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Articles 31 - 60 of 601
Full-Text Articles in Physics
All-Sky Search For Long-Duration Gravitational-Wave Transients In The First Part Of The Fourth Ligo-Virgo-Kagra Observing Run, A. G. Abac, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, Raul A. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
All-Sky Search For Long-Duration Gravitational-Wave Transients In The First Part Of The Fourth Ligo-Virgo-Kagra Observing Run, A. G. Abac, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, Raul A. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Physics & Astronomy Faculty Publications
We present an all-sky search for long-duration gravitational waves (GWs) from the first part of the LIGO-Virgo-KAGRA fourth observing run (O4), called O4a and comprising data taken between May 24, 2023, and January 16, 2024. The GW signals targeted by this search are the so-called “long-duration” ( ≳1 s) transients expected from a variety of astrophysical processes, including nonaxisymmetric deformations in magnetars or eccentric binary coalescences. We make minimal assumptions on the emitted GW waveforms in terms of morphologies and durations. Overall, our search targets signals with durations of ∼1–1000 s and frequency content in the range 16–2048 Hz. In …
Negative Superfluid Density And Spatial Instabilities In Driven Superconductors, Andrey Grankin, Victor Galitski, Vadim Oganesyan
Negative Superfluid Density And Spatial Instabilities In Driven Superconductors, Andrey Grankin, Victor Galitski, Vadim Oganesyan
Physics & Astronomy Faculty Publications
We consider the excitation of Higgs modes via the modulation of the Bardeen-Cooper-Schrieffer coupling within the Migdal-Eliashberg-Keldysh theory of time-dependent superconductivity. Despite the presence of phonons, which break integrability, we observe Higgs amplitude oscillations reminiscent of the integrable case. The dynamics of quasiparticles follows from the effective Bogolyubov–de Gennes (BdG) equations, which represent a Floquet problem for the Bogolyubov quasiparticles. We find that when the Floquet-Bogolyubov bands overlap, the homogeneous solution formally leads to a negative superfluid density, which is no longer proportional to the amplitude of the order parameter. This result indicates an instability, which we explore using spatially …
Discovery Of A New Cataclysmic Variable, Galex J211240.9–422959, Via The Exoasteroids Citizen Science Project, Mei Lin, Aaron Meisner, Siyi Xu, Arttu Sainio, Liliana E. Rivera Sandoval, Paula Szkody, Christopher Tanner, Laura K. Rogers, Sarah Casewell, Austin Humphreys
Discovery Of A New Cataclysmic Variable, Galex J211240.9–422959, Via The Exoasteroids Citizen Science Project, Mei Lin, Aaron Meisner, Siyi Xu, Arttu Sainio, Liliana E. Rivera Sandoval, Paula Szkody, Christopher Tanner, Laura K. Rogers, Sarah Casewell, Austin Humphreys
Physics & Astronomy Faculty Publications
We report the discovery and spectroscopic classification of a new cataclysmic variable (CV), GALEX J211240.9–422959 (Gaia DR3 source ID 6580244356829724928). This object was initially identified as a source exhibiting strong mid-infrared variability in Wide-field Infrared Survey Explorer (WISE) time-series data by a volunteer participating in the Exoasteroids citizen science project. Prompted by this strong variability at 3–5 μm, we obtained a follow-up optical spectrum using the Gemini Multi-Object Spectrograph at the Gemini South Observatory. The resulting spectrum displays a blue continuum dominated by strong, broad emission lines of the hydrogen Balmer series and neutral helium, spectral signatures characteristic of …
Antimicrobial Performance Of Amorphous Vs. Crystalline La1-Xsrxcoo3 Perovskites, S. M. Au Shohag, Fahmida Akhter, Ahmed Touhami, Swati Mohan, Md. Wasikur Rahman, Mohammed Jasim Uddin
Antimicrobial Performance Of Amorphous Vs. Crystalline La1-Xsrxcoo3 Perovskites, S. M. Au Shohag, Fahmida Akhter, Ahmed Touhami, Swati Mohan, Md. Wasikur Rahman, Mohammed Jasim Uddin
Physics & Astronomy Faculty Publications
