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Description: The majority of the emitted power from an optically thin million degree plasma (such as the one thought to produce the soft xray background) originates in the EUV band at wavelengths longer than 170 degrees A. Lines from Fe VIII - Fe XII dominate the emission in this wavelength region. This paper describes work in progress on the analysis of three years of data from the ALEXIS mission in search of this flux.
Date: January 1, 2001
Creator: Bloch, J. J. (Jeffrey J.); Roussel-Dupre, D. (Diane); Theiler, J. P. (James P.) & Johnson, E. M. (Elsa M.)
Partner: UNT Libraries Government Documents Department

A Study of the Celestial Gamma-ray Flux

Description: This thesis is a study of the celestial gamma-ray flux. It reviews several of the proposed mechanisms for producing high energy gamma rays and describes several of the attempts to detect their presence. Also included is a short historical review of the spark chamber, along with a qualitative description of its operation.
Date: June 1967
Creator: Keath, Edwin P. (Edwin Paul),1938-
Partner: UNT Libraries

Lyman Alpha Emitting Galaxies at 2 < z < 3: Towards a Calibrated Probe of Dark Energy

Description: The goal of this project was to establish the physical properties of Ly{alpha}#11;emitting galaxies from redshifts of 2 to 3 in order to better calibrate the use of LAEs as probes of the large scale structure of the universe for upcoming dark energy experiments, such as the Hobby Eberly Telescope Dark Energy Experiment (HETDEX). We have obtained narrow-band imaging of the Extended Chandra Deep Field South (ECDF-S) in two different narrow-band #12;filters centered at Ly{alpha}#11; at z=2.1 and 3.1. The resulting of samples of LAEs were used to determine the LAE luminosity function, equivalent width distribution and clustering properties (bias) of LAEs at these redshifts. While the results from the ECDF-S appear robust, they are based on a single field. To explore the effects of cosmic variance and galaxy environment on the physical properties of LAEs, we have also obtained narrow-band data at both redshifts (z = 2:1 and 3:1) in three additional #12;fields (SDSS 1030+-05, the Extended Hubble Deep Field South, and CW 1255+01). The narrow-band imaging data has been reduced and LAE catalogs are being generated. We have calculated preliminary luminosity functions, equivalent width distributions, and clustering properties. We have also obtained follow-up spectroscopy in the optical (using VLT/FORS) and in the near-infrared (using Magellan/MMIRS). Since individual LAEs have too little S/N to enable meaningful fits for stellar population parameters, our previous work has analyzed stacked Spectral Energy Distributions (SEDs). SED #12;fitting was performed on several subsets of LAEs selected by their rest-UV luminosity, UV spectral slope, Ly alpha luminosity, Equivalent Width, or rest-optical (IRAC) luminosity.
Date: December 3, 2012
Creator: Gronwall, Caryl
Partner: UNT Libraries Government Documents Department

Making the Standard Candle: A study of how the progenitor white dwarf modulates the peak luminosity of type Ia supernovae

Description: The goals of the proposed research as stated in the proposal were to: • Build a suite of one-dimensional initial models of different metallicities and central densities. • Using the improved flame capturing scheme, simulate the explosion of a white dwarf with embedded Lagrangian tracer particles, and post-process the thermal histories of the tracers to reconstruct the nucleosynthesis of the explosion. • Survey the effects of a changing progenitor metallicity on the isotopic yields. Of particular interest is 1) whether the linear relation between the mass of 56Ni synthesized and the pro- genitor metallicity is moderated by the effect of electron captures in the core; and 2) how a varying central density alters the relation between metallicity and 56Ni mass. • Using these results, examine how the observed metallicity distribution would affect the brightness distribution of SNe Ia and the isotopic ratios about the Fe-peak.
Date: January 21, 2010
Creator: Brown, Edward F
Partner: UNT Libraries Government Documents Department

An Error Analysis for the Use of Presently Available Lunar Radio Flux Data in Broadbeam Antenna-System Measurements

Description: From introduction: Simple, precise expressions for lunar diameter, average brightness temperature, flux density, and shape factor are presented. An analysis of the relationship between these parameters and corresponding errors are included. For broadbeam (HPBW>d) antennas, results show that flux density and shape factor can be determined with errors less than 13 percent and 0.4 percent respectively at frequencies below 10 GHz. Extension of the analysis to higher frequencies is indicated.
Date: February 1984
Creator: Daywitt, William C.
Partner: UNT Libraries Government Documents Department


Description: The light curve of the Crab Nebula Pulsar has been studied in the near infrared (.9 {micro}m - 2.4 {micro}m) and found to be similar to the optical light curve except for a shoulder after each main peak. A search for infrared pulsations from other promising candidates was negative, with typical upper limits 3 - 5 magnitudes fainter than the Crab.
Date: October 1, 1980
Creator: Pennypacker, Carlton R.
Partner: UNT Libraries Government Documents Department