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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

The Rings Node for the Planetary Data System

The Planetary Data System's Rings Node is devoted to the archiving and distributing of scientific data sets relevant to planetary ring systems. The two major classes of ring data are images and occultation profiles, although a variety of additional data types (e.g. spectra, particle absorption signatures, etc.) are also of interest. A large fraction of our data sets are from the Voyager missions to the outer planets, but Earth-based and Hubble Space Telescope data sets are also represented. Archiving work often includes re-formatting the data into standardized formats and reconstructing some of the data processing steps. The Rings Node also performs a variety of services to support research into these data sets. These services include developing on-line catalogs and information systems, filling orders for data, developing software tools, and coordinating special observing campaigns.

Showalter, Mark R.↗
NASA NTRS2004

Overview of NASA's Earth Science Data Systems

For over the last 15 years, NASA's Earth Science Enterprise (ESE) has devoted a tremendous effort to design and build the Earth Observing System (EOS) Data and Information System (EOSDIS) to acquire, process, archive and distribute the data of the EOS series of satellites and other ESE missions and field programs. The development of EOSDIS began with an early prototype to support NASA data from heritage missions and progressed through a formal development process to today's system that supports the data from multiple missions including Landsat 7, Terra, Aqua, SORCE and ICESat. The system is deployed at multiple Distributed Active Archive Centers (DAACs) and its current holdings are approximately 4.5 petabytes. The current set of unique users requesting EOS data and information products exceeds 2 million. While EOSDIS has been the centerpiece of NASA's Earth Science Data Systems, other initiatives have augmented the services of EOSDIS and have impacted its evolution and the future directions of data systems within the ESE. ESDIS had an active prototyping effort and has continued to be involved in the activities of the Earth Science Technology Office (ESTO). In response to concerns from the science community that EOSDIS was too large and monolithic, the ESE initiated the Earth Science Information Partners (ESP) Federation Experiment that funded a series of projects to develop specialized products and services to support Earth science research and applications. Last year, the enterprise made 41 awards to successful proposals to the Research, Education and Applications Solutions Network (REASON) Cooperative Agreement Notice to continue and extend the ESP activity. The ESE has also sponsored a formulation activity called the Strategy for the Evolution of ESE Data Systems (SEEDS) to develop approaches and decision support processes for the management of the collection of data system and service providers of the enterprise. Throughout the development of its earth science data systems, NASA has had an active collaboration with a number of interagency and international partners. One of the mechanisms that has been extremely helpful in initiating and promoting this collaboration has been NASA's participation in the Committee on Earth Observation Satellites (CEOS) and its Working Group on Information Systems and Services (WGISS). The CEOS members, working together, have implemented an International Directory Network that enables users to locate collections of earth science data held by the international community and an International Catalog System to search and order specific data products. CEOS WGISS has also promoted the international interest in the Open GIS Consortium s specifications that further advance the access and use of geospatial data and the interoperation of GTS components. These are just a few highlights of the benefits that member agencies gain from CEOS participation.

McDonald, Kenneth↗
DOE OSTI2022

Identifications of RR Lyrae Stars and Quasars from the Simulated Data of Mephisto-W Survey

We have investigated the feasibilities and accuracies of the identifications of RR Lyrae stars and quasars from the simulated data of the Multi-channel Photometric Survey Telescope (Mephisto) W Survey. Based on the variable sources light curve libraries from the Sloan Digital Sky Survey (SDSS) Stripe 82 data and the observation history simulation from the Mephisto-W Survey Scheduler, we have simulated the uvgriz multi-band light curves of RR Lyrae stars, quasars and other variable sources for the first-year observation of Mephisto W Survey. We have applied the ensemble machine learning algorithm Random Forest Classifier (RFC) to identify RR Lyrae stars and quasars, respectively. We build training and test samples and extract ~150 features from the simulated light curves and train two RFCs respectively for the RR Lyrae star and quasar classification. We find that, our RFCs are able to select the RR Lyrae stars and quasars with remarkably high precision and completeness, with purity = 95.4% and completeness = 96.9% for the RR Lyrae RFC and purity = 91.4% and completeness = 90.2% for the quasar RFC. In conclusion, we have also derived relative importances of the extracted features utilized to classify RR Lyrae stars and quasars.

