Bulletin of the American Physical Society
APS April Meeting 2022
Volume 67, Number 6
Saturday–Tuesday, April 9–12, 2022; New York
Session S17: Poster Session III (2:00-4:00 pm)Poster Undergrad Friendly
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Room: 9th Floor Terrace |
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S17.00001: NUCLEAR PHYSICS
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S17.00002: Fitting the cross-section probability tables with universal functions Matteo Vorabbi, David Brown, Marcus McLaurin In the unresolved resonance region (URR), cross sections for neutrons interacting with nuclei have resonances that cannot be measured nor predicted, hence only statistical values are provided. The current methodology used to describe such behavior is based on a Monte Carlo realization of resonance ladders, which makes the calculation computationally expensive. Thus, an analytical fit of these probability distributions would considerably speed up their computational time when used in real life applications. The goal of this project is to identify a “universal” function that can be used to fit the probability distribution of a particular reaction channel across the entire nuclear chart. For this project we will generate the zero-temperature probability distribution functions for all the available nuclei, and we will analyze them searching for similar patterns and regularities that can help to identify the proper functions to be used for the fit. Results will be presented for the capture channel for some selected nuclei along with a new approach for the fit of the elastic channel. |
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S17.00003: Tracking and Event Visualization for the Muon Proton Scattering Experiment Kyle J Salamone In 2010 the proton radius was measured to be 0.842 fm ± 0.001 fm, which is approximately 4 % smaller than the previously accepted CODATA value determined from electronic measurements. The Muon Proton Scattering Experiment (MUSE) is seeking to shed light on this so called "Proton Radius Puzzle" by simultaneously scattering electrons and muons off of a liquid hydrogen target at the PiM1 Beamline in the Paul Scherrer Institute. Scattered particles are measured in the Straw Tube Tracker. Tracks are formed in offline analysis, but for near-online analysis an event display is under development to quickly assess the operation of the STT. In this poster we will discuss the STT tracking efficiency and demonstrate the operation of the event display. |
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S17.00004: Monte Carlo simulation of a dedicated neutron detector for the COHERENT experiment at the SNS, ORNL Conan D Bock The COHERENT collaboration is aimed at measuring Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) with high-quality pion-decay-at-rest neutrinos from the Spallation Neutron Source (SNS) at Oak Ridge National Lab (ORNL), Tennessee. Neutrons that survive thick shielding between the source and COHERENT detectors are a serious background for CEvNS detection. A dedicated neutron detector, MARS, is used to measure this background. The performance of this detector has been characterized using various radioactive sources, including a DT neutron generator. A Geant4 Monte Carlo simulation package has been developed to evaluate the efficiency of neutron detection and to understand the detector response to neutrons at various energies. Reported here are the comparison of the recorded and simulated calibration data, as well as the simulated neutron detection efficiency. The efficiency is used to estimate the neutron background level of COHERENT detectors. |
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S17.00005: Cross section measurement for an exclusive phi meson electroproduction at CLAS12 Patrick H Moran
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S17.00006: Development of a pulsed, 0.1 to 1.0 MeV electron accelerator for High Precision Characterization McKenna R Sleeth, Albert Young, RJ Taylor, Thomas Calisto, Eric Watkins, Chris Westerfeldt, William McCray, Bret Carlin, Clay Fogelman, John P Rabaey
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S17.00007: Development of Aluminum-Based STJs for Phase-IV of the BeEST Experiment Spencer Fretwell The BeEST experiment is a model independent search for heavy neutrinos in the decay of 7Be implanted in superconducting tunnel junction (STJ) quantum sensors. The sensitivity goals for Phase-IV of the experiment require an increase in number of detectors, reduced backgrounds, and improved energy resolution from the STJs. To achieve this, we are currently developing arrays of aluminum-based STJs deposited on 500 nm silicon-nitride (SiN) membranes. In this talk, we present the design of these new devices as well as characterization of the signals. |
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S17.00008: Transfer Reactions and Nuclear Matrix Elements for Double Beta Decay James A Runge, Calvin R Howell, Timothy V Daniels, Phillip S Barbeau Nuclear matrix elements will be important for extracting insightful knowledge of the universe from the lifetime of neutrinoless double beta decay (0vBB) should it be observed. These matrix elements require approximations to do calculations, and it is important that those approximations be valid. One such approximation is the quasiboson approximation used in the quasiparticle random phase approximation(QRPA). A series of (3He,n) reactions has been carried out at the Triangle Universities Nuclear Laboratory (TUNL) to test the validity of QRPA for several 0vBB candidate nuclei. This work will discuss the analysis of 134Xe(3He,n)136Ba, where significant transitions to excited 0+ states were not observed, suggesting that the QRPA wave function may appropriately describe 136Ba, the daughter nucleus of the 0vBB decay of 136Xe. |
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S17.00009: Interference effects for 0νββ decay in the left-right symmetric model Fahim Ahmed Neutrinoless double-β decay is considered to be an important low energy probe to test beyond the Standard Model physics. There are several potentially competing beyond the Standard Model mechanisms that can induce the process. In the present study we consider the extensively investigated beyond the Standard Model scenario of the left-right symmetric model and focus on interference between the most dominant diagrams of the process contributing to the overall decay rate. The analysis of the contributions of these interference terms is important for disentangling different mechanisms. The numerical values for maximum interference for several nuclides of experimental interest are calculated. It is observed that, for most of the interference terms, the contribution is smaller than 20% for all the nuclei considered in the study. However, the interference between the mass mechanisms (light and heavy) and η mechanism is observed to be in the range 30%–50%. The variation of the interference effect with the Q values is also studied. |
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S17.00010: Nuclear Level Density Determinations via 12C+27Al Proton Evaporation Spectra Sam Carryer Models for nuclear applications and nuclear astrophysics require nuclear reaction rates for a large number of reactions, though direct measurements are typically not possible. Instead, key nuclear properties are measured indirectly. For many nuclides, statistical properties are of interest, such as the nuclear level density and optical model potentials. We report preliminary results from 12C+27Al proton evaporation spectra measured at the Edwards Accelerator Laboratory, which we are analyzing with statistical model calculations to constrain the nuclear level density of 38Ar. |
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S17.00011: First direct measurement of the 7Be electron capture Q value to aid experimental searches for sterile neutrinos with the BeEST Ramesh Bhandari, Georg Bollen, Nadeesha D Gamage, Alec S Hamaker, Madhawa H Gamage, Dakota Keblbeck, Kyle G Leach, Daniel Puentes, Matthew Redshaw, Ryan J Ringle, Stefan Schwarz, Chandana S Sumithrarachchi, Isaac T Yandow, Zachary Hockenbery The Beryllium Electron capture in Superconducting Tunnel junctions (BeEST) experiment is searching for the signature of sterile neutrinos via momentum reconstruction in the EC decay of 7Be. In EC decay, there are only two final state products, the daughter atom, and neutrino. Rather than having an energy distribution of final products, as in beta decay, in EC decay the neutrino and recoiling daughter atom have well defined energies that depend on the kinematics of the decay. In the case of 7Be EC decay, the ground-state to ground-state Q-value of 861.89(71) keV results in a recoil energy for the 7Li daughter atom of 56.83(1) eV. Although the uncertainty in the recoil energy is only 10 meV, this is already comparable to the uncertainty in the 7Li recoil energy obtained in Phase II operation of the BeEST experiment. A new, direct measurement of the 7Be Q value is called for to check its accuracy, to reduce the uncertainty for a meaningful check of systematics in the BeEST experiment, and to meet the anticipated precision of the 7Li recoil energy in future Phases of BeEST operation. We have performed such a measurement via Penning trap mass spectrometry with the LEBIT facility at the NSCL and have reduced the Q value uncertainty by a factor of about three. |
