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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Ultraviolet, Optical and X-Ray Imaging of Selected Cygnus Loop Fields

During the Astro-1 and Astro-2 Space Shuttle missions in 1990 and 1995, far ultraviolet (FUV) images of five 40 ft diameter fields around the rim of the Cygnus Loop Super Nova Remnants (SNR) were observed with the Ultraviolet Imaging Telescope (UIT). These fields sample a broad range of SNR conditions including both radiative and non-radiative shocks in various geometries and scales. The UIT B5 band images discussed here sample predominantly ion-C4 lambda 1550 and the 2-photon continuum. Smaller contributions are made by emission lines of ion He-2 lambda 1640 and ion 03 lambda 1666. A unique aspect of the B5 band is its ability to sample the hydrogen 2-photon continuum from regions where the gas is recombining. We present these new FUV images and compare them with optical H-alpha and [ion O13], and ROSAT HRI X-ray images. In non-radiative shocks, existing 2-photon flux measurements from spectra and the H-alpha images suggest we are seeing approximately equal contributions from 2-photon and ion C4 emission. In radiative filaments, however, shock models and our images suggest ion C4 should dominate while spectra of specific locations seem to indicate that 2-photon emission dominates. We surmise that spectral observations on specific bright filaments have decreased locally-observed levels of ion C41 emission due to resonance scattering in that line.

Danforth, C. W.↗
NASA NTRS1998

Optical Fuel Injector Patternation Measurements in Advanced Liquid-Fueled, High Pressure, Gas Turbine Combustors

Planar laser-induced fluorescence (PLIF) imaging and planar Mie scattering are used to examine the fuel distribution pattern (patternation) for advanced fuel injector concepts in kerosene burning, high pressure gas turbine combustors. Three fuel injector concepts for aerospace applications were investigated under a broad range of operating conditions. Fuel PLIF patternation results are contrasted with those obtained by planar Mie scattering. For one injector, further comparison is also made with data obtained through phase Doppler measurements. Differences in spray patterns for diverse conditions and fuel injector configurations are readily discernible. An examination of the data has shown that a direct determination of the fuel spray angle at realistic conditions is also possible. The results obtained in this study demonstrate the applicability and usefulness of these nonintrusive optical techniques for investigating fuel spray patternation under actual combustor conditions.

Locke, R. J.↗
NASA NTRS2011

Study of Scattered Light from Known Debris Disks

Using the Spitzer Space Telescope, a group of edge on debris disks, surrounding main-sequence shell stars have been discovered in the infrared. These disks are of high interest because they not only have dust, but an observed amount of circumstellar gas. HD158352 was an ideal target to try and image the disk because it was one of the closest stars in this group. Using the Hubble Space Telescope's Space Telescope Imaging Spectrograph (STIS), we attempted to take a direct image of the light scattered from the known disk in a broad optical bandpass. Studying these particular type of disks in high detail will allow us to learn more about gas-dust interactions. In particular, this will allow us to learn how the circumstellar gas evolves during the planet-forming phase. Even though it was predicted that the disk should have a magnitude of 20.5 at 3", no disk was seen in any of the optical images. This suggests that the parameters used to predict the brightness of the disk are not what we first anticipated and adjustments to the model must be performed. We also present the blue visible light spectrum of the scattered light from the debris disk surrounding Beta Pictoris. We are analyzing archival observations taken by Heap, using Hubble Space Telescope's STIS instrument. A long slit with a bar was used to occult Beta Pictoris as well as the PSF star. This was done because it is necessary to subtract a PSF observed the same way at the target to detect the disk. It appears that we have detected light from the disk but the work was in progress at the time of the abstract deadline.

