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Articles 1 - 9 of 9
Full-Text Articles in Physical Processes
Supernova Resonance-Scattering Line Profiles In The Absence Of A Photosphere, Brian Friesen, E. Baron, David Branch, Bin Chen, Jerod T. Parrent, R. C. Thomas
Supernova Resonance-Scattering Line Profiles In The Absence Of A Photosphere, Brian Friesen, E. Baron, David Branch, Bin Chen, Jerod T. Parrent, R. C. Thomas
Dartmouth Scholarship
In supernova (SN) spectroscopy relatively little attention has been given to the properties of optically thick spectral lines in epochs following the photosphere's recession. Most treatments and analyses of post-photospheric optical spectra of SNe assume that forbidden-line emission comprises most if not all spectral features. However, evidence exists that suggests that some spectra exhibit line profiles formed via optically thick resonance-scattering even months or years after the SN explosion. To explore this possibility, we present a geometrical approach to SN spectrum formation based on the "Elementary Supernova" model, wherein we investigate the characteristics of resonance-scattering in optically thick lines while …
Energetic Galaxy-Wide Outflows In High-Redshift Ultraluminous Infrared Galaxies Hosting Agn Activity, C. M. Harrison, D. M. Alexander, A. M. Swinbank, Ian Smail, S. Alaghband-Zadeh, F. E. Bauer, S. C. Chapman, A. Del Moro, R. C. Hickox
Energetic Galaxy-Wide Outflows In High-Redshift Ultraluminous Infrared Galaxies Hosting Agn Activity, C. M. Harrison, D. M. Alexander, A. M. Swinbank, Ian Smail, S. Alaghband-Zadeh, F. E. Bauer, S. C. Chapman, A. Del Moro, R. C. Hickox
Dartmouth Scholarship
We present integral field spectroscopy observations, covering the [O III]4959,5007 emission-line doublet of eight high-redshift (z=1.4-3.4) ultra-luminous infrared galaxies (ULIRGs) that host Active Galactic Nuclei (AGN) activity, including known sub-millimetre luminous galaxies (SMGs). The targets have moderate radio luminosities that are typical of high-redshift ULIRGs (L(1.4GHz)=10^(24)-10^(25)W/Hz) and therefore are not radio-loud AGN. We de-couple kinematic components due to the galaxy dynamics and mergers from those due to outflows. We find evidence in the four most luminous systems (L([O III])>~10^(43)erg/s) for the signatures of large-scale energetic outflows: extremely broad [O III] emission (FWHM ~ 700-1400km/s) across ~4-15kpc, with high velocity …
Electric Currents Due To Stress-Activated Positive Hole Charge Carriers In Ice, Cary T. Keller P.E., Friedemann T. Freund, Dale P. Cruikshank
Electric Currents Due To Stress-Activated Positive Hole Charge Carriers In Ice, Cary T. Keller P.E., Friedemann T. Freund, Dale P. Cruikshank
STAR Program Research Presentations
Jupiter’s satellite Europa, whose surface is composed of ice with a possible water ocean beneath, could conceivably serve as an abode for extraterrestrial life. This and other icy celestial bodies may contain organic macromolecular solid material that is produced when surface ices are exposed to ultraviolet radiation and/or electrical energy. Tidal and tectonic stresses or meteorite impacts in icy crusts may produce electrical discharges, which would provide the energy for in-situ synthesis of the organic solids. This electrical energy can be provided by positive hole charge carrier activation. Positive holes exhibit properties such as the ability to flow out of …
Stability Of Phyllosilicates On Mars, Patricia Gavin
Stability Of Phyllosilicates On Mars, Patricia Gavin
Graduate Theses and Dissertations
This study investigates the stability of phyllosilicates on the surface of Mars through laboratory experiments and analysis of terrestrial analogs. Phyllosilicates are mostly found in the oldest Noachian terrains on Mars and hence hold clues to the planet's earliest aqueous and geologic history. Phyllosilicates relevant to Mars were heated up to ~1100°C for up to 24 hours and impacted with projectile velocities up to ~4.5 km/s. Heated samples were analyzed using x-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy in the near- (NIR, 1.0-2.5 µm) and mid-infrared (MIR, 5.0-15.0 µm) ranges. Impacted samples were also analyzed using Raman spectroscopy …
