reflective Writing, Liang Zeng, Guang Zeng
Physics and Astronomy Faculty Publications and Presentations
The National Academy of Science has published studies showing strong scientific evidence that global warming is caused by human consumption of fossil fuels, yet recent surveys have shown young adults in the U.S. are disengaged or disagree with this fact. Accordingly, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) published learning objectives to educate the world population on global warming and renewable energy by 2030. In this paper, we introduce a reflective writing activity physics educators can employ to foster a deeper understanding of global warming in introductory college physics and physical science courses, without overloading their teaching time.
Gwtc-3: Compact Binary Coalescences Observed By Ligo And Virgo During The Second Part Of The Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Gwtc-3: Compact Binary Coalescences Observed By Ligo And Virgo During The Second Part Of The Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
The third Gravitational-wave Transient Catalog (GWTC-3) describes signals detected with Advanced LIGO and Advanced Virgo up to the end of their third observing run. Updating the previous GWTC-2.1, we present candidate gravitational waves from compact binary coalescences during the second half of the third observing run (O3b) between 1 November 2019, 15:00 UTC and 27 March 2020, 17:00 UTC. There are 35 compact binary coalescence candidates identified by at least one of our search algorithms with a probability of astrophysical origin pastro>0.5. Of these, 18 were previously reported as low-latency public alerts, and 17 are reported here for the …
Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, Dorota Gondek-Rosińska, Travis Hansen, Soma Mukherjee, Gaukhar Nurbek, Satzhan Sitmukhambetov, Oscar Valdez
Detecting And Reconstructing Gravitational Waves From The Next Galactic Core-Collapse Supernova In The Advanced Detector Era, Marek J. Szczepańczyk, Javier M. Antelis, Michael Benjamin, Marco Cavaglia, Dorota Gondek-Rosińska, Travis Hansen, Soma Mukherjee, Gaukhar Nurbek, Satzhan Sitmukhambetov, Oscar Valdez
Physics and Astronomy Faculty Publications and Presentations
We performed a detailed analysis of the detectability of a wide range of gravitational waves derived from core-collapse supernova simulations using gravitational-wave detector noise scaled to the sensitivity of the upcoming fourth and fifth observing runs of the Advanced LIGO, Advanced Virgo, and KAGRA. We use the coherent WaveBurst algorithm, which was used in the previous observing runs to search for gravitational waves from core-collapse supernovae. As coherent WaveBurst makes minimal assumptions on the morphology of a gravitational-wave signal, it can play an important role in the first detection of gravitational waves from an event in the Milky Way. We …
All-Sky Search For Long-Duration Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, Richard Abbott, Thomas D. Abbott, Fausto Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
All-Sky Search For Long-Duration Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, Richard Abbott, Thomas D. Abbott, Fausto Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
After the detection of gravitational waves from compact binary coalescences, the search for transient gravitational-wave signals with less well-defined waveforms for which matched filtering is not well suited is one of the frontiers for gravitational-wave astronomy. Broadly classified into "short" less than or similar to 1 s and "long" greater than or similar to 1 s duration signals, these signals are expected from a variety of astrophysical processes, including non-axisymmetric deformations in magnetars or eccentric binary black hole coalescences. In this work, we present a search for long-duration gravitational-wave transients from Advanced LIGO and Advanced Virgo's third observing run from …
Modeling And Simulation Of Janus-Like Nanoparticles Formation By Solid-Gas Exothermic Reactions, A. A. Markov, Karen S. Martirosyan
Modeling And Simulation Of Janus-Like Nanoparticles Formation By Solid-Gas Exothermic Reactions, A. A. Markov, Karen S. Martirosyan
Physics and Astronomy Faculty Publications and Presentations
Theoretical model for the simulation of synthesis of Janus-like particles (JP) consisting two different phases using the Carbon Combustion Synthesis of Oxides (CCSO) is presented. The model includes the variation of sample initial porosity, carbon concentration and oxygen flow rate used to predict the formation of JP features. The two temperature (2T) combustion model of chemically active submicron-dispersed mixture of two phases including ferroelectric and ferromagnetic was implemented and assessed by using the experimentally estimated activation energy of 112±3.3 kJ/mol and combustion temperature. The experimental values allowed to account the thermal and concentration expansion effect along with the dispersion by …