(galaxies:) quasars: general↗
DOE OSTI2025

The DESI DR1 Peculiar Velocity Survey: Mock Catalog

We describe the production of the official set of mock catalogs for the Dark Energy Spectroscopic Instrument Peculiar Velocity Survey (DESI-PV) Data Release 1 (DR1). Our mock catalogs reproduce the Bright Galaxy Survey number density and clustering at low redshift $(z<0.1)$ and the DESI PV samples of Fundamental plane and Tully-Fisher distances, from which we derive peculiar velocities. We carefully match mock and data properties and we mimic measurements of distance indicators and peculiar velocities, which follow the same statistical properties as real data. Mock samples of type-Ia supernovae also complement the other two distance indicators. Our 675 available mock realizations were used consistently by our three different methodologies described in our companion papers that measure the growth rate of structure $fσ_8$ with DESI PV DR1. Those mocks allow us to perform precise tests of clustering models and uncertainty estimation to an unprecedented level of accuracy, and compute correlations between methodologies. The consensus value for the DESI DR1 PV growth rate measurement is $fσ_8 = 0.450 \pm 0.055$. This sample of mock catalogs represents the largest and most realistic set for cosmological measurements with peculiar velocities to date.

Bautista, J. [Marseille, CPPM]↗
NASA NTRS1994

The blazar gamma-ray luminosity function and the diffuse extragalactic gamma-ray background

We have used the data from the new EGRET catalog on 'grazars' (blazers which are observed to be high-energy gamma-ray sources), together with radio data, to construct a new relation between radio and gamma-ray luminosity for these sources. Using this relation to construct a grazar gamma-ray luminosity function, we then calculate the contribution of unresolved grazars to the cosmic gamma-ray background radiation. We derive the energy spectrum of this background component above 100 MeV and the angular fluctuations in this background implied by our model.

Salamon, M. H.↗
DOE OSTI2022

Photometry on Structured Backgrounds: Local Pixel-wise Infilling by Regression

Photometric pipelines struggle to estimate both the flux and flux uncertainty for stars in the presence of structured backgrounds such as filaments or clouds. However, it is exactly stars in these complex regions that are critical to understanding star formation and the structure of the interstellar medium. We develop a method, similar to Gaussian process regression, which we term local pixel-wise infilling (LPI). Using a local covariance estimate, we predict the background behind each star and the uncertainty of that prediction in order to improve estimates of flux and flux uncertainty. We show the validity of our model on synthetic data and real dust fields. We further demonstrate that the method is stable even in the crowded field limit. While we focus on optical-IR photometry, this method is not restricted to those wavelengths. We apply this technique to the 34 billion detections in the second data release of the Dark Energy Camera Plane Survey. In addition to removing many >3σ outliers and improving uncertainty estimates by a factor of ~2–3 on nebulous fields, we also show that our method is well behaved on uncrowded fields. The entirely post-processing nature of our implementation of LPI photometry allows it to easily improve the flux and flux uncertainty estimates of past as well as future surveys.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

The Exploration of Local VolumE Satellites (ELVES) Survey: A Nearly Volume-limited Sample of Nearby Dwarf Satellite Systems

