Astrophysics and Astronomy Commons^™

Exiting Inflation With A Smooth Scale Factor, Harry Oslislo, Brett Altschul

Faculty Publications

The expectation that the physical expansion of space occurs smoothly may be expressed mathematically as a requirement for continuity in the time derivative of the metric scale factor of the Friedmann–Robertson–Walker cosmology. We explore the consequences of imposing such a smoothness requirement, examining the forms of possible interpolating functions between the end of inflation and subsequent radiation- or matter-dominated eras, using a straightforward geometric model of the interpolating behavior. We quantify the magnitude of the cusp found in a direct transition from the end of slow-roll inflation to the subsequent era, analyze the validity of several smooth interpolator candidates, and …

The High Energy X-Ray Probe: Resolved X-Ray Populations In Extragalactic Environments, Bret D. Lehmer, Kristen Garofali, Breanna A. Binder, Francesca Fornasini, Neven Vulic, Andreas Zezas, Ann Hornschemeier, Margaret Lazzarini, Hannah Moon, Toni Venters, Daniel Wik, Mihoko Yukita, Matteo Bachetti, Javier A. Garcia, Brian Grefenstette, Kristin Madsen, Kaya Mori, Daniel Stern

Physics Faculty Publications and Presentations

We construct simulated galaxy data sets based on the High Energy X-ray Probe (HEX-P) mission concept to demonstrate the significant advances in galaxy science that will be yielded by the HEX-P observatory. The combination of high spatial resolution imaging (FWHM), broad spectral coverage (0.2–80 keV), and sensitivity superior to current facilities (e.g., XMM-Newton and NuSTAR) will enable HEX-P to detect hard (4–25 keV) X-ray emission from resolved point-source populations within ∼800 galaxies and integrated emission from ∼6,000 galaxies out to 100 Mpc. These galaxies cover wide ranges of galaxy types (e.g., normal, starburst, and passive galaxies) and properties (e.g., metallicities …

Radio Emission From Low-Mass Active Galactic Nuclei, Ammara Aftab

Theses

Massive black holes of a few million to billion solar masses lurk at the centers of the most present-day massive galaxies but their origin is still unknown. The low mass galaxies (M* ~ 3x10⁹ Mʘ ) hosting black holes with masses ranging from 10³ to 10⁵ Mʘ are ideal laboratories to test the models of black hole formation and they may help in understanding the co-evolution of central black holes with their host galaxies. In this thesis, we have developed a detailed theoretical model/framework to estimate the radio emission from low-mass active galactic nuclei (AGN). We also …

Coastal Bathymetry Of The United Arab Emirates Using Satellite-Based Remote Sensing Data, Naser Salem Aldahmani

Theses

Bathymetry is the study of the bed under the water's surface, giving us the water's depth. The Thesis will be about studying the coastal area of the UAE by using satellite images that can help access large regions of the UAE Coast. Also, by using a history of 5 years of satellite visible bands and NIR images, we can see the change of depth near the coastal. The benefit of that study will help to build ship baths through shallow water and to go in and out of ports of UAE. Early warnings of the sea level increasing near the …

Broadband Quantum Enhancement Of The Ligo Detectors With Frequency-Dependent Squeezing, D. Ganapathy, W. Jia, M. Nakano, V. Xu, N. Aritomi, T. Cullen, N. Kijbunchoo, S. E. Dwyer, Francisco Llamas, Volker Quetschke

Physics & Astronomy Faculty Publications

Quantum noise imposes a fundamental limitation on the sensitivity of interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. Here, we present the first realization of frequency-dependent squeezing in full-scale gravitational-wave detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, with broadband detector enhancement from tens of hertz to several kilohertz. In the LIGO Hanford detector, squeezing reduced the detector noise amplitude by a factor of 1.6 (4.0 dB) near 1 kHz; in the Livingston detector, the noise reduction was a factor of 1.9 (5.8 dB). These improvements directly impact …

First Approximation Of Population Distributions On The International Space Station, Justin St. P. Walsh, Rao Hamza Ali, Alice C. Gorman, Amir Kanan Kashefi

Art Faculty Articles and Research

This paper presents an analysis of data derived from thousands of publicly available photographs showing life on the International Space Station (ISS) between 2000 and 2020. Our analysis uses crew and locational information from the photographs’ metadata to identify the distribution of different population groups—by gender, nationality, and space agency affiliation—across modules of the ISS, for the first time. Given the significance of the ISS as the most intensively inhabited space habitat to date, an international cooperative initiative involving 26 countries and five space agencies, and one of the most expensive building projects ever undertaken by humans, developing an understanding …

Understanding The Nature Of Pulsars And Characterizing Propagation Effects Using Pulsar Timing, Pratik Kumar