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S17.00012: Sensitivity of quasifree reactions to details of the bound-state overlap functions: A tale of tails Carlos A Bertulani It is often stated that heavy-ion nucleon knockout reactions are mostly sensitive to the tails of the bound-state wave functions. In contrast, ( p, 2 p) and ( p, pn) reactions are known to access information on the full overlap functions within the nucleus. We analyze the oxygen isotopic chain and explore the differences between single- particle wave functions generated with potential models, used in the experimental analysis of knockout reactions, and ab initio computations from self-consistent Green's function theory. Contrary to common belief, we find that not only the tail of the overlap functions, but also their internal part is assessed in both reaction mechanisms, which are crucial to yield accurately determined spectroscopic information. |
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S17.00013: Physics Opportunities Beyond the Neutrino Mass Measurement with Project 8 Pranava Teja Surukuchi Venkata The Project 8 experiment is designed to directly measure the electron-weighted neutrino mass using the novel technique called Cyclotron Radiation Emission Spectroscopy (CRES). Using the cyclotron frequency of the beta decay electrons as a proxy for kinetic energy, the experiment aims to measure the endpoint spectrum of tritium beta-decay electrons trapped in a uniform magnetic field to reach a mass sensitivity of 40 meV/c2. The use of CRES technique by Project 8 enables a simultaneous measurement of the β spectrum both above and below the endpoint and provides an opportunity to perform standard model measurements and beyond standard model searches in addition to the neutrino mass measurement with Project 8. This talk will outline the additional physics capabilities of Project 8 experiment including the determination of neutrino mass ordering, search for light sterile neutrinos, and search for cosmic neutrino background. |
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S17.00014: Pileup rejections studies for the CUPID experiment Mattia Beretta CUPID (CUORE Upgrade with Particle IDentification) is the proposed upgrade to the cryogenic calorimetric experiment CUORE. CUPID is designed to search the neutrinoless double beta decay of $^{100}$Mo and a major background for this experiment will be the pile-up of multiple two neutrino double beta decay events. To address this problem, we simulated the detector response with a dedicated software tool. We produced controlled data streams with different characteristics, to select constraints on CUPID design parameters. In addition, we also tried different algorithms to find a processing capable of maximizing the pileup rejection. In this contribution, the latest results on this subject will be presented, outlying the needed steps to be taken towards an efficient pile-up rejection. This work is supported by the US DOE Office of Nuclear Physics, the US NSF, and internal investments at all institutions. |
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S17.00015: A measurement of the inclusive cross section of the electron neutrino charged-current interactions on 127I. Peibo An A measurement of the inclusive cross section of the electron neutrino charged-current interactions on 127I can probe the quenching of gA, the axial-vector coupling constant, which affects the rate of neutrinoless double beta decays. Before 2000, at the Los Alamos Meson Production Facility (LAMPF), a measurement of the exclusive and flux-averaged cross section was made, whose statistical error was large. To make a first measurement of the inclusive cross section with low statistical uncertainty, a 185 kg NaI[Tl] prototype was deployed by the COHERENT collaboration at the Spallation Neutron Source. To further improve the signal-to-noise ratio, a four-class XGBoost model was developed. To address the non-linearity of NaI[Tl] crystals at high energies, calibrations using the Michel spectrum from stopped mu+ decays were performed. Data analysis is ongoing and we expect to open the blinded data soon. The latest COHERENT NaI results will be presented. |
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S17.00016: Visualizing MoNA/LISA data to aid in event classification Clifton D Kpadehyea Neutron-unbound systems are a special type of exotic nucleus that immediately decays by emitting one or more neutrons. Studying these systems can provide insights important to understanding nucleon-nucleon interactions inside the atomic nucleus. The Modular Neutron Array (MoNA) Collaboration uses the invariant mass spectroscopy technique to study these nuclei. Decays involving more than one neutron are challenging to analyze because care must be taken to identify events in which all emitted neutrons are detected. A current effort within the Collaboration is underway to explore new computational tools and techniques to address these challenges. The present work focuses on ways to visualize recorded data with the goal of enabling the development of a labelled event library for use in training machine learning algorithms to classify neutron hit patterns measured with the MoNA/LISA neutron detector array. |
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S17.00017: Searching for Low Energy Protons Following the Beta Decay of 32Ar Logan A Schaedig, Evan T Argo, Yassid Ayyad, Dan W Bardayan, B A Brown, Tamas A Budner, Kyungyuk Chae, Alan Chen, Kelly A Chipps, Marco Cortesi, Moshe Friedman, Brent E Glassman, Matthew Hall, Molly A Janasik, Johnson Liang, Patrick D O'Malley, David Perez Loureiro, Emmanuel Pollaco, Athanasios * Psaltis, Jordan Stomps, Lijie Sun, Jason Surbrook, Tyler Wheeler, Christopher L Wrede The decay of 32Ar is already one of the most thoroughly measured beta-delayed proton emitters. We have acquired additional data on this decay using the Gaseous Detector with Germanium Tagging (GADGET) at the National Superconducting Cyclotron Laboratory (NSCL). The unprecedented sensitivity to low energy protons provided by GADGET's Proton Detector enables us to set upper limits on the intensities of unobserved protons between 200 and 600 keV. The limits can be used to improve nuclear structure models and precision constraints on fundamental symmetries in the weak interaction. The current status of the data analysis will be presented. |
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S17.00018: Integration and performance of prototype nEXO charge-readout modules with built-in, cryogenic ASIC readout Evan Angelico
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S17.00019: The nEXO Radioactivity and Background Control Program Dmitry Chernyak nEXO is a proposed next-generation experiment to search for the neutrinoless double beta decay of 136Xe. The experiment is designed around a large time projection chamber, envisaged to contain 5000 kg of isotopically enriched xenon in order to achieve a half-life sensitivity of 1.35·1028 years. To reach such sensitivity requires a stringent radioactive background control and careful material selection effort. |
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S17.00020: Hardware design and simulation for light detection in nEXO Avinay Bhat The nEXO detector features a 5 tonne time projection chamber filled with liquid xenon enriched to 90% in the A=136 isotope. nEXO aims to detect neutrinoless double beta decay (0??ββ) of 136Xe with a 90% CL sensitivity >1028 years. This talk will give an overview of the design and simulation of the light detection system for nEXO, which is the primary driver of the detector energy resolution. In particular, I will describe the overall design of the photon detection system, which will employ ~4.6 m2 of vacuum ultra-violet (VUV) sensitive silicon photomultipliers (SiPMs). Simulations of the photon transport efficiency and light propagation performed with the Chroma software package will be described, along with estimates of the overall energy resolution. |
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S17.00021: Beta-delayed gamma decay of 32Ar Evan T Argo, Yassid Ayyad, Dan W Bardayan, Alex Brown, Tamas A Budner, Kisung Chae, Alan Chen, Kelly A Chipps, Marco Cortesi, Moshe Friedman, Brent E Glassman, Matthew Hall, Molly Janisik, Johnson Liang, Patrick D O'Malley, David Perez-Loureiro, Emmanuel Pollaco, Athanasios * Psaltis, Logan Schaedig, Jordan Stomps, Lijie Sun, Jason Surbrook, Tyler Wheeler, Christopher L Wrede Positron decay of 32Ar can be used to precisely study nuclear structure and search for physics beyond the Standard Model. Data from positron decay of 32Ar was collected at the National Superconducting Cyclotron Laboratory (NSCL) using the Gaseous Detector with Germanium Tagging (GADGET) system. GADGET detects both gamma and proton emissions from radioactive nuclides. This study’s goal is to analyze the gamma rays emitted following positron decay of 32Ar. The 32Ar was acquired serendipitously during an experiment that was focused on the decay of 31Cl. The high-resolution of the germanium detectors within GADGET allows us to gain a better understanding of the decay scheme of 32Ar in addition to searching for any coincidences between proton and gamma decays. |