Perovskite materials, with their unique crystal structure and chemical properties, are emerging as promising antimicrobial agents for potential biomedical applications. In this research, different weight percentages of Sr2 + doped amorphous and crystalline Lanthanum Cobaltite (La1-xSrxCoO3 defined as LSCO) (x = 0, 0.025, 0.05, 0.1, and 0.15) perovskite was synthesized by using a simple combination of sol-gel and molten-salt processes and characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM) ensures the uniform morphology of the materials. During antimicrobial study using the Kirby Bauer method, amorphous LSCO showed much better activity than crystalline LSCO against Escherichia coli, Vibrio …
A Search For Magnetically Active Binary Counterparts To Chandra X-Ray Sources In 47 Tucanae With Hst Imaging, Haldan N. Cohn, Phyllis M. Lugger, Craig O. Heinke, Maureen Van Den Berg, Liliana Rivera Sandoval, Jay Anderson
A Search For Magnetically Active Binary Counterparts To Chandra X-Ray Sources In 47 Tucanae With Hst Imaging, Haldan N. Cohn, Phyllis M. Lugger, Craig O. Heinke, Maureen Van Den Berg, Liliana Rivera Sandoval, Jay Anderson
Physics & Astronomy Faculty Publications
Using Hubble Space Telescope (HST) imaging, we searched for candidate magnetically active binary (AB) counterparts to low-luminosity Chandra X-ray sources in the globular cluster 47 Tucanae (NGC 104). We consider the catalog of 300 Chandra sources within the half-light radius of 47 Tuc compiled by C. O. Heinke et al. (2005). The 10-band HST imaging used to identify these sources spans the range from 275–658 nm. We generated a cross-matched catalog of objects detected by photometric reductions. We used this catalog to search for counterparts within Chandra source error circles using color–magnitude diagrams and a color–color plot. We …
Non-Hermitian Sl (3, C) Three-Mode Couplers, B. M. Rodríguez-Lara, Hamed Ghaemi-Dizicheh, Shahram Dehdashti, Andreas Hanke, Ahmed Touhami, J. Nötzel
Non-Hermitian Sl (3, C) Three-Mode Couplers, B. M. Rodríguez-Lara, Hamed Ghaemi-Dizicheh, Shahram Dehdashti, Andreas Hanke, Ahmed Touhami, J. Nötzel
Physics & Astronomy Faculty Publications
Photonic systems with exceptional points, where eigenvalues and corresponding eigenstates coalesce, have attracted interest due to their topological features and enhanced sensitivity to external perturbations. Non-Hermitian mode-coupling matrices provide a tractable analytic framework to model gain, loss, and chirality across optical, electronic, and mechanical platforms without the complexity of full open-system dynamics. Exceptional points define their spectral topology, and enable applications in mode control, amplification, and sensing. Yet N -mode couplers, the minimal setting for N th-order exceptional points, are often studied in specific designs that overlook their algebraic structure. We introduce a general sl(N , C) framework for arbitrary …
A Study Of Transients From Ground-Based Surveys Reveals New Ultra-Compact Accreting White Dwarf Binaries, Jan Kára, Liliana E. Rivera Sandoval, Wendy Mendoza, Thomas J. Maccarone, Manuel Pichardo Marcano, Luis Salazar Manzano, Ryan J. Oelkers, Jan Van Roestel
A Study Of Transients From Ground-Based Surveys Reveals New Ultra-Compact Accreting White Dwarf Binaries, Jan Kára, Liliana E. Rivera Sandoval, Wendy Mendoza, Thomas J. Maccarone, Manuel Pichardo Marcano, Luis Salazar Manzano, Ryan J. Oelkers, Jan Van Roestel
Physics & Astronomy Faculty Publications
AM CVn stars are ultra-compact semi-detached binaries consisting of a white dwarf primary and a hydrogen-depleted secondary. In this paper, we present spectroscopic and photometric results of 15 transient sources pre-classified as AM CVn candidates. Our analysis confirms 9 systems of the type AM CVn, 3 hydrogen-rich cataclysmic variables (accreting white dwarfs with near-main-sequence stars for donors), and 3 systems that could be evolved cataclysmic variables. Eight of the AM CVn stars are analysed spectroscopically for the first time, which increases the number of spectroscopically confirmed AM CVns by about 10%. TESS data revealed the orbital period of the AM …
