Astrophysics and Astronomy Commons^™

Galaxy And Mass Assembly (Gama): Time-Scales For Galaxies Crossing The Green Valley, S. Phillipps, M. N. Bremer, A. M. Hopkins, R. De Propris, E. N. Taylor, P. A. James, L. J.M. Davies, M. E. Cluver, S. P. Driver, S. A. Eales, Benne W. Holwerda, L. S. Kelvin, A. E. Sansom

Faculty and Staff Scholarship

We explore the constraints that can be placed on the evolutionary time-scales for typical low-redshift galaxies evolving from the blue cloud through the green valley and on to the red sequence. We utilize galaxies from the GAMA survey with 0.1 < z < 0.2 and classify them according to the intrinsic (u∗ - r∗) colours of their stellar populations, as determined by fits to their multiwavelength spectral energy distributions. Using these fits to also determine stellar population ages and star formation time-scales, we argue that our results are consistent with a green valley population dominated by galaxies that are simply decreasing their star formation (running out of gas) over a time-scale of 2-4 Gyr which are seen at a specific epoch in their evolution (approximately 1.6 e-folding times after their peak in star formation). If their fitted star formation histories are extrapolated forward, the green galaxies will further redden over time, until they attain the colours of a passive population. In this picture, no specific quenching event which cuts-off their star formation is required, though it remains possible that the decline in star formation in green galaxies may be expedited by internal or external forces. However, there is no evidence that green galaxies have recently changed their star formation time-scales relative to their previous longer term star formation histories.

Galaxy And Mass Assembly (Gama): Environmental Quenching Of Centrals And Satellites In Groups, L. J.M. Davies, A. S.G. Robotham, C. Del P. Lagos, S. P. Driver, A. R.H. Stevens, Y. M. Bahé, M. Alpaslan, M. N. Bremer, M. J.I. Brown, S. Brough, J. Bland-Hawthorn, L. Cortese, P. Elahi, M. W. Grootes, Benne W. Holwerda, A. D. Ludlow, S. Mcgee, M. Owers, S. Phillipps

Faculty and Staff Scholarship

Recently a number of studies have found a similarity between the passive fraction of central and satellite galaxies when controlled for both stellar and halo mass. These results suggest that the quenching processes that affect galaxies are largely agnostic to central/satellite status, which contradicts the traditional picture of increased satellite quenching via environmental processes such as stripping, strangulation, and starvation. Here we explore this further using the Galaxy And Mass Assembly (GAMA) survey, which extends to ~2 dex lower in stellar mass than SDSS, is more complete for closely separated galaxies (≳395 per cent compared to ≳370 per cent), and …

Measurement Of Solar Spectral Irradiance And Surface Ozone At Carrollton, Georgia, Usa, During The Great American Eclipse On 21 August 2017, Kirthi Tennakone, L Ajith Desilva, Charles A. Zander*, Shea Rose, Austin B. Kerlin

Georgia Journal of Science

Measurements conducted at the University of West Georgia, Carrollton, Georgia, during the time of the solar eclipse of 21^st August 2017 demonstrated that the integrated spectral irradiance in defined wavelength ranges in the ultraviolet and visible calculated as a fraction of the total irradiance reached a minimum at maximum obscuration of the Sun, whereas in an infrared range it was maximum. The method of analysis adopted supports the view that the changes in spectral irradiance during highly obscured partial phases is a consequence of limb darkening. In a surface ozone measurement, a minimum in ozone concentration occurred 30 +_ …

The Proton-Ω Correlation Function In Au + Au Collisions At √SNn = 200 Gev, J. Adam, L. Adamczyk, J. R. Adams, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, F. Atetalla, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, K. Barish, A. J. Bassill, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, Renee H. Fatemi, Suvarna Ramachandran