All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang
All-Sky Search For Short Gravitational-Wave Bursts In The Third Advanced Ligo And Advanced Virgo Run, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang
Physics and Astronomy Faculty Publications and Presentations
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 …
Technique To Solve Linear Fractional Differential Equations Using B-Polynomials Bases, Muhammad I. Bhatti, Md. Habibur Rahman
Technique To Solve Linear Fractional Differential Equations Using B-Polynomials Bases, Muhammad I. Bhatti, Md. Habibur Rahman
Physics and Astronomy Faculty Publications and Presentations
A multidimensional, modified, fractional-order B-polys technique was implemented for finding solutions of linear fractional-order partial differential equations. To calculate the results of the linear Fractional Partial Differential Equations (FPDE), the sum of the product of fractional B-polys and the coefficients was employed. Moreover, minimization of error in the coefficients was found by employing the Galerkin method. Before the Galerkin method was applied, the linear FPDE was transformed into an operational matrix equation that was inverted to provide the values of the unknown coefficients in the approximate solution. A valid multidimensional solution was determined when an appropriate number of basis sets …
Searches For Continuous Gravitational Waves From Young Supernova Remnants In The Early Third Observing Run Of Advanced Ligo And Virgo, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
Searches For Continuous Gravitational Waves From Young Supernova Remnants In The Early Third Observing Run Of Advanced Ligo And Virgo, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
We present results of three wide-band directed searches for continuous gravitational waves from 15 young supernova remnants in the first half of the third Advanced LIGO and Virgo observing run. We use three search pipelines with distinct signal models and methods of identifying noise artifacts. Without ephemerides of these sources, the searches are conducted over a fRequency band spanning from 10 to 2 kHz. We find no evidence of continuous gravitational radiation from these sources. We set upper limits on the intrinsic signal strain at 95% confidence level in sample subbands, estimate the sensitivity in the full band, and derive …
Constraints From Ligo O3 Data On Gravitational-Wave Emission Due To R-Modes In The Glitching Pulsar Psr J0537–6910, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
Constraints From Ligo O3 Data On Gravitational-Wave Emission Due To R-Modes In The Glitching Pulsar Psr J0537–6910, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Karla E. Ramirez, Wenhui Wang
Physics and Astronomy Faculty Publications and Presentations
We present a search for continuous gravitational-wave emission due to r-modes in the pulsar PSR J0537-6910 using data from the LIGO-Virgo Collaboration observing run O3. PSR J0537-6910 is a young energetic X-ray pulsar and is the most frequent glitcher known. The inter-glitch braking index of the pulsar suggests that gravitational-wave emission due to r-mode oscillations may play an important role in the spin evolution of this pulsar. Theoretical models confirm this possibility and predict emission at a level that can be probed by ground-based detectors. In order to explore this scenario, we search for r-mode emission in the epochs between …
Asymmetric Localization Of Light By Second-Harmonic Generation, H. Ghaemi-Dizicheh, A. Targholizadeh, Bao-Feng Feng, Hamidreza Ramezani
Asymmetric Localization Of Light By Second-Harmonic Generation, H. Ghaemi-Dizicheh, A. Targholizadeh, Bao-Feng Feng, Hamidreza Ramezani
Physics and Astronomy Faculty Publications and Presentations
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 …
Raman Investigations Of The Radiation-Induced Modifications In Ipp-Vgcnf Nanocomposites: The Nanofillers’ Tale, Dorina M. Chipara, Mihail Secu, Karen Lozano, Corina Secu, Mircea Chipara
Raman Investigations Of The Radiation-Induced Modifications In Ipp-Vgcnf Nanocomposites: The Nanofillers’ Tale, Dorina M. Chipara, Mihail Secu, Karen Lozano, Corina Secu, Mircea Chipara
Physics and Astronomy Faculty Publications and Presentations