Physics & Astronomy ETDs

Pulsars are highly magnetized stellar remnants, among the densest known objects, and primarily produce radio emission in the form of lighthouse beams sweeping across the line of sight as a regular train of pulses. Apart from providing tests for matter in high-density regimes, general relativity, and plasma emission; perhaps the most notable characteristic is their applicability as precise astronomical clocks to measure various effects. Pulsar Timing Arrays (PTAs) are galactic scale detectors analogous to ground-based detectors of Gravitational Waves (GWs) like LIGO, with the aim of detecting low-frequency nano-Hz GWs from coalescing binary supermassive black holes. PTAs consist of a …

A Framework To Validate Fluorescently Labeled Dna-Binding Proteins For Single-Molecule Experiments, Miranda L. Molina, Lindsey E. Way, Zhongqing Ren, Qin Liao, Bianca Guerra, Brandon Shields, Xindan Wang, Hyeongjun Kim

Physics & Astronomy Faculty Publications

Due to the enhanced labeling capability of maleimide-based fluorescent probes, lysine-cysteine-lysine (KCK) tags are frequently added to proteins for visualization. In this study, we employed an in vitro single-molecule DNA flow-stretching assay as a sensitive way to assess the impact of the KCK tag on the property of DNA-binding proteins. Using Bacillus subtilis ParB as an example, we show that, although no noticeable changes were detected by in vivo fluorescence imaging and chromatin immunoprecipitation (ChIP) assays, the KCK tag substantially altered ParB's DNA compaction rates and its response to nucleotide binding and to the presence of the specific sequence (parS) …

A Framework To Validate Fluorescently Labeled Dna-Binding Proteins For Single-Molecule Experiments, Miranda Molina, Lindsey E. Way, Zhongqing Ren, Qin Liao, Bianca Guerra, Brandon Shields, Xindan Wang, Hyeongjun Kim

Physics & Astronomy Faculty Publications

Highlights

• KCK tag can alter protein properties both quantitatively and qualitatively

• Electrostatic interactions between the KCK tag and DNA contribute to the artifacts

• Adding a short peptide tag to ParB protein does not lead to its in vivo changes

• Single-molecule DNA flow-stretching assay can detect protein property changes

Motivation

Single-molecule fluorescence microscopy has been extensively used in modern biology to define the molecular action of proteins. Appending short peptide tags is a common strategy to enhance fluorescence labeling. Here, we evaluate the impact of a commonly used tag, the lysine-cysteine-lysine (KCK) tag, on protein behavior in single-molecule DNA flow-stretching assay, …

Fast-Askap Synergy: Quantifying Coexistent Tidal And Ram Pressure Strippings In The Ngc 4636 Group, Xuchen Lin, Jing Wang, Virginia Kilborn, Eric W. Peng, Luca Cortese, Alessandro Boselli, Ze-Zhong Liang, Bumhyun Lee, Dong Yang, Juan P. Madrid

Physics & Astronomy Faculty Publications

Combining new H I data from a synergetic survey of Australian Square Kilometre Array Pathfinder (ASKAP) Widefield ASKAP L-band Legacy All-sky Blind surveY and Five-hundred-meter Aperture Spherical radio Telescope with the Arecibo Legacy Fast ALFA data, we study the effect of ram pressure and tidal interactions in the NGC 4636 group. We develop two parameters to quantify and disentangle these two effects on gas stripping in H I-bearing galaxies: the strength of external forces at the optical-disk edge, and the outside-in extents of H I-disk stripping. We find that gas stripping is widespread in this group, affecting 80% of H …

Jwst-Tst Dreams: Quartz Clouds In The Atmosphere Of Wasp-17b, David Grant, Nikole K. Lewis, Hannah R. Wakeford, Natasha E. Batalha, Ana Glidden, Jayesh Goyal, Elijah Mullens, Ryan J. Macdonald, Erin M. May, Sara Seager, Kevin B. Stevenson, Jeff A. Valenti, Channon Visscher, Lili Alderson, Natalie H. Allen, Caleb I. Canas, Knicole Colon, Mark Clampin, Nestor Espinoza, Amelie Gressier, Jingcheng Huang, Zifan Lin, Douglas Long, Dana R. Louie, Maria Pena-Guerrero, Sukrit Ranjan, Kristin S. Sotzen, Daniel Valentine, Jay Anderson, William O. Balmer, Andrea Bellini, Kielan K. W. Hoch, Jens Kammerer, Mattia Libralato, C. Matt Mountain, Marshall D. Perrin, Laurent Pueyo, Emily Rickman, Isabel Rebollido, Sangmo Tony Sohn, Roeland P. Van Der Marel, Laura L. Watkins

