Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4,
2010
Valparaiso University
Observations Of Ozone Production In A Dissipating Tropical Convective Cell During Tc4, Gary A. Morris, A. M. Thompson, K. E. Pickering, S. Chen, E. J. Bucsela, P. A. Kucera
Physics and Astronomy Faculty Publications
From 13 July–9 August 2007, 25 ozonesondes were launched from Las Tablas, Panama as part of the Tropical Composition, Cloud, and Climate Coupling (TC4) mission. On 5 August, a strong convective cell formed in the Gulf of Panama. World Wide Lightning Location Network (WWLLN) data indicated 563 flashes (09:00–17:00 UTC) in the Gulf. NO2 data from the Ozone Monitoring Instrument (OMI) show enhancements, suggesting lightning production of NOx. At 15:05 UTC, an ozonesonde ascended into the southern edge of the now dissipating convective cell as it moved west across the Azuero Peninsula. The balloon oscillated from 2.5–5.1 km five times …
A Model For Predicting Extragalactic Jet Lifetimes,
2010
Drexel University
A Model For Predicting Extragalactic Jet Lifetimes, Daniel S. Spicer, Robert Bingham, Stephen O'Sullivan
Articles
Abstract. In this letter, we propose a model to explain the disintegration of ex- tragalactic jets and to predict the associated timescale. The model assumes that a jet is current and charge neutral as well as collimated at its source; however, the forward electron current gradually decays producing a magnetic field transverse to the direction of jet propagation. This growing transverse magnetic field eventually causes the jet to disintegrate.
A Two-Dimensional, Linear–Elastic Model To Explain Radial Extensional Fractures, Pantheon Fossae, Caloris Basin, Mercury,
2010
Bridgewater State University
A Two-Dimensional, Linear–Elastic Model To Explain Radial Extensional Fractures, Pantheon Fossae, Caloris Basin, Mercury, Brianne Mcdonough
Undergraduate Review
In this study, two-dimensional linear elasticity theory is used to model the lithospheric stress field that produces radial extensional fractures observed at Pantheon Fossae in the Caloris Basin of Mercury. These fractures were imaged by the MESSENGER mission flyby of Mercury on January 14, 2008 and show radial fractures extending outward from a 40-kilometer impact crater named Apollodorus. Recent studies have proposed several different mechanisms to explain these fractures, including magmatic processes, central basin uplift, and stresses produced by the formation of the impact crater itself.
Sensitivity Of Planetary Boundary Layer To Varying Volumetric Soil Moisture: A Mesoscale Models Comparision,
2010
Western Kentucky U\
Sensitivity Of Planetary Boundary Layer To Varying Volumetric Soil Moisture: A Mesoscale Models Comparision, Asrid Suarez Gonzalez
Mahurin Honors College Capstone Experience/Thesis Projects
A comparison between two Mesoscale models, Colorado State University Regional Atmospheric Model System (RAMS) version 4.4 coupled with the Land‐Ecosystem– Atmosphere Feedback Model (LEAF2) and Penn State/NCAR’s Mesoscale Model (MM5) coupled with NOAH Land Surface Model, was conducted in order to assess the sensitivity of forecasted boundary layer variables to anomalous volumetric soil moistures. The study elaborates on the findings of Quintanar et al. (2008) using the study’s experimental design as a template for our numerical model comparison. The experiments were conducted using the same synoptic events examined by Quintanar et al. (2008): June 11, June 17 and June 22, …
Solar Observations During A Solar Minimum Using A Small Radio Telescope,
2010
Bridgewater State University
Solar Observations During A Solar Minimum Using A Small Radio Telescope, Gary Forrester
Undergraduate Review
The Sun is currently in a quiescent phase called solar minimum. We used Bridgewater State College’s (B.S.C.’s) Small Radio Telescope (SRT) to observe solar radio emission during this quiet phase and correlated our data to solar X-ray data readily available through the National Oceanic and Atmospheric Administration (NOAA). Previous observations made during a period of high solar activity (solar maximum) using one of M.I.T.’s SRTs showed that some solar radio and X-ray events were correlated, while others were not. We made observations during solar minimum and found one event where there was a correlation between radio and X-ray emission.