Nanocomposites of isotactic polypropylene loaded by various amounts of vapor-grown carbon nanotubes ranging from 0 to 20% wt. were obtained by extrusion. Raman investigations on these nanocomposites are reported. The nanocomposites were irradiated using a 60Co, with an integral dose of 1 kGy/h up to integral doses of 9 kGy, 18 kGy, and 27 kGy, in air, at room temperature. Raman measurements were performed by using a Bruker Senterra confocal Raman spectrometer operating at 785 nm. The research is focused on the information contained within the D and G Raman lines of these nanocomposites as a function of nanotube loading …
All-Sky Search For Continuous Gravitational Waves From Isolated Neutron Stars In The Early O3 Ligo Data, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Volker Quetschke, Karla E. Ramirez, Wen Hui Wang
All-Sky Search For Continuous Gravitational Waves From Isolated Neutron Stars In The Early O3 Ligo Data, R. Abbott, T. D. Abbott, S. Abraham, Teviet Creighton, Mario C. Diaz, Volker Quetschke, Karla E. Ramirez, Wen Hui Wang
Physics and Astronomy Faculty Publications and Presentations
We report on an all-sky search for continuous gravitational waves in the frequency band 20–2000 Hz and with a frequency time derivative in the range of [−1.0,+0.1]×10−8 Hz/s. Such a signal could be produced by a nearby, spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the LIGO data from the first six months of Advanced LIGO’s and Advanced Virgo’s third observational run, O3. No periodic gravitational wave signals are observed, and 95% confidence-level (C.L.) frequentist upper limits are placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼1.7×10−25 …
Ligo’S Quantum Response To Squeezed States, L. Mcculler, S. E. Dwyer, A. C. Green, Haocun Yu, K. Kuns, L. Barsotti, C. D. Blair, D. D. Brown, A. Effler, Karla E. Ramirez
Ligo’S Quantum Response To Squeezed States, L. Mcculler, S. E. Dwyer, A. C. Green, Haocun Yu, K. Kuns, L. Barsotti, C. D. Blair, D. D. Brown, A. Effler, Karla E. Ramirez
Physics and Astronomy Faculty Publications and Presentations
Gravitational wave interferometers achieve their profound sensitivity by combining a Michelson interferometer with optical cavities, suspended masses, and now, squeezed quantum states of light. These states modify the measurement process of the LIGO, VIRGO and GEO600 interferometers to reduce the quantum noise that masks astrophysical signals; thus, improvements to squeezing are essential to further expand our gravitational view of the Universe. Further reducing quantum noise will require both lowering decoherence from losses as well more sophisticated manipulations to counter the quantum back-action from radiation pressure. Both tasks require fully understanding the physical interactions between squeezed light and the many components …
Mapping The Gravitational-Wave Sky With Lisa: A Bayesian Spherical Harmonic Approach, Sharan Banagiri, Alexander Criswell, Tommy Kuan, Vuk Mandic, Joseph D. Romano, Stephen R. Taylor
Mapping The Gravitational-Wave Sky With Lisa: A Bayesian Spherical Harmonic Approach, Sharan Banagiri, Alexander Criswell, Tommy Kuan, Vuk Mandic, Joseph D. Romano, Stephen R. Taylor
Physics and Astronomy Faculty Publications and Presentations
The millihertz gravitational-wave frequency band is expected to contain a rich symphony of signals with sources ranging from Galactic white dwarf binaries to extreme mass ratio inspirals. Many of these gravitational-wave signals will not be individually resolvable. Instead, they will incoherently add to produce stochastic gravitational-wave confusion noise whose frequency content will be governed by the dynamics of the sources. The angular structure of the power of the confusion noise will be modulated by the distribution of the sources across the sky. Measurement of this structure can yield important information about the distribution of sources on Galactic and extragalactic scales, …
Approximate Solutions Of Nonlinear Partial Differential Equations Using B-Polynomial Bases, Muhammad I. Bhatti, Md. Habibur Rahman, N. Dimakis
Approximate Solutions Of Nonlinear Partial Differential Equations Using B-Polynomial Bases, Muhammad I. Bhatti, Md. Habibur Rahman, N. Dimakis
Physics and Astronomy Faculty Publications and Presentations
A multivariable technique has been incorporated for guesstimating solutions of Nonlinear Partial Differential Equations (NPDE) using bases set of B-Polynomials (B-polys). To approximate the anticipated solution of the NPD equation, a linear product of variable coefficients ai(t) and Bi(x) B-polys has been employed. Additionally, the variable quantities in the anticipated solution are determined using the Galerkin method for minimizing errors. Before the minimization process is to take place, the NPDE is converted into an operational matrix equation which, when inverted, yields values of the undefined coefficients in the expected solution. The nonlinear terms of the NPDE are combined in the …
