Answers To Frequently Asked Questions About The Pulsar Timing Array Hellings And Downs Curve,
2024
The University of Texas Rio Grande Valley
Answers To Frequently Asked Questions About The Pulsar Timing Array Hellings And Downs Curve, Joseph D. Romano, Bruce Allen
Physics & Astronomy Faculty Publications
We answer frequently asked questions (FAQs) about the Hellings and Downs correlation curve—the ‘smoking-gun’ signature that pulsar timing arrays (PTAs) have detected gravitational waves (GWs). Many of these questions arise from inadvertently applying intuition about the effects of GWs on LIGO-like detectors to the case of pulsar timing, where not all of it applies. This is because Earth-based detectors, like LIGO and Virgo, have arms that are short (km scale) compared to the wavelengths of the GWs that they detect (≈102–104 km). In contrast, PTAs respond to GWs whose wavelengths (tens of light-years) are much shorter than their arms (a …
Space Radiation Assessment And Mitigation: Meeting The Growing Demand For Shielding Solutions By Enhancing Models And Exploring Novel Shielding Opportunities,
2024
Embry-Riddle Aeronautical University
Space Radiation Assessment And Mitigation: Meeting The Growing Demand For Shielding Solutions By Enhancing Models And Exploring Novel Shielding Opportunities, M. Laura Sorgi Johann
Doctoral Dissertations and Master's Theses
The rapid growth of satellite technology and the increasing presence of vulnerable technology and human life in space have highlighted the need for improved shielding materials. Industry standard protocols for shielding are being pushed to their limits as we gain a deeper understanding of the harsh space environment and as chip sizes approach the scale of radiation wavelengths. Furthermore, the commercialization of space is attracting interest from industries such as pharmaceuticals and semiconductor crystal growing, as they explore the potential benefits of zero-gravity production environments. However, the eagerness to develop lighter shielding and the lack of consideration for existing tools …
Constraining Giant Planet Occurrence Rates With The Multi-Band Imaging Survey For High-Alpha Planets (Mishaps) Observations Of 47 Tucanae,
2024
Louisiana State University and Agricultural and Mechanical College
Constraining Giant Planet Occurrence Rates With The Multi-Band Imaging Survey For High-Alpha Planets (Mishaps) Observations Of 47 Tucanae, Alison Crisp
LSU Doctoral Dissertations
Though the confirmed exoplanet population has now reached over 5,500 planets, we still have a plethora of unanswered questions, e.g., regarding their formation mechanisms, true demographics, occurrence rates, and habitability. One remaining question is whether hot Jupiters formed in situ or migrated to their current orbits, so close to their host stars that their periods are 10 days or less. This question can potentially be answered by probing the effects of elemental abundances on hot Jupiter occurrence rates. These rates have been found to correlate with metallicity, but the specific elements responsible for the correlation have largely been unresolved. The …
Glitch Veto Based On Unphysical Gravitational Wave Binary Inspiral Templates,
2024
The University of Texas Rio Grande Valley
Glitch Veto Based On Unphysical Gravitational Wave Binary Inspiral Templates, Raghav Girgaonkar, Soumya D. Mohanty
Physics & Astronomy Faculty Publications
Transient signals arising from instrumental or environmental factors, commonly referred to as glitches, constitute the predominant background of false alarms in gravitational wave searches with ground-based detectors. Therefore, effective data analysis methods for vetoing glitch-induced false alarms are crucial to enhancing the sensitivity of a search. We present a veto method for glitches that impact matched filtering-based searches for binary inspiral signals. The veto uses unphysical sectors in the space of chirp time parameters as well as an unphysical extension including negative chirp times to efficiently segregate glitches from gravitational wave signals in data from a single detector. Inhabited predominantly …
Identifying The O’Connell Effect In Eclipsing Binary Stars,
2024
Kutztown University of Pennsylvania
Identifying The O’Connell Effect In Eclipsing Binary Stars, Nicholas Paolella
Computer Science and Information Technology Faculty
Data science techniques have wide-ranging applications throughout scientific explorations. One, is filtering astronomical data to better understand specific populations, such as binary stars. Specifically, binary stars that exhibit the O’Connell effect are worthy of study as this phenomenon is still not well understood. The O’Connell effect can be defined as the asymmetry of maxima in the light curves, as captured by the instrument, while observing the eclipsing binary system in question. There is significant data captured by NASA and curated by Villanova University, which enabled the investigation of eclipsing binary stars and the attributes of which may help identify the …