Subsurface Planetary Investigation Techniques And Their Role For Assessing Subsurface Planetary Composition, Ahmed Elshafie
Subsurface Planetary Investigation Techniques And Their Role For Assessing Subsurface Planetary Composition, Ahmed Elshafie
Graduate Theses and Dissertations
Subsurface planetary investigation techniques are of high interest and importance for the scientific community. Not only they can enhance our knowledge of the history of planetary formation but also can lead to information about its future. Whether the investigation is being conducted remotely using imagers, radars or physically using penetrometers or drills, a pre-existed knowledge of the mechanical and electrical properties of the subsurface regolith should be acquired for better data interpretation and analysis. Therefore, the main objective of this work is to investigate the mechanical and electrical properties of planetary analogs, understand their role for assessing the subsurface structure …
The Clustering Of Ha Emitters At Z=2.23 From Hizels, J. E. Geach, D. Sobral, R. C. Hickox, D. A. Wake
The Clustering Of Ha Emitters At Z=2.23 From Hizels, J. E. Geach, D. Sobral, R. C. Hickox, D. A. Wake
Dartmouth Scholarship
We present a clustering analysis of 370 high-confidence Hα emitters (HAEs) at z = 2.23. The HAEs are detected in the Hi-Z Emission Line Survey (HiZELS), a large-area blank field 2.121 μm narrow-band survey using the United Kingdom Infrared Telescope Wide Field Camera (WFCAM). Averaging the two-point correlation function of HAEs in two ∼1° scale fields [United Kingdom Infrared Deep Sky Survey/Ultra Deep Survey (UDS) and Cosmological Evolution Survey (COSMOS) fields] we find a clustering amplitude equivalent to a correlation length of r0 = 3.7 ± 0.3 h−1 Mpc for galaxies with star formation rates of ≳7 M⊙ yr−1. The …
Hypervelocity Planets And Transits Around Hypervelocity Stars, Idan Ginsburg, Abraham Loeb, Gary A. Wegner
Hypervelocity Planets And Transits Around Hypervelocity Stars, Idan Ginsburg, Abraham Loeb, Gary A. Wegner
Dartmouth Scholarship
The disruption of a binary star system by the massive black hole at the Galactic Centre, SgrA*, can lead to the capture of one star around SgrA* and the ejection of its companion as a hypervelocity star (HVS). We consider the possibility that these stars may have planets and study the dynamics of these planets. Using a direct N-body integration code, we simulated a large number of different binary orbits around SgrA*. For some orbital parameters, a planet is ejected at a high speed. In other instances, a HVS is ejected with one or more planets orbiting around it. …
Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, Daniel J. Emmons Ii
Ensemble Forecasting Of Coronal Mass Ejections Using The Wsa-Enlil With Coned Model, Daniel J. Emmons Ii
Theses and Dissertations
The combination of the Wang-Sheeley-Arge (WSA) coronal model, ENLIL heliospherical model version 2.7, and Coned Model version 1.3 (WSA-ENLIL with Coned Model) was employed to form ensemble forecasts for 15 halo coronal mass ejections (CME's). The input parameter distributions were formed from 100 sets of CME cone parameters derived from the Coned Model. The Coned Model employed image processing along with the bootstrap approach to automatically calculate cone parameter distributions from SOHO-LASCO imagery based on techniques described by Pulkkinen et al. [2010]. The input parameter distributions were used as input to WSA-ENLIL to calculate the temporal evolution of the …
Vacuum, Space-Time, Matter And The Models Of Smarandache Geometry, Florentin Smarandache, Hu Chang-Wei
Vacuum, Space-Time, Matter And The Models Of Smarandache Geometry, Florentin Smarandache, Hu Chang-Wei
Branch Mathematics and Statistics Faculty and Staff Publications
Many fundamental concepts in physics remain unsolved: What is time? Is it pure relative? What is the vacuum? Is it void space or special medium? What is mass? Can it be created? I believe that physicists have not got definite answers for the above questions. Isaac Newton said: I was like a boy playing on the sea-shore, and diverting myself now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me. For instance, we still do not know what the clear definition of time …