Search NASA⌕ Search

Engineering topics

Wright, E.

Publications and source records attributed to Wright, E..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

SPICE Tools Supporting Planetary Remote Sensing

NASA's "SPICE" ancillary information system has gradually become the de facto international standard for providing scientists the fundamental observation geometry needed to perform photogrammetry, map making and other kinds of planetary science data analysis. SPICE provides position and orientation ephemerides of both the robotic spacecraft and the target body; target body size and shape data; instrument mounting alignment and field-of-view geometry; reference frame specifications; and underlying time system conversions.

Observation geometry↗
DOE OSTI2016

Mössbauer parameters of Fe-related defects in group-IV semiconductors: First principles calculations

We employ a combination of pseudopotential and all-electron density functional calculations, to relate the structure of defects in supercells to the isomer shifts and quadrupole splittings observed in Mössbauer spectroscopy experiments. The methodology is comprehensively reviewed and applied to the technologically relevant case of iron-related defects in silicon, and to other group-IV hosts to a lesser degree. Investigated defects include interstitial and substitutional iron, iron-boron pairs, iron-vacancy, and iron-divacancy. We find that, in general, agreement between the calculations and Mössbauer data is within a 10% error bar. Nonetheless, we show that the methodology can be used to make accurate assignments, including to separate peaks of similar defects in slightly different environments.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS2013

SPICE: A Geometry Information System Supporting Planetary Mapping, Remote Sensing and Data Mining

SPICE is an information system providing space scientists ready access to a wide assortment of space geometry useful in planning science observations and analyzing the instrument data returned therefrom. The system includes software used to compute many derived parameters such as altitude, LAT/LON and lighting angles, and software able to find when user-specified geometric conditions are obtained. While not a formal standard, it has achieved widespread use in the worldwide planetary science community

planetary science investigations↗
DOE OSTI2013

CHARACTERIZING THE MID-INFRARED EXTRAGALACTIC SKY WITH WISE AND SDSS

The Wide-field Infrared Survey Explorer (WISE) has completed its all-sky survey in four channels at 3.4-22 {mu}m, detecting hundreds of millions of objects. We merge the WISE mid-infrared data with optical data from the Sloan Digital Sky Survey (SDSS) and provide a phenomenological characterization of WISE extragalactic sources. WISE is most sensitive at 3.4 {mu}m (W1) and least sensitive at 22 {mu}m (W4). The W1 band probes massive early-type galaxies out to z {approx}> 1. This is more distant than SDSS identified early-type galaxies, consistent with the fact that 28% of 3.4 {mu}m sources have faint or no r-band counterparts (r > 22.2). In contrast, 92%-95% of 12 {mu}m and 22 {mu}m sources have SDSS optical counterparts with r {<=} 22.2. WISE 3.4 {mu}m detects 89.8% of the entire SDSS QSO catalog at S/N{sub W1} >7{sigma}, but only 18.9% at 22 {mu}m with S/N{sub W4} > 5{sigma}. We show that WISE colors alone are effective in isolating stars (or local early-type galaxies), star-forming galaxies, and strong active galactic nuclei (AGNs)/QSOs at z {approx}< 3. We highlight three major applications of WISE colors: (1) Selection of strong AGNs/QSOs at z {<=} 3 using W1 - W2 > 0.8 and W2 < 15.2 criteria, producing a better census of this population. The surface density of these strong AGN/QSO candidates is 67.5 {+-} 0.14 deg{sup -2}. (2) Selection of dust-obscured, type-2 AGN/QSO candidates. We show that WISE W1 - W2 > 0.8, W2 < 15.2 combined with r - W2 > 6 (Vega) colors can be used to identify type-2 AGN candidates. The fraction of these type-2 AGN candidates is one-third of all WISE color-selected AGNs. (3) Selection of ultraluminous infrared galaxies (ULIRGs) at z {approx} 2 with extremely red colors, r - W4 > 14 or well-detected 22 {mu}m sources lacking detections in the 3.4 and 4.6 {mu}m bands. The surface density of z {approx} 2 ULIRG candidates selected with r - W4 > 14 is 0.9 {+-} 0.07 deg{sup -2} at S/N{sub W4} {>=} 5 (the corresponding, lowest flux density of 2.5 mJy), which is consistent with that inferred from smaller area Spitzer surveys. Optical spectroscopy of a small number of these high-redshift ULIRG candidates confirms our selection, and reveals a possible trend that optically fainter or r - W4 redder candidates are at higher redshifts.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