We present the final sample of the Exploration of Local VolumE Satellites (ELVES) survey, a survey of the dwarf satellites of a nearly volume-limited sample of Milky Way (MW)-like hosts in the Local Volume. Hosts are selected simply via a cut in luminosity (${M}_{{K}_{s}}\lt -22.1$ mag) and distance (D < 12 Mpc). We cataloged the satellites of 25 of the 31 such hosts, with another five taken from the literature. All hosts are surveyed out to at least 150 projected kpc ( ~ R vir /2), with the majority surveyed to 300 kpc ( ~ R vir ). Satellites are detected using a consistent semiautomated algorithm specialized for low surface brightness dwarfs. As shown through extensive tests with injected galaxies, the catalogs are complete to M V ~ -9 mag and μ 0,V ~ 26.5 mag arcsec -2 . Candidates are confirmed to be real satellites through distance measurements including redshift, tip of the red giant branch, and surface brightness fluctuations. Across all 30 surveyed hosts, there are 338 confirmed satellites with M V < -9 mag, with a further 106 candidates awaiting distance measurement. For the vast majority of these, we provide consistent multiband Sérsic photometry. We show that satellite abundance correlates with host mass, with the MW being quite typical among comparable systems, and that satellite quenched fraction rises steeply with decreasing satellite mass, mirroring the quenched fraction for the MW and M31. The ELVES survey represents a massive increase in the statistics of surveyed systems with known completeness, and the provided catalogs are a unique data set to explore various aspects of small-scale structure and dwarf galaxy evolution.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1976

Sequence characterization of 5S ribosomal RNA from eight gram positive procaryotes

Complete nucleotide sequences are presented for 5S rRNA from Bacillus subtilis, B. firmus, B. pasteurii, B. brevis, Lactobacillus brevis, and Streptococcus faecalis, and 5S rRNA oligonucleotide catalogs and partial sequence data are given for B. cereus and Sporosarcina ureae. These data demonstrate a striking consistency of 5S rRNA primary and secondary structure within a given bacterial grouping. An exception is B. brevis, in which the 5S rRNA sequence varies significantly from that of other bacilli in the tuned helix and the procaryotic loop. The localization of these variations suggests that B. brevis occupies an ecological niche that selects such changes. It is noted that this organism produces antibiotics which affect ribosome function.

Woese, C. R.↗
NASA NTRS1978

New morphometric data for fresh lunar craters

Morphometric relations have been determined for 2598 fresh craters on the lunar nearside using data given in the catalog of Wood and Andersson (1978). For each of five principal morphological types, typified by Albategnius C, Biot, Sosigenes, Triesnecker, and Tycho, statistical relations are documented for the following: crater diameter and depth; floor diameter and crater diameter; central peak height and crater diameter; average wall slope and crater depth; central peak occurrence and crater diameter; occurrence of scallops or terraces and crater diameter. The first four relations generally confirm the conclusions of Pike (1977), but the last two differ from results reported by Smith and Sanchez (1973). Small (diameter less than 20 km) flat-floored craters formed in mare terrains are as much as 10% deeper than those formed in the highlands, and the depths of small bowl-shaped craters reflect even greater dependence on terrain. Larger, scalloped-walled craters are deeper in highland terrain than on the maria. Although wall failure does not occur until the crater diameter reaches 13 km, central peaks are found in flat floor craters as small as 2 km.

Wood, C. A.↗
NASA NTRS1985

The radio-optical-X-ray spectral flux distributions of blazars

Ten confirmed and probable BL Lac objects were searched for X-ray emission using the Einstein Observatory. All 10 were detected. These data were combined with existing data to form a catalog of 99 confirmed (by measured, high, optical linear polarization) and probable blazars (BL Lac objects and highly polarized quasars). Radio, optical, and X-ray observations are available for 77 of these. One of the ten program objects was observed at four epochs during large radio and optical outbursts. The correlations of radio, optical, and X-ray luminosities are examined.

Ledden, J. E.↗
NASA NTRS1991

The IRAS faint source survey

The principal features of the IRAS Faint Source Survey (FSS), a new product resulting from the extended IRAS mission, are reviewed. The FSS has achieved an increase in sensitivity of about a factor of 2.5 relative to the IRAS Point Source Catalog by coadding the data before extracting sources. The FSS was produced by point-source filtering the individual detector data streams and then coadding the data streams using a trimmed-average algorithm. The discussion covers FSS production methods; reliability, completeness, and positional accuracy of the FSS; and FSS view of the IR sky.

