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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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NASA NTRS1993

The Einstein Observatory catalog of IPC x ray sources. Volume 7E: Right ascension range 20h 00m to 23h 59m

The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

Harris, D. E.↗
NASA NTRS1993

The Einstein Observatory catalog of IPC x ray sources. Volume 1E: Documentation

The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics, which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers, and data useful for calculating upper limits and fluxes.

Harris, D. E.↗
NASA NTRS1993

The Einstein Observatory catalog of IPC x ray sources. Volume 2E: Right ascension range 00h 00m to 03h 59m

The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers and data useful for calculating upper limits and fluxes.

Harris, D. E.↗
NASA NTRS1993

The Einstein Observatory catalog of IPC x ray sources. Volume 3E: Right ascension range 04h 00m to 07h 59m

The Einstein Observatory (HEAO-2, launched November 13, 1978) achieved radically improved sensitivity over previous x-ray missions through the use of focusing optics which simultaneously afforded greatly reduced background and produced true images. During its 2.5-yr mission, the Einstein X-Ray Telescope was pointed toward some 5,000 celestial targets, most of which were detected, and discovered several thousand additional 'serendipitous' sources in the observed fields. This catalog contains contour diagrams and source data, obtained with the imaging proportional counter in the 0.16 to 3.5 keV energy band, and describes methods for recovering upper limits for any sky position within the observed images. The main catalog consists of six volumes (numbered 2 through 7) of right ascension ordered pages, each containing data for one observation. Along with the primary documentation describing how the catalog was constructed, volume 1 contains a complete source list, results for merged fields, a reference system to published papers and data useful for calculating upper limits and fluxes.

Harris, D. E.↗
NASA NTRS2003

EXIST: The Next Large GRB Observatory

Studies have begun on the EXIST (Energetic X-ray Imaging Survey Telescope) Mission as a Black Hole Survey 'Einstein Probe', a major element in the new NASA Beyond Einstein Program in the Office of Space Science. This program was approved by the US Congress, in February 2003 as part of the NASA FY2004 NASA budget. EXIST is planned as a very wide-field coded aperture telescope and a positional accuracy for GRBs better than one arc-minute. The baseline detectors are Cadmium-Zinc-Telluride (CZT), with a total sensitive area of approximately 8 m2. EXIST will use SWIFT as a pathfinder mission; the findings of SWIFT will refine the scientific objectives of EXIST and will help to determine many of its design parameters. EXIST will study early star and galaxy formation at high redshifts through observations of thousands of GRBs, their afterglows and host galaxies. It is intended that the international GRB community will play a large role in EXIST through direct participation as well as with complementary observational programs, both space-based and ground-based. Some preliminary design features and capabilities of the EXIST Mission will be presented.

Fishman, Gerald J.↗
DOE OSTI2024

Cold Dark Matter and Self-interacting Dark Matter Interpretations of the Strong Gravitational Lensing Object JWST-ER1

Abstract van Dokkum et al. reported the discovery of JWST-ER1, a strong lensing object at redshift z ≈ 2, using data from the James Webb Space Telescope. The lens mass within the Einstein ring is 5.9 times higher than the expected stellar mass from a Chabrier initial mass function, indicating a high dark matter density. In this work, we show that a cold dark matter halo, influenced by gas-driven adiabatic contraction, can account for the observed lens mass. We interpret the measurement of JWST-ER1 in the self-interacting dark matter scenario and show that the cross section per particle mass σ / m ≈ 0.1 cm 2 g −1 is generally favored. Intriguingly, σ / m ≈ 0.1 cm 2 g −1 can also be consistent with the strong lensing observations of early-type galaxies at redshift z ≈ 0.2, where adiabatic contraction is not observed overall.

Astronomy & Astrophysics↗
NASA NTRS1986

The advanced X-ray Astrophysics Facility (AXAF)

NASA's Advanced X-ray Astrophysics Facility (AXAF) will be an orbiting X-ray observatory, designed to address fundamental questions in astronomy and astrophysics. AXAF is the successor to NASA's second High Energy Astronomy Observatory, the Einstein X-ray Observatory, which operated from 1978 to 1981. Like the Einstein, the AXAF will be built around a grazing incidence telescope capable of forming X-ray images. AXAF, however, will go far beyond the Einstein in capability having about 10 times the angular resolution, about 100 times the sensitivity for imaging, and up to about 1000 times the sensitivity for spectroscopy. The AXAF will operate in space for 15 years, and be maintained and refurbished by use of NASA's Space Station.

