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Articles 181 - 210 of 858
Full-Text Articles in Astrophysics and Astronomy
Computational And Experimental Study On Undoped And Er-Doped Lithium Tantalate Nanofluorescent Probes, Mkhitar A. Hobosyan, Andrea Pelayo Carvajal, Bhupendra B. Srivastava, Tamanna Zakia, Mohammed Uddin, Karen S. Martirosyan, Eric Rodriguez, Kofi Nketia Ackaah-Gyasi, Nicholas Dimakis
Computational And Experimental Study On Undoped And Er-Doped Lithium Tantalate Nanofluorescent Probes, Mkhitar A. Hobosyan, Andrea Pelayo Carvajal, Bhupendra B. Srivastava, Tamanna Zakia, Mohammed Uddin, Karen S. Martirosyan, Eric Rodriguez, Kofi Nketia Ackaah-Gyasi, Nicholas Dimakis
Physics & Astronomy Faculty Publications
We present a combined density functional theory (DFT) and experimental work on lithium tantalate LiTaO3 (LT) and its Er-doped counterparts. We calculate the electronic and optical properties for both LT and LT:Er+3, with Er occupying either Li or Ta sites, at 4.167 mol%. The generalized gradient approximation (GGA) calculations show that the Er-4 f bands appear closer to the conduction band bottom and to the valance band top, for the first and second doped configurations, respectively. This agrees with changes in the imaginary part of the frequency dependent dielectric function between the doped configurations. There are striking differences between the …
Dataset Of Optical And Electronic Properties For Mos2-Graphene Vertical Heterostructures And Mos2-Graphene-Au Heterointerfaces, Sanju Gupta, Panagiota Pimenidou, Miguel Garcia, Shivanshi Das, Nicholas Dimakis
Dataset Of Optical And Electronic Properties For Mos2-Graphene Vertical Heterostructures And Mos2-Graphene-Au Heterointerfaces, Sanju Gupta, Panagiota Pimenidou, Miguel Garcia, Shivanshi Das, Nicholas Dimakis
Physics & Astronomy Faculty Publications
The computational and experimental data presented in this paper refer to the research article "First-Principles Calculations Integrated with Experimental Optical and Electronic Properties for MoS2-graphene Heterostructures and MoS2-graphene-Au Heterointerfaces". The computational data includes structural information, electronic and optical properties, and data to calculate the work functions for various molybdenum disulfide and graphene heterostructures and their heterointerfaces with gold. The optical properties calculations include the frequency-dependent dielectric function, the refractive index, the reflectivity, the extinction coefficient, and the energy loss function. These properties were calculated using the independent particle approximation (IPA). As for the experimental optoelectronic properties, we measured photoluminescence spectra …
Open Data From The Third Observing Run Of Ligo, Virgo, Kagra, And Geo, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Open Data From The Third Observing Run Of Ligo, Virgo, Kagra, And Geo, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Physics & Astronomy Faculty Publications
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series …
A Method For Calculating Lateral Surface Area Of Bistatic Radar Beam Overlap, James I. Murray, Fredrick A. Jenet
A Method For Calculating Lateral Surface Area Of Bistatic Radar Beam Overlap, James I. Murray, Fredrick A. Jenet
Physics & Astronomy Faculty Publications
It has been shown that bistatic radars using radio telescopes as receivers can be used to increase the sensitivity of orbital debris measurements over traditional terrestrial monostatic radar. A method to calculate the lateral surface area of a bistatic radar is needed to evaluate the efficacy of a proposed bistatic radar configuration for orbital debris measurements. For over three decades, models of the orbital debris (OD) environment in low Earth orbit (LEO) have been developed to assess the risk posed by OD to spacecraft. While terrestrial radar measures debris 3 mm and larger and in situ measurements provide data for …
Noise Analysis Of The Indian Pulsar Timing Array Data Release I, Aman Srivastava, Shantanu Desai, Neel Kolhe, Mayuresh Surnis, Bhal Chandra Joshi, Abhimanyu Susobhanan, Aurélien Chalumeau, Shinnosuke Hisano, Nobleson K, Raghav Girgaonkar