Bacillus Subtilis Parb C-Terminal Lysine Residues Are Essential For Dimerization And In Vivo Function, Indicating Their Roles In Dna Sliding, Aleksey Aleshintsev, Lindsey E. Way, Ngoc Khanh Lai, Bianca Guerra, Paloma Dorantes, Lois Akosua Serwaa, Sealtiel Anulao, Miranda Molina, Xindan Wang, Hyeongjun Kim
Bacillus Subtilis Parb C-Terminal Lysine Residues Are Essential For Dimerization And In Vivo Function, Indicating Their Roles In Dna Sliding, Aleksey Aleshintsev, Lindsey E. Way, Ngoc Khanh Lai, Bianca Guerra, Paloma Dorantes, Lois Akosua Serwaa, Sealtiel Anulao, Miranda Molina, Xindan Wang, Hyeongjun Kim
Physics & Astronomy Faculty Publications
The broadly conserved ParB protein performs crucial functions in bacterial chromosome segregation and replication regulation. The cellular function of ParB requires it to dimerize, recognize parS DNA sequences, clamp on DNA, then slide to adjacent sequences through nonspecific DNA binding. How ParB coordinates nonspecific DNA binding and sliding remains elusive. Here, we combine multiple in vitro biophysical and computational tools and in vivo approaches to address this question. We found that five conserved lysine residues in the C-terminal domain (CTD) of ParB play distinct roles. While the two central rigid lysine residues provide the structural platform for the CTD, the …
Integrable-To-Thermalizing Crossover In Nonequilibrium Superconductors, Andrey Grankin, Victor Galitski
Integrable-To-Thermalizing Crossover In Nonequilibrium Superconductors, Andrey Grankin, Victor Galitski
Physics & Astronomy Faculty Publications
Motivated by the experiment by Budden et al. [Nat. Phys. 17, 611 (2021)], who observed signatures of long-lived photoinduced superconductivity, we develop an accurate analytical and computational approach to nonequilibrium superconductivity following a quench. We consider the BCS-Holstein model, which includes both integrable local electron-electron interactions and integrability-breaking electron-phonon coupling. We develop the Keldysh-Eliashberg theory on the Kadanoff-Baym contour, which enables us to describe nonequilibrium dynamics of the superconductor. We consider a quench in interactions, which results in a dynamic transition from the initial superconducting state to a normal thermal state in the end of the evolution. It …
Anomalous Spontaneous Induction Of Magnetic And Electric Fields In Dense Quark Matter, Efrain J. Ferrer, Jose Miguel Perez-Fernandez
Anomalous Spontaneous Induction Of Magnetic And Electric Fields In Dense Quark Matter, Efrain J. Ferrer, Jose Miguel Perez-Fernandez
Physics & Astronomy Faculty Publications
In this paper, we will demonstrate that a dense quark-matter system in the dual chiral density wave (DCDW) phase behaves as a ferromagnet in the sense that its magnetic-field dependent magnetization remains different from zero even at 𝐵 →0. The corresponding permanent magnetization is a function of the baryonic chemical potential 𝜇, decreasing up to zero as 𝜇 increases in the range of intermediate densities (312 MeV⩽𝜇⩽342 MeV) and then increasing from zero in the higher density interval 490 MeV⩽𝜇⩽550 MeV. We will show that this system’s ability to generate permanent magnetization, together with the existence of the axial anomaly, …
A 682-Second X-Ray Periodicity In Ch Cygni: Evidence For A Magnetic White Dwarf, Manuel Pichardo Marcano, Thomas J. Maccarone, Liliana E. Rivera Sandoval
A 682-Second X-Ray Periodicity In Ch Cygni: Evidence For A Magnetic White Dwarf, Manuel Pichardo Marcano, Thomas J. Maccarone, Liliana E. Rivera Sandoval
Physics & Astronomy Faculty Publications
Symbiotic stars are interacting binaries consisting of a red giant and typically a white dwarf (WD), which are important as potential Type Ia supernova progenitors. Despite theoretical predictions that WDs in symbiotic systems should often be magnetic, direct evidence has been elusive. We report the discovery of a 682.5 ± 7 s periodicity in the XMM–Newton X-ray light curve that we interpret as the spin period of the WD in CH Cygni. This detection provides strong evidence for a magnetic WD in CH Cygni, making it only the second WD symbiotic star with confirmed X-ray pulsations after R Aquarii. Our …
Kinematic Anisotropies In Pta Observations: Analytical Toolkit, Maximilian Blümke, Kai Schmitz, Tobias Schröder, Deepali Agarwal, Joseph D. Romano