Rodriguez, Joseph E.↗
NASA NTRS1986

The soft X-ray/EUV calibration facility at the University of Colorado

The components of the calibration facility at the University of Colorado are described. The system is capable of analyzing the performance of optical components in the wavelength range from 2.7 to 2500 A. The system uses two light sources: a water-cooled hollow cathode gas discharge source and a soft X-ray source. The 2.2-m grazing incidence monochrometer, slits, large chamber, and computer-controlled manipulator are examined. The NBS aluminum oxide photodiode, a flowing gas proportional counter, and an imaging microchannel plate device are employed to detect the light. The optics, detectors, and data acquisition system are computer controlled. The facility is applicable for evaluating the performance of diffraction gratings, multilayer mirrors, reflective coatings, spectrographs, surface roughness scattering, and absolute detector efficiencies. Examples demonstrating the capabilities of the facility and a diagram of the facility are presented.

Windt, David L.↗
NASA NTRS1992

Acousto-Optical Imaging Spectropolarimeter

Imaging spectropolarimeter designed around acousto-optical tunable filter (AOTF) takes polarization-specific spectral images of solid surfaces, aerosols, and absorption and emission phenomena in gas phase, at wavelengths from 500 to 1,000 nm. Produces side-by-side spectral images in two mutually perpendicular polarizations, one corresponding to ordinary, other corresponding to extraordinary waves in acousto-optical material. Offers large aperture, high resolving power, and rapid tunability, with no moving parts.

Saif, Babak↗
NASA NTRS1982

A detailed X-ray study of the cooling intracluster gas in A496

X-ray observations of the galaxy cluster A496 are presented. Imaging and spectral data, together with the presence of optical filaments, show that radiative cooling is occurring in the cluster core and indicates a mass flow rate of about 200 solar masses per year on to the central galaxy. The gas temperature and density profiles within the core are similar to those in the Perseus cluster (A426) despite a six-fold difference in total X-ray luminosity. This is consistent with the model of Fabian and Nulsen (1977, 1979) for steady flows caused by cooling. The evolution of cooling flows is discussed and it is shown that thermal conduction is suppressed to well below the Spitzer rate.

Nulsen, P. E. J.↗
NASA NTRS1993

High-resolution study of luminous infrared galaxies. I - The composite nature of the Seyfert 1 galaxy IRAS 20044-6114 (NGC 6860)

The physical conditions in the ionized gas, the stellar population, and the kinematics of the Seyfert 1 galaxy IRAS 20044-6114 (NGC 6860) are studied by high spatial resolution optical imaging and optical and near-IR spectroscopy of this luminous IR source. The broadband images show a compact nucleus, two weak spiral arms, a bar, a bulge, an inner ring, and a possible outer ring. The I-alpha image reveals bright emission-line regions associated with the Seyfert nucleus and an inner ring of intense star formation. The forbidden O III 5007-A image shows that the high-excitation gas is elongated perpendicularly to the direction of the bar, and reveals a bright compact object at about 40 arcsec NE of the nucleus which is undetectable in the broadband images. This object is interpreted as a dwarf young H II galaxy. The optical, near-IR, and FIR results show clear evidence that the nuclear and circumnuclear regions have composite and complex structure: a variable Seyfert 1 nucleus embedded in an intense and dusty star formation. environment.

Lipari, Sebastian↗
NASA NTRS1996

High-Resolution X-Ray Imaging of Colliding Radio-Jet Galaxies

We received ROSAT data for four program objects:3C31,3C278,3C449,and NGC1044. The first three sources were observed with the ROSAT HRI instrument. Our plan was to use the HRI to image the hot gas distribution in a few pairs of strongly disturbed interacting elliptical galaxies which are also strong radio sources having a bent-jet source morphology. The PSPC was used for NGC1044 in order to obtain a flux measurement to use in planning future High Resolution Imager (HRI) observations of that source. Though we never requested such HRI observations of NGC1044, others have used those archival PSPC data from our project for other research projects and analyses. The goal of the program was to elucidate the detailed distribution of hot gas into which the jets flow. The X-ray data were consequently analyzed in conjunction with existing VLA radio maps, optical broad-band and H-alpha Charge Couple device (CCD) images, and optical kinematic data to constrain models for the propagation of ballistic jets in interacting galaxies. We were able to test and validate the claimed causal connection between tidal interaction, the presence of gas, and the onset of activity in galaxies. The full multi-wavelength multi-observatory analyses described here are still on-going and will be published in the future. Because of the relevance of this research to on-going work in the field of active galaxies, the grant was used to support travel to several scientific meetings where our x-ray analysis, numerical modeling, and related radio results were presented and discussed.

