Astrophysics and Astronomy Commons^™

Unbiased Estimation Of Gravitational-Wave Anisotropies From Noisy Data, Nikolaos Kouvatsos, Alexander C. Jenkins, Arianna I. Renzini, Joseph D. Romano, Mairi Sakellariadou

Physics & Astronomy Faculty Publications

One of the most exciting targets of current and future gravitational-wave observations is the angular power spectrum of the astrophysical GW background. This cumulative signal encodes information about the large-scale structure of the Universe, as well as the formation and evolution of compact binaries throughout cosmic time. However, the finite rate of compact binary mergers gives rise to temporal shot noise, which introduces a significant bias in measurements of the angular power spectrum if not explicitly accounted for. Previous work showed that this bias can be removed by cross-correlating GW sky maps constructed from different observing times. However, this …

Technology Innovation Is The Key To Future Space Science Missions, Ji Wu

Bulletin of Chinese Academy of Sciences (Chinese Version)

Space science is one of the important space activities of China together with space technology and space application. Although it is a space program aimed at scientific discovery and breakthrough, with the development of technology and the increasing number of achievements received in the past, space science missions require more and more technological innovation to achieve their goals. This study first reviews the development trend of space science missions since their birth, then analyzes the cultivation process of space science mission proposals with technological innovation and the responsibilities of the chief scientist leading such tasks, and finally analyzes and proposes …

A Novel Positive-Contrast Magnetic Resonance Imaging Line Marker For High-Dose-Rate (Hdr) Mri-Assisted Radiosurgery (Mars), Li Wang, Yao Ding, Teresa L. Bruno, R. Jason Stafford, Eric Lin, Tharakeswara K. Bathala, Jeremiah W. Sanders, Matthew S. Ning, Jingfei Ma, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

Magnetic resonance imaging (MRI) can facilitate accurate organ delineation and optimal dose distributions in high-dose-rate (HDR) MRI-Assisted Radiosurgery (MARS). Its use for this purpose has been limited by the lack of positive-contrast MRI markers that can clearly delineate the lumen of the HDR applicator and precisely show the path of the HDR source on T1- and T2-weighted MRI sequences. We investigated a novel MRI positive-contrast HDR brachytherapy or interventional radiotherapy line marker, C4:S, consisting of C4 (visible on T1-weighted images) complexed with saline. Longitudinal relaxation time (T1) and transverse relaxation time (T2) for C4:S were measured on a 1.5 T …

Nidus Idearum. Scilogs, Xiii: Structure / Neutrostructure / Antistructure, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In this thirteenth book of scilogs – one may find topics on Neutrosophy, Plithogeny, Physics, Mathematics, Philosophy – email messages to research colleagues, or replies, notes, comments, remarks about authors, articles, or books, spontaneous ideas, and so on. It presents new types of soft sets and new types of topologies.

Exchanging ideas with Mohammad Abobala, Ishfaq Ahmad, Ibrahim M. Almanjahie, Fatimah Alshahrani, Nizar Altounji, Muhammad Aslam, Said Broumi, Victor Christianto, R. Diksh, Feng Liu, Frank Julian Gelli, Erick Gonzalez Caballero, Riad Hamido, Yaser Al-Hasan, Ahmed Hatip, Yasin Karmouta, Nivetha Martin, Preda Mihăilescu, V. Lakshmana Gomathi Nayagam, Ze Carlos Tiago de …

Avoiding Pitfalls In Molecular Simulation Of Vapor Sorption: Example Of Propane And Isobutane In Metal–Organic Frameworks For Adsorption Cooling Applications, Filip Formalik, Haoyuan Chen, Randall Q. Snurr

Physics & Astronomy Faculty Publications

This study introduces recommendations for conducting molecular simulations of vapor adsorption, with an emphasis on enhancing the accuracy, reproducibility, and comparability of results. The first aspect we address is consistency in the implementation of some details of typical molecular models, including tail corrections and cutoff distances, due to their significant influence on generated data. We highlight the importance of explicitly calculating the saturation pressures at relevant temperatures using methods such as Gibbs ensemble Monte Carlo simulations and illustrate some pitfalls in extrapolating saturation pressures using this method. For grand canonical Monte Carlo (GCMC) simulations, the input fugacity is usually calculated …

