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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 253 records · Page 14
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NASA NTRS2007

SN 1987A after 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant

We present high resolution 11.7 and 18.3 micron mid-IR images of SN 1987A obtained on day 6526 since the explosion with the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope. The 11.7 micron flux has increased significantly since our last observations on day 6067. The images clearly show that all the emission arises from the equatorial ring (ER). Nearly contemporaneous spectra obtained on day 6184 with the MIPS at 24 micron, on day 6130 with the IRAC in 3.6- 8 micron region, and on day 6190 with the IRS in the 12-37 micron instruments on board the Spitzer Space Telescope's show that the emission consists of thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is 1662(sup +18) (sub -12) K, and the emitting dust mass is (2.6(sup +2.0 (sub -1.4)) x 10 (exp -6) M(solar). Lines of [Ne II] 12.82 micron and [Ne III] 15.56 pm are clearly present in the Spitzer spectrum, as well as a weak [Si II] 3 34.8 micron line. We also detect two lines near 26 micron which we tentatively ascribe to [Fe II] 25.99 pm and [0 IV] 25.91 micron. Comparison of the mid-IR Gemini 11.7 micron image with X-ray images obtained by Chandra, UV-optical images obtained by HST, and radio synchrotron images obtained by the ATCA show generally good correlation of the images across all wavelengths. Because of the limited resolution of the mid-IR images we cannot uniquely determine the location. or heating mechanism of the dust giving rise to the emission. The dust could be collisionally heated by the X-ray emitting plasma, providing a unique diagnostic of plasma conditions. Alternatively, the dust could be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly lower than that in the general interstellar medium of the LMC, suggesting either a low condensation efficiency in the wind of the progenitor star, or the efficient destruction of the dust by the SN blast wave. Overall, we are witnessing the interaction of the SN blast wave with its surrounding medium, creating an environment that is rapidly evolving at all wavelengths. Continuous multiwavelength observations of SN 1987A such as these provide unique snapshots of the very early evolution of supernova remnants.

Bouchet, Patrice↗
NASA NTRS1988

The twin-nucleus merging galaxy Markarian 266 (NGC 5256)

Optical imaging in continuum and line wavelengths, spatially resolved optical spectroscopy, and 21 cm radio imaging of Markarian 266 are presented. The galaxy has faint extended plumes of luminosity, which indicate that it is a recent merger. There are extended regions of blue luminosity suggestive of recent star formation, and remarkable structure in forbidden O III line emission. Spectroscopic data show the velocities and densities in the ionized gas. Radio observations taken with the VLA show that both nuclei are resolved radio sources, and that there is a third radio source between them which has no optical counterpart; 21-cm absorption is seen against the brighter optical nucleus, indicating possible infall. These results are discussed in terms of galaxy mergers, nuclear activation, and ionized gas. Mkn 266 has many similarities to Arp 220 and appears to be a somewhat lower-luminosity version of the IRAS ultraluminous galaxies.

Hutchings, J. B.↗
NASA NTRS1983

The optical emission from the supernova remnant HB 3

The supernova remnant HB 3 was first detected as a radio source by Brown and Hazard (1953). On the basis of subsequent radio studies, it was concluded that the object was a supernova remnant (SNR). HB 3 is located at the far western edge of the H II region/molecular cloud complex W3-W4-W5 (IC 1795-1805-1848). However, a physical association of HB 3 with this complex is uncertain. In the present investigation, attention is called to the probability that HB 3 exhibits a more extensive optical emission structure than previously realized, and one which agrees well with both the position and morphology of the radio emission. It is found that narrow-passband optical images strongly suggest an almost complete optical emission shell for HB 3. Spectroscopic observations are, however, required to confirm that this emission is characteristic of a SNR.