Moshir, Mehrdad↗
NASA NTRS1993

Acceleration Studies

Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

Rogers, Melissa J. B.↗
NASA NTRS1993

Are groups of galaxies virialized systems?

Groups are systems of galaxies with crossing times t(cr) much smaller than the Hubble time. Most of them have t(cr) less than 0.1/H0. The usual interpretation is that they are in virial equilibrium. We compare the data of the group catalog selected from the CfA redshift survey extension with different N-body models. We show that the distributions of kinematic and dynamical quantities of the groups in the CfA catalog can be reproduced by a single collapsing group observed along different line of sights. This result shows that (1) projection effects dominate the statistics of these systems, and (2) observed groups of galaxies are probably still in the collapse phase.

Diaferio, Antonaldo↗
NASA NTRS1994

The continuum spectral characteristics of gamma ray bursts observed by BATSE

Distributions of the continuum spectral characteristics of 260 bursts in the first Burst and Transient Source Experiment (BATSE) catalog are presented. The data are derived from flux ratios calculated from the BATSE Large Area Detector (LAD) four channel discriminator data. The data are converted from counts to photons using a direct spectral inversion technique to remove the effects of atmospheric scattering and the energy dependence of the detector angular response. Although there are intriguing clusterings of bursts in the spectral hardness ratio distributions, no evidence for the presence of distinct burst classes based on spectral hardness ratios alone is found. All subsets of bursts selected for their spectral characteristics in this analysis exhibit spatial distributions consistent with isotropy. The spectral diversity of the burst population appears to be caused largely by the highly variable nature of the burst production mechanisms themselves.

Pendleton, Geoffrey N.↗
NASA NTRS1994

The continuum spectral characteristics of gamma-ray bursts observed by BATSE

Distributions of the continuum spectral characteristics of 260 bursts in the first Burst And Transient Source Experiement (BATSE) catalog are presented. The data are derived from flux calculated from BATSE Large Area Detector (LAD) four-channel discriminator data. The data are converted from counts to protons using a direct spectral inversion technique to remove the effects of atmospheric scattering and the energy dependence of the detector angular response. Although there are intriguing clusters of bursts in the spectral hardness ratio distributions, no evidence for the presence of distinct burst classes based in spectral hardness ratios alone is found. All subsets of bursts selected for their spectral characteristics in this analysis exhibit spatial distributions consistent with isotropy. The spectral diversity of the burst population appears to be caused largely by the highly variable nature of the burst production mechanisms themselves.

Pendleton, Geoffrey N.↗
NASA NTRS1995

Distributed Computerized Catalog System

DarkStar Distributed Catalog System describes arbitrary data objects in unified manner, providing end users with versatile, yet simple search mechanism for locating and identifying objects. Provides built-in generic and dynamic graphical user interfaces. Design of system avoids some of problems of standard DBMS, and system provides more flexibility than do conventional relational data bases, or object-oriented data bases. Data-collection lattice partly hierarchical representation of relationships among collections, subcollections, and data objects.

Borgen, Richard L.↗
NASA NTRS2006

The 2005 HST Calibration Workshop Hubble After the Transition to Two-Gyro Mode

The 2005 HST Calibration Workshop was held at the Space Telescope Science Institute during October 26, 2005 to bring together members of the observing community, the instrument development teams, and the STScI instrument support teams to share information and techniques. Presentations included the two-gyro performance of HST and FGS, advances in the calibration of a number of instruments, the results of other instruments after their return from space, and the status of still others which are scheduled for installation during the next servicing mission. Cross-calibration between HST and JWST was discussed, as well as the new Guide Star Catalog and advances in data analysis software. This book contains the published record of the workshop, while all the talks and posters are available electronically on the workshop Web site.

Koekemoer, Anton M.↗