Born, Kirk D.↗
NASA NTRS1995

The far-infrared distribution in the Dusty Hand Galaxy NGC 2146

Our high spatial resolution 50 and 100 micro m observations of the peculiar galaxy NGC 2146 show that the FIR emission arises in a 21 arc-sec x is less than 16 arc-sec (1.5 kpc x is less than 1.1 kpc) region (FWHM) elongated along the major axis. This size limit is similar to that of the radio continuum, the (12)CO (1 - 0), and the H alpha. From an investigation of the energetics in this galaxy, we conclude that young massive stars are largely responsible for powering the FIR luminosity of this galaxy. The FIR and CO (1 - 0) distributions differ from the extinction morphology as seen in optical images and in the Br gamma/H alpha ratio. The starlight and the ionized gas are most highly reddened at the prominent dust lane 15 arc-sec to the west of the nucleus, while the CO and FIR emission peak near the nucleus. This result can be explained by either a high proportion of cold dust and gas at the dust lane, or a geometry in which the dust lane lies in front of the main body of the galaxy.

Smith, Beverly J.↗
NASA NTRS2012

NASA Tech Briefs, March 2012

The topics include: 1) Spectral Profiler Probe for In Situ Snow Grain Size and Composition Stratigraphy; 2) Portable Fourier Transform Spectroscopy for Analysis of Surface Contamination and Quality Control; 3) In Situ Geochemical Analysis and Age Dating of Rocks Using Laser Ablation-Miniature Mass Spectrometer; 4) Physics Mining of Multi-Source Data Sets; 5) Photogrammetry Tool for Forensic Analysis; 6) Connect Global Positioning System RF Module; 7) Simple Cell Balance Circuit; 8) Miniature EVA Software Defined Radio; 9) Remotely Accessible Testbed for Software Defined Radio Development; 10) System-of-Systems Technology-Portfolio-Analysis Tool; 11) VESGEN Software for Mapping and Quantification of Vascular Regulators; 12) Constructing a Database From Multiple 2D Images for Camera Pose Estimation and Robot Localization; 13) Adaption of G-TAG Software for Validating Touch and Go Asteroid Sample Return Design Methodology; 14) 3D Visualization for Phoenix Mars Lander Science Operations; 15) RxGen General Optical Model Prescription Generator; 16) Carbon Nanotube Bonding Strength Enhancement Using Metal Wicking Process; 17) Multi-Layer Far-Infrared Component Technology; 18) Germanium Lift-Off Masks for Thin Metal Film Patterning; 19) Sealing Materials for Use in Vacuum at High Temperatures; 20) Radiation Shielding System Using a Composite of Carbon Nanotubes Loaded With Electropolymers; 21) Nano Sponges for Drug Delivery and Medicinal Applications; 22) Molecular Technique to Understand Deep Microbial Diversity; 23) Methods and Compositions Based on Culturing Microorganisms in Low Sedimental Fluid Shear Conditions; 24) Secure Peer-to-Peer Networks for Scientific Information Sharing; 25) Multiplexer/Demultiplexer Loading Tool (MDMLT); 26) High-Rate Data-Capture for an Airborne Lidar System; 27) Wavefront Sensing Analysis of Grazing Incidence Optical Systems; 28) Foam-on-Tile Damage Model; 29) Instrument Package Manipulation Through the Generation and Use of an Attenuated-Fluent Gas Fold; 30) Multicolor Detectors for Ultrasensitive Long-Wave Imaging Cameras; 31) Lunar Reconnaissance Orbiter (LRO) Command and Data Handling Flight Electronics Subsystem; and 32) Electro-Optic Segment-Segment Sensors for Radio and Optical Telescopes.

