Astrophysics and Astronomy Commons^™

Finding The Missing Link: Host Galaxies Of Intermediate-Mass Black Holes In Illustris, Michael J. Pinto Ii

Science University Research Symposium (SURS)

Black holes are significant cosmological objects that challenge the fundamentals of physics and our understanding of black hole evolution. Moreover, formation pathways and lifetimes for intermediate-mass black holes (IMBHs) remain poorly constrained. This raises the question of whether these bodies persist as stable remnants or represent transient stages in supermassive black hole (SMBH) evolution. This study utilizes the Illustris Project’s Illustris-3, a cosmological hydrodynamical simulation, to build and characterize different galactic environments that host IMBHs across four distinct environmental samples: dwarf galaxies, Milky Way-mass galaxies, massive galaxies, and cluster-mass halos at redshifts z ≈ 4.9, 0.6, and 0. We then …

Planetarium Show: “One Sky”, Jim & Linda Lee Planetarium

International Education Week

Look beyond borders and experience the wonder of the universe in One Sky. This planetarium presentation offers a captivating opportunity to explore the night sky and reflect on the shared world we all inhabit.

The Conquest For Information V The Fermi Paradox, Matthew A. Kramer

PANDION: The Osprey Journal of Research and Ideas

The concepts of intelligent life beyond earth and extraterrestrial civilizations have intrigued scientists and scholars alike. Intellectuals have suggested that extraterrestrial intelligence should be detectable somewhere in the grand universe; however, despite continued effort, no one has reliably documented evidence supporting extraterrestrial life, culminating in the Fermi Paradox. One perspective to solve the Fermi Paradox involves using logic and analytical reasoning skills to deduce the limits of detection based on what is most probabilistically determinable via the Drake equation. However, with information comes costs and these emergent energetic complexities drive civilizations to maximize computing power, converging into a blackhole transcendent …

Gravitational Constraints And Graviphilic Systems, Bradley E. Cantrell

PANDION: The Osprey Journal of Research and Ideas

Astronomical observation is revealing thousands of new worlds while inferentially suggesting the existence of countless others, as advances in gravitational-wave astronomy and cosmology continue to expand our grasp of the observable universe. This study introduces the gravitational viability factor, 𝐺v, and the concept of graviphilic systems as a framework for organizing astrobiological inquiry. 𝐺v is proposed as a conceptual framework for connecting universal biological constraints with contingent biological outcomes. Gravity is not merely a constraint on life but a useful organizing parameter for evaluating biological plausibility across environments. An abundance of potential telescope targets is available through …

How Neutron Star Radii Encode The Dense-Matter Equation Of State And Hadron-Quark Transition, Bao-An Li, Xavier Grundler

Faculty Publications

We investigate how future high-precision neutron star (NS) radius measurements encode microscopic information about the dense-matter equation of state (EOS), focusing on a possible first-order hadron–quark phase transition and the resulting mass–radius topology. Within a Bayesian framework using metamodel EOSs with nine microscopic parameters, we analyze mock radius measurements R 1.4 =11.9 ± σ R km with σ =0.9 and 0.1 km for canonical NSs. Rather than relying only on marginalized posterior probability distributions, we introduce inverse EOS–radius mappings by studying the conditional mean of each EOS parameter as a function of the model-predicted canonical radius R R 1.4 . …

Exploring The Dynamics Of Tilted, Truncated Accretion Disks, José L. Montés, Chris Fragile, Deepika Bollimpalli, Matthew Liska

Journal of the South Carolina Academy of Science

Tilted accretion disks are theoretically not uncommon in stellar mass black hole systems. The dynamics of tilted disks display interesting physical behaviors that could explain certain observational phenomena such as quasi-periodic oscillations. We present results of recent numerical simulations of tilted, truncated accretion disks around rotating black holes. Our simulations model systems composed of a thick inner torus surrounded by a thin outer disk and were run with the goal of investigating the behaviors of the torus because of the exchange of angular momentum between it and the outer disk. Multiple simulations produced surprising results, such as the potential tearing …