Variable Radio Emission Of Neutron Star X-Ray Binary Ser X–1 During Its Persistent Soft State,
2024
Texas Tech University
Variable Radio Emission Of Neutron Star X-Ray Binary Ser X–1 During Its Persistent Soft State, Eli C. Pattie, Thomas J. Maccarone, Alexandra J. Tetarenko, James C. A. Miller-Jones, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval
Physics & Astronomy Faculty Publications
Ser X–1 is a low-mass neutron star X-ray binary and has been persistently accreting since its discovery in the 1960s. It has always been observed to be in a soft spectral state and has never showed substantial long-term X-ray variability. Ser X–1 has one previous radio observation in the literature in which radio emission was detected during this soft state, which is contrary to the behavior of black hole X-ray binaries. We have recently obtained 10 randomly sampled radio epochs of Ser X–1 in order to further investigate its anomalous soft-state radio emission. Out of 10 epochs, we find 8 …
Calibrating The Global Network Of Gravitational Wave Observatories Via Laser Power Calibration At Nist And Ptb,
2024
The University of Texas Rio Grande Valley
Calibrating The Global Network Of Gravitational Wave Observatories Via Laser Power Calibration At Nist And Ptb, Dripta Bhattacharjee, Richard Lenox Savage, Rishabh Bajpai, Joseph Betzwieser, Vladimir Bossilkov, Dan Chen, Cervane Grimaud, Shingo Hido, Sudarshan Karki, Francisco Llamas
Physics & Astronomy Faculty Publications
Current gravitational wave (GW) observatories rely on photon calibrators that use laser radiation pressure to generate displacement fiducials used to calibrate detector output signals. Reducing calibration uncertainty enables optimal extraction of astrophysical information such as source distance and sky position from detected signals. For the ongoing O4 observing run that started on 24 May 2023, the global GW detector network is employing a new calibration scheme with transfer standards calibrated at both the National Institute of Standards and Technology (NIST) and the Physikalisch-Technische Bundesanstalt (PTB). These transfer standards will circulate between the observatories and the metrology institutes to provide laser …
Evaluating Spatial Clustering As A Lunar Crater Classification Method,
2024
Ursinus College
Evaluating Spatial Clustering As A Lunar Crater Classification Method, Annalyse Dickinson
Physics and Astronomy Summer Fellows
Crater identification is important for investigating and determining the age of planetary surfaces. Based on the number of primary craters—which are formed from a bolide impacting a planetary surface—one can determine the surface’s absolute model age, but the secondary craters—which are formed from the many fragments ejected during a primary crater’s creation—contaminate that count. The abundant variability in crater identification methods is a prominent issue in the field of planetary science. In addition, there is no single characteristic that can set these craters apart due to the processes involved in their formation and degradation. This is why we aim to …
Lunar Crater Categorization And Why Accessibility Matters For Planetary Scientists,
2024
Ursinus College
Lunar Crater Categorization And Why Accessibility Matters For Planetary Scientists, Gavin Soueidan, Mckenzie Snyder
Physics and Astronomy Summer Fellows
One can determine the absolute model age of any planetary body in the solar system by compiling statistics about primary craters. However, secondary craters contaminate those statistics. Differentiating between primary craters—which are formed from an impact of an object from space onto a planetary surface—and secondary craters—which are formed from the fragments ejected from primaries—is an outstanding question in planetary science literature. No one characteristic can universally distinguish primaries from secondaries, and workers have developed numerous methods for sorting the two classes of craters. This is why we are developing a semi-automated, transparent, reproducible procedure that will compile datasets that …
Satellite Group Infall Into The Milky Way: Exploring The Crater-Leo Case With New Hst Proper Motions,
2024
Case Western Reserve University
Satellite Group Infall Into The Milky Way: Exploring The Crater-Leo Case With New Hst Proper Motions, Stacy S. Mcgaugh
Faculty Scholarship
Context. Within Λ cold dark matter (ΛCDM) simulations, Milky Way-like galaxies accrete some of their satellite galaxies in groups of 3–5 members rather than individually, and this has been suggested as a possible mechanism driving the formation of satellite planes. Objects accreted in groups are expected to share similar specific total energy and angular momentum, and to also have identical orbital planes and directions. Aims. Looking at observatio ns of Milky Way satellites, the dwarf galaxies Leo II, IV, V, and Crater II, and the star cluster Crater 1 were proposed to be a vestige of group infall. The suggested …
