A Determination Of The Gamma-Ray Flux And Photon Spectral Index Distributions Of Blazars From The Fermi-Lat 3lac, 2015 University of Richmond
A Determination Of The Gamma-Ray Flux And Photon Spectral Index Distributions Of Blazars From The Fermi-Lat 3lac, Jack Singal
Physics Faculty Publications
We present a determination of the distributions of gamma-ray photon flux – the so-called LogN–LogS relation – and photon spectral index for blazars, based on the third extragalactic source catalogue of the Fermi Gamma-ray Space Telescope's Large Area Telescope, and considering the photon energy range from 100 MeV to 100 GeV. The data set consists of the 774 blazars in the so-called Clean sample detected with a greater than approximately 7σ detection threshold and located above ±20° Galactic latitude. We use non-parametric methods verified in previous works to reconstruct the intrinsic distributions from the observed ones which account ...
Cosmic Radiation, 2015 Dublin Institute of Technology
Cosmic Radiation, Dr. Anthony J. Keane
The ITB Journal
The planet Earth orbits the Sun in what is often considered to be empty space but is in fact full of very small charged particles speeding in all directions. The situation can be compared to the Earth having to constantly travel in a light shower of rain and with the atmosphere acting like an umbrella. The 'rain' is made up of charged particles called 'Cosmic Rays'. The name cosmic ray was given long ago to invisible ionising radiation that could mysteriously discharge an electroscope even when the electroscope was heavy insulated. Early scientists quickly established a relationship between the rate ...
Excess Mid-Infrared Flux: An Indicator Of Mass Loss In Cepheids?, 2015 University of Nebraska-Lincoln
Excess Mid-Infrared Flux: An Indicator Of Mass Loss In Cepheids?, Edward G. Schmidt
Edward Schmidt Publications
Spectral energy distributions for 132 classical and type II Cepheids were searched for evidence of excess flux above the photospheric level in the mid-infrared. Eight of them were found to have unambiguously strong excess emission while a further 13 showed evidence of weak emission. The presence of emission appears to be unrelated to either the pulsational amplitude or the effective temperature while strong emission is limited to stars with periods longer than 11 days, with a single exception. For the stars with strong emission we attempted to fit the energy distribution with a stellar wind model. No acceptable fit could ...
New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, 2015 (LISA), UMR CNRS 7583
New Benzene Absorption Cross Sections In The Vuv, Relevance For Titan’S, Fernando J. Capalbo, Yves Bénilan, Nicolas Fray, Martin Schwell, Norbert Champion, Et-Touhami Es-Sebbar, Tommi T. Koskinen, Ivan Lehocki, Roger V. Yelle
Dr. Et-touhami Es-sebbar
Benzene is an important molecule in Titan’s atmosphere because it is a potential link between the gas phase and the organic solid phase. We measured photoabsorption in the ultraviolet by benzene gas at temperatures covering the range from room temperature to 215 K. We derived benzene absorption cross sections and analyzed them in terms of the transitions observed. No significant variation with measurement temperature was observed. We discuss the implications of our measurements for the derivation of benzene abundance profiles in Titan’s thermosphere, by the Cassini/Ultraviolet Imaging Spectrograph (UVIS). The use of absorption cross sections at low ...
Information Literacy & Open Access For Physics And Astronomy Graduate Students, 2015 Georgia State University
Information Literacy & Open Access For Physics And Astronomy Graduate Students, Jackie K. Werner
University Library Faculty Presentations
This presentation covers research on the physics and astronomy graduate students’ use and understanding of open access resources. The research, which was conducted in summer 2015, surveyed the physics and astronomy graduate students of Georgia Institute of Technology to discover how graduate students discover open access and other academic resources, as well as their level of awareness about open access in general and specific OA databases in particular. The research also included an interview with the graduate studies advisor in the Physics & Astronomy department Georgia Tech. The presentation also describes open access resources in Physics and Astronomy and relates the ...
Research And Development Of A Smart Module Integrated Converter For The Future Of Renewable Energy, 2015 University of Montana - Missoula
Research And Development Of A Smart Module Integrated Converter For The Future Of Renewable Energy, Phong Tran
University Grant Program Reports
This research focused on developing of a Smart Module Integrated Converter for grid-connected solar photovoltaic (PV) system. This technology enhances the commercial micro-inverters with novel network-supported, grid-adapted functionalities. The micro-inverter utilizes open source and reference design from Microchip to keep design and production at low cost.
