Astrophysics and Astronomy Commons^™

Optically Targeted Search For Gravitational Waves Emitted By Core-Collapse Supernovae During The Third Observing Run Of Advanced Ligo And Advanced Virgo, Marek J. Szczepańczyk, Yanyan Zheng, Javier M. Antelis, Michael G. Benjamin, Marie-Anne Bizouard, Alejandro Casallas-Lagos, Pablo Cerda-Duran, Derek Davis, Dorota Gondek-Rosinska, Soma Mukherjee

Physics & Astronomy Faculty Publications

We present the results from a search for gravitational-wave transients associated with core-collapse supernovae observed optically within 30 Mpc during the third observing run of Advanced LIGO and Advanced Virgo. No gravitational wave associated with a core-collapse supernova has been identified. We then report the detection efficiency for a variety of possible gravitational-wave emissions. For neutrino-driven explosions, the distance at which we reach 50% detection efficiency is up to 8.9 kpc, while more energetic magnetorotationally driven explosions are detectable at larger distances. The distance reaches for selected models of the black hole formation, and quantum chromodynamics phase transition are also …

Cosmic Variance Of The Hellings And Downs Correlation For Ensembles Of Universes Having Nonzero Angular Power Spectra, Deepali Agarwal, Joseph D. Romano

Physics & Astronomy Faculty Publications

Gravitational waves (GWs) induce correlated perturbations to the arrival times of pulses from an array of galactic millisecond pulsars. The expected correlations, obtained by averaging over many pairs of pulsars having the same angular separation (pulsar averaging) and over an ensemble of model universes (ensemble averaging), are described by the Hellings and Downs curve. As shown by Allen [Phys. Rev. D 107, 043018 (2023)], the pulsar-averaged correlation will not agree exactly with the expected Hellings and Downs prediction if the gravitational-wave sources interfere with one another, differing instead by a “cosmic variance” contribution. The …

On The Formation And Detectability Of H2Cncn And Its Progenitors, Ryan C. Fortenberry, Vincent J. Esposito

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

New highly exothermic formation pathways incorporating both thermodynamic and kinetic control for the newly astronomically detected H₂CNCN molecule are paired with extremely accurate quantum chemical rovibrational spectroscopic computations. The reactions between astronomically known CH₂CN/CH₂CCH + HNCN follow effectively identical pathways and proceed through stable intermediates and over deeply submerged transition states to form H₂CNCN and HCN/HCCH coproducts. Similarly, the reaction between CHM₂CN and NCN⁻ can also form H₂CNCN, although this pathway first requires the initial formation of NCN⁻, which is currently undetected in space, via …

Ultralight Vector Dark Matter Search Using Data From The Kagra O3gk Run, A. Abac, R. Abbott, H. Abe, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the …

Mhongoose: A Meerkat Nearby Galaxy H I Survey, Stacy S. Mcgaugh

Faculty Scholarship

The MHONGOOSE (MeerKAT H i Observations of Nearby Galactic Objects: Observing Southern Emitters) survey maps the distribution and kinematics of the neutral atomic hydrogen (H i) gas in and around 30 nearby star-forming spiral and dwarf galaxies to extremely low H i column densities. The H i column density sensitivity (3σ over 16 km s−1) ranges from ∼5 × 1017 cm−2 at 9000 resolution to ∼4 × 1019 cm−2 at the highest resolution of 700. The H i mass sensitivity (3σ over 50 km s−1) is ∼5.5×105 M at a distance of 10 Mpc (the median distance of the sample …

Experimental Determination Of The Unusual Ch Stretch Frequency Of Protonated Fullerenes, Laura Finazzi, Vincent J. Esposito, Julianna Palotás, Jonathan Martens, Els Peeters, Jan Cami, Giel Berden, Jos Oomens

