Bulletin of the American Physical Society
Far West Section Fall 2021 Meeting
Volume 66, Number 12
Friday–Saturday, October 29–30, 2021; Virtual
Session F02: Astro and Grav and Applied Physics -1 |
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Chair: Alessandra Lanzara, UCBerkeley |
Friday, October 29, 2021 2:00PM - 2:12PM |
F02.00001: Small Lensed ${z}\geq5.5$ Galaxies Selected as Potential Lyman Continuum Leakers Chloe Neufeld, Marusa Bradac, Victoria Strait, Brian Lemaux, Lilan Yang, Tomasso Treu, Dan Coe, Larry Bradely, Adi Zitrin, Mario Nonino The study of high-redshift galaxies is a key aspect of constructing a complete picture of galaxy formation and evolution, and their properties can lend insight into the conditions of the early universe and the process of reionization (the ionization of neutral hydrogen in the intergalactic medium by light sources in the early universe). Galaxies magnified by gravitational lensing are especially important to analyze these high-redshift populations, with the advantage of appearing brighter with higher spatial resolution while remaining intrinsically faint. I will present size measurements of 78 high-redshift ($z\geq 5.5$) lensed galaxy candidates from the Reionization Lensing Cluster Survey (RELICS), imaged by the Hubble Space Telescope and the Spitzer Space Telescope. I compute sizes using the forward-modeling code Lenstruction and account for magnification using public lens models. I will discuss the resulting small size measurements and highlight compact and highly star-forming sources as possible Lyman continuum leaker candidates with high inferred [OIII]+H$\beta$ that could be major contributors to the process of reionization. [Preview Abstract] |
Friday, October 29, 2021 2:12PM - 2:24PM |
F02.00002: G-Mode Oscillations of Finite Temperature Neutron Stars Nicholas Lozano, Prashanth Jaikumar Neutron star merger events provide a unique opportunity to study the properties of matter at high density and temperature. We study a diagnostic of the composition of high-density matter, namely, g-mode oscillations, which are driven by buoyancy forces. These oscillations can be excited by tidal forces and couple to gravitational waves Prior work has calculated these oscillations for cold neutron star matter, while we present the extension to high temperatures by employing a parameterized model proposed by Raithel, Ozel, and Psaltis (Raithel et.al, ApJ 785, 12 (2019)). A third-generation gravitational wave detector should be capable of detecting such oscillations from a merger event and provide valuable information on the composition of neutron star interiors. [Preview Abstract] |
Friday, October 29, 2021 2:24PM - 2:36PM |
F02.00003: Sounds Speed in Neutron Stars with Hyperons Vinh Tran, Prashanth Jaikumar The exact composition of matter in the interior of a neutron star is unknown. One such composition is the standard neutron, proton, electron matter. However, due to the high pressures, it is also possible for heavier particles like hyperons, baryons that include one or more strange quarks, to exist. The composition of neutron stars has an immediate effect on g-mode oscillations of neutron stars, through the dependence on two sound speeds -- the adiabatic and equilibrium sound speed. We study the two sound speeds in dense matter with hyperons. The difference between the two sound speeds, though small in magnitude, is crucial in supporting g-mode oscillations. We observe a noticeable, sharp rise in the frequencies when we consider hyperonic matter versus standard neutron, proton, electron matter. The hope is that with third-generation gravitational wave detectors, we should be able to detect g-mode oscillations in neutron stars and thereby constrain the type of matter contained inside of neutron stars. [Preview Abstract] |
Friday, October 29, 2021 2:36PM - 2:48PM |
F02.00004: Optimization of an Active Leveling Scheme for Short-Range Gravity Experiment Alyssa Johnson, Michael Gengo, Claire Rogers, C.D. Hoyle At Humboldt State University undergraduate researchers and faculty have constructed a torsion pendulum experiment that works to measure gravitational interactions below 50 microns. The aim of this project is to look for deviations in the Weak Equivalence Principle (WEP) and/or Inverse-Square Law (ISL). The scale at which this experiment is operating is within an untested range at the millimeter scale. This apparatus’ torsion pendulum consists of equal masses with differing materials arranged as a composition dipole. The twist of this configuration is measured by an attractor mass that oscillates in a parallel-plate arrangement nearby. The oscillation creates a torque (time-dependent) on the pendulum which can be studied for deviations in the WEP and/or ISL. At present, an active leveling scheme has been implemented to mediate the apparatus’s tilt over the course of the day. This scheme has been optimized through the use of a power supply and PID loop that mitigates the variations in tilt by way of applying a voltage via a resistor to one of the legs of the experiment. This talk will update on the progress of optimizing this tilt sensor setup. [Preview Abstract] |
Friday, October 29, 2021 2:48PM - 3:00PM |
F02.00005: Learning from materials to uncover protein functionality with infrared light Daniel Banin, Luca Moreschini, Burhan Ahmed, Daniel Elbott, Shannon Yan, Zhijie Chen, Liana Klivansky5, Alessandra Lanzara, Carlos Bustamante Over the past decade, the advancement of lasers sources and application to materials has led to the study and control of material's properties in novel ways. Here I will present a study where we used coherent infrared photons to probe the functionality of the enzyme alkaline phosphatase (ALP), a protein responsible for catalytic reaction, by adopting a similar methodology as the one developed for materials. By measuring specific protein's vibrations via FTIR and their dynamical evolution via absorption spectroscopy, new information about the catalytic process is provided. This work demonstrates that the combination of these two techniques, can be more broadly applied to the study of a variety of biological activity, and inform in general on the protein's functionality. [Preview Abstract] |
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