Kinematic Anisotropies In Pta Observations: Analytical Toolkit, Maximilian Blümke, Kai Schmitz, Tobias Schröder, Deepali Agarwal, Joseph D. Romano
Physics & Astronomy Faculty Publications
The reported evidence for an isotropic gravitational-wave background (GWB) from pulsar timing array (PTA) collaborations has motivated searches for extrinsic and intrinsic anisotropies. Kinematic anisotropies may arise as a consequence of a boosted observer moving with respect to the frame in which the GWB appears isotropic. In this work, we present an analytical toolbox to describe the effects of kinematic anisotropies on the overlap reduction function. Our analytical results differ from previous findings at the quadrupole order and are detailed in three appendices. For the first time, we also derive the corresponding auto-correlation using two approaches, taking the pulsar distances …
A Solution To The Tension Of Burning On Neutron Stars And Nuclear Physics, Yuri Cavecchi, D. K. Galloway, A. Heger, P. Santillán-Ortega, M. Nava-Callejas, F. M. Vincentelli, Liliana E. Rivera Sandoval, A. Goodwin, Z. Johnston
A Solution To The Tension Of Burning On Neutron Stars And Nuclear Physics, Yuri Cavecchi, D. K. Galloway, A. Heger, P. Santillán-Ortega, M. Nava-Callejas, F. M. Vincentelli, Liliana E. Rivera Sandoval, A. Goodwin, Z. Johnston
Physics & Astronomy Faculty Publications
When neutron stars accrete matter from a companion star, this matter forms a disk around them and eventually falls on their surface. Here, the fuel can ignite into bright flashes called Type I bursts. Theoretical calculations based on state-of-the-art nuclear reactions are able to explain many features of the bursts. However, models predict that the bursts should cease at high accretion rates, whereas in many sources they disappear at much lower rates. Moreover, their recurrence times also show strong discrepancies with predictions. Although various solutions have been proposed, none can account for all the observational constraints. Here, we describe a …
Black Hole Spectroscopy And Tests Of General Relativity With Gw250114, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Black Hole Spectroscopy And Tests Of General Relativity With Gw250114, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Physics & Astronomy Faculty Publications
The binary black hole signal GW250114, the loudest gravitational wave detected to date, offers a unique opportunity to test Einstein’s general relativity (GR) in the high-velocity, strong-gravity regime and probe whether the remnant conforms to the Kerr metric. Upon perturbation, black holes emit a spectrum of damped sinusoids with specific, complex frequencies. Our analysis of the postmerger signal shows that at least two quasinormal modes are required to explain the data, with the most damped remaining statistically significant for about one cycle. We probe the remnant’s Kerr nature by constraining the spectroscopic pattern of the dominant quadrupolar (ℓ =𝑚 =2) …
A Transferable Force Field For Simulating Adsorption In Metal–Organic Frameworks With Open Metal Sites Based On The 12–6–4 Lennard-Jones Potential, Meng Du, Alan Rodriguez, Matthew Z. Lin, Haoyuan Chen
A Transferable Force Field For Simulating Adsorption In Metal–Organic Frameworks With Open Metal Sites Based On The 12–6–4 Lennard-Jones Potential, Meng Du, Alan Rodriguez, Matthew Z. Lin, Haoyuan Chen
Physics & Astronomy Faculty Publications
Metal–organic frameworks (MOFs) that contain coordinatively unsaturated open metal sites (OMSs) provide strong host–guest interactions, making them promising sorbents for low-concentration gas adsorption applications such as direct air capture and atmospheric water harvesting. However, accurately modeling host–guest interactions involving OMSs remains challenging for classical force fields (FFs) based on the 12–6 Lennard–Jones (LJ) potential, as the polarization effect of the guest molecule induced by the positively charged OMS is not considered. Here, we introduce an FF based on the 12–6–4 LJ potential, which incorporates charge–induced dipole interactions and is parametrized against a diverse set of host–guest potential energy surfaces (PESs) …