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We report experimental values for the CH stretch frequencies of the protonated fullerenes C₆₀H⁺ and C₇₀H⁺. Anharmonic frequency calculations at the B3LYP/6-31G level of theory, which are independent of empirical scaling factors, reproduce the experimental values to within approximately 5 cm⁻¹. Scaling theoretical harmonic frequencies by applying factors derived for polycyclic aromatic hydrocarbons deviate significantly from the experimentally measured frequency. We attribute this deviation to the unusual hydrocarbon structure that affects the degree of anharmonicity of the CH stretch. This result allows us to propose an original, specific scaling factor of …

A Review Of Stable, Traversable Wormholes In F(R) Gravity Theories, Ramesh Radhakrishnan, Patrick Brown, Jacob Matulevich, Eric Davis, Delaram Mirfendereski, Gerald Cleaver

Physics & Astronomy Faculty Publications

It has been proven that in standard Einstein gravity, exotic matter (i.e., matter violating the pointwise and averaged Weak and Null Energy Conditions) is required to stabilize traversable wormholes. Quantum field theory permits these violations due to the quantum coherent effects found in any quantum field. Even reasonable classical scalar fields violate the energy conditions. In the case of the Casimir effect and squeezed vacuum states, these violations have been experimentally proven. It is advantageous to investigate methods to minimize the use of exotic matter. One such area of interest is extended theories of Einstein gravity. It has been claimed …

Archaeology In Space: The Sampling Quadrangle Assemblages Research Experiment (Square) On The International Space Station. Report 1: Squares 03 And 05, Justin St. P. Walsh, Shawn Graham, Alice C. Gorman, Chantal Brousseau, Salma Abdullah

Art Faculty Articles and Research

Between January and March 2022, crew aboard the International Space Station (ISS) performed the first archaeological fieldwork in space, the Sampling Quadrangle Assemblages Research Experiment (SQuARE). The experiment aimed to: (1) develop a new understanding of how humans adapt to life in an environmental context for which we are not evolutionarily adapted, using evidence from the observation of material culture; (2) identify disjunctions between planned and actual usage of facilities on a space station; (3) develop and test techniques that enable archaeological research at a distance; and (4) demonstrate the relevance of social science methods and perspectives for improving life …

Let There Be Light, Erik Johnson

Natural Science Faculty

On May 10, Earth experienced the greatest solar storm in decades. When scientists predicted a high chance for auroras, also known as the northern lights, observers around the world traveled away from light-polluted cities to look for them.

Prospects For Time-Domain And Multi-Messenger Science With Axis, Riccardo Arcodia, Franz E. Bauer, S. Bradley Cenko, Kristen C. Dage, Daryl Haggard, Wynn C.G. Ho, Erin Kara, Michael Koss, Tingting Liu, Labani Mallick, Michela Negro, Pragati Pradhan, J. Quirola-Vásquez, Mark T. Reynolds, Claudio Ricci, Richard E. Rothschild, Navin Sridhar, Eleonora Troja, Yuhan Yao

Publications

The Advanced X-ray Imaging Satellite (AXIS) promises revolutionary science in the X-ray and multi-messenger time domain. AXIS will leverage excellent spatial resolution (< 1.5 arcsec), sensitivity (80× that of Swift), and a large collecting area (5–10× that of Chandra) across a 24-arcmin diameter field of view at soft X-ray energies (0.3–10.0 keV) to discover and characterize a wide range of X-ray transients from supernova-shock breakouts to tidal disruption events to highly variable supermassive black holes. The observatory’s ability to localize and monitor faint X-ray sources opens up new opportunities to hunt for counterparts to distant binary neutron star mergers, fast radio bursts, and exotic phenomena like fast X-ray transients. AXIS will offer a response time of < 2 h to community alerts, enabling studies of gravitational wave sources, high-energy neutrino emitters, X-ray binaries, magnetars, and other targets of opportunity. This white paper highlights some of the discovery science that will be driven by AXIS in this burgeoning field of time domain and multi-messenger astrophysics. This White Paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS White Papers can be found at the AXIS website.