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S17.00022: Coincidence timing and Compton suppression techniques for nuclear structure studies using the La Crosse fIREBAll Michael Ryan Throughout the history of nuclear experimentation, more precise detection methods have been theorized and accomplished to further understand the foundations of nuclear structure. We explored the viability of various scintillation detectors for potential use in coincidence with the La Crosse fInternal conveRsion Electron Ball Array (fIREBAll). One of the objectives of fIREBAll is to search for E0 transitions and to measure conversion coefficients from E2 transitions with large E0 components between J-J transitions in nuclei with multiple 0+ states. We assessed the capability of Bismuth Germanate (BGO) detectors to suppress the Compton scattering of a Germanium (HPGe) detector. Using a ROOT script incorporating data from both detectors, we greatly reduced background caused by Compton scattering. In addition, we tested two groups of Barium Fluoride (BaF2) detectors, incorporating a pulse-shape discrimination technique to remove self-activities and to determine timing and energy resolution properties. We also tested a group of Cerium Bromide (CeBr3) detectors, which exhibited exemplary fast timing and energy resolution properties. |
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S17.00023: New results on the generalized polarizabilities of the proton from the VCS experiment at Jefferson Lab Nikos Sparveris, RUONAN LI The Generalized Polarizabilities (GPs) are fundamental properties of the nucleon. They characterize the nucleon's response to an applied electromagnetic field, giving access to the polarization densities inside the nucleon. As such, they represent a central path towards a complete understanding of the nucleon dynamics. Previous measurements have challenged the theoretical predictions, raising questions in regard to the underlying mechanism responsible for a local enhancement of the electric GP at intermediate four-momentum transfer squared. The measurement of the magnetic GP, on the other hand, promises to quantify the interplay of the paramagnetic and the diamagnetic contributions inside the proton. New results on the proton GPs from the VCS experiment in Hall C at JLab will be presented in this talk. |
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S17.00024: Chemical analysis of nuclear debris via a portable LIBS device Christina L DUGAN, Ashwin Rao, Christopher Sutphin This work demonstrates the efficacy of a commercial off-the-shelf (COTS) portable laser-induced breakdown spectroscopy (LIBS) device for the rapid geochemical analysis of nuclear debris. The geological makeup of debris samples from the Nevada test site are analyzed; geochemical signatures are established from the recorded LIBS spectra allowing for the discrimination of samples based on the detonation environment. This study represents the first effort to field a COTS LIBS analyzer for in-field nuclear debris analysis; the results indicate the device has high potential to yield pertinent nuclear forensic information of debris from recorded spectra. |
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S17.00025: Experimental Measurements of the Internal Energy of Non-Ideal Carbon Dioxide Matthew D Marko An experimental effort was conducted to measure the change in internal energy of non-ideal carbon dioxide as its volume rapidly expanded with the sudden opening of a valve from one to two compressed gas cylinders. This was achieved by measuring the mass heat capacity of the gas cylinders and the manifold-valve, and measuring the change in temperature from the sudden doubling of volume of the non-ideal carbon dioxide. It was determined that an empirical equation for the change in internal energy of a non-ideal fluid, obtained via earlier measurements of the enthalpy of vaporization for multiple different molecules, was more accurate than previous estimated methods used for estimating the change in internal energy by estimating the change in entropy. |
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S17.00026: First operation of undoped CsI directly coupled with SiPM at 77 Kelvin Keyu Ding The light yield of a combination of an undoped CsI crystal plus two SiPMs at about 77 Kelvin was measured to be 38.88 ±2.96 photo-electrons (PE) per keV electron-equivalent (keVee) using the 26.3 keV γ-ray peaks from an 241Am radioactive source. The feasibility of using an undoped CsI crystal coupled with two SiPMs at 77 K at a lower energy region was the first attempt in the world. The high light yield together with some other technical advantages makes it a great neutrino and dark matter detector at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). |
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S17.00027: Structure of the carbon nucleus Alan C Folmsbee In this paper, carbon nuclear structure is described geometrically, using the pyramidal cube theory of the static nucleus. This theory successfully described the iron nucleus. All other elements have been evaluated using the same sphere stacking rules that produced a new understanding of ferromagnetic phenomena. All elements heavier than boron have a cubic lattice of protons and neutrons in their centers. Outside of the cube, protons form lines of protons. The carbon nucleus has a cube of two protons and six neutrons. Four protons are positioned on the cube's surface in symmetrical locations. Carbon has three protons positioned to define one plane. The other three protons define a parallel plane. This is why graphite has planar crystals. |
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S17.00028: Inelastic quark collisions during hadonization suresh AHUJA Abstract: Relativistic heavy-ion collisions provide a unique opportunity to study nuclear matter under extreme density and temperature. It is now generally acknowledged that a color-deconfined QCD matter, known as Quark-Gluon Plasma (QGP), has been produced in high-energy nuclear collisions at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC) Strong multiparticle correlations that are long range in rapidity have been observed in high energy collisions of protons with protons or heavy nuclei at both the Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC). In a color glass condensate effective theory, whose collision creates the gluon fields of the glasma. Individual gluons are then sampled from the gluon fields’ Husimi (smeared Wigner) distributions and clustered using a new spacetime based algorithm. Clusters are fed into the Herwig event generator, which performs the hadronization, conserving energy and momentum. The hadronization process and, in particular, the heavy flavor hadronization of HQs in pp collisions is usually described by the traditional fragmentation mechanism. Many experimental and theoretical studies have revealed a new state of matter, the quark-gluon plasma (QGP), in these collisions where quarks and gluons are no longer confined within hadrons. In the formation of the QGP, jet quenching, the non-viscous flow, direct photons, and Debye screening effects have been reported. Lattice quantum chromodynamics (lQCD) predict that hadronic matter at high temperatures and high energy densities melts into a deconfined state of quarks and gluons called the quark–gluon plasma (QGP). A model.is proposed which considers inelastic collision between quarks and gluon during coalescence stage and formation of small particles up and down quarks and strange quarks during fragmentation stage in hadronization.. |
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S17.00029: Left-right symmetry and electric dipole moments. A global analysis Juan Carlos Vasquez Carmona, Michael J Ramsey-Musolf We perform a global fit using results of searches for electric dipole moments (EDM) of diamagnetic systems within the context of the minimal left-right symmetric model. In this way, we disentangle the new "left-right" electroweak and θ contributions that cannot be separated using a single EDM system. Although the fit is done for a specific model, the approach can be applied to any particle physics model. Finally, we revisit the constraint on the D coefficient in β-decay and find that current EDM bounds do not preclude observation of this T-violating effect in a possible next generation β-decay experiment |
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S17.00030: ASTROPHYSICS