Physics and Astronomy Faculty Publications

We present the first measurement of the proton–Ω correlation function in heavy-ion collisions for the central (0–40%) and peripheral (40–80%) Au + Au collisions at √s_NN = 200 GeV by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Predictions for the ratio of peripheral collisions to central collisions for the proton–Ω correlation function are sensitive to the presence of a nucleon–Ω bound state. These predictions are based on the proton–Ω interaction extracted from (2+1)-flavor lattice QCD calculations at the physical point. The measured ratio of the proton–Ω correlation function between the peripheral (small system) and central (large system) …

Charged Compact Binary Coalescence Signal And Electromagnetic Counterpart Of Plunging Black Hole–Neutron Star Mergers, Bing Zhang

Physics & Astronomy Faculty Research

If at least one of the members of a compact binary coalescence is charged, the inspiral of the two members would generate a Poynting flux with an increasing power, giving rise to a brief electromagnetic counterpart temporally associated with the chirp signal of the merger (with possibly a small temporal offset), which we term as the charged compact binary coalescence (cCBC) signal. We develop a general theory of cCBC for any mass and amount of charge for each member. Neutron stars (NSs), as spinning magnets, are guaranteed to be charged, so the cCBC signal should accompany all NS mergers. The …

Polymer Gels With Tunable Ionic Seebeck Coefficient For Ultra-Sensitive Printed Thermopiles, Dan Zhao, Anna Martinelli, Andreas Willfahrt, Thomas Fischer, Diana Bernin, Zia Ullah Khan, Maryam Shahi, Joseph W. Brill, Magnus P. Jonsson, Simone Fabiano, Xavier Crispin

Physics and Astronomy Faculty Publications

Measuring temperature and heat flux is important for regulating any physical, chemical, and biological processes. Traditional thermopiles can provide accurate and stable temperature reading but they are based on brittle inorganic materials with low Seebeck coefficient, and are difficult to manufacture over large areas. Recently, polymer electrolytes have been proposed for thermoelectric applications because of their giant ionic Seebeck coefficient, high flexibility and ease of manufacturing. However, the materials reported to date have positive Seebeck coefficients, hampering the design of ultra-sensitive ionic thermopiles. Here we report an “ambipolar” ionic polymer gel with giant negative ionic Seebeck coefficient. The latter can …

Coordinated Uv And X-Ray Spectroscopic Observations Of The O-Type Giant Ξ Per: The Connection Between X-Rays And Large-Scale Wind Structure, Derek Massa, Lidi Oskinova, Raman Prinja, Richard Ignace

ETSU Faculty Works

We present new, contemporaneous Hubble Space Telescope STIS and XMM-Newton observations of the O7 III(n)((f)) star ξ Per. We supplement the new data with archival IUE spectra, to analyze the variability of the wind lines and X-ray flux of ξ Per. The variable wind of this star is known to have a 2.086-day periodicity. We use a simple, heuristic spot model that fits the low-velocity (near-surface) IUE wind line variability very well, to demonstrate that the low-velocity absorption in the new STIS spectra of N iv λ1718 and Si iv λ1402 vary with the same 2.086-day period. It …

The Potential Science And Engineering Value Of Samples Delivered To Earth By Mars Sample Return, David W. Beaty, Monica M. Grady, Harry Y. Mcsween, Elliot Sefton-Nash, B. L. Carrier, Francesca Altieri, Yuri Amelin, Eleonora Ammannito, Mahesh Anand, Liane G. Benning, Janice L. Bishop, Lars E. Borg, Dale Boucher, John R. Brucato, Henner Busemann, Kathleen A. Campbell, Andrew D. Czaja, Vinciane Debaille, David J. Des Marais, Michael Dixon, Bethany L. Ehlmann, Jack D. Farmer, David C. Fernandez-Remolar, Justin Filiberto, Jennifer Fogarty, Daniel P. Galvin, Y. S. Goreva, Lydia J. Hallis, Andrea Dawn Harrington, Elisabeth M. Hausrath, Chris D.K. Herd

Geoscience Faculty Research

Executive summary provided in lieu of abstract.