Noise Analysis Of The Indian Pulsar Timing Array Data Release I, Aman Srivastava, Shantanu Desai, Neel Kolhe, Mayuresh Surnis, Bhal Chandra Joshi, Abhimanyu Susobhanan, Aurélien Chalumeau, Shinnosuke Hisano, Nobleson K, Raghav Girgaonkar
Physics & Astronomy Faculty Publications
The Indian Pulsar Timing Array (InPTA) collaboration has recently made its first official data release (DR1) for a sample of 14 pulsars using 3.5 years of uGMRT observations. We present the results of single-pulsar noise analysis for each of these 14 pulsars using the InPTA DR1. For this purpose, we consider white noise, achromatic red noise, dispersion measure (DM) variations, and scattering variations in our analysis. We apply Bayesian model selection to obtain the preferred noise models among these for each pulsar. For PSR J1600−3053, we find no evidence of DM and scattering variations, while for PSR J1909−3744, we find …
Optimizing Convolutional Neural Networks For Transient Detection In Optical Astronomy With Augmented Datasets, Wendy Mendoza
Optimizing Convolutional Neural Networks For Transient Detection In Optical Astronomy With Augmented Datasets, Wendy Mendoza
Theses and Dissertations
We present a technique for optical transient detection using artificial neural networks, particularly a Convolutional Neural Network (CNN), a deep learning algorithm. This method analyzes images of the same area of the sky captured by several telescopes, with one image serving as a reference for a probable transient’s epoch and the other as an image from a previous epoch. We train the CNN on simulated sources and test it on actual image data samples using data from the Dr. Cristina V. Torres Memorial Astronomical Observatory and Sloan Digital Sky Survey. This autonomous detection method replaces the standard procedure, which involves …
Observation Of Robust Zero Energy Extended States, Jannatul Ferdous, Cem Yuce, Andrea Alu, Hamidreza Ramezani
Observation Of Robust Zero Energy Extended States, Jannatul Ferdous, Cem Yuce, Andrea Alu, Hamidreza Ramezani
Physics & Astronomy Faculty Publications
Topological edge states arise at the interface of two topologically distinct structures and have two distinct features: they are localized and robust against symmetry protecting disorder. On the other hand, conventional transport in one dimension is associated with extended states, which typically do not have topological robustness. In this letter, using lossy coupled resonators in one dimension, we demonstrate both theoretically and experimentally the existence of robust states residing in the bulk. We show that they are unusually robust against disorders in coupling between adjacent sites and losses. Our work paves the way to a different form of robust transport …
Constraints On The Cosmic Expansion History From Gwtc–3, R. Abbott, H. Abe, F. Acernese, K. Ackley, N. Adhikari, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Constraints On The Cosmic Expansion History From Gwtc–3, R. Abbott, H. Abe, F. 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 use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming …
Photon Propagation In Magnetized Dense Quark Matter. A Possible Solution For The Missing Pulsar Problem., Efrain J. Ferrer
Photon Propagation In Magnetized Dense Quark Matter. A Possible Solution For The Missing Pulsar Problem., Efrain J. Ferrer
Physics & Astronomy Faculty Publications
In this paper it is reviewed the topological properties and possible astrophysical consequences of a spatially inhomogeneous phase of quark matter, known as the Magnetic Dual Chiral Density Wave (MDCDW) phase, that can exist at intermediate baryon density in the presence of a magnetic field. Going beyond mean-field approximation, it is shown how linearly polarized electromagnetic waves penetrating the MDCDW medium can mix with the phonon fluctuations to give rise to two hybridized modes of propagation called as axion polaritons because of their similarity with certain modes found in condensed matter for topological magnetic insulators. The formation of axion polaritons …
Exceptional Point Based Lattice Gyroscopes, Masoumeh Izadparast, Gururaj V. Naik, Henry O. Everitt, Hamidreza Ramezani
Exceptional Point Based Lattice Gyroscopes, Masoumeh Izadparast, Gururaj V. Naik, Henry O. Everitt, Hamidreza Ramezani
Physics & Astronomy Faculty Publications