Jwst-Tst High Contrast: Jwst/Nircam Observations Of The Young Giant Planet Β Pic B, Jens Kammerer, Kellen Lawson, Marshall D. Perrin, Isabel Rebollido, Christopher C. Stark, Tomas Stolker, Julien H. Girard, Laurent Pueyo, William O. Balmer, Kadin Worthen, Christine Chen, Roeland P. Van Der Marel, Nikole K. Lewis, Kimberly Ward-Duong, Jeff A. Valenti, Mark Clampin, C. Matt Mountain

Astronomy: Faculty Publications

We present the first JWST/NIRCam observations of the directly imaged gas giant exoplanet β Pic b. Observations in six filters using NIRCam's round coronagraphic masks provide a high-signal-to-noise-ratio detection of β Pic b and the archetypal debris disk around β Pic over a wavelength range of ∼1.7-5 μm. This paper focuses on the detection of β Pic b and other potential point sources in the NIRCam data, following a paper by Rebollido et al. that presented the NIRCam and MIRI view of the debris disk around β Pic. We develop and validate approaches to obtaining accurate photometry of planets in …

The Nature Of X-Rays From Young Stellar Objects In The Orion Nebula Cluster—A Chandra Hetgs Legacy Project, Norbert S. Schulz, David P. Huenemoerder, David A. Principe, Marc Gagné, Hans Mortiz Günther, Joel Kastner, Joy Nichols, Andrew Pollock, Thomas Preibisch, Paola Testa, Fabio Reale, Fabio Favata, Claude R. Canizares

Earth & Space Sciences Faculty Publications

The Orion Nebula Cluster (ONC) is the closest site of very young (∼1 Myr) massive star formation The ONC hosts more than 1600 young and X-ray bright stars with masses ranging from ∼0.1–35 Me. The Chandra HETGS Orion Legacy Project observed the ONC with the Chandra High Energy Transmission Grating Spectrometer (HETGS) for 2.1 Ms. We describe the spectral extraction and cleaning processes necessary to separate overlapping spectra. We obtained 36 high-resolution spectra, which include a high-brilliance X-ray spectrum of θ1 Ori C with over 100 highly significant X-ray lines. The lines show Doppler broadening between 300 and 400 km …

Analyzing Hubble Space Telescope Images Of Agn Host Galaxies With Keck Integral Field Spectra, Sebastian Contreras

Physics

In the center of most massive galaxies is a supermassive black hole (SMBH) with a mass that can range from millions to billions of solar masses. It has been observed that more massive SMBHs have a more massive host galaxy bulge, as evidenced by the larger bulge luminosity and stellar velocity dispersion, a correlation known as the BH mass - host-galaxy scaling relation. It suggests a close evolutionary connection between the growth of the SMBH and the growth of its host galaxy. If a SMBH develops an accretion disk to fuel an active galactic nucleus (AGN), it will emit radiation …

A Nustar Census Of The X-Ray Binary Population Of The M31 Disk, Hannah Moon, Daniel Wik, V. Antoniou, M. Eracleous, Ann Hornschemeier, Margaret Lazzarini, Bret D. Lehmer, Neven Vulic, Benjamin F. Williams, T. J. Maccarone, K. Pottschmidt, Andrew Ptak, Mihoko Yukita, Andreas Zezas

Physics Faculty Publications and Presentations

Using hard (E > 10 keV) X-ray observations with NuSTAR, we are able to differentiate between the accretion states, and thus compact object types, of neutron stars (NSs) and black holes (BHs) in X-ray binaries (XRBs) in M31, our nearest Milky Way–type neighbor. Using 10 moderate-depth (20–50 ks) observations of the disk of M31 covering a total of ∼0.45 deg², we detect 20 sources at 2σ in the 4–25 keV bandpass, 14 of which we consider to be XRB candidates. This complements an existing, deeper (100–400 ks) survey covering ∼0.2 deg² of the bulge and the …

Equilibria And Effective Transition Rates In Linear Networks, Sayani Ghosh

All Dissertations

Investigating equilibration in nucleosynthetic processes is crucial for understanding stellar chemical abundances in nuclear astrophysical scenarios. While current computational models are effective at predicting final species abundances at the end of these stellar processes, they fail to provide insights into the evolution of equilibrium. Without this deeper understanding, it is challenging to determine the impact of individual reaction rates on timescales and the resultant equilibrium.