Spectroscopic Investigations On Polyvinylidene Fluoride Nanofibers, Parinaz Amaniabdolmalaki, Jui Vitthal Kharade, Alexandro Trevino, Lydia Morales, Karen Lozano, Victoria Padilla, Karen S. Martirosyan, Horacio Vasquez, Mircea Chipara
Spectroscopic Investigations On Polyvinylidene Fluoride Nanofibers, Parinaz Amaniabdolmalaki, Jui Vitthal Kharade, Alexandro Trevino, Lydia Morales, Karen Lozano, Victoria Padilla, Karen S. Martirosyan, Horacio Vasquez, Mircea Chipara
Physics & Astronomy Faculty Publications
The production of polyvinylidene fluoride nanofibers by force-spinning from polymer solutions was confirmed by electron microscopy. The structural and phase characteristics of the resulting nanofiber mats were examined using Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode, Raman spectroscopy, and X-ray Diffraction. Results from all these techniques consistently indicated that both the powder and the mats of polyvinylidene fluoride predominantly contain the α phase, with a small admixture of the β phase. Within experimental errors, no other phases were noticed both in the powder and in the as-obtained mats. The ratios of the areas of the Raman lines at …
Gpu And Pso Accelerated Low-Latency Fully-Coherent All-Sky Search For Compact Binary Coalescences, Soumya D. Mohanty
Gpu And Pso Accelerated Low-Latency Fully-Coherent All-Sky Search For Compact Binary Coalescences, Soumya D. Mohanty
Physics & Astronomy Faculty Publications
The fully-coherent all-sky (FCAS) search, which combines data from a gravitational wave detector network into a single likelihood function, is the preferred method prescribed by statistical theory for Gaussian noise. However, so far, its exorbitant computational cost has blocked its use for compact binary coalescence searches. We introduce a solution combining Particle Swarm Optimization with Graphics Processing Unit (GPU) acceleration that is ≈ 50-fold faster than real-time analysis. This transforms the prospect of a low-latency FCAS search on all GW data into a practical reality for the first time. With large-scale simulations enabled by this speedup, we examine the issue …
Scalable Continuous Gravitational Wave Detection In Pta Data With Nonparametric Red Noise Suppression And Optimal Pulsar Selection, Yi-Qian Qian, Yan Wang, Soumya Mohanty, Siyuan Chen
Scalable Continuous Gravitational Wave Detection In Pta Data With Nonparametric Red Noise Suppression And Optimal Pulsar Selection, Yi-Qian Qian, Yan Wang, Soumya Mohanty, Siyuan Chen
Physics & Astronomy Faculty Publications
Bayesian methods for the detection of continuous gravitational waves (CGWs) in pulsar timing array (PTA) data incur substantial computational costs that grow rapidly due to the number of noise and signal parameters characterizing the fitted model being proportional to the size of the PTA. This computational burden limits the scalability of these methods for large-scale PTAs comprising hundreds of pulsars anticipated from next-generation radio astronomy facilities. In this work, we introduce a computationally efficient frequentist method designed to circumvent this challenge. This is achieved by combining an adaptive spline fitting algorithm that nonparametrically suppresses red noise, thereby eliminating the need …
Gauge-Invariant Gravitational Wave Polarization In Metric F(R) Gravity With Cosmological Implications, Ramesh Radhakrishnan, David Mcnutt, Delaram Mirfendereski, Alejandro Pinero, Eric Davis, William Julius, Gerald Cleaver
Gauge-Invariant Gravitational Wave Polarization In Metric F(R) Gravity With Cosmological Implications, Ramesh Radhakrishnan, David Mcnutt, Delaram Mirfendereski, Alejandro Pinero, Eric Davis, William Julius, Gerald Cleaver
Physics & Astronomy Faculty Publications
We develop a fully gauge-invariant analysis of gravitational-wave polarizations in metric 𝑓(𝑅) gravity with a particular focus on the modified Starobinsky model 𝑓(𝑅) =𝑅 +𝛼𝑅2 −2Λ, whose constant-curvature solution 𝑅𝑑 =4Λ provides a natural de Sitter background for both early- and late-time cosmology. Linearizing the field equations around this background, we derive the Klein–Gordon equation for the curvature perturbation 𝛿𝑅 and show that the scalar propagating mode acquires a mass 𝑚2𝜓 =1/(6𝛼), highlighting how the same scalar degree of freedom governs inflationary dynamics at high curvature and the propagation of gravitational waves in the current accelerating Universe. Using the scalar–vector–tensor …