Ring laser gyroscopes (RLGs) based on non-Hermitian exceptional points (EPs) have garnered much recent interest due to their exceptional sensitivity. Such gyroscopes typically consist of two-ring laser resonators, one with loss and one with an equal amount of optical gain. The coupling strength between these ring resonators is a key parameter determining the sensitivity of EP-based RLGs. Here we explore how the exceptional sensitivity demonstrated in this coupled dimer may be further enhanced by adding more dimers in an array. Specifically, we propose two types of ring laser gyroscope lattice arrays, each composed of N coupled dimers arrayed serially or …
Can The Mdcdw Condensate Withstand The Heat Of A Cold Neutron Star?, William Gyory
Can The Mdcdw Condensate Withstand The Heat Of A Cold Neutron Star?, William Gyory
Physics & Astronomy Faculty Publications
The correct description of strongly interacting matter at low temperatures and moderately high densities—in particular the conditions realized inside neutron stars—is still unknown. We review some recent results on the magnetic dual chiral density wave (MDCDW) phase, a candidate phase of quark matter for this region of the QCD phase diagram. We highlight the effects of magnetic fields and temperature on the condensate, which can be explored using a high-order Ginzburg-Landau (GL) expansion. We also explain how the condensate's nontrivial topology, which arises due to the asymmetry in the lowest Landau level modes, affects its physical properties. Finally, we comment …
Multimessenger Observations Of Double Neutron Stars In The Galactic Disk With Gravitational And Radio Waves, Wen-Fan Feng, Jie-Wen Chen, Yan Wang, Soumya D. Mohanty, Yong Shao
Multimessenger Observations Of Double Neutron Stars In The Galactic Disk With Gravitational And Radio Waves, Wen-Fan Feng, Jie-Wen Chen, Yan Wang, Soumya D. Mohanty, Yong Shao
Physics & Astronomy Faculty Publications
We evaluate the prospects for radio follow-up of the double neutron stars (DNSs) in the Galactic disk that could be detected through future space-borne gravitational wave (GW) detectors. We first simulate the DNS population in the Galactic disk that is accessible to space-borne GW detectors according to the merger rate from recent LIGO results. Using the inspiraling waveform for the eccentric binary, the average number of the DNSs detectable by TianQin (TQ), LISA, and TQ+LISA are 217, 368, and 429, respectively. For the joint GW detection of TQ+LISA, the forecasted parameter estimation accuracies, based on the Fisher information matrix, for …
A Stochastic Search For Intermittent Gravitational-Wave Backgrounds, Jessica Lawrence, Kevin Turbang, Andrew Matas, Arianna I. Renzini, Nick Van Remortel, Joseph D. Romano
A Stochastic Search For Intermittent Gravitational-Wave Backgrounds, Jessica Lawrence, Kevin Turbang, Andrew Matas, Arianna I. Renzini, Nick Van Remortel, Joseph D. Romano
Physics & Astronomy Faculty Publications
A likely source of a gravitational-wave background (GWB) in the frequency band of the Advanced LIGO, Virgo, and KAGRA detectors is the superposition of signals from the population of unresolvable stellar-mass binary-black-hole (BBH) mergers throughout the Universe. Since the duration of a BBH merger in band (similar to 1 s) is much shorter than the expected separation between neighboring mergers (similar to 103 s), the observed signal will be "popcornlike" or intermittent with duty cycles of order 10-3. However, the standard cross-correlation search for stochastic GWBs currently performed by the LIGO-Virgo-KAGRA Collaboration is based on a continuous-Gaussian signal model, which …
Glitch Subtraction From Gravitational Wave Data Using Adaptive Spline Fitting, Soumya D. Mohanty, Mohammad A. T. Chowdhury
Glitch Subtraction From Gravitational Wave Data Using Adaptive Spline Fitting, Soumya D. Mohanty, Mohammad A. T. Chowdhury
Physics & Astronomy Faculty Publications