Astrophysical Radiative Capture Reaction Rates In Light Nuclei: A Review Of Results From The Modified Potential Cluster Model, S. B. Dubovichenko, B. M. Yeleusheva, A. S. Tkachenko, R. Ya. Kezerashvili

Publications and Research

A review of results obtained within a single theoretical framework—the Modified Potential Cluster Model (MPCM)—is presented for astrophysical radiative capture reactions involving the lightest and 1p-shell nuclei. The approach has been applied to reactions relevant to the r-process, the CNO and HCNO cycles, and parts of the Big Bang nucleosynthesis (BBN) and post-BBN scenarios. The model incorporates the classification of orbital states according to Young’s diagrams and has been successfully applied to describe the available experimental data on the total cross sections of the radiative capture of neutrons, protons, and the lightest clusters by 40 light nuclei at astrophysical energies. …

Sub-Torque-Balance Upper Limits On Continuous Gravitational Waves From Scorpius X-1, A. G. Abac, I. Abouelfettouh, Teviet Creighton, Mario C. Diaz, Raul Alberto Espinosa Perez, J. Lawrence, Francisco Llamas Villarreal, Miriam Ramos Arevalo, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present the results of a search for continuous gravitational waves (GWs) from the low-mass X-ray binary Scorpius X-1 using LIGO data from the first part of the fourth LIGO–Virgo–KAGRA observing run. By applying the resampling version of the cross-correlation pipeline to search for signal frequencies f0 between 25 and 200 Hz (corresponding to neutron star spin frequencies of 12.5–100 Hz for GWs due to triaxiality, or ∼15–20 to ∼120–150 Hz for GWs due to r-modes), we are able to achieve longer coherence times than before, and for the first time set upper limits below the standard torque …

Detector Orientation Matters: Consequences For Gravitational-Wave Background Detectability, Nelson Christensen, Joseph D. Romano, Mairi Sakellariadou, Jishnu Suresh

Physics & Astronomy Faculty Publications

Cross-correlation searches for gravitational-wave backgrounds depend on the geometrical configuration (physical separation and relative orientation) of the detectors comprising the network. Applying standard techniques to a few simple examples, we illustrate how the relative orientation of a pair of Earth-based L-shaped laser interferometers can drastically impact the detectability of both isotropic and anisotropic gravitational-wave backgrounds.

Where Are Linearized Gauge Invariants Encoded For Plane Waves In Linearized Gravity, Ramesh Radhakrishnan, David Mcnutt, Delaram Mirfendereski, Eric Davis, William Julius, Gerald Cleaver

Physics & Astronomy Faculty Publications

In this work we will investigate the structures of invariants within the class of plane waves in linearized General Relativity, to introduce a new approach to determine the linearized gauge invariants encoding the polarization of the plane waves. The Newman–Penrose (NP) formalism is traditionally used to analyze the polarization content of gravitational waves, while the gauge-invariant Bardeen formalism provides a complementary description based on the irreducible scalar, vector, and tensor perturbations of the metric. We will apply the Bardeen formalism to compute all scalar, vector, and tensor gauge-invariant variables explicitly and verify that only the two transverse–traceless tensor modes survive. …

An Ion-Neutral Reaction To Form Cyanobenzene And Ethynylbenzene In Titan’S Atmosphere, Rachel M. Huchmala, Vincent J. Esposito

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The ion-neutral reaction between cyanoacetylene (HC₃N) and phenyl anion (C₆H₅^–) leads to the formation of cyanobenzene (C₆H₅CN) and the ethynyl anion (C₂H^–) via a submerged, exothermic pathway. Through a different mechanism, the same two reactants also form ethynylbenzene (C₆H₅C₂H) and CN^–. These new reactions can be a foundation for the production of substituted benzenes using molecules currently present on Saturn’s largest moon, Titan. Cyclic aromatic molecules like C₆H₅CN and C₆H_{5 …}