Efficient Search For Detection Candidates Using A Peak Finder Strategy For All-Sky-All-Frequency Gravitational Wave Radiometer, Arindam Sharma, Deepali Agarwal, Sanjit Mitra
Efficient Search For Detection Candidates Using A Peak Finder Strategy For All-Sky-All-Frequency Gravitational Wave Radiometer, Arindam Sharma, Deepali Agarwal, Sanjit Mitra
Physics & Astronomy Faculty Publications
The first all-sky-all-frequency (ASAF) radiometer search was conducted using data from the first three observing runs of the Advanced LIGO and Advanced Virgo detectors. The significance of this search lies in its fast and unmodeled approach, leveraging a cross-correlation technique to identify common signals across the detector network. As a result, this method serves as an excellent alternative to search for unknown or poorly modeled continuous wave sources and narrow band components of the gravitational wave (GW) background. For continuous wave sources whose waveform can be modeled, this method can serve as the first stage of a hierarchical scheme by …
Gwtc-4.0: An Introduction To Version 4.0 Of The Gravitational-Wave Transient Catalog, A. G. Abac, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Gwtc-4.0: An Introduction To Version 4.0 Of The Gravitational-Wave Transient Catalog, A. G. Abac, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Wenhui Wang
Physics & Astronomy Faculty Publications
The Gravitational-Wave Transient Catalog (GWTC) is a collection of short-duration (transient) gravitational-wave signals identified by the LIGO–Virgo–KAGRA Collaboration in gravitational-wave data produced by the eponymous detectors. The catalog provides information about the identified candidates, such as the arrival time and amplitude of the signal and properties of the signal’s source as inferred from the observational data. GWTC is the data release of this dataset, and version 4.0 extends the catalog to include observations made during the first part of the fourth LIGO–Virgo–KAGRA observing run up until 2024 January 31. This Letter marks an introduction to a collection of articles related …
Adsorption-Photodegradation Performance Of Silver Titanate For Methylene Blue Removal: Kinetics, Thermodynamics And Isotherm Studies, Nawrin Rahman Shefa, Most. Afroza Khatun, Ahmed Hasnain Jalal, M. Jasim Uddin, Md. Wasikur Rahman
Adsorption-Photodegradation Performance Of Silver Titanate For Methylene Blue Removal: Kinetics, Thermodynamics And Isotherm Studies, Nawrin Rahman Shefa, Most. Afroza Khatun, Ahmed Hasnain Jalal, M. Jasim Uddin, Md. Wasikur Rahman
Physics & Astronomy Faculty Publications
Silver titanate (AgTO) was synthesized via an ion-exchange reaction between sodium titanate and silver nitrate. This study investigates the efficiency of AgTO in the combined adsorption-photodegradation process for removing Methylene Blue (MB). The synthesized material was characterized using FTIR, XRD, SEM, and EDX techniques. Batch adsorption experiments were conducted to assess the effects of AgTO dosage (0.1–1.0 g/L), initial MB concentration (5–20 mg/L), pH (3–11), and temperature (313–333 K). The highest MB removal efficiency (90 %) was achieved at 313 K, pH 3, and an initial MB concentration of 5 mg/L. The photocatalytic performance of AgTO was further evaluated under …
Converging On The Cepheid Metallicity Dependence: Implications Of Nonstandard Gaia Parallax Recalibration On Distance Measures, Louise Breuval, Gagandeep S. Anand, Richard I. Anderson, Rachael Beaton, Anupam Bhardwaj, Stefano Casertano, Gisella Clementini, Mauricio Cruz Reyes, Giulia De Somma, Lucas M. Macri
Converging On The Cepheid Metallicity Dependence: Implications Of Nonstandard Gaia Parallax Recalibration On Distance Measures, Louise Breuval, Gagandeep S. Anand, Richard I. Anderson, Rachael Beaton, Anupam Bhardwaj, Stefano Casertano, Gisella Clementini, Mauricio Cruz Reyes, Giulia De Somma, Lucas M. Macri