EXTENDING THE NEARBY GALAXY HERITAGE WITH WISE: FIRST RESULTS FROM THE WISE ENHANCED RESOLUTION GALAXY ATLAS

The Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at mid-infrared wavelengths 3.4 {mu}m, 4.6 {mu}m, 12 {mu}m, and 22 {mu}m. The mission was primarily designed to extract point sources, leaving resolved and extended sources, for the most part, unexplored. Accordingly, we have begun a dedicated WISE Enhanced Resolution Galaxy Atlas (WERGA) project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we demonstrate the first results of the WERGA project for a sample of 17 galaxies, chosen to be of large angular size, diverse morphology, and covering a range in color, stellar mass, and star formation. It includes many well-studied galaxies, such as M 51, M 81, M 87, M 83, M 101, and IC 342. Photometry and surface brightness decomposition is carried out after special super-resolution processing, achieving spatial resolutions similar to that of Spitzer Infrared Array Camera. The enhanced resolution method is summarized in the first paper of this two-part series. In this second work, we present WISE, Spitzer, and Galaxy Evolution Explorer (GALEX) photometric and characterization measurements for the sample galaxies, combining the measurements to study the global properties. We derive star formation rates using the polycyclic aromatic hydrocarbon sensitive 12 {mu}m (W3) fluxes, warm-dust sensitive 22 {mu}m (W4) fluxes, and young massive-star sensitive ultraviolet (UV) fluxes. Stellar masses are estimated using the 3.4 {mu}m (W1) and 4.6 {mu}m (W2) measurements that trace the dominant stellar mass content. We highlight and showcase the detailed results of M 83, comparing the WISE/Spitzer results with the Australia Telescope Compact Array H I gas distribution and GALEX UV emission, tracing the evolution from gas to stars. In addition to the enhanced images, WISE's all-sky coverage provides a tremendous advantage over Spitzer for building a complete nearby galaxy catalog, tracing both stellar mass and star formation histories. We discuss the construction of a complete mid-infrared catalog of galaxies and its complementary role of studying the assembly and evolution of galaxies in the local universe.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2012

Constructing a WISE High Resolution Galaxy Atlas

After eight months of continuous observations, the Wide-field Infrared Survey Explorer (WISE) mapped the entire sky at 3.4 micron, 4.6 micron, 12 micron, and 22 micron. We have begun a dedicated WISE High Resolution Galaxy Atlas project to fully characterize large, nearby galaxies and produce a legacy image atlas and source catalog. Here we summarize the deconvolution techniques used to significantly improve the spatial resolution of WISE imaging, specifically designed to study the internal anatomy of nearby galaxies. As a case study, we present results for the galaxy NGC 1566, comparing the WISE enhanced-resolution image processing to that of Spitzer, Galaxy Evolution Explorer, and ground-based imaging. This is the first paper in a two-part series; results for a larger sample of nearby galaxies are presented in the second paper.

Jarrett, T. H.↗
NASA NTRS2007

Mid-infrared selection of brown dwarfs and high-redshift quasars

We discuss color selection of rare objects in a wide-field multiband survey spanning from the optical to the mid-infrared. Simple color criteria simultaneously identify and distinguish two of the most sought after astrophysical sources: the coolest brown dwarfs and the most distant quasars.We present spectroscopically confirmed examples of each class identified in the IRAC Shallow Survey of the Boo¨tes field of the NOAO Deep Wide-Field Survey. IRAC J142950.8+333011 is a T4.5 brown dwarf at a distance of approximately 30-40 pc, and IRAC J142738.5+331242 is a radio-loud quasar at redshift z=6:12. Our selection criteria identify a total of four candidates over 8 deg2 of the Boo¨tes field. The other two candidates are both confirmed 5:5 < z < 6 quasars, previously reported by Cool et al. (2006).We discuss the implications of these discoveries and conclude that there are excellent prospects for extending such searches to cooler brown dwarfs and higher redshift quasars.

Wright, E.↗