Physical Sciences and Mathematics | Open Access Articles

The Jcmt Nearby Galaxies Legacy Survey – Xi. Environmental Variations In The Atomic And Molecular Gas Radial Profiles Of Nearby Galaxies, Angus Mok, C. D. Wilson, J. H. Knapen, José R. Sánchez-Gallego, E. Brinks, E. Rosolowsky

Physics and Astronomy Faculty Publications

We present an analysis of the radial profiles of a sample of 43 H I-flux selected spiral galaxies from the Nearby Galaxies Legacy Survey (NGLS) with resolved James Clerk Maxwell Telescope (JCMT) CO J = 3 − 2 and/or Very Large Array (VLA) H I maps. Comparing the Virgo and non-Virgo populations, we confirm that the H i discs are truncated in the Virgo sample, even for these relatively H i-rich galaxies. On the other hand, the H₂ distribution is enhanced for the Virgo galaxies near their centres, resulting in higher H₂ to H I ratios and steeper …

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The Dusty Tori Of Nearby Qsos As Constrained By High-Resolution Mid-Ir Observations, M. Martínez-Paredes, I. Aretxaga, A. Alonso-Herrero, O. González-Martín, E. Lopéz-Rodríguez, C. Ramos Almeida, A. Asensio Ramos, T. Diaz Santos, Moshe Elitzur, P. Esquej, A. Hernán-Caballero, K. Ichikawa, R. Nikutta, C. Packham, M. Pereira-Santaella, C. Telesco

Physics and Astronomy Faculty Publications

We present mid-infrared (MIR; 7.5–13.5 μm) imaging and spectroscopy observations obtained with the CanariCam (CC) instrument on the 10.4-m Gran Telescopio CANARIAS for a sample of 20 nearby, MIR bright and X-ray luminous quasi-stellar objects (QSOs). We find that for the majority of QSOs the MIR emission is unresolved at angular scales ∼0.3 arcsec, corresponding to physical scales ≲ 600 pc. We find that the higher-spatial resolution CC spectra have similar shapes to those obtained with Spitzer/IRS, and hence we can assume that the spectra are not heavily contaminated by extended emission in the host galaxy. We thus take …

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Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland

Physics and Astronomy Faculty Publications

Accurate rates for energy-degenerate l-changing collisions are needed to determine cosmological abundances and recombination. There are now several competing theories for the treatment of this process, and it is not possible to test these experimentally. We show that the H i two-photon continuum produced by astrophysical nebulae is strongly affected by l-changing collisions. We perform an analysis of the different underlying atomic processes and simulate the recombination and two-photon spectrum of a nebula containing H and He. We provide an extended set of effective recombination coefficients and updated l-changing 2s − 2p transition rates using …

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Design And Performance Of Sipm-Based Readout Of Pbf2 Crystals For High-Rate, Precision Timing Applications, J. Kaspar, A. T. Fienberg, D. W. Hertzog, M. A. Huehn, P. Kammel, K. S. Khaw, D. A. Peterson, M. W. Smith, T. D. Vanwechel, A. Chapelain, L. K. Gibbons, D. A. Sweigart, C. Ferrari, A. Fioretti, C. Gabbanini, G. Venanzoni, M. Iacovacci, S. Mastroianni, K. Giovanetti, W. Gohn, Tim Gorringe, D. Pocanic

Physics and Astronomy Faculty Publications

We have developed a custom amplifier board coupled to a large-format 16-channel Hamamatsu silicon photomultiplier device for use as the light sensor for the electromagnetic calorimeters in the Muon g - 2 experiment at Fermilab. The calorimeter absorber is an array of lead-fluoride crystals, which produces short-duration Cherenkov light. The detector sits in the high magnetic field of the muon storage ring. The SiPMs selected, and their accompanying custom electronics, must preserve the short pulse shape, have high quantum efficiency, be non-magnetic, exhibit gain stability under varying rate conditions, and cover a fairly large fraction of the crystal exit surface …

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Research At The University Of Kentucky Accelerator Laboratory, S. F. Hicks, Michael A. Kovash

Physics and Astronomy Faculty Publications

The Department of Physics and Astronomy at the University of Kentucky operates a 7-MV CN Van de Graaff accelerator that produces primary beams of protons, deuterons, and helium ions. An in-terminal pulsing and bunching system operates at 1.875 MHz and is capable of providing 1 ns beam bunches at an average current of several microamperes. Nearly all ongoing research programs involve secondary pulsed neutrons produced with gas cells containing deuterium or tritium, as well as with a variety of solid targets. Most experiments are performed at a target station positioned over a deep pit, so as to reduce the background …

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Full-Text Articles in Physical Sciences and Mathematics

The Jcmt Nearby Galaxies Legacy Survey – Xi. Environmental Variations In The Atomic And Molecular Gas Radial Profiles Of Nearby Galaxies, Angus Mok, C. D. Wilson, J. H. Knapen, José R. Sánchez-Gallego, E. Brinks, E. Rosolowsky

Physics and Astronomy Faculty Publications

Physics and Astronomy Faculty Publications

Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland

Physics and Astronomy Faculty Publications

Physics and Astronomy Faculty Publications

Research At The University Of Kentucky Accelerator Laboratory, S. F. Hicks, Michael A. Kovash

Physics and Astronomy Faculty Publications