Physics & Astronomy Faculty Publications
By comparing Cepheid brightnesses with geometric distance measures including Gaia EDR3 parallaxes, most recent analyses conclude metal-rich Cepheids are brighter, quantified as γ ∼ −0.2 mag dex−1 . While the value of γ has little impact on the determination of the Hubble constant in contemporary distance ladders (due to the similarity of metallicity across these ladders), γ plays a role in gauging the distances to metal-poor dwarf galaxies like the Magellanic Clouds and is of considerable interest in testing stellar models. Recently, B. F. Madore & W. L. Freedman (hereafter MF25) recalibrated Gaia EDR3 parallaxes by adding to them a …
Thermodynamic Feasibility Of Nanoenergetic Systems Based On Metal Oxynitrides, Manoj Chhetri, Mkhitar A. Hobosyan, Maxim Zyskin, Karen S. Martirosyan
Thermodynamic Feasibility Of Nanoenergetic Systems Based On Metal Oxynitrides, Manoj Chhetri, Mkhitar A. Hobosyan, Maxim Zyskin, Karen S. Martirosyan
Physics & Astronomy Faculty Publications
A comprehensive computational study was conducted to identify and evaluate nano-energetic systems utilizing aluminum (Al) as the fuel and a range of metal oxynitrides as oxidizers. The primary objective was to determine combinations that yield highly exothermic reactions, specifically those that maximize gas generation, adiabatic combustion temperature, and energy release. These parameters are critical for optimizing the performance of energetic materials in applications such as controlled energy delivery, propulsion, and pyrotechnics. By systematically analyzing thermodynamic properties including the heat of formation, enthalpy of reaction, Gibbs free energy, and equilibrium reaction products across a range of Al/oxynitride stoichiometries, the study aimed …
Likelihoods For Stochastic Gravitational Wave Background Data Analysis, Gabriele Franciolini, Mauro Pieroni, Angelo Ricciardone, Joseph D. Romano
Likelihoods For Stochastic Gravitational Wave Background Data Analysis, Gabriele Franciolini, Mauro Pieroni, Angelo Ricciardone, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present a systematic study of likelihood functions used for stochastic gravitational wave background (SGWB) searches. By dividing the data into many short segments, one customarily takes advantage of the central limit theorem to justify a Gaussian cross-correlation likelihood. We show, with a hierarchy of ever more realistic examples—beginning with a single frequency bin and one detector, and then moving to two and three detectors with white and colored signal and noise—that approximating the exact Whittle likelihood by various Gaussian alternatives can induce systematic biases in the estimation of the SGWB parameters. We derive several approximations for the full likelihood …
Gw241011 And Gw241110: Exploring Binary Formation And Fundamental Physics With Asymmetric, High-Spin Black Hole Coalescences, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Gw241011 And Gw241110: Exploring Binary Formation And Fundamental Physics With Asymmetric, High-Spin Black Hole Coalescences, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Physics & Astronomy Faculty Publications
We report the observation of gravitational waves from two binary black hole coalescences during the fourth observing run of the LIGO–Virgo–KAGRA detector network, GW241011 and GW241110. The sources of these two signals are characterized by rapid and precisely measured primary spins, nonnegligible spin–orbit misalignment, and unequal mass ratios between their constituent black holes. These properties are characteristic of binaries in which the more massive object was itself formed from a previous binary black hole merger and suggest that the sources of GW241011 and GW241110 may have formed in dense stellar environments in which repeated mergers can take place. As the …
Constraining Deviations From The Kerr Metric Via A Bumpy Parametrization And Particle Swarm Optimization In Extreme Mass-Ratio Inspirals, Xiaobo Zou, Xingyu Zhong, Wen-Biao Han, Soumya D. Mohanty
Constraining Deviations From The Kerr Metric Via A Bumpy Parametrization And Particle Swarm Optimization In Extreme Mass-Ratio Inspirals, Xiaobo Zou, Xingyu Zhong, Wen-Biao Han, Soumya D. Mohanty
