Bulletin of the American Physical Society
2019 Annual Meeting of the APS Far West Section
Volume 64, Number 17
Friday–Saturday, November 1–2, 2019; Stanford, California
Session E03: Astrophysics I |
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Chair: Nicholas J. Nelson, California State University, Chico Room: Science Teaching and Learning Center STLC 115 |
Saturday, November 2, 2019 8:30AM - 8:42AM |
E03.00001: A New Paradigm to Explain Amino Acid Chirality and Isotopic Anomalies in Meteorites Richard Boyd, Michael Famiano, Takashi Onaka, Toshitaka Kajino, Satoshi Chiba, Yirong Mo, Toshio Suzuki The Supernova Neutrino Amino Acid Processing (SNAAP) model selects left-handed amino acids (AAs) via electron anti-neutrinos interacting with $^{14}$N (spin 1) nuclei oriented by a magnetic field. Within the AAs, the shielding tensor alters the local magnetic field in a way that is sensitive to molecular chirality. A binary system of a Wolf-Rayet star and a neutron star, when the WR star explodes, or a two-neutron star merger, might supply the required magnetic field and anti-neutrinos. An accretion disk around a neutron star could enable meteoroid and AA formation. Quantum molecular calculations that included perturbation effects on the shielding tensor for N from the reorientation of the molecular electric dipole showed the AAs moving in an external magnetic field to be chirally distinct. An enantiomeric excess of a fraction of a percent was found for isovaline and alanine. Isotopic anomalies have also been observed in meteoritic AAs; they agree qualitatively with model predictions. These results suggest the Galaxy might have been seeded with AAs by one such system. Measurements of $^{60}$Fe (T$_{1/2}$=1.6 My) in ancient meteorites suggest that required events have occurred close to Earth. [Preview Abstract] |
Saturday, November 2, 2019 8:42AM - 8:54AM |
E03.00002: The Nature of Compact Stellar Systems in Massive Galaxy Clusters Using the Hubble Frontier Fields Jeremy Ha, Mahir Arora, Justin Barber, Elisa Toloba, Guillermo Barro, Puragra Guhathakurta We present a study of globular clusters (GCs) in the Hubble Frontier Field cluster Abell 2744 (Pandora's cluster) located at z\textasciitilde 0.31. Our goal is to use compact stellar systems, GCs, as fossil records of the interactions that shaped Pandora's cluster and the galaxies in it to gain new insight into cluster formation processes. We use the publicly available point-source catalogs published by Livermore et al. (2017) and Shipley et al. (2018). These two teams made catalogs from the deepest photometrical images obtained after stacking multiwavelength cleaned images; thus the detection is performed with the lowest spatial resolution. We are generating a single-band point-source catalog in F814W, where the spatial resolution is significantly higher. Although our detection cannot go as deep as Shipley et al. and Livermore et al., we have better control of the removal of stellar light, specifically around the centers of galaxies. Preliminary analysis shows that the Shipley et al. catalog lacks a large number of faint point sources, while the Livermore et al. catalog contains more sources as well as instrumental artifacts and spurious sources. We are combining these catalogs with our own with the aim of obtaining the most complete sample of GCs in Abell 2744. [Preview Abstract] |
Saturday, November 2, 2019 8:54AM - 9:06AM |
E03.00003: Integral Gauss's Law of Gravity with Gravitational Field Flux Lines to Interpret Rotation Curves and Tully-Fisher Relation of Disk Galaxies Te-Chun Wang Objects in disk galaxies can show Non-Keplerian rotational behaviors below a critical acceleration of the order of 10\textasciicircum -10 m/s\textasciicircum 2. MOND (Modified Newtonian Dynamics) theory provided good fits for the rotation curves and the Tully-Fisher relation by postulating that either the Newton's force law or equivalently the Newtonian gravity can be modified. In this report, a physical mechanism of 1/r distance dependent field at non-relativistic limit is proposed within a gravitational field flux conservation picture by generalizing the Integral Gauss's law of gravity. Firstly, 1/r dependence together with a disk thickness dependence of gravitational field and in turn the flat rotation curves are obtained by a Gaussian surface with cylindrical symmetry where most of the gravitational fluxes are distributed eventually along the radial direction of the disk plane. The Gaussian disk thickness as a hidden dynamical variable is discussed with observational evidences. Subsequently, a spherical to cylindrical transition, across a certain critical field, of the Gaussian surface symmetry is shown to give the exact algebraic M$\propto $v\textasciicircum 4 Tully-Fisher relation. The structural-dynamical relations revealed by the radial acceleration relation from SPARC (Spitzer Photometry and Accurate Rotation Curves ) data of Stacy McGaugh's team are mapped to the field flux distribution picture. The bulge to disk structural transition can be directly interpreted by the Newtonian to Non-Newtonian gravitational flux distribution. Extensions of this gravitational lines of force picture to larger scale structures are discussed. [Preview Abstract] |