The V471 Tauri System: A Multi-Data-Type Probe, 2015 St. Cloud State University
The V471 Tauri System: A Multi-Data-Type Probe, Todd R. Vaccaro, Robert E. Wilson, W. Van Hamme, Dirk Terrell
Physics and Astronomy Faculty Publications
V471 Tauri, a white dwarf–red dwarf eclipsing binary ( EB) in the Hyades, is well known for stimulating development of common envelope theory, whereby novae and other cataclysmic variables form from much wider binaries by catastrophic orbit shrinkage. Our evaluation of a recent imaging search that reported negative results for a much postulated third body shows that the object could have escaped detection or may have actually been seen. The balance of evidence continues to favor a brown dwarf companion about 12 AU from the EB. A recently developed algorithm finds unified solutions from three data types. New radial velocities ...
Low Intensity Gamma-Ray Spectroscopy Of The Lake Labyrinth Meteorite, 2015 California Polytechnic State University - San Luis Obispo
Low Intensity Gamma-Ray Spectroscopy Of The Lake Labyrinth Meteorite, Tristan C. Paul
A 23.7g fragment of the Lake Labyrinth Meteorite (fell in 1924, collected in 1934 at Lake Labyrinth in South Australia, Australia) was re-investigated for evidence of the presence of 98Tc using a two dimensional low-intensity gamma-ray spectrometer. A new calibration technique using 26Al sources found the gamma-rays previously thought to be due to 98Tc are more likely from 166Ho. The presence of 166Ho is most likely due to activation of the stable 165Ho in the meteorite from terrestrial background sources where it was stored.
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Orionis Aa. Iii. Analysis Of Optical Photometric (Most) And Spectroscopic (Ground Based) Variations., 2015 Université de Montréal
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Orionis Aa. Iii. Analysis Of Optical Photometric (Most) And Spectroscopic (Ground Based) Variations., Herbert Pablo, Noel D. Richardson, Anthony F. J. Moffat, Michael Corcoran, Tomer Shenar, Omar Benvenuto, Jim Fuller, Yaël Nazé, Jennifer L. Hoffman, Anatoly Miroshnichenko, Jesús Maíz Apellániz, Nancy Evans, Thomas Eversberg, Ken Gayley, Ted Gull, Kenji Hamaguchi, Wolf-Rainer Hamann, Huib Henrichs, Tabetha Hole, Richard Ignace, Rosina Iping, Jennifer Lauer, Maurice Leutenegger, Jamie Lomax, Joy Nichols, Lida Oskinova, Stan Owocki, Andy Pollock, Christopher M. P. Russell, Wayne Waldron, Christian Buil, Thierry Garrel, Keith Graham, Bernard Heathcote, Thierry Lemoult, Dong Li, Benjamin Mauclaire, Mike Potter, Jose Ribeiro, Jaymie Matthews, Chris Cameron, David Guenther, Rainer Kuschnig, Jason Rowe, Slavek Rucinski, Dimitar Sasselov, Werner Weiss
We report on both high-precision photometry from the Microvariability and Oscillations of Stars (MOST) space telescope and ground-based spectroscopy of the triple system δ Ori A, consisting of a binary O9.5II+early-B(Aa1 and Aa2) with P=5.7 days, and a more distant tertiary(O9 IV P 400 years). This data was collected in concert with X-ray spectroscopy from the Chandra X-ray Observatory. Thanks to continuous coverage for three weeks, the MOST light curve reveals clear eclipses between Aa1 and Aa2 for the first time in non-phased data. From the spectroscopy, we have a well-constrained radial velocity (RV ...