Physics & Astronomy Faculty Publications
The measurement of deviations in the Kerr metric using gravitational-wave observations will provide a clear signal of new physics. Previous studies have developed multiple parametrizations (e.g., “bumpy” spacetime) to characterize such deviations in extreme mass-ratio inspirals (EMRIs). These approaches often rely on the Fisher information matrix (FIM) formalism to quantify the constraining power of future space-borne gravitational-wave detectors, such as LISA and Tianqin. For instance, using the analytical kludge waveform model under varying source configurations, such methods have achieved constraint sensitivity levels ranging from 10−4 to 10−2 on the dimensionless bumpy parameter 𝛿˜𝑄 for LISA. In this paper, we advance …
Gw231123: A Binary Black Hole Merger With Total Mass 190–265 M⊙, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Gw231123: A Binary Black Hole Merger With Total Mass 190–265 M⊙, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, R. Espinosa, J. Lawrence, Francisco Llamas Villarreal, Soma Mukherjee, Volker Quetschke, Miriam Ramos Arevalo, Wenhui Wang
Physics & Astronomy Faculty Publications
On 2023 November 23 the two LIGO observatories both detected GW231123, a gravitational-wave signal consistent with the merger of two black holes with masses and (90\% credible intervals), at luminosity distance 0.7-4.1 Gpc and redshift of , and a network signal-to-noise ratio of 20.7. Both black holes exhibit high spins, and respectively. A massive black hole remnant is supported by an independent ringdown analysis. Some properties of GW231123 are subject to large systematic uncertainties, as indicated by differences in inferred parameters between signal models. The primary black hole lies within or above the theorized mass gap where black holes between …
The Perfect Host: Jwst Cepheid Observations In A Background-Free Type Ia Supernova Host Confirm No Bias In Hubble-Constant Measurements, Adam G. Riess, Siyang Li, Gagandeep S. Anand, Wenlong Yuan, Louise Breuval, Stefano Casertano, Lucas M. Macri, Dan Scolnic, Yukei S. Murakami, Alexei V. Filippenko
The Perfect Host: Jwst Cepheid Observations In A Background-Free Type Ia Supernova Host Confirm No Bias In Hubble-Constant Measurements, Adam G. Riess, Siyang Li, Gagandeep S. Anand, Wenlong Yuan, Louise Breuval, Stefano Casertano, Lucas M. Macri, Dan Scolnic, Yukei S. Murakami, Alexei V. Filippenko
Physics & Astronomy Faculty Publications
Cycle 1 JWST observations of Cepheids in Type Ia supernova (SN Ia) hosts resolved their red-giant-dominated near-infrared backgrounds, sharply reducing crowding and showing that photometric bias in lower-resolution Hubble Space Telescope (HST) data does not account for the Hubble tension. We present cycle 2 JWST observations of >100 Cepheids in NGC 3447, a unique system that pushes this test to the limit by transitioning from low to no background contamination. NGC 3447, an SN Ia host at D ≈ 25 Mpc, is an interacting pair comprising (i) a spiral with mixed stellar populations, typical of H0 calibrators, and (ii) a …
Tess Light Curves And Period Changes In Low-Mass Eclipsing Binary Bb Persei, Marek Wolf, Petr Zasche, Miloslav Zejda, Martin Mašek, Andrej Mudray, Hana Kučáková, Waldemar Ogłoza, Jaroslav Merc, Jan Kára, Vojtěch Dienstbier
Tess Light Curves And Period Changes In Low-Mass Eclipsing Binary Bb Persei, Marek Wolf, Petr Zasche, Miloslav Zejda, Martin Mašek, Andrej Mudray, Hana Kučáková, Waldemar Ogłoza, Jaroslav Merc, Jan Kára, Vojtěch Dienstbier
Physics & Astronomy Faculty Publications
We present a detailed analysis of the low-mass detached eclipsing binary system BB Persei, which contains two K-type stars in a circular orbit with a short period of 0.4856 d. We used light curves from the Transiting Exoplanet Survey Satellite (Tess), which observed BB Per in five sectors, to determine its photometric properties and a precise orbital ephemeris. The solution of the Tess light curve in Phoebe results in a detached configuration, where the temperature of the primary component was fixed to T 1 = 5 300 K according to Lamost, which gives us T 2 = 5 050 ± …