Fesen, R. A.↗
NASA NTRS1995

Faint Object Camera imaging and spectroscopy of NGC 4151

We describe ultraviolet and optical imaging and spectroscopy within the central few arcseconds of the Seyfert galaxy NGC 4151, obtained with the Faint Object Camera on the Hubble Space Telescope. A narrowband image including (O III) lambda(5007) shows a bright nucleus centered on a complex biconical structure having apparent opening angle approximately 65 deg and axis at a position angle along 65 deg-245 deg; images in bands including Lyman-alpha and C IV lambda(1550) and in the optical continuum near 5500 A, show only the bright nucleus. In an off-nuclear optical long-slit spectrum we find a high and a low radial velocity component within the narrow emission lines. We identify the low-velocity component with the bright, extended, knotty structure within the cones, and the high-velocity component with more confined diffuse emission. Also present are strong continuum emission and broad Balmer emission line components, which we attribute to the extended point spread function arising from the intense nuclear emission. Adopting the geometry pointed out by Pedlar et al. (1993) to explain the observed misalignment of the radio jets and the main optical structure we model an ionizing radiation bicone, originating within a galactic disk, with apex at the active nucleus and axis centered on the extended radio jets. We confirm that through density bounding the gross spatial structure of the emission line region can be reproduced with a wide opening angle that includes the line of sight, consistent with the presence of a simple opaque torus allowing direct view of the nucleus. In particular, our modelling reproduces the observed decrease in position angle with distance from the nucleus, progressing initially from the direction of the extended radio jet, through our optical structure, and on to the extended narrow-line region. We explore the kinematics of the narrow-line low- and high-velocity components on the basis of our spectroscopy and adopted model structure.

Boksenberg, A.↗
NASA NTRS1990

Eos visible imagers

Some of the proposed Earth Observing System (Eos) optical imagers are examined. These imagers include: moderate resolution imaging spectrometer (MODIS); geoscience laser ranging system (GLRS); high resolution imaging spectrometer (HIRIS); the intermediate thermal infrared spectrometer (ITIR); multi-angle imaging spectrometer (MISR); earth observing scanning polarimeter (EOSP); and the lightening imaging sensor (LIS).

Barnes, W. L.↗
NASA NTRS2008

Grazing-Incidence Neutron Optics based on Wolter Geometries

The feasibility of grazing-incidence neutron imaging optics based on the Wolter geometries have been successfully demonstrated. Biological microscopy, neutron radiography, medical imaging, neutron crystallography and boron neutron capture therapy would benefit from high resolution focusing neutron optics. Two bounce optics can also be used to focus neutrons in SANS experiments. Here, the use of the optics would result in lower values of obtainable scattering angles. The high efficiency of the optics permits a decrease in the minimum scattering vector without lowering the neutron intensity on sample. In this application, a significant advantage of the reflective optics over refractive optics is that the focus is independent of wavelength, so that the technique can be applied to polychromatic beams at pulsed neutron sources.

Gubarev, M. V.↗
NASA NTRS1973

Multiple pass reimaging optical system

An optical imaging system for enabling nonabsorbed light imaged onto a photodetective surface to be collected and reimaged one or more times onto that surface in register with the original image. The system includes an objective lens, one or more imaging lenses, one or more retroreflectors and perhaps a prism for providing optical matching of the imaging lens focal planes to the photo detective surface.

Gunter, W. D., Jr.↗
NASA NTRS1974

Image reproduction with interactive graphics

Software application or development in optical image digital data processing requires a fast, good quality, yet inexpensive hard copy of processed images. To achieve this, a Cambo camera with an f 2.8/150-mm Xenotar lens in a Copal shutter having a Graflok back for 4 x 5 Polaroid type 57 pack-film has been interfaced to an existing Adage, AGT-30/Electro-Mechanical Research, EMR 6050 graphic computer system. Time-lapse photography in conjunction with a log to linear voltage transformation has resulted in an interactive system capable of producing a hard copy in 54 sec. The interactive aspect of the system lies in a Tektronix 4002 graphic computer terminal and its associated hard copy unit.

Buckner, J. D.↗
NASA NTRS1986

The far-infrared and optical structure of Arp 220

The spatial structure of the luminous peculiar galaxy Arp 220 has been investigated in the far infrared. The results reveal that most of the luminosity is from a source less than 3 kpc in extent, located in the nuclear region of the galaxy. The size constraints yield a lower limit of 0.05 for the 100 micron optical depth, implying a hydrogen column density over 5 x 10 to the 22nd/sq cm. New optical images confirm that the double-lobed optical appearance results from strong absorption across the true nucleus. Arp 220 exhibits three primary features which provide strong evidence for an external source of energy: (1) a chaotic and highly asymmetric galactic halo; (2) a large internal velocity dispersion in CO and H I; and (3) extreme compression of gas and dust. These features are natural consequences of previously proposed models which invoke a direct galactic collision and merger, and are unlikely to result from a long-range tidal interaction with the neighboring galaxy IC 4554.