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S17.00031: Searching for Gamma- and X-ray Counterparts to Gravitational-wave events with Fermi-GBM and Swift-BAT Milena Crnogorcevic, Corinne Fletcher, Joshua R Wood, Rachel Hamburg, Eric Burns, Adam M Goldstein, Tyson Littenberg The era of multi-messenger astronomy began with the gravitational-wave detection of the binary neutron-star merger, GW170817, in coincidence with a short gamma-ray burst, GRB 170817A. One of its primary goals is a detection of another coincidence of gravitational and electromagnentic emission. With that in mind, we present a follow-up search for excess emission of gamma-rays with the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and that of X-rays with the Swift Burst Alert Telescope (Swift-BAT), in spatial and temporal correspondence to gravitational-wave events reported by LIGO/Virgo/Kagra (LVK) Collaboration. We utilize Fermi-GBM on-board triggers and sub-threshold searches in combination with Swift-BAT rate data to determine whether there is any statistically significant excess emission around the given gravitational-wave trigger. We report no new joint detections to date; however, we place joint flux upper-limits, allowing us to constrain the current theoretical models that describe the production of gamma- and X-rays in these environments. |
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S17.00032: Origin Of Galactic,Stellar, Planetary and Satellite Rotation/Formation As Tangential Accretion Of Decaying Relevant Orbital Material Sections Transfering Orbital Angular Momentum To Accreted Body Thereby Increasing Its Rotation Angular Motion: A Natural Law Stewart Brekke Stars, planets and satellites began as cores orbited by sections of relevant material. Due to gravitational attraction the orbits of these sections decayed and then tangentiaklly is the Iaccreted to the more slowly rotating cores to rotate faster due to addtion of the sections' angular momentum: If Iω (core) is the rotational angular momemtum of a pre stellar, planet satellite core, and Iω (orbiting section) is the angular momentum of the orbiting section, the equation for the origin of stellar, planetary and satellite present rotation is: |
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S17.00033: Comparing Feature Extraction of Variable Star Light Curves Using Raw and Detrended/Cleaned Data Ana Sammel, Nina Hernitschek Variable stars such as RR Lyrae and Cepheids are crucial in astronomy to understanding properties of stars and the evolution of the Milky Way. These stars can be identified manually by their light curves, but the amount of raw data makes this time consuming and ineffective. Using data from sector 1 of the TESS survey, our team aims to test the effectiveness of machine learning in identifying and classifying types of variable stars. In order to use machine learning algorithms, we must first calculate various features of each star’s light curve. Our team's goal was to test the effectiveness of covariant basis vector (CBV) detrending and median cleaning in improving the calculation of light curve features. We begin by calculating the features of each light curve and use corner plots to compare the distribution of features among star types from the raw as well as the detrended and cleaned data. The results show that while some features show significant changes when using cleaned data, most features do not show significant changes indicating that feature calculation of variable stars is not heavily influenced by using cleaned data but could potentially be improved by applying a data celaning process. |
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S17.00034: Particle-In-Cell Simulations of Mildly Relativistic Outflows in Kilonova Emissions. Mohira N Rassel, Patrick Killian, Chris Fryer, Nicole M Lloyd-Ronning, Federico Fraschetti, Chengkun Huang Collisionless shocks are ubiquitous in astrophysical plasmas, and are observed to be the production sites of very high energy particles (which then radiate over a wide range of the EM spectrum). A long-standing, unsolved problem in high energy astrophysics is how magnetic fields are generated in these shocks, and how they relate to the process of particle acceleration. Particle-in-cell codes are ideally suited to address this question and previous work has looked at cases of magnetic field generation and particle acceleration in both highly relativistic and non-relativistic shocks. Our aim is to examine shock development, magnetic field generation and particle acceleration in the case of mildly relativistic shocks, which are expected when the tidal ejecta of neutron star mergers drive a shock into the external medium.Using LANL's VPIC (vector particle-in-cell), code we have run simulations of such mildly-relativistic, collisionless, weakly magnetized plasmas and compute the resultant magnetic fields and particle energy spectra. We show the effects of varying plasma conditions, as well as explore the validity of using different p+/e- mass ratios in VPIC. Our results have implications for observing late-time EM counterparts to gravitational wave detections of neutron star mergers. |
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S17.00035: Numerical Simulations of Dissipation in Accretion Disks Catherine Gibson, Theodore Dezen We perform general relativistic magneto-hydrodynamic simulations to study the dynamics of and radiation from accretion onto stellar mass black holes. Recent theoretical work suggested magnetic torques exerted at the innermost stable circular orbit can drive significant bulk vertical energy transport in regions close to the black hole, and hence dissipate a larger fraction of accretion power near the photosphere compared to standard models. This additional heating in turn may lead to the non-thermal high-energy (into several hundred keVs) radiation observed in some systems. We analyze time-dependent global simulations to further assess the feasibility of such models and illuminate the underlying physical mechanisms. |
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S17.00036: Missing Absorption Features in the Soft State Spectra of Black Hole X-ray Binaries Roy Velasco In this work, we investigate a long-standing discrepancy between theory and observations of accretion disks in black hole X-ray binaries, where numerical models predict relativistically broadened atomic absorption features in the photon spectra that are absent from data. We self-consistently solved the disk vertical structure and radiative transfer equations using a range of dissipation profiles based on results from recent three-dimensional simulations. We found that the strength of these features decreases as the fraction of gravitational potential energy lost that goes into heating the region near the photosphere increases and that the absorption is optically thin. |
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S17.00037: 2D Axisymmetric Monte Carlo Simulations of Post-Merger Disk Phillip J Kovarik, Francois V Foucart The accretion disks created in compact binary mergers generate outflows that power gamma-ray bursts and kilonovae. Simulating these objects in 2-dimensional axisymmetry can reduce computation costs. Some approximations need to be made for 2D, but we can still realistically evolve properties of the disks such as the large-scale structure of magnetic fields and dynamo mechanics. Simulations of these disks have been run using SpEC in 2D axisymmetry with Monte Carlo transport, viscous hydrodynamics, and general relativity. The results of these simulations will be presented as well as tests for different parts of the code. |
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S17.00038: Analysis of a Sample of High-Energy Peaked BL Lac Objects with the HAWC Observatory Erica Heller, Hugo Ayala, Miguel A Mostafa We identified candidate TeV emitters from a list of published High-Energy peaked BL Lac (HBL). We searched for very-high energy (VHE) gamma-ray emission from these objects using the six-year data set from the High Altitude Water Cherenkov (HAWC) Observatory. We established flux upper limits assuming extrapolated power laws for each source. We will present the results of our search in the VHE range as well as preliminary physical models of these sources using both X-ray and gamma-ray data. |
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S17.00039: Pulsars and Fundamental Physics with the Next-Generation Very Large Array (ngVLA) Megan DeCesar, Joseph Lazio, Eric Murphy, Shami Chatterjee, Jim Cordes, Geoffrey Bower, Scott Ransom, Julia Deneva, Thomas J Maccarone, Joan Wrobel The ngVLA is a large, transformative radio telescope that will cover a wide range of radio frequencies. One of its key science goals is to find and use Galactic pulsars to study fundamental physics. Of special interest to the astrophysics community are Galactic Center (GC) pulsars, for example a pulsar closely orbiting Sag A*, enabling a suite of general relativistic tests complementing those of VLTI/GRAVITY and the Event Horizon Telescope; a possible population of GC millisecond pulsars, the absence of which would imply that dark matter is the origin of the GC gamma-ray excess; and magnetars and pulsar-black hole binary systems, both of which are rare objects and thus likely to reside very far from our Solar System. All of these pulsar types are extremely difficult to detect with current instruments because they are distant and thus highly scattered at typical pulsar observing frequencies (usually under 2-3 GHz). Because of the ngVLA’s unprecedented sensitivity, it will be able to detect pulsars at significantly higher frequencies (5 or more GHz), where they are much weaker but also experience negligible scattering even at very high distances. In addition to distant pulsars, the ngVLA will also be a valuable instrument for improved pulsar timing for the NANOGrav pulsar timing array, and will therefore play an important role in detecting and characterizing gravitational wave-emitting binary supermassive black holes. |