The Horizontal Electric Field Induced By A Lightning Return Stroke,
2010
Trinity University
The Horizontal Electric Field Induced By A Lightning Return Stroke, S L. Meredith, S K. Earles, Niescja E. Turner
Physics and Astronomy Faculty Research
Problem statement: Develop a new formula which describes the horizontal electric field induced by a lightning return stroke in contact with an imperfect conductive surface. Approach: A new method for describing the horizontal electric field induced by a lightning return stroke will be presented. The method presented here had utilized an approach which purposely downplayed the physics of how image theory was employed in the presence of an imperfect conductive surface. It did so by adopting a technique which had focused on the geometry that existed between the lightning channel and surface ground. In doing so, new expressions …
A New Method To Describe Image Theory For An Imperfect Conductor,
2010
Trinity University
A New Method To Describe Image Theory For An Imperfect Conductor, S L. Meredith, S K. Earles, Niescja E. Turner
Physics and Astronomy Faculty Research
Problem statement: Modify the equations associated with image theory in order to account for perfect and imperfect conductors. Approach: A novel approach for describing the application of image theory for an imperfect conductive surface was presented. The method presented here purposely downplays the physics of how image theory was employed to account for a charge which is in the presence of an imperfect conductive surface. In turn, it adopted an approach which focused on the geometry that existed between the charged particle and surface ground. In doing so, the proposed method formulated a solution that had minimized the …
Dual Gamma-Ray Mission,
2010
Space Sciences Laboratory, University of California
Dual Gamma-Ray Mission, S. Boggs, C. Wunderer, P. Von Ballmoos, T. Takahashi, N. Gehrels, J. Tueller, M. Baring, J. Beacom, R. Diehl, J Greiner, E Grove, Dieter H. Hartmann
Publications
Gamma-rays at MeV energies provide a unique window on the high energy Universe, especially so for nuclear astrophysics. The potential for significant contributions, e.g., to the understanding of SNe Ia as well as the large potential for new discoveries has long been recognized, but technical progress in this challenging energy band has been slow. The groundbreaking discoveries of CGRO’s COMPTEL, however, have inspired and driven the development of powerful new instrumentation over the past decade. Novel detector technologies developed in the US and Japan enable compact Compton telescopes, greatly improving the efficiency and field-of-view achievable with this technique successfully employed …
The Dynamic X-Ray Sky Of The Local Universe,
2010
Space Sciences Laboratory, University of California, Berkeley
The Dynamic X-Ray Sky Of The Local Universe, S. Boggs, C. Wunderer, P. Von Ballmoos, T. Takahashi, N. Gehrels, J. Tueller, M. Baring, J. Beacom, R. Diehl, Dieter H. Hartmann
Publications
Over the next decade, we can expect time domain astronomy to flourish at optical and radio wavelengths. In parallel with these efforts, a dedicated transient "machine" operating at higher energies (X-ray band through soft gamma-rays) is required to reveal the unique subset of events with variable emission predominantly visible above 100 eV. Here we focus on the transient phase space never yet sampled due to the lack of a sensitive, wide-field and triggering facility dedicated exclusively to catching high energy transients and enabling rapid coordinated multi-wavelength follow-up. We first describe the advancements in our understanding of known X-ray transients that …
On The Origin Of The Highest Redshift Gamma-Ray Bursts,