Elucidating The Effects Of Oxygen- And Nitrogen-Containing Functional Groups In Graphene Nanomaterials For Applied Electrochemistry By Density Functional Theory, Sanju Gupta, N. Dimakis
Elucidating The Effects Of Oxygen- And Nitrogen-Containing Functional Groups In Graphene Nanomaterials For Applied Electrochemistry By Density Functional Theory, Sanju Gupta, N. Dimakis
Physics and Astronomy Faculty Publications and Presentations
Graphene nanomaterials functionalized with oxygen groups [graphene oxide (GO) and reduced GO (rGO)] are either doped with element nitrogen or nitrogen-containing aromatic moieties followed by the investigation of electrochemical properties that generally show enhanced electroanalytical performance. We studied structural, morphological, and physical–chemical properties using correlative techniques. While we attribute their improved properties promoted simultaneously by topologically interconnected mesoporous network morphology, the presence of heteroatom species, and lattice vibrational structure, the complex interpretation requires the need to supplement the experimental observations with theoretical calculations for further insights. The complex interplay of pore size and redox properties revealing distinctive supercapacitive (ion-adsorption controlled) …
Wallaby Pre-Pilot Survey: Two Dark Clouds In The Vicinity Of Ngc 1395, O. I. Wong, A. R. H. Stevens, B. Q. For, Tobias Westmeier, M. Dixon, S. -H. Oh, G. I. G. Jozsa, T. N. Reynolds, K. Lee-Waddell, Juan P. Madrid
Wallaby Pre-Pilot Survey: Two Dark Clouds In The Vicinity Of Ngc 1395, O. I. Wong, A. R. H. Stevens, B. Q. For, Tobias Westmeier, M. Dixon, S. -H. Oh, G. I. G. Jozsa, T. N. Reynolds, K. Lee-Waddell, Juan P. Madrid
Physics and Astronomy Faculty Publications and Presentations
We present the Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pre-pilot observations of two ‘dark’ HI sources (with HI masses of a few times 108 M⊙ and no known stellar counterpart) that reside within 363 kpc of NGC 1395, the most massive early-type galaxy in the Eridanus group of galaxies. We investigate whether these ‘dark’ HI sources have resulted from past tidal interactions or whether they are an extreme class of low surface brightness galaxies. Our results suggest that both scenarios are possible, and not mutually exclusive. The two ‘dark’ HI sources are compact, reside in relative isolation and are …
Wallaby Pre-Pilot Survey: H I Content Of The Eridanus Supergroup, B. Q. For, J. Wang, Tobias Westmeier, O. I. Wong, C. Murugeshan, L. Staveley-Smith, H. M. Courtois, D. Pomarede, Juan P. Madrid
Wallaby Pre-Pilot Survey: H I Content Of The Eridanus Supergroup, B. Q. For, J. Wang, Tobias Westmeier, O. I. Wong, C. Murugeshan, L. Staveley-Smith, H. M. Courtois, D. Pomarede, Juan P. Madrid
Physics and Astronomy Faculty Publications and Presentations
We present observations of the Eridanus supergroup obtained with the Australian Square Kilometre Array Pathfinder (ASKAP) as part of the pre-pilot survey for the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). The total number of detected H I sources is 55, of which 12 are background galaxies not associated with the Eridanus supergroup. Two massive H I clouds are identified and large H I debris fields are seen in the NGC 1359 interacting galaxy pair, and the face-on spiral galaxy NGC 1385. We describe the data products from the source finding algorithm and present the basic parameters. The …
Detecting Optical Transients Using Artificial Neural Networks And Reference Images From Different Surveys, Katarzyna Wardęga, Adam Zadrozny, Martin Beroiz, Richard S. Camuccio, Mario C. Diaz
Detecting Optical Transients Using Artificial Neural Networks And Reference Images From Different Surveys, Katarzyna Wardęga, Adam Zadrozny, Martin Beroiz, Richard S. Camuccio, Mario C. Diaz
Physics and Astronomy Faculty Publications and Presentations
We present a technique to detect optical transients based on an artificial neural networks method. We describe the architecture of two networks capable of comparing images of the same part of the sky taken by different telescopes. One image corresponds to the epoch in which a potential transient could exist; the other is a reference image of an earlier epoch. We use data obtained by the Dr. Cristina V. Torres Memorial Astronomical Observatory and archival reference images from the Sloan Digital Sky Survey. We trained a convolutional neural network and a dense layer network on simulated source samples and then …