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S17.00040: Modeling the extragalactic gamma-ray background at Fermi-LAT energies Ian McKinnon, Ilias Cholis The extragalactic gamma-ray background is the result of the combined emission of numerous galaxies, high-energy astrophysical mechanisms, and unresolved galactic sources. In addition to that the extragalactic gamma-ray background may contain a signal of dark matter particles undergoing annihilation or decay. Thus, an accurate modeling of this emission will not only allow us to acquire a better understanding of the astrophysical objects and mechanisms contributing to it, but can be used to further constrain the properties of dark matter. We use the improved data on the gamma-ray background from the Fermi Large Area Telescope, to model the contribution to said background from various astrophysical objects, such as star-forming galaxies and blazars. We model the luminosity and redshift distribution and the gamma-ray spectra from these objects. |
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S17.00041: Quasi-periodic Oscillations in Black Hole X-ray Binaries kathryn anawalt, Theodore Dezen, Nicholas Zecchini Sufficiently massive stars end their lives as black holes, which may be surrounded by an accretion disk, |
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S17.00042: Probing the Dark Solar System: Detecting Binary Asteroids with a Space-Based Interferometric Asteroid Explorer Andrew G Sullivan, Doga Veske, Zsuzsanna Marka, Imre Bartos, Szabolcs Marka With the inception of gravitational wave astronomy, astrophysical studies using interferometric techniques have begun to probe previously unknown parts of the universe. In this work, we investigate the potential of a new interferometric experiment to study a unique group of gravitationally interacting sources within our solar system: binary asteroids. We present the first study into binary asteroid detection via gravitational signals. We identify the interferometer sensitivity necessary for detecting a population of binary asteroids in the asteroid belt. We find that the space-based gravitational wave detector LISA will have negligible ability to detect these sources as these signals will be well below the LISA noise curve. Consequently, we propose a 4.6 AU and a 1 AU arm-length interferometers specialized for binary asteroid detection, targeting frequencies between 10-6 and $10-4 Hz. Our results demonstrate that the detection of binary asteroids with space-based gravitational wave interferometers is possible though very difficult, requiring substantially improved interferometric technology over what is presently proposed for space-based missions. If that technology threshold can be met, an interferometer may be used to map the asteroid belt, allowing for new studies into the evolution of our solar system. |
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S17.00043: Expanding the Footprint of EXONEST by Code Conversion John Morris EXONEST, a Bayesian-based inference engine, is used for exoplanet detection, characterization, and hypothesis testing by employing multinested sampling. The purpose of this project is to increase the accuracy of model testing and parameter estimation, while decreasing execution time by converting from MATLAB to Python. The transition should increase the adoption of EXONEST within the astronomy community, given Python's open-source platform and its increasing use within the community. A basic linear fit was used to determine if the full conversion could produce the desired results. The test was promising because in a 1024 sample run on synthetic data the execution time of the test decreased from 125 seconds in MATLAB to 7 seconds in the Python implementation, with accuracy of parameter estimation improving. Further transition of EXONEST's libraries, implementation of time-reducing strategies such as multithreading, and testing on both synthetic and real exoplanet light curve data will be explored to further improve EXONEST prior to full release. |
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S17.00044: Binary Neutron Star Gravitational Wave Signal Classification using Machine Learning Nathan D Ormsby, Ryan P Fisher, Michael A Patel The PyGRB offline analysis pipeline utilizes data from both Advanced LIGO and Advanced Virgo detectors in an effort to detect gravitational waves coincident with gamma ray bursts (GRBs). PyGRB offline currently utilizes a heuristic method called BestNR to distinguish between true gravitational wave signals and transient bursts of noise. This project explores an alternative method to classify gravitational wave signals using a neural network trained with data from chi-squared tests of each signal in offline GRB boxes. Initial testing using data from GRBs in the second half of the third observing run of Advanced LIGO and Advanced Virgo shows promising results, including an increased 90% confidence range of detection as well as a larger number of correctly classified injections compared to BestNR. Testing of different configurations will continue, including changing the GRBs used to train the model, utilizing subsets of the available chi-squared tests, as well as attempting to optimize the hyperparameters of the neural network in an effort to create the best performing model. We will present the status of these tests. |
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S17.00045: Black hole spins in radio-quiet type I active galaxies: Markov chain Monte Carlo based analysis Ashkbiz Danehkar X-ray emissions from the innermost stable circular orbit (ISCO) regions around supermassive black holes (SMBHs), which have footprints of general-relativistic frame-dragging, give us an insight into SMBH spins. In particular, the active galactic nucleus (AGN) ISCO regions in radio-quiet type I active galaxies with low line-of-sight inclinations are not heavily blocked by the surrounding dusty toroidal regions, so they could be the perfect sample for a spin survey of SMBHs. In this work, an advanced Markov chain Monte Carlo (MCMC) statistical technique is applied to relativistic ray-tracing reflection modeling of the relativistically broadened Fe Kα line at 6.4 keV and the Compton bump above 10 keV in XMM-Newton and NuSTAR archival data of a sample of radio-quiet type I active galaxies, including MCG-6-30-15, NGC 3783, and NGC 4593. Reflection model characteristics such as SMBH spin and inclination angle are well constrained by using the MCMC-based statistical analysis. A further study of a larger sample of radio-quiet type I active galaxies will help us acquire a clearer picture of the effects of black hole spins on regulating AGN outflows and possible impacts on their host active galaxies. |
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S17.00046: Snails Across Scales: characterizing phase-space spirals in N-body simulations Elise Darragh-ford, Kathryn V Johnston, Adrian M Price-Whelan, Jason A Hunt The discovery of phase-space spirals from projections of the z-vz plane in the Gaia data by Antoja et al. (2018) opened up the exciting possibility that detailed stellar kinematics in the local Galactic disk can be used to study global interactions between the Milky Way and its satellites. The morphology and spatial dependence of these phase-space spirals and other signatures of disequilibrium encodes information both about the shape of the Milky Way’s potential and the specifics of the perturbation and interaction. However, any interpretation must rely on the properties of the spirals themselves and robustly extracting these signatures is challenging. Here, we present an algorithm designed to characterize the strength and morphology of phase-space spirals. We test the algorithm on self-consistent simulations of the Milky Way–Sagittarius merger. We show that while the physics behind spiral formation is conceptually simple, interactions between the Milky Way and an outside perturber can cause complicated dynamical responses in the disk. However, by characterizing these spirals as a function of location, we can start to piece together the merger history of the Milky Way. |