Chandra Hetg X-Ray Spectra And Variability Of Π Aqr, A Γ Cas-Type Be Star, David P. Huenemoerder, Pragati Pradhan, Claude R. Canizares, Sean Gunderson, Richard Ignace, Joy S. Nichols, A.M.T. Pollock, Norbert S. Schulz, Dustin K. Swarm, José M. Torrejón

Publications

High-resolution X-ray spectra of π Aqr, a γ Cas-type star, obtained with the Chandra/HETG spectrometer, revealed emission lines of H-like ions of Mg, Si, S, and Fe; a strong, hard continuum; and a lack of He-like ions, indicating the presence of very hot thermal plasma. The X-ray light curve showed significant fluctuations, with coherent variability at a period of about 3400 s in one observation. The hardness ratio was relatively constant except for one observation in which the spectrum was much harder and more absorbed. We interpret the X-ray emission as arising from accretion onto the secondary, which is likely …

Analysis Of Modeled 3d Solar Magnetic Field During 30 X/M-Class Solar Flares, Seth H. Garland, Vasyl B. Yurchyshyn, Robert D. Loper, Benjamin F. Akers, Daniel J. Emmons Ii

Faculty Publications

Using non-linear force free field (NLFFF) extrapolation, 3D magnetic fields were modeled from the 12-min cadence Solar Dynamics Observatory Helioseismic and Magnetic Imager (HMI) photospheric vector magnetograms, spanning a time period of 1 hour before through 1 hour after the start of 18 X-class and 12 M-class solar flares. Several magnetic field parameters were calculated from the modeled fields directly, as well as from the power spectrum of surface maps generated by summing the fields along the vertical axis, for two different regions: areas with photospheric |B_z|≥ 300 G (active region—AR) and areas above the photosphere with the …

Sunyaev-Zeldovich Effect In The Intra-Cluster Medium, Nathan Fronk

Senior Seminars and Capstones

This paper covers the Sunyaev-Zeldovich effect, it’s derivation, and it’s applications in astronomy. The effect is a result of inverse Compton scattering in a cloud of hot charged particles, causing an increase in the temperature of the the cosmic microwave background radiation passing through the cloud. This change in temperature can be measured, and used to calculate the physical properties of the structure in question. This paper focuses on the a method used by Adam et al. (2017) to find a temperature map of the intra-cluster medium.

Nanograv 15-Year Gravitational-Wave Background Methods, Aaron D. Johnson, Patrick M. Meyers, Paul T. Baker, Neil J. Cornish, ‪Jeffrey S. Hazboun, Tyson B. Littenberg, Joseph D. Romano, Stephen R. Taylor, Michele Vallisneri

Physics & Astronomy Faculty Publications

Pulsar timing arrays (PTAs) use an array of millisecond pulsars to search for gravitational waves in the nanohertz regime in pulse time of arrival data. This paper presents rigorous tests of PTA methods, examining their consistency across the relevant parameter space. We discuss updates to the 15-year isotropic gravitational-wave background analyses and their corresponding code representations. Descriptions of the internal structure of the flagship algorithms enterprise and ptmcmcsampler are given to facilitate understanding of the PTA likelihood structure, how models are built, and what methods are currently used in sampling the high-dimensional PTA parameter space. We introduce a novel version …

Theoretical Spectroscopic Predictions Of Electronically Excited States, Noah R. Garrett

Honors Theses

The quest for faster computation of anharmonic vibrational frequencies of both ground and excited electronic states has led to combining coupled cluster theory harmonic force constants with density functional theory (DFT) cubic and quartic force constants for defining a quartic force field (QFF) utilized in conjunction with vibrational perturbation theory at second order (VPT2). This work shows that explicitly correlated coupled cluster theory at the singles, doubles, and perturbative triples level [CCSD(T)-F12] provides accurate anharmonic vibrational frequencies and rotational constants when conjoined with any of B3LYP, CAM-B3LYP, BHandHLYP, PBE0, and ωB97XD for roughly one-quarter of the computational time of the …