Transient signals of instrumental and environmental origins ("glitches") in gravitational wave data elevate the false alarm rate of searches for astrophysical signals and reduce their sensitivity. Glitches that directly overlap astrophysical signals hinder their detection and worsen parameter estimation errors. As the fraction of data occupied by detectable astrophysical signals will be higher in next generation detectors, such problematic overlaps could become more frequent. These adverse effects of glitches can be mitigated by estimating and subtracting them out from the data, but their unpredictable waveforms and large morphological diversity pose a challenge. Subtraction of glitches using data from auxiliary sensors …
Evaluation Of Black Holes In An Evolving Universe, John P. Naan
Evaluation Of Black Holes In An Evolving Universe, John P. Naan
Theses and Dissertations
There are various solutions to the Einstein field equations that represent different physical assumptions, but how to represent multiple black holes within an expanding universe remains an area of open interest. The first step to resolving this question involves evaluating spacetime models that contain a single black hole in an expanding universe. Here, we are primarily interested in understanding the energy distribution of black hole models by solving Einstein's equations using the associated spacetime metric and comparing the propagation of waves within the model against other known spacetime models. Specifically, we will evaluate the combined Schwarschild-de Sitter solution under a …
Another Shipment Of Six Short-Period Giant Planets From Tess, Joseph E. Rodriguez, Samuel N. Quinn, Andrew Vanderburg, George Zhou, Jason D. Eastman, Erica Thygesen, Bryson Cale, David R. Ciardi, Phillip A. Reed, Ryan J. Oelkers
Another Shipment Of Six Short-Period Giant Planets From Tess, Joseph E. Rodriguez, Samuel N. Quinn, Andrew Vanderburg, George Zhou, Jason D. Eastman, Erica Thygesen, Bryson Cale, David R. Ciardi, Phillip A. Reed, Ryan J. Oelkers
Physics & Astronomy Faculty Publications
We present the discovery and characterization of six short-period, transiting giant planets from NASA’s Transiting Exoplanet Survey Satellite (TESS) -- TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), and TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9 <G < 11.8, 7.7 <K < 10.1). Using a combination of time-series photometric and spectroscopic follow-up observations from the TESS Follow-up Observing Program Working Group, we have determined that the planets are Jovian-sized (RP = 0.99--1.45 RJ), have masses ranging from 0.92 to 5.26 MJ, and orbit F, G, and K stars (4766 ≤ Teff ≤ 7360 K). We detect a significant orbital …
Non-Hermitian Edge Burst Without Skin Localization, Cem Yuce, Hamidreza Ramezani
Non-Hermitian Edge Burst Without Skin Localization, Cem Yuce, Hamidreza Ramezani
Physics & Astronomy Faculty Publications
In a class of non-Hermitian quantum walk in lossy lattices with open boundary conditions, an unexpected peak in the distribution of the decay probabilities appears at the edge, referred to as an edge burst. It is proposed that the edge burst originates jointly from the non-Hermitian skin effect (NHSE) and the imaginary gaplessness of the spectrum [W.-T. Xue et al., Phys. Rev. Lett. 128, 120401 (2022)]. Using a particular one-dimensional lossy lattice with a nonuniform loss rate, we show that the edge burst can occur even in the absence of skin localizations. Furthermore, we discuss that the edge …
Wallaby Pre-Pilot Survey: Radio Continuum Properties Of The Eridanus Supergroup, J. A. Grundy, O. I. Wong, K. Lee-Waddell, N. Seymour, B. -Q. For, C. Murugeshan, B. S. Koribalski, Juan P. Madrid, J. Rhee, T. Westmeier
Wallaby Pre-Pilot Survey: Radio Continuum Properties Of The Eridanus Supergroup, J. A. Grundy, O. I. Wong, K. Lee-Waddell, N. Seymour, B. -Q. For, C. Murugeshan, B. S. Koribalski, Juan P. Madrid, J. Rhee, T. Westmeier
Physics & Astronomy Faculty Publications
We present the highest resolution and sensitivity ∼ 1.4 GHz continuum observations of the Eridanus supergroup obtained as a part of the Widefield Australian Square Kilometer Array Pathfinder (ASKAP) L-band Legacy All-sky Blind surveY (WALLABY) pre-pilot observations using the ASKAP. We detect 9461 sources at 1.37 GHz down to a flux density limit of ∼ 0.1 mJy at 6.1′′×7.9′′ resolution with a median root mean square of 0.05 mJy beam −1 . We find that the flux scale is accurate to within 5 % (compared to NVSS at 1.4 GHz). We then determine the global properties of eight Eridanus supergroup …