Joy, M.↗
NASA NTRS1989

The structure of host galaxies of radio-loud quasars and possible triggering mechanisms for quasar activity

An image modeling program is used to analyze optical imaging data for a sample of radio-loud quasars with redshifts between 0.2 and 0.7. It is found that the host galaxies of these quasars tend to be more compact than normal ellipticals. The cooling flow cluster elliptical galaxies near these host galaxies are studied. It is suggested that these cooling flow galaxies are also compact due to star formation in their central regions. Two populations of quasars are identified. One, in which activity is triggered by galaxy mergers of interactions has predominately spiral galaxies and are radio quiet. The other, in which activity is triggered by star formation bursts induced by cooling flows, has predominately elliptical hosts and may be radio loud.

Romanishin, W.↗
NASA NTRS1990

Shock layer vacuum UV spectroscopy in an arc-jet wind tunnel

An experimental program is being developed to obtain measurements of the incident surface radiation in the 1000 A to 2000 A range from the shock stagnation region of a blunt model in the Ames 20 MW Arc-Jet Wind Tunnel. The setup consists of a water-cooled blunt model, with a magnesium fluoride forward-viewing window. Radiation incident on the window is optically imaged via an evacuated system and reflective optical elements onto the entrance slit of a spectrograph. The model will be exposed to the supersonic plasma stream from the exit nozzle of the arc-jet tunnel. The resulting bow shock radiation will be measured. It is expected that this experiment will help evaluate the importance of atomic N and O lines to the radiative heating of future Aeroassist Space Transfer Vehicles (ASTVs).

Palumbo, G.↗
NASA NTRS1989

Three-dimensional quantitative flow diagnostics

The principles, capabilities, and practical implementation of advanced measurement techniques for the quantitative characterization of three-dimensional flows are reviewed. Consideration is given to particle, Rayleigh, and Raman scattering; fluorescence; flow marking by H2 bubbles, photochromism, photodissociation, and vibrationally excited molecules; light-sheet volume imaging; and stereo imaging. Also discussed are stereo schlieren methods, holographic particle imaging, optical tomography, acoustic and magnetic-resonance imaging, and the display of space-filling data. Extensive diagrams, graphs, photographs, sample images, and tables of numerical data are provided.

Miles, Richard B.↗
NASA NTRS1991

The enigmatic jets of NGC 1097

We use deep optical images, spectroscopy, and radio observations of the optical jets in NGC 1097 to constrain models for their origin. Our detection limit on 20-cm radio emission from the region of the optical jets is ten times fainter than previous results. We detect no steep-spectrum emission at 90-cm associated with fossil radio lobes. If star formation in the optical jets was triggered by ejection of relativistic matter from an active nucleus, the time of activity was at least 10 million years ago.

Wehrle, Ann E.↗
NASA NTRS2005

Alignment, Assembly and Testing of High Energy X-Ray Optics

We are developing grazing-incidence x-ray imaging optics for a balloon-borne hard x-ray telescope (HERO). The HERO payload, scheduled for launch in May 2005, currently consists of 8 mirror modules each containing 12 mirror shells fabricated using electroform-nickel replication off super-polished cylindrical mandrels. An optical system developed for aligning and assembling the shells in the modules will be described. Sources for systematic errors associated with this process will be discussed and results from on-ground x-ray testing of each module will be presented.

Gubarev, Mikhail↗
NASA NTRS2013

SCExAO: First Results and On-Sky Performance

We present new on-sky results for the Subaru Coronagraphic Extreme Adaptive Optics imager (SCExAO) verifying and quantifying the contrast gain enabled by key components: the closed-loop coronagraphic low-order wavefront sensor (CLOWFS) and focal plane wavefront control ("speckle nulling"). SCExAO will soon be coupled with a high-order, Pyramid wavefront sensor which will yield greater than 90% Strehl ratio and enable 10(exp 6) -10(exp 7) contrast at small angular separations allowing us to image gas giant planets at solar system scales. Upcoming instruments like VAMPIRES, FIRST, and CHARIS will expand SCExAO's science capabilities.

Subaru Coronagraphic Extreme Adaptive Optics image↗
NASA NTRS1971

Integral image tube-optical systems for the far UV.

Description of proposed image tube optical systems for narrow-band direct photography and broad bandpass photography from spacecraft outside the atmosphere. For narrow-band photography an f/1.5 Schmidt camera with a photocathode located on the focal surface is recommended. The photoelectrons are accelerated and magnetically focused onto a phosphor/fiber optics surface, the curvature of which partially corrects for distortions of the electric field introduced by the curved photocathode. The second stage can be any other tube, electrostatically or magnetically focused, having a fiber optics faceplate butted to the first stage. For broad bandpass a spectrograph with an f/3 all-reflecting Schmidt image tube camera is recommended.

Chincarini, G.↗