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S17.00047: Variable Stars and Quasars in the Canada-France-Hawaii Telescope Legacy Survey Deep Fields Puragra Guha Thakurta, Joanne Zhao, Chris Donnelly, Tawny Sit, Yuting Feng, Eric W Peng Studies of the substructure of the Milky Way’s stellar halo provide a window into our galaxy’s accretion history. RR Lyrae are arguably the most reliable tracers of the Milky Way’s stellar halo for two reasons: (1) their periodic pattern of photometric variation makes them relatively easy to identify; (2) they are excellent standard candles. AGNs/quasars are the most significant source of contamination when identifying RR Lyrae. The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) is a deep, multi-epoch (~300 epochs per filter), multi-band (ugriz filters) photometric survey. Its depth and exquisite cadence allow for accurate identification of RR Lyrae and quantifying degrees of incompleteness and contamination in other time domain surveys. In this work we analyze the CFHTLS data to: (1) identify candidate variable objects; (2) classify variable objects. We fit polynomials to the ridge line of log(RMS) vs. median ugriz magnitude to find the measurement error. We sum the intrinsic RMS of the 5 bands for each object weighted by the measurement error in each band. Objects are categorized as “marginal,” “intermediate” or “extreme” variable candidates based on their weighted intrinsic RMS. The Lomb-Scargle periodogram helps create phase-folded light curves to classify variables. |
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S17.00048: Analyzing orphan TeV excesses in the 3HWC catalog Kenya Mitchell, Valeria Ventura There are 65 significant detections in the third catalog (3HWC) of TeV gamma-ray sources from the High Altitude Water Cherenkov (HAWC) observatory. Among many interesting objects, the 3HWC catalog contains twenty sources that are more than 1 degree away from any previously detected TeV source. These are called either orphan or unassociated TeV sources. With two more years of HAWC data than presented in the 3HWC catalog, we followed up on these twenty objects in time. We will present the temporal evolution of the excess significance for these candidates and compare our results with the expectation for steady sources. |
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S17.00049: Poseidon : An Relativistic Gravity Solver for Core Collapse Supernova Simulations James N Roberts II, Anthony Mezzacappa, Eirik Endeve The Poseidon code is designed to solve the system of equations for the general relativistic metric in the eXtended Conformally Flat Condition (XCFC) formulation of the Einstein equations. The code is based on a discretization of the system of equations on a spherical polar grid, using a mixed spectral--finite-element method consisting of an angular decomposition in spherical harmonics and a radial expansion in Lagrange polynomials. The non-linear algebraic equations are then solved iteratively using a fixed-point method with Anderson acceleration.Poseidon has been developed for use in core collapse supernova simulations, as part of the toolkit for high-order neutrino-radiation hydrodynamics (thornado) development. It has been designed to operate on distributed and shared memory systems using MPI and OpenMP, respectively, and within the AMReX framework for block-structured adaptive mesh refinement. Results will be presented showing the accuracy of Poseidon’s treatment of the XCFC system, performance on distributed and shared memory systems, use within the AMReX framework, and the successful coupling to thornado's general relativistic hydrodynamics module. |
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S17.00050: Studying the production cross-section of cosmic-ray antimeter nuclei in high-energy inelastic collisions Jenna Bacon With the increased sensitivity of cosmic-ray particle detectors at the Alpha Magnetic Spectrometer-02 and |
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S17.00051: Lyman-alpha forest studies of cosmological simulations with inelastic two-component dark matter (2cDM) Ryan Low, Rakshak Adhikari, Mikhail V Medvedev, Mark Vogelsberger, Stephanie O'Neil, Paul Torrey, Jonah Rose The LambdaCDM model assumes that dark matter is collisionless. This model is very successful of large scales but seems to face some problems at galactic scales. Noteworthily, one have developed a model in which dark matter may experience dark inelastic interactions. The simplest two-component dark matter model has been shown to robustly resolve the small-scale problems in N-body dark-matter-only simulations. Thus, further modeling with baryons and baryonic feedback are needed to draw accurate conclusions. It is known that baryons provide strong feedback at low redshifts, which complicates disentangling baryonic and dark matter effects. Thus, understanding of structure formation at a higher redshift would be highly beneficial. The high-redshift structure formation can be deduced from the Lyman-alpha forest observations. Here we present the Lyman-alpha spectral analysis of the cosmological simulations using the full, state-of-the-art baryonic feedback model used in IllustrisTNG simulations. Our results indicate that the novel dark matter effects suppress the power spectrum at large k. The strength and the location of the suppression depend upon the DM interaction cross-section and the mass degeneracy parameter. |
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S17.00052: Cosmological simulations of structure formation with inelastic two-component dark matter (2cDM) Rakshak Adhikari, Ryan Low, Mikhail V Medvedev, Mark Vogelsberger, Stephanie O'Neil, Paul Torrey, Jonah Rose Conventional LambdaCDM paradigm assumes that dark matter is passive: it forms large-scale structure which gravitationally pulls gas into them. The rich physics of star formation, ISM physics, cosmic ray production and other baryonic effects and feedback are regulated by MHD or plasma kinetics. Such a paradigm seems to face some problems at galactic and sub-galactic scales known as the missing satellite, core-cusp, and too-big-to-fail problems. Noteworthily, one have developed a model in which dark matter may experience inelastic interactions in the dark sector. The simplest two-component dark matter model has been shown to robustly resolve the small-scale problems in N-body dark-matter-only simulations. Thus, further modeling with baryons and baryonic feedback are needed to draw accurate conclusions. Here we present simulations of cosmological volume using the full, state-of-the-art baryonic feedback model used in IllustrisTNG simulations. Our results indicate that the novel dark matter effects lead to `effective' heating of the central parts leading to the reduction of central cusps and decreased formation of dwarf satellites. We discuss some observational predictions following from our study. |
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S17.00053: Achieving Precision Photometry of T Tauri Stars With a DSLR Camera Joshua Liberman, Jeffrey Bary, Olivier Guyon, Preethi Krishnamoorthy T Tauri stars are known to exhibit variability at all wavelengths. Starspots, cool magnetic field |
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S17.00054: General Relativistic Stellar Structure Equations in Julia Mathew A Leon, David Radice, Aviral Prakash Understanding the characteristics of the condensed matter within neutron stars (NSs) is an important objective in astrophysics. By measuring the properties of NSs, we are able to obtain clues about the kind of strange matter that reside within them. We develop a new Tolman-Oppenheimer-Volkoff (TOV) solver in the Julia language to generate data that simulates various characteristics of many NSs when provided an equation of state (EOS). We then make connections between the data from our solver to what is known from real world observations. |
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S17.00055: A full scale fifth spacetime dimension with implications - dark matter and energy... Frank S Hafner There is a full scale fifth spacetime dimension where the Universe expands in two degrees of freedom, parallel and normal to light. At Inception, near infinite mass density created near infinite spacetime curvature. The Universe unwinds normal to light in the fifth dimension as mass density decreases. The gravitational constant is replaced by a new constant via vector addition of gravity magnitudes in both degrees of freedom. The cosmological constant is replaced by unwinding spacetime. Dark matter is the new gravitational constant applied to decayed antimatter via weak force charge parity violation near inception – baryon asymmetry. Dark energy is the Universe unwinding in the fifth dimension. |