Addressing Leakage And Mode Suppression In Angular Power Spectrum Estimation For Gravitational-Wave Backgrounds Using Pulsar Timing Arrays, Deepali Agarwal, Joseph D. Romano, Yacine Ali-Haïmoud, Tristan L. Smith

Physics & Astronomy Faculty Publications

Mapping gravitational-wave background (GWB) anisotropy with pulsar timing arrays (PTAs) is affected by harmonic space mode suppression and mode coupling arising from an array’s nonuniform sky response. Due to computational limitations, one must truncate spherical harmonic expansions at a finite multipole for recovery, ℓrec max, often chosen to equal ℓ𝑁pair max ≡int⁢[√𝑁pair−1], where 𝑁pair ≡𝑁psr⁢(𝑁psr −1)/2 is the number of distinct pulsar pairs in an array comprised of 𝑁psr pulsars. This choice is motivated by the counting argument that cross-correlations provide at most 𝑁pair independent pieces of information for a single frequency bin. Here, we explicitly obtain the multipole value …

K 1-6 Is A Photoionised Interstellar Medium Nebula Shaped By A Fast-Moving Hot White Dwarf In A Triple System, Jaroslav Merc, David Jones, Ana Escorza, Henri M. J. Boffin, Nicole Reindl, Michael Abdul-Masih, Thomas Masseron, Paulina Sowicka, Jan Kára, Jorge Jorge García-Rojas

Physics & Astronomy Faculty Publications

Aims. K 1-6 has long been classified as a planetary nebula (PN) hosting a binary central star; however, it has remained poorly studied due to its faintness. The central star exhibits pronounced photometric variability whose origin is still unclear. We present a comprehensive characterisation of the K 1-6 system, including the physical properties of its stellar components and the nature of the surrounding nebulosity.

Methods. We conducted a multi-wavelength analysis combining optical and UV spectroscopy obtained with the Gran Telescopio Canarias, the Telescopio Nazionale Galileo, the Nordic Optical Telescope, and the Hubble Space Telescope. We also present long-term multi-band ground- …

Fully Anharmonic Infrared Spectra Of Neutral Polycyclic Aromatic Hydrocarbons With Up To 38 Carbons, Nolan J. H. White, Vincent J. Esposito, Christiaan Boersma, Louis J. Allamandola, Jesse D. Bregman, Alexandros Maragkoudakis, Pasquale Temi, Ryan Fortenberry

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Interstellar aromatic infrared band (AIB) spectra show agreement with presently computed anharmonic spectra for various types of polycyclic aromatic hydrocarbons (PAHs) determined using a novel semiempirical quantum chemical method. Since the AIB spectrum is a blend of emission spectra from a vast number of different PAHs, likely with an array of different molecular structures, the spectra for a sample set of 31 PAHs ranging in size from naphthalene (C₁₀H₈) up to circumbiphenyl (C₃₈H₁₆) are combined, giving consideration to almost all PAH structural motifs. The computed numerical quartic force fields coupled to second-order …

Infrared Spectroscopy And Photochemistry Of Aromatic Nitriles In Para-Hydrogen Matrices, Sam Mcgrath, Vincent J. Esposito, Linshan Zeng, Thomas H. Speak, Brendan Moore, Pavle Djuricanin, Jun Miyazaki, Takamasa Momose, Ilsa R. Cooke

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Motivated by recent detections of several aromatic nitriles in Taurus Molecular Cloud 1, we report laboratory and theoretical investigations of the vibrational spectroscopy and photochemistry of singly and doubly cyanosubstituted benzene in solid para-hydrogen matrices. We compare the photochemistry of cyanobenzene (benzonitrile) and three dicyanobenzene isomers initiated by excitations at 193 nm. In addition, we report the photochemistry of deuterated cyanobenzene (d5-cyanobenzene), enabling us to determine the major products produced during the cyanobenzene photodissociation. The major products observed in the photolysis of all the nitriles are HCN and HNC, which are likely produced by hydrogen abstraction from para-hydrogen by the …