Saturday, November 2, 2019 9:06AM - 9:18AM |
E03.00004: Impacts of Outflows on NGC 1333 Using Observations of HH6 Madalyn Johnson, Dan Watson, Adam Rubinstein NGC 1333 is a low-mass nebula consisting of many young stellar objects with bipolar outflows. The outflows interact with the surrounding molecular cloud, which causes small shock regions referred to as Herbig-Haro (HH) Objects. These regions emit light as atomic and molecular spectral lines. The Spitzer Space Telescope and the Hubble Space Telescope took images of the emission from HH objects in NGC 1333. We focus on HH6 and use photometry on the images to measure its spectral lines' intensities. By comparing the intensities for each wavelength and the simulated model observations, we found pre- and post-shock parameters for HH6. From these parameters, we derived the mass flow rates, momentum, and kinetic energy injection rate into the surrounding molecular cloud. This information can not only indicate the effects HH6 may have on NGC 1333 but also give us more information about the young stellar objects' star formation rate. [Preview Abstract] |
Saturday, November 2, 2019 9:18AM - 9:30AM |
E03.00005: Studying the gamma-ray emission of the blazar Mrk 421, an 11 years data set from the Fermi-LAT space telescope William Ryan The blazar Mrk 421 is the brightest HBL (High-frequency peaked BL Lac) in the sky and the only HBL with enough gamma-ray emission in its average state to build a daily (or bi-daily) light-curve from the Fermi-LAT telescope. With 11 years worth of data, 3 more years than the most recent Fermi catalog 4FGL, we can define with high accuracy the gamma-ray spectral shape of Mrk 421. I used the `Binned Likelihood Analysis' technique to statistically compare four models, Log-parabola and Power-law, with and without an exponential cutoff over a spectrum spanning from 100 MeV to 513 GeV. I will be presenting the model comparisons and the one statistically favored. The final goal of this analysis is to create a day binned light-curve to study variability patterns of the source which may be linked to successive shocks accelerating particles. [Preview Abstract] |
Saturday, November 2, 2019 9:30AM - 9:42AM |
E03.00006: Long-term very high-energy gamma-ray flux variations of Markarian 421 with VERITAS Edward Park, Aidan Cervantes Flares within the jet of the prominent blazar Mrk 421 (Markarian 421) have been observed in multiple energy bands. We present a very high-energy (E > 100 GeV) gamma-ray analysis based on data collected from the VERITAS (Very Energetic Radiation Imaging Telescope Array System) atmospheric Cherenkov telescopes across the time period 2007 May 6 to 2019 June 27 (about 12 years). We have found that the average spectrum of Mrk 421 can be described as a power law with an exponential cutoff. Using the power-law index and cutoff energy obtained from a fit to the full data set, we fit the spectrum for each day of observations with the normalization as the only free parameter. Mrk 421 shows several significant flares in the light curve of the integral flux above a threshold of 200 GeV. The behavior of these flares is discussed. [Preview Abstract] |
Saturday, November 2, 2019 9:42AM - 9:54AM |
E03.00007: Volume Field Model (VFM) Versus Particle Model (PM) Rongwu Liu, Tianchen Liu Within the frames of Standard Model and General Relativity, the most problems in natural world are explained perfectly in terms of particle , but there still exist some problems unsolved, such as black hole, the origin of universe, dark matter, and dark energy etc. Maybe there exist different forms of matter and motion in the basic level of natural world. This author proposes that: (1) Fundamental matter mass and electricity exist in the form of particle, fundamental matter flavor and color exist in the form of volume field with limited volume; Thus, fundamental body, such as quark, is composed of fundamental particle (mass and electricity) and fundamental volume field (flavor and color). (2) Volume field takes volume motion instead of displacement motion, it has the property of restoration when volume field deforms due to external force, which is like the inertia of a particle. (3) Volume motion has the property of absoluteness instead of relativity. (4) Predicting the existence of volume-field-like quark and neutrino. (5) Hadron has atom-like structure with its hadronic nucleus (composed of particle-like quarks) surrounded by extranuclear quarks (composed of volume-field-like quarks), therefore the particle model of strong interaction and weak interaction must be modified . (6) The essence of black hole and the origin of universe is the dynamics of volume field in hadron. (7) Predicting the existence of dark matter particle which only carries mass. (8) Dark matter particles connect each other to form into another kind of dark matter volume field, the inflating universe attributes to the dynamics of dark matter volume field. [Preview Abstract] |