Fe-Rich X-Ray Amorphous Material Records Past Climate And Persistence Of Water On Mars,
2024
University of Nevada, Las Vegas
Fe-Rich X-Ray Amorphous Material Records Past Climate And Persistence Of Water On Mars, Anthony D. Feldman, Elisabeth M. Hausrath, Elizabeth B. Rampe, Valerie Tu, Tanya S. Peretyazhko, Christopher Defelice, Thomas Sharp
Geoscience Faculty Research
X-ray amorphous material comprises 15-73 wt.% of sedimentary rocks and eolian sediments in Gale crater. This material is variably siliceous and iron rich but aluminum poor. The presence of volatiles is consistent with the existence of incipient weathering products. To better understand the implications of this material for past aqueous conditions on Mars, here we investigate X-ray amorphous material formation and longevity within terrestrial iron rich soils with varying ages and environmental conditions using bulk and selective dissolution methods, X-ray diffraction, and transmission electron microscopy. Results indicate that in situ aqueous alteration is required to concentrate iron into clay-size fraction …
Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles.,
2024
Rowan University
Numerical Simulations Suggest Asteroids (101955) Bennu And (162173) Ryugu Are Likely Second Or Later Generation Rubble Piles., K J Walsh, R-L Ballouz, W F Bottke, C Avdellidou, Harold Connolly Jr., M Delbo, D N Dellagiustina, E R Jawin, T Mccoy, P Michel, T Morota, M C Nolan, S R Schwartz, S Sugita, D S Lauretta
School of Earth & Environment Departmental Research
Rubble pile asteroids are widely understood to be composed of reaccumulated debris following a catastrophic collision between asteroids in the main asteroid belt, where each disruption can make a family of new asteroids. Near-Earth asteroids Ryugu and Bennu have been linked to collisional families in the main asteroid belt, but surface age analyses of each asteroid suggest these bodies are substantially younger than their putative families. Here we show, through a coupled collisional and dynamical evolution of members of these families, that neither asteroid was likely to have been created at the same time as the original family breakups, but …
Rising Tides: An Analytic Modeling Code Of Tidal Effects In Binary Neutron Star Mergers,
2024
Marshall University
Rising Tides: An Analytic Modeling Code Of Tidal Effects In Binary Neutron Star Mergers, Alexander O'Dell, Maria Babiuc-Hamilton
Physics Faculty Research
Gravitational waves produced by binary neutron star mergers offer a unique window into matter behavior under extreme conditions. In this context, we analytically model the effect of matter on gravitational waves from binary neutron star mergers. We start with a binary black hole system, leveraging the post-Newtonian formalism for the inspiral and the Backwards-one-Body model for the merger. We combine the two methods to generate a baseline waveform and we validate our results against numerical relativity simulations. Next, we integrate tidal effects in phase and amplitude to account for matter and spacetime interaction using the NRTidal model and test its …
The Large-Scale Environments Of Active Galactic Nuclei,
2024
Dartmouth College
The Large-Scale Environments Of Active Galactic Nuclei, Grayson C. Petter
Dartmouth College Ph.D Dissertations
It is now recognized that the energy released by accreting supermassive black holes observed as Active Galactic Nuclei (AGN) is integral in shaping the dynamics of baryons on up to cosmological scales, and AGN thus play a significant role in regulating the formation and evolution of galaxies. Studying the clustering properties of AGN reveals which environments they release this feedback energy into, testing models of AGN-galaxy coevolution and AGN structure. In this thesis, I leverage wide-area photometric and spectroscopic survey data to measure the clustering properties of various AGN samples containing millions of systems, placing tight constraints on the properties …
On The Nature Of Low-Frequency Power Spectra In Solar Wind Turbulence,
2024
Florida Institute of Technology
On The Nature Of Low-Frequency Power Spectra In Solar Wind Turbulence, Mason Alden Dorseth
Theses and Dissertations
An important challenge in the accurate estimation of power spectra of plasma fluctuations in the solar wind at very low frequencies is that it requires extremely long signals, which will necessarily contain a mixture of qualitatively different solar wind streams. This unavoidably affects the structure of the power spectra by conflating all these different properties into a single power spectrum. This work develops a conditional statistical analysis to accurately estimate the power spectrum at arbitrarily low frequencies for ``pure'' slow solar wind stream, based on estimated autocorrelation functions of signals excluding portions that do not satisfy the required conditions. The …