Engaging The Greater Lafayette Community In A Journey Through The Earth Sciences: Purdue’S Eaps Earth Science Passport Day Event, Dara Laczniak, Bradley Garczynski

Engagement & Service-Learning Summit

No abstract provided.

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

The Limited Reign Of Saturn's Rings, Laurence A. Marschall

Physics and Astronomy Faculty Publications

Saturn’s rings—stretching tens of thousands of miles above its equator but no more than a few hundred yards thick—mark an ancient debris field of orbiting ice shards, the remains of a moon-sized object that strayed too close and was torn to pieces by Saturn’s intense gravitation. Astronomers have debated when the rings formed and how long they will stay in orbit. Recent observations from large, land-based telescopes and orbiting spacecraft reveal that Saturn’s rings are remarkably young and are dissipating at a rapid rate. [excerpt]

From Big Science To “Deep Science”, Florentin Smarandache, Victor Christianto

Branch Mathematics and Statistics Faculty and Staff Publications

The Standard Model of particle physics has accomplished a great deal including the discovery of Higgs boson in 2012. However, since the supersymmetric extension of the Standard Model has not been successful so far, some physicists are asking what alternative deeper theory could be beyond the Standard Model? This article discusses the relationship between mathematics and physical reality and explores the ways to go from Big Science to “Deep Science”.

Taller In The Saddle: Constraining Cmb Physics Using Saddle Points, Jow L. Dylan, Dagoberto Contreras, Douglas Scott, Emory F. Bunn

Physics Faculty Publications

The statistics of extremal points in the cosmic microwave background (CMB) temperature (hot and cold spots) have been well explored in the literature, and have been used to constrain models of the early Universe. Here, we extend the study of critical points in the CMB to the set that remains after removing extrema, namely the saddle points. We perform stacks of temperature and polarization about temperature saddle points in simulations of the CMB, as well as in data from the Plancksatellite. We then compute the theoretical profile of saddle-point stacks, given the underlying power spectra of the CMB. As an …

Kondo Signatures Of A Quantum Magnetic Impurity In Topological Superconductors, Rui Wang, Wei-Yi Su, Jian-Xin Zhu, Chin-Sen Ting, Hai Li, Changfeng Chen, Baigeng Wang, Xiaoqun Wang

Physics & Astronomy Faculty Research

We study the Kondo physics of a quantum magnetic impurity in two-dimensional topological superconductors (TSCs), either intrinsic or induced on the surface of a bulk topological insulator, using a numerical renormalization group technique. We show that, despite sharing the p+ip pairing symmetry, intrinsic and extrinsic TSCs host different physical processes that produce distinct Kondo signatures. Extrinsic TSCs harbor an unusual screening mechanism involving both electron and orbital degrees of freedom that produces rich and prominent Kondo phenomena, especially an intriguing pseudospin Kondo singlet state in the superconducting gap and a spatially anisotropic spin correlation. In sharp contrast, intrinsic TSCs support …

Erratum: “The Sluggs Survey: A Catalog Of Globular Cluster Radial Velocities” (2017, Aj, 153, 114), Duncan Forbes, Adebusola Alabi, Jean Brodie, Aaron Romanowsky, Jay Strader, Caroline Foster, Christopher Usher, Lee Spitler, Sabine Bellstedt, Nicola Pastorello, Sreeja Kartha, Zach Jennings, Alexa Villaume, Asher Wasserman, Vincenzo Pota

Faculty Publications

We would like to point out to the reader that the catalog of globular cluster (GC) radial velocities (listed in Table 5) still contains some multiple entries. In such cases GCs were observed more than once and are recorded in Table 5 with a unique GC ID, along with their coordinates and radial velocity measurement. If the reader wishes to exclude, or average, multiple measurements then GCs within one spatial pixel (i.e., 0.119 arcsec) in R.A. and decl. can be identified. This would include two dozen GCs in the galaxies NGC 720, 1407, 2768, 3608, 4365, 4459, 4474, and 4697. …