Source record↗
NASA NTRS1989

0714 - 2914 (M4-1) - Another Seyfert galaxy with aligned radio continuum and optical emission-line morphologies

Direct imaging and long-slit spectroscopic mapping of the emission-line gas in the Seyfert 2 galaxy 0714 - 2914 (M4-1, MCG - 5-18-2) are reported. The nuclear regions contain an extended (1 kpc size), high-excitation nebulosity that is well aligned with the jet-like nonthermal radio source. The profiles of Forbidden O III 5007A are asymmetric, with extended red wings to the north and west of the nucleus and extended blue wings to the south and east. This switch in the sense of asymmetry is accounted for in terms of a combination of normal rotational motions in the galaxy disk and high-velocity outflow or infall associated with the Seyfert activity.

Wilson, A. S.↗
NASA NTRS2013

'Direct' Gas-Phase Metallicities, Stellar Properties, and Local Environments of Emission-Line Galaxies at Redshifts Below 0.90

Using deep narrow-band (NB) imaging and optical spectroscopy from the Keck telescope and the Multi Mirror Telescope (MMT), we identify a sample of 20 emission-line galaxies (ELGs) at z = 0.065-0.90 where the weak auroral emission line, [O iii] lambda4363, is detected at >=3sigma. These detections allow us to determine the gas-phase metallicity using the "direct" method. With electron temperature measurements, and dust attenuation corrections from Balmer decrements, we find that 4 of these low-mass galaxies are extremely metal-poor with 12+log(O/H) <= 7.65 or one-tenth solar. Our most metal-deficient galaxy has 12+log(O/H)= 7.24(+0.45 / −0.30) (95% confidence), similar to some of the lowest metallicity galaxies identified in the local universe. We find that our galaxies are all undergoing significant star formation with average specific star formation rate (SFR) of (100 Myra)(exp −1), and that they have high central SFR surface densities (average of 0.5 Solar M / yr/ sq. kpc). In addition, more than two-thirds of our galaxies have between one and four nearby companions within a projected radius of 100 kpc, which we find is an excess among star-forming galaxies at z =0.4 -- 0.85. We also find that the gas-phase metallicities for a given stellar mass and SFR lie systematically lower than the local stellar M-Z-(SFR) relation by approx. = 0.2 dex (2 sigma significance). These results are partly due to selection effects, since galaxies with strong star formation and low metallicity are more likely to yield [O iii] lambda4363 detections. Finally, the observed higher ionization parameter and high electron density suggest that they are lower redshift analogs to typical z approx. > 1 galaxies.

Direct↗
NASA NTRS1993

Application of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to Determination of Atmospheric Aerosol Optical Depth and Precipitable Water Content

This paper focuses on determination of the temporal and spatial gas absorption and aerosol scattering properties of the atmosphere itself including the radiative properties of clouds, specifically derivation of estimates of aerosol optical depth, atmospheric water vapor, and oxygen pressure surface altitude form upwelling near-TOA spectral radiance measurements obtained with the AVIRIS.

Remote SensingAVIRIS↗
NASA NTRS1995

The distribution of far-infrared light in the 'Dusty Hand' galaxy NGC 2146

The Kuiper Airborne Observatory (KAO) has been used to obtain high spatial resolution 50 and 100 micrometers observations of the peculiar galaxy NGC 2146. We find that the far-infrared luminosity of NGC 2146 arises in a 21 arcsecs x less than or = 16 arcsecs (1.5 kpc x less than or equal 1.1 kpc) region (FWHM) elongated along the major axis. This limit is consistent with the size of the central radio continuum and (12)CO (1-0) sources. The far-infrared distribution is slightly more compact than that of the H-alpha; this difference is consistent with observed pattern of extinction in this galaxy. From a study of the energetics in this galaxy, we conclude that young massive stars are largely responsible for powering the far-infrared luminosity of NGC 2146. The far-infrared and CO (1-0) distributions differ from the reddening morphology as seen in optical images and in the Br-gamma/H-alpha ratio. The starlight and the ionized gas appear most highly reddened at the prominent dust lane 15 arcsecs to the west of the nucleus, while the CO and far-infrared emission peak near the nucleus. This result dust lane lies in front of the main body of the galaxy.