Faculty Work Comprehensive List

Clouds are prevalent in many of the exoplanet atmospheres that have been observed to date. For transiting exoplanets, we know if clouds are present because they mute spectral features and cause wavelength-dependent scattering. While the exact composition of these clouds is largely unknown, this information is vital to understanding the chemistry and energy budget of planetary atmospheres. In this work, we observe one transit of the hot Jupiter WASP-17b with JWST's Mid-Infrared Instrument Low Resolution Spectrometer and generate a transmission spectrum from 5 to 12 μm. These wavelengths allow us to probe absorption due to the vibrational modes of …

Core Destruction In Knockout Reactions, Carlos A. Bertulani

Faculty Publications

A model is presented to calculate projectile core destruction in knockout reactions. It incorporates physics arguments similar to the formulation of the state of the art theory to calculate stripping and diffraction dissociation cross sections in heavy ion collisions with bombarding energies around 100 MeV/nucleon and larger. It is shown that secondary collisions between the incoming and struck nucleons with the projectile core decrease the core survival probability by as much as 9.5%. However, no clear evidence is found for reduction of the cross section with increasing binding energy of the removed nucleon.

The Accumulation And Growth Of Pseudomonas Aeruginosa On Surfaces Is Modulated By Surface Mechanics Via Cyclic-Di-Gmp Signaling, Liyun Wang, Yu-Chern Wong, Joshua M. Correira, Megan Wancura, Chris J. Geiger, Shanice S. Webster, Ahmed Touhami, Benjamin J. Butler, George A. O’Toole, Richard M. Langford

Physics & Astronomy Faculty Publications

Attachment of bacteria onto a surface, consequent signaling, and accumulation and growth of the surface-bound bacterial population are key initial steps in the formation of pathogenic biofilms. While recent reports have hinted that surface mechanics may affect the accumulation of bacteria on that surface, the processes that underlie bacterial perception of surface mechanics and modulation of accumulation in response to surface mechanics remain largely unknown. We use thin and thick hydrogels coated on glass to create composite materials with different mechanics (higher elasticity for thin composites; lower elasticity for thick composites) but with the same surface adhesivity and chemistry. The …

An Introduction To The Veritas Observatory, Alexander Bittle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Located at the base of Mount Hopkins, Arizona, at an elevation of approximately 4200 feet, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based gamma ray observatory containing four Cherenkov telescopes designed to detect very high energy gamma rays with energies ranging from 100GeV to 10TeV using the Imaging Atmospheric Cherenkov Technique. In April 2007, VERITAS began successful operations with all four telescopes. As of today, over 15 years of data has been taken by the VERITAS array, stored in an archive of data, and used for a wide variety of research, publications, PhD theses, and conventions …

Analysis Of The Crab Nebula And Pulsar, Alexander Bittle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Although the Crab Nebula is well understood, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) still regularly observes the Crab's highest energy emissions. These emissions are used to calibrate the telescopes, further, document the system, and investigate the validity of physical models. Our research this summer is geared to analyze data from 2018-2022 to add to an ongoing research project investigating the long term variability of the Crab Nebula’s emission.

The Gbt Diffuse Ionized Gas Survey (Gdigs): Discrete Sources, Dylan J. Linville, Matteo Luisi, Bin Liu, T. M. Bania, Dana S. Balser, Trey V. Wenger, L. M. Haffner

Publications

The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by observing radio recombination line (RRL) emission from 4–8 GHz. The nominal survey zone is 32.3◦ > ℓ > −5◦, | b | < 0.5◦. Here, we analyze GDIGS Hnα ionized gas emission toward discrete sources. Using GDIGS data, we identify the velocity of 35 H II regions that have multiple detected RRL velocity components. We identify and characterize RRL emission from 88 H II regions that previously lacked measured ionized gas velocities. We also identify and characterize RRL emission from eight locations that appear to be previously-unidentified H II regions and 30 locations of RRL emission that do not appear to be H II regions based on their lack of mid-infrared emission. This latter group may be a compact component of the Galactic Diffuse Ionized Gas (DIG). There are an additional 10 discrete sources that have anomalously high RRL velocities for their locations in the Galactic plane. We compare these objects’ RRL data to 13CO, H I and mid-infrared data, and find that these sources do not have the expected 24 µm emission characteristic of H II regions. Based on this comparison we do not think these objects are H II regions, but we are unable to classify them as a known type of object.

Phys 431/831

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 811

Department of Physics and Astronomy: Syllabi

No abstract provided.

Astr 103

Department of Physics and Astronomy: Syllabi

No abstract provided.

Astr 204

Department of Physics and Astronomy: Syllabi

No abstract provided.