Bulletin of the American Physical Society
2019 Annual Meeting of the APS Four Corners Section
Volume 64, Number 16
Friday–Saturday, October 11–12, 2019; Prescott, Arizona
Session L01: Gravitation / Cosmology II |
Hide Abstracts |
Chair: Michele Zanolin, ERAU Room: AC1 114 |
Saturday, October 12, 2019 11:00AM - 11:24AM |
L01.00001: Cosmology from CMB Polarization with POLARBEAR and the Simons Array Invited Speaker: Darcy Barron POLARBEAR is a cosmic microwave background (CMB) polarization experiment located in the Atacama desert in Chile. The science goals of the POLARBEAR project are to do a deep search for CMB B-mode polarization created by inflationary gravitational waves, as well as characterize the CMB B-mode signal from gravitational lensing. POLARBEAR-1 started observations in 2012, and the POLARBEAR team has published a series of results from its observations, including the first measurement of a non-zero B-mode polarization angular power spectrum, measured at sub-degree scales where the dominant signal is gravitational lensing of the CMB. POLARBEAR is expanding to POLARBEAR-2/Simons Array, with two new telescopes and three new multi-chroic receivers, increasing sensitivity and frequency coverage. The first of the next-generation receivers, known as PB-2a, had first light in early 2019. With high sensitivity and large sky coverage, PB-2/Simons Array will create a detailed survey of B-mode polarization, and its spectral information will be used to extract the CMB signal from astrophysical foregrounds. We will present the latest POLARBEAR results, as well as the status of commissioning the Simons Array. [Preview Abstract] |
Saturday, October 12, 2019 11:24AM - 11:36AM |
L01.00002: Measuring the Timeline of Cosmic Reionization with Galaxies Lily Whitler, Charlotte Mason Reionization of hydrogen is driven by the first structures in the universe, so understanding the timeline of reionization promises to shed light on the nature of these early objects. In particular, transmission of Lyman alpha (Lya) from galaxies through the intergalactic medium (IGM) is sensitive to neutral hydrogen in the IGM, so can be used to probe reionization. In this work, we implement an improved model of the galaxy UV luminosity--dark matter halo mass relation to infer the fraction of neutral hydrogen in the IGM from Lya observations. Many models assume that UV-bright galaxies reside in massive dark matter halos in overdense regions of the IGM, and thus in relatively large ionized regions. However, observations and N-body simulations indicate that scatter in the UV luminosity--halo mass relation is expected. We model the relation with scatter to assess the impact on Lya visibility during reionization. We show that scatter in the UV luminosity--halo mass relation tends to reduce Lya visibility compared to models without scatter, and that this is most significant for UV-bright galaxies. We infer the neutral fraction at $z \sim 7$, updating the inference without scatter, and place our results in the context of other constraints on the reionization timeline. [Preview Abstract] |
Saturday, October 12, 2019 11:36AM - 11:48AM |
L01.00003: From Navier Stokes to Maxwell: A look at the fluid-gravity duality in the context of the double copy. Nikhil Monga, Cynthia Keeler, Tucker Manton Work done by Bredberg et. al. 2011 showed that for certain algebraically special metrics it was possible to obtain the incompressible Navier Stokes equations. They show that satisfying Einstein's equations for these metrics is equivalent to obtaining the incompressible Navier Stokes equations. Monteiro et. al. 2014 showed that for metrics which can be written in the Kerr-Schild form, i.e. $g_{\mu\nu}=\eta_{\mu\nu}+\phi k_{\mu}k_{\nu}$, for $k^2=0$, one can identify $\phi k_{\mu}$ with Maxwell fields on the flat background. We extend the fluid-gravity picture by combining these ideas, in particular by using the Weyl double copy (Luna et. al. 2018). We observe for algebraically special type D spacetimes, the Maxwell field strength tensor is proportional to the vorticity of the fluid. In the limit that we produce only magnetic fields, we observe that the Maxwell fields $A_{\mu}$ are proportional to the velocity fields of the fluid. Further we show that the surface integral of the Poynting vector of our single copy gauge fields is equivalent to the enstrophy of the fluid modulo a constant. This proportionality constant depends upon the gauge choice we make. These parallels are strongly suggestive of a fluid-gauge duality for such metrics. [Preview Abstract] |
Saturday, October 12, 2019 11:48AM - 12:00PM |
L01.00004: Three methods for characterizing thermo-optic noise in optical cavities Andri Gretarsson, Elizabeth Gretarsson Phase noise due to the thermo-optic effect in mirror coatings is likely to be a dominant noise source in next generation ultra-low noise optical cavities. We developed three measurement and analysis methods allowing us to estimate the level of such coating thermo-optic noise in gravitational wave detectors and elsewhere. We present the measurements and discuss the intricate procedure used to obtain a good estimate of thermo-optic noise. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2025 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700