Smith, Beverly J.↗
NASA NTRS1996

Demonstration and Analysis of Filtered Rayleigh Scattering Flow Field Diagnostic System

Filtered Rayleigh Scattering (FRS) is a diagnostic technique which measures velocity, temperature, and pressure by determining Doppler shift, total intensity, and spectral line shape of laser induced Rayleigh-Brillouin scattering. In the work reported here, this is accomplished by using a narrow line width, injection seeded Nd-YAG laser sheet to induce Rayleigh-Brillouin scattering from a gas flow. This light is passed through an optical notch filter, and transmitted light is imaged onto an intensified charge coupled display (CCD) camera. By monitoring the grayscale value at a particular pixel while the laser frequency is tuned, the convolution between the Rayleigh-Brillouin scattering profile and the filter transmission profile is attained. Since the filter profile can be independently measured, it can be deconvolved from the measuring signal, yielding the Rayleigh-Brillouin scattering profile. From this profile, flow velocity, temperature, and pressure are determined. In this paper the construction and characterization of the optical notch filter and a newly developed frequency apparatus are discussed.

Forkey, Joseph N.↗
NASA NTRS2000

The First Few Parsecs of the Jets in NGC 4261

The double-lobed radio galaxy NGC 4261 (3C270) contains a pair of highly symmetric kpc-scale jets, as well as a two-sided morphology on parsec scales. Optical imaging with HST has revealed a large, nearly edge-on nuclear disk of gas and dust. This suggests that the radio axis is close to the plane of the sky and consequently that the relative brightness of the two jets is not significantly affected by relativistic beaming.

Jones, Dayton L.↗
NASA NTRS1989

Interstellar matter in early-type galaxies - Optical observations

Results of optical observations of 26 bright elliptical galaxies selected on the basis of IRAS data are discussed. Optical broadband imaging (using B and R filters) and narrow-band imaging (using H-alpha interference filters) have been performed to study dust patches and ionized gas. Long-split spectroscopy has also been made to determine gas kinematics and relative line ratios. The spectroscopic data confirm the presence and distribution of interstellar matter (dust lanes and ionized gas) seen in the direct imaging. Decoupled kinematics of interstellar gas and stars favors an external origin of the interstellar matter. However, for one isolated galaxy, an internal origin is not excluded. The rotation curves determined by optical emission lines are symmetric around the center in most galaxies observed. Galaxy masses and mass-to-light ratios are estimated using the rotation curves of the ionized gas.

Kim, Dong-Woo↗
NASA NTRS1990

NGC 3312: A victim of ram pressure sweeping

Researchers are undertaking a volume limited survey of the Hydra I cluster in neutral hydrogen using the National Radio Astronomy Observatory's Very Large Array (VLA). The main purpose is to study the effects of a dense environment on the gaseous component of the galaxies. Observational evidence has been accumulating recently that ram pressure sweeping does occur in the centers of clusters, but it is possible that tidal interactions play a role as well. Results of high resolution HI imaging of NGC 3312, the large peculiar spiral near the cluster center are presented. Hydra I (= A1060) is the nearest rich cluster beyond Virgo and, as such, presents a unique opportunity to do a complete survey of a cluster. It is similar to the Virgo cluster in many of its general physical characteristics, such as size, x ray luminosity, velocity dispersion, and galaxy content (high spiral fraction). However, Hydra I appears to be more regular and relaxed. This is evident in the x ray distribution in its central region, which is radially symmetric and centered on the dominant galaxy, NGC 3311, a cD-like elliptical. The observed x ray luminosity implies a central gas density of 4.5 x 10 to the 3rd power cm(-3). Gallagher (1978) argued from optical images of NGC 3312 that this galaxy might be an ideal candidate to directly study effects of the ram pressure process; it might currently be undergoing stripping of its interstellar medium. The researchers' data are consistent with this suggestion, but other origins of the peculiar appearance cannot yet be ruled out.

Mcmahon, P. M.↗