2010
Los Alamos National Laboratory & Astronomical Observatory, University of Warsaw &
On The Origin Of The Highest Redshift Gamma-Ray Bursts, Krzysztof Belczynski, Daniel E. Holz, Chris L. Fryer, Edo Berger, Dieter H. Hartmann, Brain O'Shea
Publications
GRB 080913 and GRB 090423 are the most distant gamma-ray bursts (GRBs) known to date, with spectroscop-ically determined redshifts of z = 6.7 and z = 8.1, respectively. The detection of bursts at this early epoch of the universe significantly constrains the nature of GRBs and their progenitors. We perform population synthesis studies of the formation and evolution of early stars, and calculate the resulting formation rates of short- and long-duration GRBs at high redshift. The peak of the GRB rate from Population II stars occurs at z ∼ 7for a model with efficient/fast mixing of metals, while it is …
Aztec Half Square Degree Survey Of The Shades Fields - I. Maps, Catalogues And Source Counts,
2010
University of Massachusetts Amherst
Aztec Half Square Degree Survey Of The Shades Fields - I. Maps, Catalogues And Source Counts, J. E. Austermann, J. S. Dunlop, T. A. Perera, K. S. Scott, G. W. Wilson, I. Aretxaga, D. H. Hughes, O. Almaini, E. L. Chapin, S. C. Chapman, M. Cirasuolo, D. L. Clements, K. E.K. Coppin, L. Dunne, S. Dye, S. A. Eales, E. Egami, D. Farrah, D. Ferrusca, S. Flynn, D. Haig, M. Halpern, E. Ibar, R. J. Ivison, E. Van Kampen, Y. Kang, S. Kim, C. Lacey, James D. Lowenthal, P. D. Mauskopf, R. J. Mclure, A. M.J. Mortier
Astronomy: Faculty Publications
We present the first results from the largest deep extragalactic mm-wavelength survey undertaken to date. These results are derived from maps covering over 0.7 deg , made at λ = 1.1 mm, using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope. The maps were made in the two fields originally targeted at λ = 850 μm with the Submillimetre Common-User Bolometer Array (SCUBA) in the SCUBA Half-Degree Extragalactic Survey (SHADES) project, namely the Lockman Hole East (mapped to a depth of 0.9-1.3 mJy rms) and the Subaru/XMM-Newton Deep Field (mapped to a depth of 1.0-1.7 mJy rms). …
Unidirectional Nonlinear Pt-Symmetric Optical Structures,
2010
The University of Texas Rio Grande Valley
Unidirectional Nonlinear Pt-Symmetric Optical Structures, Hamidreza Ramezani, Tsampikos Kottos
Physics & Astronomy Faculty Publications
We show that nonlinear optical structures involving a balanced gain-loss profile can act as unidirectional optical valves. This is made possible by exploiting the interplay between the fundamental symmetries of parity (P) and time (T), with optical nonlinear effects. This unidirectional dynamics is specifically demonstrated for the case of an integrable PT-symmetric nonlinear system.
Evidence For Supernova-Synthesized Dust From The Rising Afterglow Of Grb071025 At Z ∼ 5,
2010
Roger Williams University
Evidence For Supernova-Synthesized Dust From The Rising Afterglow Of Grb071025 At Z ∼ 5, Daniel A. Perley, J. S. Bloom, C. R. Klein, S. Covino, T. Minezaki, P. Wo´Zniak, W. T. Vestrand, G. G. Williams, P. Milne, N. R. Butler, Adria Updike, T. Kr¨Uhler, P. Afonso, A. Antonelli, L. Cowie, P. Ferrero, J. Greiner, D. H. Hartmann, Y. Kakazu, A. K¨Upc¨U Yoldas¸, A. N. Morgan, P. A. Price, J. X. Prochaska, Y. Yoshii
Arts & Sciences Faculty Publications
No abstract provided.
A Very Metal-Poor Damped Lyman-Α System Revealed Through The Most Energetic Grb 090926a,
2010
Roger Williams University
A Very Metal-Poor Damped Lyman-Α System Revealed Through The Most Energetic Grb 090926a, A. Rau, S. Savaglio, T. Kr¨ Uhler, P. Afonso, J. Greiner, S. Klose, P. Schady, S. Mcbreen, R. Filgas, F. Olivares E., A. Rossi, Adria Updike
Arts & Sciences Faculty Publications
No abstract provided.
Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism,
2010
Florida Institute of Technology
Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Deosthenes Kazanas
Aerospace, Physics, and Space Science Faculty Publications
We present new Chandra observations of the radio galaxy 3C 445, centered on its southern radio hot spot. Our observations detect X-ray emission displaced upstream and to the west of the radio-optical hot spot. Attempting to reproduce both the observed spectral energy distribution and the displacement excludes all one-zone models. Modeling of the radio-optical hot spot spectrum suggests that the electron distribution has a low-energy cutoff or break approximately at the proton rest mass energy. The X-rays could be due to external Compton scattering of the cosmic microwave background coming from the fast (Lorentz factor Γ ≈ 4) part of …
A Multi-Wavelength Spectral And Polarimetric Study Of The Jet Of 3c 264,
2010
Florida Institute of Technology
A Multi-Wavelength Spectral And Polarimetric Study Of The Jet Of 3c 264, Eric S. Perlman
Aerospace, Physics, and Space Science Faculty Publications
We present a comprehensive multi-band spectral and polarimetric study of the jet of 3C 264 (NGC 3862). Included in this study are three Hubble Space Telescope (HST) optical and ultraviolet polarimetry data sets, along with new and archival Very Large Array radio imaging and polarimetry, a re-analysis of numerous HST broadband data sets from the near infrared to the far ultraviolet, and a Chandra ACIS-S observation. We investigate similarities and differences between optical and radio polarimetry, in both degree of polarization and projected magnetic field direction. We also examine the broadband spectral energy distribution of both the nucleus and jet …
Magnetic Cloud Boundary Layer Of 9 November 2004 And Its Associated Space Weather Effects,
2010
Florida Institute of Technology
Magnetic Cloud Boundary Layer Of 9 November 2004 And Its Associated Space Weather Effects, Pingbing Zuo, Fengsi Wei, Xueshang Feng, Xiaojun Xu, Wenbin Song
Aerospace, Physics, and Space Science Faculty Publications
On 9 November 2004, the WIND spacecraft detected a magnetic cloud boundary layer (MCBL) during the interval from 19:07 UT to 20:30 UT. Within the MCBL, there is intense southward magnetic field and the dynamic pressure is rather high, which makes it much geoeffective. Twenty-three minutes later, the MCBL arrived on the magnetopause. An intense geomagnetic storm main phase was driven by the sustaining strong southward magnetic field within the MCBL. During the passage of the MCBL, a typical magnetospheric substorm was triggered. The substorm onset was synthetically identified by the aurora breakup, magnetic dipolarization, dispersionless particle injection, Pi2 pulsation, …
The Heavily Polluted Atmosphere Of The Daz White Dwarf Galex J193156.8+011745,
2010
Astronomical Institute of Czech Academy of Sciences
The Heavily Polluted Atmosphere Of The Daz White Dwarf Galex J193156.8+011745, Stephane Vennes, Adéla Kawka, Péter Németh
Aerospace, Physics, and Space Science Faculty Publications
We report on the discovery of a new heavily polluted white dwarf. The DAZ white dwarf GALEX J193156.8+011745 was identified in a joint Galaxy Evolution Explorer (GALEX)/GSC survey of ultraviolet-excess objects. Optical spectra obtained at ESO New Technology Telescope show strong absorption lines of magnesium and silicon, and a detailed abundance analysis based on Very Large Telescope-Kueyen UVES spectra reveal super-solar abundances of silicon and magnesium and near-solar abundances of oxygen, calcium and iron. The overall abundance pattern bears the signature of on-going accretion on to the white dwarf atmosphere. The infrared spectral energy distribution shows an excess in the …
Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism,
2010
Florida Institute of Technology
Chandra Observations Of The Radio Galaxy 3c 445 And The Hot Spot X-Ray Emission Mechanism, Eric S. Perlman, Markos Georganopoulos, Emily M. May, Demosthenes Kazanas
Aerospace, Physics, and Space Science Faculty Publications
We present new Chandra observations of the radio galaxy 3C 445, centered on its southern radio hot spot. Our observations detect X-ray emission displaced upstream and to the west of the radio-optical hot spot. Attempting to reproduce both the observed spectral energy distribution and the displacement excludes all one-zone models. Modeling of the radio-optical hot spot spectrum suggests that the electron distribution has a low-energy cutoff or break approximately at the proton rest mass energy. The X-rays could be due to external Compton scattering of the cosmic microwave background coming from the fast (Lorentz factor Γ ≈ 4) part of …
Thunderstorm Characteristics Associated With Rhessi Identified Terrestrial Gamma Ray Flashes,
2010
Florida Institute of Technology
Thunderstorm Characteristics Associated With Rhessi Identified Terrestrial Gamma Ray Flashes, Michael E. Splitt, Steven M. Lazarus, Diana H. Barnes, Joseph R. Dwyer, Hamid K. Rassoul, David M. Smith, Bryna J. Hazelton, Brian W. Grefenstette
Aerospace, Physics, and Space Science Faculty Publications
The characteristics of thunderstorms that produce terrestrial gamma-ray flashes (TGFs) observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are determined using climatological and meteorological data. RHESSI observed TGFs follow diurnal, seasonal, and geographic patterns that are very similar to those of thunderstorms confirming, in part, that these events are directly connected to thunderstorm activity. The TGF producing thunderstorms are shown to be closely associated with tall (ranging from 13.6 km to 17.3 km) tropical thunderstorm systems, a finding that is consistent with theoretical expectations from models of relativistic breakdown that relate the source region to the spectral …