In this work, we model nucleosynthetic processes as directed graphs. We develop theorems that allow us to express the mass fractions of species as spanning arborescences of these graphs. By obtaining eigenvalues in terms of …

Role Of Planetary Wave-Tide-Gravity Wave Interactions In Whole Atmosphere Coupling, Zishun Qiao

Doctoral Dissertations and Master's Theses

This dissertation investigates the mechanism by which the Earth's whole atmosphere couples from the bottom to the top, pole to pole. The work in this dissertation utilizes observational data and numerical simulations, with a particular emphasis on sudden stratospheric warming (SSW) events. The development of a new multi-static meteor radar at 30ºS, named Chilean Observation Network De MeteOr Radars (CONDOR), provides a key dataset for the present studies. Wind validation of this new radar system is performed across different sites and compared to a co-located sodium lidar. Wave-wave interactions in the mesosphere and lower thermosphere (MLT) that may be responsible …

An Analysis Of The Propagation Of Gravitational Radiation Under A Graviton Of Nonzero Mass And Its Implications For Cosmological Measurements, Margaret Johnston

UNLV Theses, Dissertations, Professional Papers, and Capstones

Under the assumptions of General Relativity (GR), gravitational waves propagate at the speed of light and their mediation can be represented as a particle through a massless graviton. We investigate the impact and observability of the presence of a massive graviton, how such a modification to GR would also modify the observed gravitational waves from astrophysical sources, and how this effect can be used as an independent measurement of cosmmological parameters, including the Hubble parameter H0. We simulate the impact of a massive graviton on compact binary coalescence observation in a near-future LIGO-Virgo-KAGRA interferometer network through a modification to the …

Temperature-Dependent Optical Constants Of Vanadium Dioxide Thin Films Deposited On Polar Dielectrics, Imtiaz Ahmad, Satya R. Kachiraju, Sundar Kunwar, Zachary M. Brown, Pinku Roy, Matthew Gaddy, Vladimir Kuryatkov, Yejin Kwon, Ayrton A. Bernussi, Myoung-Hwan Kim

Physics & Astronomy Faculty Publications

Coating polar dielectrics with thin film vanadium dioxide (VO2) enables one to exploit the temperature-dependent phase transition within VO2 to actively tune and modulate surface phonon polaritons at mid-infrared. However, controlling the behavior of such systems requires intimate knowledge of the temperature-dependent optical constants of VO2, which depend greatly on the growth conditions and substrate material. Here, we accurately determine the complex optical constants of VO2 on polar dielectrics across the insulator-to-metal phase transition (IMT) using only normal incident reflectance spectra by analyzing the reflectance with Kramers–Kronig relations and thin film Fresnel equations. This non-ellipsometry technique offers an …

Observation Of Gravitational Waves From The Coalescence Of A 2.5–4.5 M⊙ Compact Object And A Neutron Star, A. Abac, R. Abbott, I. Abouelfettouh, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We report the observation of a coalescing compact binary with component masses 2.5–4.5 M⊙ and 1.2–2.0 M⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find …

Microwave Spectroscopy And Large Amplitude Motion Of Chlorosulfonic Acid (Clso2oh), Aaron J. Reynolds, Diego E. Rodriguez, Wei Lin, Kenneth R. Leopold

Physics & Astronomy Faculty Publications

The high-resolution rotational spectrum of chlorosulfonic acid (ClSO2OH) has been studied using both broadband and cavity-based Fourier transform microwave spectrometers over the frequency range of 5–18 GHz. a-, b-, and c-type transitions have been recorded for both the 35Cl and 37Cl isotopologues. The observation of c-type lines establishes that the molecule lacks a plane of symmetry and suggests that the OH group can undergo large amplitude motion between equivalent structures. Interconversion between these structures can be achieved via internal rotation through two inequivalent barriers occurring at Cl-S-O-H torsional angles of 0 or 180 degrees. As in …