The Jwst Weather Report: Unravelling The Atmospheric Variability Of Isolated Worlds Using Principal Component Analysis, Merle A. Schrader, Johanna M. Vos, Evert Nasedkin, Jennifer Kestell, Nicolas B. Cowan, Roman Akhmetshyn, Samuel Beiler, Beth A. Biller, Ben Burningham, Jacqueline Faherty, Eileen C. Gonzales, Allison M. Mccarthy, Caroline V. Morley, Barry O'Donovan, Cian O'Toole, Genaro Suárez, Xianyu Tan, Channon Visscher, Niall Whiteford, Yifan Zhou

Faculty Work Comprehensive List

Brown dwarf variability directly probes atmospheric dynamics beyond the Solar System, and recent James Webb Space Telescope (JWST) time-resolved spectroscopy has opened a new window into these processes. Principal component analysis (PCA) offers a data-driven framework to identify the dominant, independent patterns of spectral variability of variable targets without relying on prior atmospheric assumptions. simp (simp) is a young, T2.5, brown dwarf at the planetary-mass boundary, making it an ideal analogue for directly imaged exoplanets. We analysed one rotation of JWST/NIRSpec PRISM time-series spectroscopy to investigate the drivers of its variability using PCA. Prior analyses of these data revealed …

Cedar: Investigating The Mesosphere And Lower Thermosphere Neutral Temperature And Winds Responses To Geomagnetic Storms Equatorward Of The Auroral Zone, Tao Yuan

Funded Research Records

No abstract provided.

Enhanced Cooper Pairing Via Random Matrix Phonons In Superconducting Grains, Andrey Grankin, Mohammad Hafezi, Victor Galitski

Physics & Astronomy Faculty Publications

There is rich experimental evidence that granular superconductors and superconducting films often exhibit a higher transition temperature 𝑇𝑐 than that in bulk samples of the same material. This Letter suggests that this enhancement hinges on random matrix phonons mediating Cooper pairing more efficiently than bulk phonons. We develop the Eliashberg theory of superconductivity in chaotic grains, calculate the random phonon spectrum, and solve the Eliashberg equations numerically. Self-averaging of the effective electron-phonon coupling constant is noted, which allows us to fit the numerical data with analytical results based on a generalization of the Berry conjecture. The key insight is that …

Δ−Scuti Star Hr 1170, Salman A. Nejad

Aquila: The Journal of Embry-Riddle Observatory

HR 1170, a variable star in the constellation Perseus, exhibits multi-periodic pulsations consistent with its classification as a δ−Scuti star. Through photometric and spectroscopic observations using the 1-meter ERAU telescope and the SARA-RM telescope, this study investigates its variability and spectral characteristics. Photometry conducted over several nights reveals pulsation periods that closely align with previously reported values. Time-resolved spectroscopy highlights prominent absorption features, including Balmer lines and metallic elements, offering further insights into the star’s atmospheric dynamics.

A Multiwavelength Study Of A Long-Duration Very-High-Energy Flare From Bl Lacertae With Veritas, Avery Archer, Et Al.

Physics & Astronomy Faculty publications

We report the first observations of a long-duration very-high-energy (VHE; E>100 GeV) flare from BL Lacertae (VER J2202+422), taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). On 2022 October 15, the Fermi-Large Area Telescope (LAT) detected elevated GeV activity originating from this blazar. This triggered a multiwavelength campaign, which includes observations from VERITAS, Swift, NuSTAR, and select optical and radio observatories. VERITAS observed the source for a total of ∼9.8 hr between 2022 September 1 and 2022 December 1. An analysis of these data yields a ∼28σ detection of the source. While previously observed VHE …