Saturday, November 2, 2019 9:54AM - 10:06AM |
E03.00008: Axionic Dark Matter Search: Status of HAYSTAC Heather Jackson Haloscope at Yale Sensitive To Axion Cold Dark Matter (HAYSTAC) serves as both a data pathfinder and an innovation test-bed for new technologies in searching for the axion, a leading dark matter candidate. Because axionic dark matter interacts with baryonic matter extremely weakly, HAYSTAC employs a strong magnet and a tunable microwave cavity to enhance the interaction of axions with virtual photons, thus resulting in a miniscule power deposition. HAYSTAC strives to increase the signal to noise ratio by using a dilution refrigerator and advanced amplifier technology/techniques. HAYSTAC - Phase I used a Josephson parametric amplifier to reduce noise to a near-quantum level and exclude axion models in the range 23.15 - 24.0 micro-eV. As HAYSTAC enters Phase II, I will discuss the current state of the experiment which uses recent developments in quantum measurement technology to circumvent the standard quantum limit, i.e. squeezed states, as well as future plans to improve cavity design. [Preview Abstract] |
Saturday, November 2, 2019 10:06AM - 10:18AM |
E03.00009: Development of a Tunable Axion Plasma Haloscopes Al Kenany Long-established theories suggest that dark matter, in the form of axions, could account for the missing mass in the universe, however; the detection of dark matter has long eluded physics. As proposed by Lawson et al. [1], we are studying a new method of detecting axions by using a tunable plasma. The plasma haloscope is designed such that if the plasma frequency matches the axion mass, a weak microwave signal is generated. At high frequencies (\textgreater 10 GHz), this concept should permit the use of larger resonator volumes than can be practically achieved with traditional cavities. We are pursuing a series of engineering/proof-of-concept studies beginning with the development of a benchtop experiment of a three-dimensional array of planar wire frames. The combined structures lead to metamaterial behavior, which will enable the measuring of the plasmon-axion interaction. [1] Matthew Lawson, Alexander J. Millar, Matteo Pancaldi, Edoardo Vitagliano, and Frank Wilczek, "Tunable Axion Plasma Haloscopes", 29 August~ 2019. Physical Review Letters (Accepted). [Preview Abstract] |
Saturday, November 2, 2019 10:18AM - 10:30AM |
E03.00010: A Principle Component Analysis of the HI Mass Fraction of Galaxies in the MaNGA Survey Sean Dillon, Karen Masters, David Stark Neutral Hydrogen (HI) is the main fuel for star formation in galaxies. Using data from the MaNGA survey and HI follow-up of MaNGA galaxies as part of the HI-MaNGA program on the Green Bank Radio Telescope, we investigate correlations between the ratio of HI gas to stellar mass and other galactic properties, such as dust content, star formation rates, and stellar population age. We perform a Principle Component Analysis to reveal the most significant correlations. [Preview Abstract] |
Saturday, November 2, 2019 10:30AM - 10:42AM |
E03.00011: An Automated Pipeline for Globular Cluster Detection in Virgo Cluster Dwarf Galaxies Emily Zhou, Justin Yao Du, Brian Perez Wences, Puragra Guhathakurta, Eric W. Peng, Youkyung Ko The goal of this research is to characterize globular clusters (GCs) in Virgo Cluster dwarf galaxies. We focus on GCs close to the centers of their host galaxy, where the host galaxies’ light inevitably interferes with GC detection. Our dataset contains 1145 Virgo Cluster dwarf galaxies imaged in u*, g’, i’, and z’ bands, obtained using CFHT/MegaCam from the Next Generation Virgo Cluster Survey. For each galaxy, we use isophote fitting to estimate its light distribution and subtract that distribution model from the image, revealing compact objects close to the galaxy. An automation of this technique subtracted galaxy light for about 56\% of the images. This method was most effective for elliptical galaxies; irregular galaxies produced poor results because they departed from the expected elliptical symmetry. If a satisfactory light model couldn’t be generated, then a ring median filter approximated the galaxy light distribution by estimating each pixel's background. We show a proof of concept using Source Extractor to characterize objects in the subtracted images and identify GC candidates through comparisons with other known GCs. This research was conducted by high school students under the auspices of the Science Internship Program at the University of California Santa Cruz. [Preview Abstract] |
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