Isolated And Dynamical Black Hole Mergers With B-Pop: The Role Of Star Formation And Dynamics, Star Cluster Evolution, Natal Kicks, Mass And Spins, And Hierarchical Mergers, Manuel Arca Sedda, Michaela Mapelli, Matthew Benacquista, Mario Spera
Isolated And Dynamical Black Hole Mergers With B-Pop: The Role Of Star Formation And Dynamics, Star Cluster Evolution, Natal Kicks, Mass And Spins, And Hierarchical Mergers, Manuel Arca Sedda, Michaela Mapelli, Matthew Benacquista, Mario Spera
Physics & Astronomy Faculty Publications
The current interpretation of LIGO–Virgo–KAGRA data suggests that the primary mass function of merging binary black holes (BBHs) at redshift z ≲ 1 contains multiple structures, while spins are relatively low. Theoretical models of BBH formation in different environments can provide a key to interpreting the population of observed mergers, but they require the simultaneous treatment of stellar evolution and dynamics, galaxy evolution, and general relativity. We present B-POP, a population synthesis tool to model BBH mergers formed in the field or via dynamical interactions in young, globular, and nuclear clusters. Using B-POP, we explore how black hole (BH) formation …
Population Of Merging Compact Binaries Inferred Using Gravitational Waves Through Gwtc-3, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang
Population Of Merging Compact Binaries Inferred Using Gravitational Waves Through Gwtc-3, R. Abbott, T. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wen Hui Wang
Physics & Astronomy Faculty Publications
We report on the population properties of compact binary mergers inferred from gravitational-wave observations of these systems during the first three LIGO-Virgo observing runs. The Gravitational-Wave Transient Catalog 3 (GWTC-3) contains signals consistent with three classes of binary mergers: binary black hole, binary neutron star, and neutron star–black hole mergers. We infer the binary neutron star merger rate to be between 10 and 1700 Gpc−3 yr−1 and the neutron star–black hole merger rate to be between 7.8 and 140 Gpc−3 yr−1, assuming a constant rate density in the comoving frame and taking the union of 90% credible intervals for methods …
Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh
Transport Effects In Non-Hermitian Nonreciprocal Systems: General Approach, Hamed Ghaemi-Dizicheh
Physics & Astronomy Faculty Publications
In this paper, we present a unifying analytical framework for identifying conditions for transport effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in non-Hermitian nonreciprocal systems using a generalized transfer matrix method. This provides a universal approach to studying the transport of tight-binding platforms, including higher-dimensional models and those with an internal degree of freedom going beyond the previously studied case of one-dimensional chains with nearest-neighbor couplings. For a specific class of tight-binding models, the relevant transport conditions and their signatures of non-Hermitian, nonreciprocal, and topological behavior are analytically tractable from a general perspective. We investigate …
Powerful Radio Sources In The Southern Sky. I. Optical Identifications, Francesco Massaro, S. V. White, A. García-Pérez, A. Jimenez-Gallardo, A. Capetti, C. C. Cheung, W. R. Forman, C. Mazzucchelli, A. Paggi, Juan P. Madrid
Powerful Radio Sources In The Southern Sky. I. Optical Identifications, Francesco Massaro, S. V. White, A. García-Pérez, A. Jimenez-Gallardo, A. Capetti, C. C. Cheung, W. R. Forman, C. Mazzucchelli, A. Paggi, Juan P. Madrid
Physics & Astronomy Faculty Publications
Since the early sixties, our view of radio galaxies and quasars has been drastically shaped by discoveries made thanks to observations of radio sources listed in the Third Cambridge Catalog and its revised version (3CR). However, the largest fraction of data collected to date on 3CR sources was performed with relatively old instruments, rarely repeated and/or updated. Importantly, the 3CR contains only objects located in the Northern Hemisphere, thus having limited access to new and innovative astronomical facilities. To mitigate these limitations, we present a new catalog of powerful radio sources visible from the Southern Hemisphere, extracted from the GLEAM …