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S17.00056: Comparing the Substructure of the Milky Way Galaxy to the Besançon Model Iona Z Xia, William Huang, Pujita Tangirala, Sofiya Belovich, Paulo Villafana, Miranda Apfel, Puragra Guhathakurta The Milky Way is a spiral galaxy, which has a rotating disc with spiral arms that spread outwards from a dense center and a stellar halo surrounding the disc. The formation of spiral galaxies is thought to follow the Hierarchal Merger Model where small dwarf galaxies accrete to form large objects. A galaxy's substructure, or its specific features, is greatly dependent on its accretion history. In this work, we examine the Milky Way's substructure to learn more about its accretion history. We used data from the Halo Assembly in Lambda-CDM: Observations in 7 Dimensions (HALO7D) survey, a survey of stars from 30 lines of sights with a combination of data from the Keck, Gaia, and Hubble telescopes. We compared this data to the Besançon model, a smooth multi-component model of the Milky Way with no substructure. We found that the Besançon model served as a good comparison to the HALO7D data for density of stars in relation to latitude as well as for proper motion versus color. However, due to the parallax error of Gaia telescopes, it differed from Besançon's prediction of proper motion versus distance. Future work can be done to compare the LOS velocities from Keck DEIMOS spectra of stars to further outline the substructure of the Milky Way. |
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S17.00057: Constraining the Anomalous Microwave Emission beyond the Milky Way Sofia Fatigoni The microwave emission from astrophysical sources is mostly dominated by well-understood emission mechanisms (free-free, synchrothron and thermal dust). However, observations of our own galaxy have revealed an unexpected excess of emission in the microwave between 10GHz and 50GHz which cannot be explained by standard emission mechanisms. The importance of a full understanding of this excess emission (Anomalous Microwave Emission, AME) depends not only on our comprehension of the astrophysical mechanisms at its origin, but also on the need for CMB experiments in order to understand and remove foreground signals. |
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S17.00058: General relativistic neutrino transport implemented using the two-moment method Zachary M Elledge, Anthony Mezzacappa, Eirik Endeve Core Collapse Supernovae (CCSNe) occur when massive stars are at the end of their life cycles, and it has been shown that neutrinos play a pivotal role in the death-throes of these stars. CCSNe are known to be laboratories to study the creation of many of the heavier elements, the formation of black holes and neutron stars, and production of gravitational waves. To model CCSNe, we use a 3+1 formulation of general relativity along with general relativistic hydrodynamics and a general relativistic two-moment approach for neutrino transport, which is what we focus on here. We solve the transport equations numerically using the discontinuous-Galerkin method to discretize the equations in phase-space, because it is scalable, high-order accurate, and asymptotic preserving, and implicit-explicit time integration, because we must solve the neutrino-matter coupling problem implicitly. We will discuss these methods and show results from test problems for the neutrino sector of the model, specifically the so-called general relativistic homogeneous sphere problem, which tests the general relativistic properties of the code, and relaxation problems, which uses tabulated opacities and non-linear solves, to test the coupling of the neutrino and matter equations. |
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S17.00059: The preferred perturbative dynamics of early dark energy Tristan Smith, Alexa Bartlett, Shar Daniels The tension between direct measurements of the current expansion rate, H0, and the value predicted from observations of early universe physics (from either the cosmic microwave background (CMB) or measurements of the light element abundances from Big Bang nucleosynthesis (BBN)), can be resolved by positing the existence of a scalar field which contributes about 10% of the total energy density around the time of matter/radiation equality. The increased energy density leads to a decrease in the sound horizon which, in turn, leads to an increase in the CMB/BBN predicted value of H0. Several studies have shown that measurements of the CMB anisotropies are sensitive to the detailed perturbative dynamics of this scalar field. The scalar field perturbations are predominately controlled by the shape of its potential. We explore constraints to a scalar field potential which consists of one power law around its minimum and another power law far from its minimum. We find that the flatter the potential is far from its minimum, the higher the inferred value of H0. We discuss how this result can be understood in terms of an effective sound speed for the scalar field. These results can be generalized in order to give guidelines for building models to address this tension. |
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S17.00060: Performance of HAWC with the improved reconstruction algorithm Sohyoun L Yun Carcamo, Andrew J Smith The High Altitude Water Cherenkov Gamma-ray Observatory (HAWC) has been operational since 2015 on the flanks of the Sierra Negra volcano, México. HAWC's reconstruction algorithm performance has been recently upgraded from Pass 4 to Pass 5. Improvements include gamma-hadron separation efficiency, especially for higher energy events, and angular resolution, with the most significant advancements for events from large zenith angles. Moreover, the reconstruction of air showers hitting a small fraction of the detector has been enhanced, which improves the low-energy resolution of HAWC despite the noise. Here, we show the effective area, angular resolution, and gamma-hadron separation efficiency as a function of primary gamma-ray energy and zenith angle in contrast to the Pass 4 performance. |
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S17.00061: Studying the impact of heuristic data cuts on compact binary coalescence gravitational wave detection range in coherent searches. Kaemon Watada, Ryan P Fisher
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S17.00062: Conservation of Angular Momentum in the Fast Multipole Method Hyun Lim, Oleg Korobkin, Julien Loiseau, Christopher Mauney, Irina Sagert, Alexander Kaltenborn, Bing-Jyun Tsao, Wesley Even Smoothed particle hydrodynamics is positioned as having ideal conservation properties. When properly implemented, conservation of total mass, energy, and both linear and angular momentum is guaranteed exactly, up to machine precision. |
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S17.00063: Exploring the Effects of Radiation Pressure on Orbiting Mirrors Hannah M Bechtel, Jamin Wilson, Shauna Sallmen Satellites around exoplanets would change the light curve of a transiting exoplanet, potentially providing evidence for extraterrestrial civilizations. These could be large, thin, lightweight mirrors used to redirect sunlight from a star to the surface of a planet. The feasibility and fuel efficiency of such an undertaking depends heavily on the effects of radiation pressure (RP). We simulated those satellites using REBOUND (Rein and Liu 2012), an N-body simulator, to understand the effect of RP on mirrors orbiting potentially habitable exoplanets. We varied the star type, initial semi-major axis, eccentricity, and other mirror orbital elements, and ran all simulations to crash, escape, or 1000 orbits. In some simulations RP affected the mirror throughout its orbit, while in others RP only affected the mirror when it was on the planet's night side. We compared these with simulations involving only gravitational effects. We compiled survival times and plotted orbital properties versus time to identify somewhat stable orbits. We are still investigating potentially stable configurations and analyzing data to decide whether full simulations need to be run in order to know a simulation's end state or if it shows in early trends. |
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S17.00064: The TOROS project: A status report Mario C Diaz We present a status report on the Transient Optical Robotic Observatory of the South project. The TOROS telescope obtained first light on April 7, 2021. Since then successive campaigns have achieved different milestones towards design sensitivity. We describe the first photometric results and discuss the projections for TOROS final sensitivity. We discuss the plans for the immediate future as well as our planned survey strategy and expected capabilities for the LIGO VIRGO KAGRA O4 observational campaign in 2023. |
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S17.00065: Spiral galaxy rotation favors prolate dark matter haloes Adriana Bariego Quintana, Felipe J Llanes-Estrada, Oliver Manzanilla Carretero The flattening rotation velocity v(r)→constant found by Rubin and collaborators, and very distinct in the SPARC galaxy rotation data coincides with Kepler's law in one less dimension. Thus, it is naturally reproduced by filamentary sources of gravity, for example elongated dark matter distributions with the axis of prolateness perpendicular to the galactic plane as we here consider. |
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S17.00066: CCSN Simulation with Spectral Two-Moment Neutrino Transport Using Flash-X Ran Chu, Austin Harris, Eirik Endeve, Paul Laiu, Bronson Messer, Anthony Mezzacappa We are developing the toolkit for high-order neutrino-radiation hydrodynamics (thornado) to simulate neutrino transport and its coupling to matter in core-collapse supernova (CCSN) explosions. |