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Ori Aa: I. Overview Of The X-Ray Spectrum., 2015 NASA/Goddard Space Flight Center
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Ori Aa: I. Overview Of The X-Ray Spectrum., M. F. Corcoran, J. S. Nichols, H. Pablo, T. Shenar, A. M. T. Pollock, W. L. Waldron, A. F. J. Moffat, N. D. Richardson, C. M. P. Russell, K. Hamaguchi, D. P. Huenemoerder, L. Oskinova, W.-R. Hamann, Y. Nazé, R. Ignace, N. R. Evans, J. R. Lomax, J. L. Hoffman, K. Gayley, S. P. Owocki, M. Leutenegger, T. R. Gull, K. T. Hole, J. Lauer, R. C. Iping
We present an overview of four deep phase-constrained Chandra HETGS X-ray observations of δ Ori A. Delta Ori A is actually a triple system that includes the nearest massive eclipsing spectroscopic binary, δ Ori Aa, the only such object that can be observed with little phase-smearing with the Chandra gratings. Since the fainter star, δ Ori Aa2, has a much lower X-ray luminosity than the brighter primary (δ Ori Aa1), δ Ori Aa provides a unique system with which to test the spatial distribution of the X-ray emitting gas around δ Ori Aa1 via occultation by the photosphere of, and ...
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Orionis Aa: Ii. X-Ray Variability., 2015 Harvard-Smithsonian Center for Astrophysics
A Coordinated X-Ray And Optical Campaign Of The Nearest Massive Eclipsing Binary, Δ Orionis Aa: Ii. X-Ray Variability., J. Nichols, D. P. Huenemoerder, M. F. Corcoran, W. Waldron, Y. Nazé, A. M. T. Pollock, A. F. J. Moffat, J. Lauer, T. Shenar, C. M. P. Russell, N. D. Richardson, H. Pablo, N. R. Evans, K. Hamaguchi, T. Gull, W.-R. Hamann, L. Oskinova, R. Ignace, Jennifer L. Hoffman, K. T. Hole, J. R. Lomax
We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the δ Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of ≈ 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5–25 Å is confirmed, with a maximum amplitude of about ±15% within a single ≈ 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout ...
The Spatial Distribution Of The Red Giants In The Distant Galactic Globular Cluster Cluster Ngc2419, 2015 Indiana University - Purdue University Fort Wayne
The Spatial Distribution Of The Red Giants In The Distant Galactic Globular Cluster Cluster Ngc2419, Stephen D. Gillam
Physics Faculty Presentations
I present the results of a study of the radial variations of the ratio of the two populations of stars in the galactic globu-lar cluster NGC2419 as seen in eight broad-band, HST/WFC3 colors. The populations are identified as a metal-poor first generation (FG) with an age of 12 Gyr and a relatively metal-rich, oxygen and helium-rich, second generation (SG), with an age of 10 Gyr. Synthetic color-magnitude diagrams of NGC2419 are used to determine the fractions of the present-day stellar population that are FG and SG stars. The distance modulus of this cluster and the color excess, E(B-V ...
Population Gradients In Globular Clusters, 2015 Indiana University - Purdue University Fort Wayne
Population Gradients In Globular Clusters, Catherine A. Pilachowski, Stephen D. Gillam, Brian J. Brondel
Physics Faculty Presentations
We report preliminary observations with the WIYN 3.5-m telescope to detect color and composition gradients in globular clusters using the red CN system at 8150 A. Globular clusters in the Milky Way are not simple stellar populations, but rather contain the products of multiple epochs of star formation. In dynamically young clusters, later generations of stars are more centrally concentrated in the clusters and are polluted with elements produced in first generation stars, showing enhanced CN band strengths. These differences suggest that multiple populations can be detected from photometric observations of the red CN system at 8100 A. The ...
Muslims Lunar’S Blindness, 2015 Politecnico di Torino
Muslims Lunar’S Blindness, Sajjad Khaksari
The age of scientists such as Muhammad ibn Musa al-Khwarizmi (خوارزمی), Al-Farabi (فارابی), Avicenna (پور سینا), Ghiyāth al-Dīn Jamshīd Masʿūd al-Kāshī (غیاث الدین جمشید کاشانی) And Bērūnī (بیرونی) has passed and middle east regions face hideous and offensive figures of Iranian/Saudi/ISIS etc. regimes. What happened to these people and why?!
Design And Fabrication Of Liquid Scintillator Counter, 2015 California State University - Long Beach
Design And Fabrication Of Liquid Scintillator Counter, Andrea Calderon Saucedo, John L. Orrell
STAR (STEM Teacher and Researcher) Program Posters
Pacific Northwest National Laboratory (PNNL) is currently developing an ultra-low background liquid scintillator counter (ULB LSC) in the shallow underground laboratory. At a depth of 35-meters water-equivalent, the underground laboratory has a multi-layered shielding to keep out cosmic-ray induced background. The ULB LSC, which is located in a clean room facility, is a multi-layered design made up of various materials, including plastic scintillator veto panels, borated polyethylene, lead and copper. These layers help lower the contributions of the terrestrial background and intrinsic background, resulting from the impurities present in the materials, to the overall background count rate observed by the ...