A Candidate Magnetic Helium-Core White Dwarf In The Globular Cluster Ngc 6397, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. Maccarone, Rene D. Rohrmann, Craig O. Heinke, Diogo Belloni, Leandro G. Althaus, Arash Bahramian
A Candidate Magnetic Helium-Core White Dwarf In The Globular Cluster Ngc 6397, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. Maccarone, Rene D. Rohrmann, Craig O. Heinke, Diogo Belloni, Leandro G. Althaus, Arash Bahramian
Physics & Astronomy Faculty Publications
We report a peculiar variable blue star in the globular cluster (GC) NGC 6397, using Hubble Space Telescope optical imaging. Its position in the colour–magnitude diagrams and its spectrum are consistent with this star being a helium-core white dwarf (He WD) in a binary system. The optical light curve shows a periodicity at 18.5 h. We argue that this periodicity is due to the rotation of the WD and possibly due to magnetic spots on the surface of the WD. This would make this object the first candidate magnetic He WD in any GC, and the first candidate magnetic WD …
Non-Hermitian Floquet-Free Analytically Solvable Time-Dependent Systems, Hamed Ghaemi-Dizicheh, Hamidreza Ramezani
Non-Hermitian Floquet-Free Analytically Solvable Time-Dependent Systems, Hamed Ghaemi-Dizicheh, Hamidreza Ramezani
Physics & Astronomy Faculty Publications
The non-Hermitian models, which are symmetric under parity (P) and time-reversal (T) operators, are the cornerstone for the fabrication of new ultra-sensitive optoelectronic devices. However, providing the gain in such systems usually demands precise control of nonlinear processes, limiting their application. In this paper, to bypass this obstacle, we introduce a class of time-dependent non-Hermitian Hamiltonians (not necessarily Floquet) that can describe a two-level system with temporally modulated on-site potential and couplings. We show that implementing an appropriate non-Unitary gauge transformation converts the original system to an effective one with a balanced gain and loss. This …
Speed Of Sound For Hadronic And Quark Phases In A Magnetic Field, Efrain J. Ferrer, Aric Hackebill
Speed Of Sound For Hadronic And Quark Phases In A Magnetic Field, Efrain J. Ferrer, Aric Hackebill
Physics & Astronomy Faculty Publications
In this paper we calculate the speed of sound for three phases that may exist inside a magnetized hybrid neutron star at different density regions: A hadronic phase at low densities, quark-matter in the magnetic dual chiral density wave (MDCDW) phase at intermediate densities and a free-quark phase modeled by the MIT bag model at higher densities. It is found that the speed of sound exhibits a non-monotonic behavior, that goes from values smaller than the conformal limit ( c 2 s < 1 / 3 ) in the hadronic phase, to peak ( c 2 s > 1 / 3 ) in the MDCDW phase, to finally reach the conformal limit ( c 2 s …
Wallaby Pilot Survey: H I Gas Kinematics Of Galaxy Pairs In Cluster Environment, Shin-Jeong Kim, Se-Heon Oh, Jing Wang, Lister Staveley-Smith, Bärbel S. Koribalski, Minsu Kim, Hye-Jin Park, Shinna Kim, Kristine Spekkens, Juan P. Madrid
Wallaby Pilot Survey: H I Gas Kinematics Of Galaxy Pairs In Cluster Environment, Shin-Jeong Kim, Se-Heon Oh, Jing Wang, Lister Staveley-Smith, Bärbel S. Koribalski, Minsu Kim, Hye-Jin Park, Shinna Kim, Kristine Spekkens, Juan P. Madrid
Physics & Astronomy Faculty Publications
We examine the H I gas kinematics of galaxy pairs in two clusters and a group using Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot survey observations. We compare the H I properties of galaxy pair candidates in the Hydra I and Norma clusters, and the NGC 4636 group, with those of non-paired control galaxies selected in the same fields. We perform H I profile decomposition of the sample galaxies using a tool, BAYGAUD, which allows us to deblend a line-of-sight velocity profile with an optimal number of Gaussian components. We construct H I superprofiles of the sample galaxies via …
Effects Of Silicon Dioxide As The Polar Dielectric On The Infrared Absorption Spectrum Ofthemetal-Insulator-Metal Metasurface, Ahmad K. Jafari, Matthew Gaddy, Imtiaz Ahmad, Satya R. Kachiraju, M D. Borhan Mia, Ishtiaque Ahmed, Sergey Nikishin, Myoung-Hwan Kim, Ayrton A. Bernussi