Examining Galaxy Bulge Regions With The Sloan Digital Sky Survey, Sarah E. Draves, Ariyeh Maller

Publications and Research

Nearly all of the ordinary matter in the universe is located in galaxies, which are made up stars, gas, dust, and black holes, and range in size from a few thousand to a few hundred thousand light years across. Galaxies come in different shapes, but many of them are spiral shaped, and some of those have a central bulge region that is distinct from the rest of the galactic disk. This project used a large data set of galaxies that had their bulge and disk components separated to see what correlations those fractions of each galaxy have with other galaxy …

Cn Stretches Around 4.4 Microns Dominate The Ir Absorption Spectra Of Cyanopolycyclic Aromatic Hydrocarbons, Vincent J. Esposito, Ryan C. Fortenberry, Christiaan Boersma, Alexandros Maragkoudakis, Louis J. Allamandola

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Anharmonic quantum chemical computations reveal a strong, narrow (width = 0.075 μm) band in the 4.3–4.5 μm region of the absorption spectra of the cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) cyanonaphthalene, cyanoanthracene, c yanophenanthrene, and c yanopyrene. This narro w windo w with intense IR lines implies that CN-PAHs of various shapes and sizes offer little variation in both wavelength and intensity in this region. Subsequently, this band can be used as a tracer for CN-PAHs. The distinct features making up the band are assigned to mixed vibrational states consisting of the CN stretch fundamental and various combination bands, including in-plane …

Analysis Of Bayesian Transfer Function Fitting Method - A Potential Tool For Estimating Interferometer Uncertainty, Caden Swain

Honors Thesis

The Response Function of the LIGO Interferometer is central to reconstructing the strain produced by incoming gravitational waves. As a function of the interferometer's response to external stimuli, the Response Function is both analytically modeled and experimentally measured using excitations from the photon calibrator system at discrete frequencies. The uncertainty in each data point is propagated to the residual between the model and measurements, with both the uncertainty and residual being interpolated over a broadband frequency range. This project explores an alternative method to estimating the uncertainty and systematic error present in the Response function model through the utilization of …

Energy Dependence Of Quasi-Periodic Oscillations In Accreting X-Ray Pulsars, Hemanth Manikantan, Biswajit Paul, Rahul Sharma, Pragati Pradhan, Vikram Rana

Publications

We present the results from an investigation of the energy dependence of quasi-periodic oscillations (QPOs) exhibited by accreting X-ray pulsars using data from archival XMM-Newton, NuSTAR, RXTE, and NICER observations. In a search for the presence of QPOs in 99 XMM-Newton and NuSTAR observations, we detected QPOs in eleven observations of five sources, viz., 4U 1626–67 (48 mHz), IGR J19294+1816 (30 mHz), V 0332+53 (2, 18, and 40 mHz), Cen X–3 (30 mHz), and XTE J1858+034 (180 mHz). A positive correlation of the QPO rms amplitude with energy is exhibited by 4U 1626–67, IGR J19294+1816, Cen X–3 and XTE J1858+034, …