Search For Gravitational-Lensing Signatures In The Full Third Observing Run Of The Ligo–Virgo Network,
2024
The University of Texas Rio Grande Valley
Search For Gravitational-Lensing Signatures In The Full Third Observing Run Of The Ligo–Virgo Network, R. Abbott, H. Abe, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang
Physics & Astronomy Faculty Publications
Gravitational lensing by massive objects along the line of sight to the source causes distortions to gravitational wave (GW) signals; such distortions may reveal information about fundamental physics, cosmology, and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO-Virgo network. We search for repeated signals from strong lensing by (1) performing targeted searches for subthreshold signals, (2) calculating the degree of overlap among the intrinsic parameters and sky location of pairs of signals, (3) comparing the similarities of the spectrograms among pairs of …
Indefinitely Flat Circular Velocities And The Baryonic Tully-Fisher Relation From Weak Lensing,
2024
Case Western Reserve University
Indefinitely Flat Circular Velocities And The Baryonic Tully-Fisher Relation From Weak Lensing, Tobias Mistele, Stacy Mcgaugh
Faculty Scholarship
We use a new deprojection formula to infer the gravitational potential around isolated galaxies from weak gravitational lensing. The results imply circular velocity curves that remain flat for hundreds of kiloparsecs, greatly extending the classic result from 21 cm observations. Indeed, there is no clear hint of a decline out to 1 Mpc, well beyond the expected virial radii of dark matter halos. Binning the data by mass reveals a correlation with the flat circular speed that closely agrees with the baryonic Tully-Fisher relation known from kinematic data. These results apply to both early- and late-type galaxies, indicating a common …
The Baryonic Tully-Fisher Relation. I. Wise/Spitzer Photometry,
2024
Case Western Reserve University
The Baryonic Tully-Fisher Relation. I. Wise/Spitzer Photometry, Francis Duey, Stacy Mcgaugh
Faculty Scholarship
We present Wide-field Infrared Survey Explorer (WISE) W1 photometry of the Spitzer Photometry and Accurate Rotation Curves sample. The baseline of near-IR fluxes is established for use by stellar mass models, a key component to the baryonic Tully-Fisher relation and other kinematic galaxies scaling relations. We focus this paper on determination of the characteristics of the W1 fluxes compared to IRAC 3.6 μm fluxes, internal accuracy limitations from photometric techniques, external accuracy by comparison to other work in the literature and the range of W1 to IRAC 3.6 μm colors. We outline the behavior of SDSS g, W1 and IRAC …
On The Impact Of Geospace Weather On The Occurrence Of M7.8/M7.5 Earthquakes On 6 February 2023 (Turkey), Possibly Associated With The Geomagnetic Storm Of 7 November 2022,
2024
Chapman University
On The Impact Of Geospace Weather On The Occurrence Of M7.8/M7.5 Earthquakes On 6 February 2023 (Turkey), Possibly Associated With The Geomagnetic Storm Of 7 November 2022, Dimitar Ouzounov, Galina Khachikyan
Mathematics, Physics, and Computer Science Faculty Articles and Research
A joint analysis of solar wind, geomagnetic field, and earthquake catalog data showed that before the catastrophic M = 7.8 and M = 7.5 Kahramanmaras earthquake sequence on 6 February 2023, a closed strong magnetic storm occurred on 7 November 2022, SYM/H = −117 nT. The storm started at 08:04 UT. At this time, the high-latitudinal part of Turkey’s longitudinal region of future epicenters was located under the polar cusp, where the solar wind plasma would directly access the Earth’s environment. The time delay between storm onset and earthquake occurrence was ~91 days. We analyzed all seven strong (M7+) earthquakes …
Strong Edge Burst With Bipolar Non-Hermitian Skin Effect,
2024
The University of Texas Rio Grande Valley
Strong Edge Burst With Bipolar Non-Hermitian Skin Effect, Cem Yuce, Hamidreza Ramezani
Physics & Astronomy Faculty Publications
We consider a system exhibiting the bipolar non-Hermitian skin effect (NHSE), where bipolar skin states are localized at both edges, and discuss how the topological funneling effect can occur with a single focal point in this system. We explore a topological phase transition from bipolar NHSE to NHSE, which alters the localization characteristics of the eigenstates. After the transition, both the delocalized and bipolar skin states transform into skin states. The non-Hermitian edge burst is a novel and unexpected feature of non-Hermitian quantum dynamics, characterized by substantial particle loss at the boundary of a system. Using the model displaying bipolar …