Effects Of Silicon Dioxide As The Polar Dielectric On The Infrared Absorption Spectrum Ofthemetal-Insulator-Metal Metasurface, Ahmad K. Jafari, Matthew Gaddy, Imtiaz Ahmad, Satya R. Kachiraju, M D. Borhan Mia, Ishtiaque Ahmed, Sergey Nikishin, Myoung-Hwan Kim, Ayrton A. Bernussi
Physics & Astronomy Faculty Publications
Metal-insulator-metal metasurfaces have been widely used as high-performance absorbers in almost all electromagnetic spectral ranges. Their absorption spectra can be engineered by making variations in the geometry of the unit cells and/or by embedding materials with specific optical constants. Including a polar dielectric in their structure is another approach for manipulating their absorption spectra. In this research, we have numerically and experimentally investigated the effect of using silicon dioxide (SiO2) as a polar dielectric on the absorption spectrum of a metal-insulator-metal metasurface composed of a tri-layer of Ni-SiO2-Ni. Our results have shown the presence of …
The Importance Of The Pressure Anisotropy Induced By Strong Magnetic Fields On Neutron Star Physics, Efrain J. Ferrer, Aric Hackebill
The Importance Of The Pressure Anisotropy Induced By Strong Magnetic Fields On Neutron Star Physics, Efrain J. Ferrer, Aric Hackebill
Physics & Astronomy Faculty Publications
In this paper we discuss in some detail how the pressures determined from semi-classical statistical averaging of the energy momentum tensor in the presence of a uniform background magnetic field are anisotropic with different pressures arising along and perpendicular to the magnetic field direction. Hence, we analyze how this result can affect two important characteristics of dense magnetized systems: (i) The hadron-quark phase transition in the presence of a magnetic field, (ii) The behavior of the speed of sound in dense magnetized systems. Taking into account that large magnetic fields are expected to be present in the interior of neutron …
Model-Based Cross-Correlation Search For Gravitational Waves From The Low-Mass X-Ray Binary Scorpius X-1 In Ligo O3 Data, R. Abbott, H. Abe, Fausto Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Model-Based Cross-Correlation Search For Gravitational Waves From The Low-Mass X-Ray Binary Scorpius X-1 In Ligo O3 Data, R. Abbott, H. Abe, Fausto Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Physics & Astronomy Faculty Publications
We present the results of a model-based search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1 using LIGO detector data from the third observing run of Advanced LIGO and Advanced Virgo. This is a semicoherent search that uses details of the signal model to coherently combine data separated by less than a specified coherence time, which can be adjusted to balance sensitivity with computing cost. The search covered a range of gravitational-wave frequencies from 25 to 1600 Hz, as well as ranges in orbital speed, frequency, and phase determined from observational constraints. No significant detection candidates were …
Powerful Yet Lonely: Is 3c 297 A High-Redshift Fossil Group?, Valentina Missaglia, Juan P. Madrid, Mischa Schirmer, Francesco Massaro, Alberto Rodríguez-Ardila, Carlos J. Donzelli, Martell Valencia, Alessandro Paggi, Ralph P. Kraft, Chiara Stuardi, Belinda J. Wilkes
Powerful Yet Lonely: Is 3c 297 A High-Redshift Fossil Group?, Valentina Missaglia, Juan P. Madrid, Mischa Schirmer, Francesco Massaro, Alberto Rodríguez-Ardila, Carlos J. Donzelli, Martell Valencia, Alessandro Paggi, Ralph P. Kraft, Chiara Stuardi, Belinda J. Wilkes
Physics & Astronomy Faculty Publications
The environment of the high-redshift (z = 1.408), powerful radio-loud galaxy 3C 297 has several distinctive features of a galaxy cluster. Among them, a characteristic halo of hot gas revealed by Chandra X-ray observations. In addition, a radio map obtained with the Very Large Array shows a bright hotspot in the northwestern direction, created by the interaction of the active galactic nucleus (AGN) jet arising from 3C 297 with its environment. In the X-ray images, emission cospatial with the northwestern radio lobe is detected, and peaks at the position of the radio hotspot. The extended, complex X-ray emission observed …