Book Review: Exoplanets : Hidden Worlds And The Quest For Extraterrestrial Life, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Exoplanets : Hidden Worlds and the Quest for Extraterrestrial Life. Harvard, 2018. 254p bibl index, 9780674976900 $24.95, 9780674988897

Nanosat Tracking And Identification Techniques And Technologies, Mark A. Skinner

Space Traffic Management Conference

Nanosats (and CubeSats, ‘Smallsats’, etc.) are of order 10 cm in size, and are at or near the limits of what can be tracked and characterized, using existing space surveillance assets. Additionally, given the CubeSat form-factor, they are often launched in large numbers (scores), and can be virtually identical. Thus are they difficult to track and to identify.

We have identified a number of technologies that future nanosat missions could employ that would enhance the trackability and/or identification of their satellites when on-orbit. Some of these technologies require active illumination of the satellite with electromagnetic energy, either in the radio …

Resolved Young Binary Systems And Their Disks, R. L. Akeson, Eric L.N. Jensen, J. Carpenter, L. Ricci, S. Laos, N. F. Nogueira, Emma M. Suen-Lewis , '18

Physics & Astronomy Faculty Works

We have conducted a survey of young single and multiple systems in the Taurus–Auriga star-forming region with the Atacama Large Millimeter Array (ALMA), substantially improving both the spatial resolution and sensitivity with which individual protoplanetary disks in these systems have been observed. These ALMA observations can resolve binary separations as small as 25–30 au and have an average 3σ detection level of 0.35 mJy, equivalent to a disk mass of 4 × 10−5 M _⊙ for an M3 star. Our sample was constructed from stars that have an infrared excess and/or signs of accretion and have been classified as Class …

Multiple Spiral Arms In The Disk Around Intermediate-Mass Binary Hd 34700a, John D. Monnier, Tim Harries, Jaehan Bae, Benjamin R. Setterholm, Anna Laws, Alicia Aarnio, Fred C. Adams, Sean Andrews, Nuria Calvet, Catherine Espaillat, Lee Hartmann, Stefan Kraus, Melissa Mcclure, Chris Miller, Rebecca Oppenheimer, David Wilner, Zhaohuan Zhu

Physics & Astronomy Faculty Research

We present the first images of the transition disk around the close binary system HD 34700A in polarized scattered light using the Gemini Planet Imager instrument on Gemini South. The J and H band images reveal multiple spiral-arm structures outside a large (R = 0.49" = 175 au) cavity along with a bluish spiral structure inside the cavity. The cavity wall shows a strong discontinuity and we clearly see significant non-azimuthal polarization Uphi consistent with multiple scattering within a disk at an inferred inclination ~42deg. Radiative transfer modeling along with a new Gaia distance suggest HD 37400A is a young …

Li And Na Adsorption On Graphene And Graphene Oxide Examined By Density Functional Theory Quantum Theory Of Atoms In Molecules And Electron Localization Function, Nicholas Dimakis, Isaiah Salas, Luis Gonzalez, Om Vadodaria, Korinna Ruiz, Muhammad I. Bhatti

Physics & Astronomy Faculty Publications

Adsorption of Li and Na on pristine and defective graphene and graphene oxide (GO) is studied using density functional theory (DFT) structural and electronic calculations, quantum theory of atoms in molecules (QTAIM), and electron localization function (ELF) analyses. DFT calculations show that Li and Na adsorptions on pristine graphene are not stable at all metal coverages examined here. However, the presence of defects on graphene support stabilizes both Li and Na adsorptions. Increased Li and Na coverages cause metal nucleation and weaken adsorption. Defective graphene is associated with the presence of band gaps and, thus, Li and Na adsorptions can …