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S17.00067: Blackhole as time machine Philip I Shin There is no idol and only human is existing. So there is no start as no alpha and no end as no omega. It means blackhole is not the existence as block forever as monism. And also there can be blackhole as dualism and it block forever the humans, man is captured in blackhole forever and cannot exit from it, so we need to delete our existence to get out of the blackhole. It is impossible mission as dualism so it is time machine as eschatology to delete our existence problem. So when we make the blackhole, it is theory as god, so it is one truth. So as the truth, we use them as good thing by the theory as one.(We can be back as blackhole existence to before as moving existence.) |
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S17.00068: A next-generation multi-PMT optical sensor for IceCube-Gen2 Vedant Basu A new in-ice optical sensor, the Long Optical Module (LOM), is under development for IceCube-Gen2, the proposed expansion to the IceCube Neutrino Observatory at the South Pole. The sensor design encloses 16 new 4-inch Photomultiplier Tubes (PMTs) in a borosilicate glass pressure vessel, distributed homogeneously to guarantee full angular coverage. Challenges arise for the mechanical design from the tight constraints on the bore hole diameter and from the close packing of the PMTs. A support structure has been designed to enable precise alignment of the PMTs. The supports also aid in coupling PMTs to the pressure vessel using moulded optical gel ‘pads’. The conical gel pads provide an increase in photon collection efficiency, and enhance the module sensitivity. Modular electronics have been custom-designed to fit into the available space and to minimize cost and power requirements for the ~10000 modules to be installed. We will provide an overview of our approach to these design considerations and summarize the results of our tests and simulations. Prototype modules will be installed in the upcoming IceCube Upgrade. |
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S17.00069: Multi-wavelength study of footprints of AGN feedback in host galaxies in the local universe Sundar M N, Prajval Shastri The supermassive black hole scaling relationships imply there exist feedback mechanisms between |
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S17.00070: Mixed Sterile Neutrino Dark Matter and Small Scale Structure Formation Emma L Horner, Francisco D Munguia Wulftange, Chad T Kishimoto Dark matter is abundant within our universe, yet its origins and exact nature remains unknown. CMB and large scale structure observations constrain the total quantity and distribution of dark matter, and a possibly anomalous 3.55 keV X-Ray line could have dark matter origins. These constraints allow us to probe the properties of dark matter and the means of their production. In this poster, we explore production mechanisms for sterile neutrino dark matter that may be consistent with dark matter interpretations of the X-Ray line and large scale structure constraints. |
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S17.00071: Neutrino Evolution in the Early Universe Ashkaun Bashar, Chad T Kishimoto, Brandon Eickert In the hot and dense early universe, neutrino evolution is driven by both the coherent development of quantum phase and the decoherent destruction of this phase through scattering. In this environment, the quantum mechanical oscillation rate and kinetic scattering rate of neutrinos are affected by their interactions with a thermal background of the primordial soup of Standard Model particles; both these rates are large compared to the universal expansion rate. We solve the Quantum Kinetic Equations for neutrino states in the early universe for a variety of scenarios and discuss the characteristics of their solutions. |
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S17.00072: Sterile Neutrino Decays During Weak Decoupling Joseph Garbarino, Chad T Kishimoto, Alex McNichol, Hannah Rasmussen, George M Fuller Probing Beyond Standard Model (BSM) physics in the early universe provides an opportunity to address the relationship between modern cosmological observations and theoretical expectations. We explore the consequences of a population of sterile neutrinos that form very early in the history of the universe and decay around the time of weak decoupling. In this poster, we discuss the effects of these decays in generating a population of high-energy active neutrinos and a prodigious amount of entropy. We also discuss the total relativistic energy density, Big Bang Nucleosynthesis, and the cosmologically-inferred measurement of neutrino masses. |
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S17.00073: Fine structure constant variation Hurum Maksora Tohfa, Daniel Grin In some extensions of the standard model of particle physics, the values of the fundamental coupling constants could vary in space and time, as they relate to the size of extra dimensions. Some recent observations of QSO have shown a possibility of time and spatial variation of the fine structure constant, alpha. We started our work by trying to understand the Bekenstein-Sandvik-Barrow-Magueijo (BSBM) model which places a cosmological scalar field and allows the field and alpha to evolve with the expansion of the universe and a low energy string theory model (Runaway Dilaton) that allows existence of a scalar field (known as Dilaton). Extensions of the scalar field in BSBM and the runaway of the dilaton allow us to consider strong and predict alpha variation across time and space. From those models, we then explore which models are allowed by QSO data by constraining free parameters and couplings: 10-2< mass,m < 102, -.0002< coupling of BSBM, ζ/ω <.0006 (consistent within 2σ of QSO data in BSBM) and dilaton couplings (-.4< bm<.4 , -1< Γ< 1) and then make predictions for variations in alpha at the surface of last scattering, which could be tested using the CMB. After constraining the coupling parameters in both of these models we explored what happens at late times and we are currently using principal component analysis to find the likelihood functions of our parameter spaces. |
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S17.00074: Heisenberg uncertainty principle. chirag r rai Heisenberg’s uncertainty principle is a principle in quantum mechanics. Very roughly, it states that we know everything about where a particle is located but we know nothing about its momentum and vice versa. Versions of the uncertainty principle also exist for other quantities as well, such as energy and time, the uncertainty principle is only working for the subatomic particle. According to the uncertainty principle, if the position is known then the momentum is more uncertain and vice versa. |
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S17.00075: Atomic Shannon Entropy in Astrophysical Lorentzian Plasmas Myoung-Jae Lee, Young-Dae Jung The non-thermal effects on the Shannon entropy for the atomic states are investigated in astrophysical non-thermal Lorentzian plasmas. The Shannon entropies for the ground and excited states in astrophysical Lorentzian plasmas are also obtained as functions of the spectral index, effective screening lengths, and plasma parameters including the radial and angular parts. It is shown that the nonthermal characteristics of the Lorentzian plasma suppresses the entropy changes in the ground state as well as in the excited states. In addition, it is found that the entropy change in excited states is more effective than that in the ground state in non-thermal Lorentzian astrophysical plasmas. |
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S17.00076: AreThere Lives On Jovian Planet Dayong Cao When water was found on Europa and Enceladus from 2018 to 2019, scientists consider there are lives on/in here. |
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S17.00077: Fundamental Cosmology and Physics Beyond the Standard Model John G Nicholson This is an outrageous hypothetical exploration of what is possible when you expand on some of the principles of physics, for the purpose of explaining some of the biggest questions left in physics. The paper expands on the work of Plato, Newton, Einstein and many others to establish a two-part Universe with one part quantum computational. Thermodynamics is revised accordingly. Information takes it rightful place, where many theoretical models leave it out, as the most critical foundation for cosmology. In the modeling process, a simple pathway to a different and deeper understanding of the problems we have in physics is revealed. The singularity is defined as a transition and a pivot. Dark matter and energy are hypothesized as antimatter held in a separate frame of reference and as a superfluid of negative mass. The real observations are discussed and explained as the hypothesis is applied, including accelerated expansion due to transition. Uncertainty and entanglement are illuminated with the properties of information. |
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