Identification Of The Top Tess Objects Of Interest For Atmospheric Characterization Of Transiting Exoplanets With Jwst, B. J. Hord, E. M.-R. Kempton, T. M. Evans-Soma, D. W. Latham, D. R. Ciardi, D. Dragomir, K. D. Colón, G. Ross, A. Vanderburg, Z. L. De Beurs, K. A. Collins, C. N. Watkins, J. Bean, N. B. Cowan, T. Daylan, C. V. Morley, J. Ih, D. Baker, K. Barkaoui, N. M. Batalha, A. Behmard, A. Belinski, Z. Benkhaldoun, P. Benni, K. Bernacki, A. Bieryla, A. Binnenfeld, P. Bosch-Cabot, F. Bouchy, V. Bozza, R. Brahm, L. A. Buchhave, M. Calkins, A. Chontos, C. A. Clark, R. Cloutier, M. Cointepas, K. I. Collins, D. M. Conti, I. J. M. Crossfield, F. Dai, J. P. De Leon, G. Dransfield, C. Dressing, A. Dustor, G. Esquerdo, P. Evans, S. B. Fajardo-Acosta, J. Fiołka, R. Forés-Toribio, A. Frasca, A. Fukui, B. Fulton, E. Furlan, T. Gan, D. Gandolfi, M. Ghachoui, S. Giacalone, E. A. Gilbert, M. Gillon, E. Girardin, E. Gonzales, F. Grau Horta, J. Gregorio, M. Greklek-Mckeon, P. Guerra, J. D. Hartman, C. Hellier, I. Helm, K. G. Hełminiak, T. Henning, M. L. Hill, K. Horne, A. W. Howard, S. B. Howell, D. Huber, G. Isopi, E. Jehin, J. M. Jenkins, Eric L.N. Jensen, M. C. Johnson, A. Jordán, S. R. Kane, J. F. Kielkopf, V. Krushinsky, S. Lasota, E. Lee, P. Lewin, J. H. Livingston, J. Lubin, M. B. Lund, F. Mallia, C. R. Mann, G. Marino, N. Maslennikova, B. Massey, R. Matson, E. Matthews, A. W. Mayo, T. Mazeh, K. K. Mcleod, E. J. Michaels, T. Močnik, M. Mori, G. Mraz, J. A. Muñoz, N. Narita, K. Natarajan, L. D. Nielsen, H. Osborn, E. Palle, A. Panahi, R. Papini, P. Plavchan, A. S. Polanski, A. Popowicz, F. J. Pozuelos, S. N. Quinn, D. J. Radford, P. A. Reed, H. M. Relles, M. Rice, P. Robertson, J. E. Rodriguez, L. J. Rosenthal, R. A. Rubenzahl, N. Schanche, J. Schlieder, R. P. Schwarz, R. Sefako, A. Shporer, A. Sozzetti, G. Srdoc, C. Stockdale, A. Tarasenkov, T.-G. Tan, M. Timmermans, E. B. Ting, J. Van Zandt, Jp Vignes, I. Waite, N. Watanabe, L. M. Weiss, J. Wittrock, G. Zhou, C. Ziegler, S. Zucker

Physics & Astronomy Faculty Works

JWST has ushered in an era of unprecedented ability to characterize exoplanetary atmospheres. While there are over 5000 confirmed planets, more than 4000 Transiting Exoplanet Survey Satellite (TESS) planet candidates are still unconfirmed and many of the best planets for atmospheric characterization may remain to be identified. We present a sample of TESS planets and planet candidates that we identify as "best-in-class" for transmission and emission spectroscopy with JWST. These targets are sorted into bins across equilibrium temperature T_eq and planetary radius R_p and are ranked by a transmission and an emission spectroscopy metric (TSM and ESM, respectively) …

Sites Of Planet Formation In Binary Systems. I. Evidence For Disk−Orbit Alignment In The Close Binary Fo Tau, B. M. Tofflemire, L. Prato, A. L. Kraus, D. Segura-Cox, G. H. Schaefer, R. Akeson, S. Andrews, Eric L.N. Jensen, C. M. Johns-Krull, J. J. Zanazzi, M. Simon

Physics & Astronomy Faculty Works

Close binary systems present challenges to planet formation. As binary separations decrease, so do the occurrence rates of protoplanetary disks in young systems and planets in mature systems. For systems that do retain disks, their disk masses and sizes are altered by the presence of the binary companion. Through the study of protoplanetary disks in binary systems with known orbital parameters, we seek to determine the properties that promote disk retention and therefore planet formation. In this work, we characterize the young binary−disk system FO Tau. We determine the first full orbital solution for the system, finding masses of 0.35 …

A Search For Pulsars And An Exploration Of Dispersion Measure Within The Milky Way Galaxy, Emily Ware

Physics Undergraduate Honors Theses

A pulsar is a rapidly rotating neutron star which emits electromagnetic radiation from its magnetic poles. Upon detection from Earth, these signals have been dispersed in phase due to electron interactions in transit. The extent of this dispersion indicates information about both the distance to and the location of the pulsar, with respect to Earth and the Galactic plane. This project makes use of radio data from the 100m Robert C. Byrd Green Bank Telescope (GBT), presented in the form of prepfold plots assembled by the Pulsar Science Collaboratory (PSC). 1,007 of these plots were analyzed in order to determine …