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, 2015 California Polytechnic State University
Resolving Emission Lines Of Sodiumlike Fe Xvi Using Ebit, Sandi Lavito
STAR (STEM Teacher and Researcher) Program Posters
High resolution crystal spectrometers on sounding rockets and orbiting satellites, such as the Solar Maximum Mission, show strong X-ray emission from the n= 3 to 2 transitions in neon-like Fe XVII. Two of the strongest lines are the 3d to 2p resonance and inter combination lines at 15.01 Å (3C) and 15.26 Å (3D).
Intensity ratios of these solar lines range from ~ 1.6 to 2.8. The lower ratios are a result of a line from Na-like Fe XVI inner shell satellite line blending with the Fe XVII inter combination line, 3D. The wavelength of the Na-like ...
Retrieval Of Aerosol Microphysical Properties From Aeronet Photopolarimetric Measurements, 2015 University of Nebraska-Lincoln
Retrieval Of Aerosol Microphysical Properties From Aeronet Photopolarimetric Measurements, Xiaoguang Xu
Dissertations & Theses in Earth and Atmospheric Sciences
Atmospheric aerosols play an important role in earth climate by scattering and absorbing solar and terrestrial radiation, and indirectly through altering the cloud formation, life- time, and radiative properties. However, accurate quantification of these effects is in no small part hindered by our limited knowledge about the particle size distribution (PSD) and refractive index, the aerosol microphysical properties essentially pertain to aerosol optical and cloud-forming properties. The research goal of this thesis is to obtain the aerosol microphysical properties of both fine and coarse modes from the polarimetric solar radiation measured by the SunPhotometer of the Aerosol Robotic Network (AERONET ...
On The Existence And Uniqueness Of Static, Spherically Symmetric Stellar Models In General Relativity, 2015 University of Tennessee - Knoxville
On The Existence And Uniqueness Of Static, Spherically Symmetric Stellar Models In General Relativity, Josh Michael Lipsmeyer
The "Fluid Ball Conjecture" states that a static stellar model is spherically symmetric. This conjecture has been the motivation of much work since first mentioned by Kunzle and Savage in 1980. There have been many partial results( ul-Alam, Lindblom, Beig and Simon,etc) which rely heavily on arguments using the positive mass theorem and the equivalence of conformal flatness and spherical symmetry. The purpose of this paper is to outline the general problem, analyze and compare the key differences in several of the partial results, and give existence and uniqueness proofs for a particular class of equations of state which ...
On The Spin Evolution Of Isolated Pulsars, 2015 University of Tennessee - Knoxville
On The Spin Evolution Of Isolated Pulsars, Oliver Quinn Hamil
Neutron stars are the remnants of supernova explosions, and harbor the densest matter found in the universe. Because of their extreme physical characteristics, neutron stars make superb laboratories from which to study the nature of matter under conditions of extreme density that are not reproducible on Earth. The understanding of QCD matter is of fundamental importance to modern physics, and neutron stars provide a means of probing into the cold, dense region of the QCD phase diagram.
Isolated pulsars are rotating neutron stars that emit beams of electromagnetic radiation into space which appear like lighthouses to observers on Earth. Observations ...
The Effects Of Realistic Nuclear Kinetics, Dimensionality, And Resolution On Detonations In Low-Density Type Ia Supernovae Environments, 2015 University of Tennessee - Knoxville
The Effects Of Realistic Nuclear Kinetics, Dimensionality, And Resolution On Detonations In Low-Density Type Ia Supernovae Environments, Thomas L. Papatheodore
Type Ia supernovae are most likely thermonuclear explosions of carbon/oxygen white dwarves in binary stellar systems. These events contribute to the chemical and dynamical evolution of their host galaxies and are essential to our understanding of the evolution of our universe through their use as cosmological distance indicators. Nearly all of the currently favored explosion scenarios for these supernovae involve detonations. However, modeling astrophysical detonations can be complicated by numerical effects related to grid resolution. In addition, the fidelity of the reaction network chosen to evolve the nuclear burning can alter the time and length scales over which the ...