Lhs 475 B: A Potential Venus Analog Orbiting A Nearby M Dwarf, K. Ment, D. Charbonneau, J. Irwin, J. G. Winters, E. Pass, A. Shporer, K. A. Collins, K. I. Collins, Eric L.N. Jensen, R. P. Schwarz, K. Horne, Z. Essack, V. B. Kostov, M. Kunimoto, A. Levine, S. Seager, R. Vanderspek, J. N. Winn

Physics & Astronomy Faculty Works

Based on photometric observations by TESS, we present the discovery of a potential Venus analog transiting LHS 475, an M3 dwarf located 12.5 pc from the Sun. The mass of the star is 0.274 ± 0.015 M_☉. The planet, originally reported as TOI 910.01, has an orbital period of 2.0291010 ± 0.0000017 days and an estimated radius of 0.975 ± 0.058 R_⊕. We confirm the validity and source of the transit signal with MEarth and Las Cumbres Observatory Global Telescope ground-based follow-up photometry. We present radial velocity data from CHIRON that rule out massive companions. In …

The Jwst Early Release Science Program For Direct Observations Of Exoplanetary Systems. V. Do Self-Consistent Atmospheric Models Represent Jwst Spectra? A Showcase With Vhs 1256-1257 B, Simon Petrus, Niall Whiteford, Polychronis Patapis, Beth A. Biller, Andrew Skemer, Sasha Hinkley, Genaro Suárez, Paulina Palma-Bifani, Caroline V. Morley, Pascal Tremblin, Benjamin Charnay, Johanna M. Vos, Jason J. Wang, Jordan M. Stone, Mickaël Bonnefoy, Gaël Chauvin, Brittany E. Miles, Aarynn L. Carter, Anna Lueber, Christiane Helling, Ben J. Sutlieff, Markus Janson, Eileen C. Gonzales, Kielan K.W. Hoch, Olivier Absil, William O. Balmer, Anthony Boccaletti, Mariangela Bonavita, Mark Booth, Brendan P. Bowler, Et Al, Kimberly Ward-Duong

Astronomy: Faculty Publications

The unprecedented medium-resolution (R λ ∼ 1500-3500) near- and mid-infrared (1-18 μm) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12-20 M Jup) L-T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present a comprehensive analysis of this data set utilizing a forward-modeling approach applying our Bayesian framework, ForMoSA. We explore five distinct atmospheric models to assess their performance in estimating key atmospheric parameters: T eff, log(g), [M/H], C/O, γ, f sed, and R. Our findings reveal that each parameter’s estimate is significantly influenced by factors …

Toi-1135 B: A Young Hot Saturn-Size Planet Orbiting A Solar-Type Star, M. Mallorquín, N. Lodieu, V. J. S. Béjar, M. R. Zapatero Osorio, J. Sanz-Forcada, M. R. Alarcon, H. M. Tabernero, E. Nagel, K. A. Collins, D. R. Ciardi, M. Serra-Ricart, J. Orell-Miquel, K. Barkaoui, A. Burdanov, J. De Wit, M. E. Everett, M. Gillon, Eric L.N. Jensen, L. G. Murphy, P. A. Reed, B. Safonov, I. A. Strakhov, C. Ziegler

Physics & Astronomy Faculty Works

Despite the thousands of planets in orbit around stars known to date, the mechanisms of planetary formation, migration, and atmospheric loss remain unresolved. In this work, we confirm the planetary nature of a young Saturn-size planet transiting a solar-type star every 8.03 d, TOI-1135 b. The age of the parent star is estimated to be in the interval of 125-1000 Myr based on various activity and age indicators, including its stellar rotation period of 5.13 ± 0.27 days and the intensity of photospheric lithium. We obtained follow-up photometry and spectroscopy, including precise radial velocity measurements using the CARMENES spectrograph, which …