Weisskopf, M. C.↗
NASA NTRS1993

IUEAGN: A database of ultraviolet spectra of active galactic nuclei

In 13 years of operation, IUE has gathered approximately 5000 spectra of almost 600 Active Galactic Nuclei (AGN). In order to undertake AGN studies which require large amounts of data, we are consistently reducing this entire archive and creating a homogeneous, easy-to-use database. First, the spectra are extracted using the Optimal extraction algorithm. Continuum fluxes are then measured across predefined bands, and line fluxes are measured with a multi-component fit. These results, along with source information such as redshifts and positions, are placed in the IUEAGN relational database. Analysis algorithms, statistical tests, and plotting packages run within the structure, and this flexible database can accommodate future data when they are released. This archival approach has already been used to survey line and continuum variability in six bright Seyfert 1s and rapid continuum variability in 14 blazars. Among the results that could only be obtained using a large archival study is evidence that blazars show a positive correlation between degree of variability and apparent luminosity, while Seyfert 1s show an anti-correlation. This suggests that beaming dominates the ultraviolet properties for blazars, while thermal emission from an accretion disk dominates for Seyfert 1s. Our future plans include a survey of line ratios in Seyfert 1s, to be fitted with photoionization models to test the models and determine the range of temperatures, densities and ionization parameters. We will also include data from IRAS, Einstein, EXOSAT, and ground-based telescopes to measure multi-wavelength correlations and broadband spectral energy distributions.

Pike, G.↗
NASA NTRS1981

A soft X-ray study of the Large Magellanic Cloud

It is estimated on statistical grounds that of the 97 sources detected in a survey of the Large Magellanic Cloud (LMC) by means of the Einstein Laboratory's imaging X-ray telescope, less than 25 are likely to be either foreground stars or background quasars. The largest class of identified sources discovered is that of supernova remnants (SNRs). It is confirmed by means of high resolution maps that six more sources are also SNRs, and an additional 20 to 25 unidentified sources are suspected, in light of the available temporal, spatial and spectral information, to be SNRs. Of the remaining approximately 40 sources, about half are expected to be either background active galactic nuclei or foreground stars. The unexpectedly large number of SNRs found in the survey suggests that present knowledge of the galactic remnant population may be incomplete.

Long, K. S.↗
NASA NTRS2017

A Telescope at the Solar Gravitational Lens: Problems and Solutions

By Einstein's general theory of relativity, gravity of a massive body deflects light, and thus the sun can be used as a lens. The focus of the sun's gravitational lens is about 550 AU (Astronomical Units). (The sun continues to act as a lens beyond this minimum; at longer distances, the focused light passes increasingly far from the solar limb.) A mission to the gravitational focus of the sun, beyond the edge of the solar system, but far closer than the nearest stars, could be a target for an interstellar precursor. Proposed methods of reaching the focal distance include electric propulsion or laser- or solar sails. An objective for such a mission is to use the gravitational lens to image and map an extrasolar planet.

Landis, Geoffrey A.↗
NASA NTRS1995

Evidence for elemental variation in the ejecta of the Tycho supernova remnant

We present an X-ray study of the Tycho supernova remnant utilizing archival data from the high-resolution imagers (HRIs) on Einstein and ROSAT, the low-energy imaging telescopes (LEITs) on EXOSAT, and spectral data from the Broad Band X-ray Telescope (BBXRT). We have made use of the differing HRI bandpasses to construct images of Tycho in two spectral bands, o.7-1.8 keV and 1.8-4.5 keV. We find that the two images differ, with the harder image showing enhanced emission along much of the south, west, and north periphery. There appears to be enhanced soft emission in the interior and in one particular knot of emission in the southeast. Besides continuum (which we model here as thermal bremsstrahlung emission), we believe the hard image shows primarily the distribution of high-ionization Si and S K-shell lines which lie in the 1.8-2.6 keV band, while the softer image has contributions from Si as well as Fe XVII to Fe XXIV L-shell lines in the 0.7-1.4 keV band. Guided by the results of nonequilibrium ionization modeling of the BBXRT spectral data, we interpret the observed contrast in hard and soft X-ray emission in terms of variations in abundance, ionization timescale, and temperature. The most likely explanation for the spectral differences are spatial variations of the relative abundances of Si, S, and Fe.

Vancura, O.↗
NASA NTRS2007

Hubble 2006: Science Year in Review

The 10 science articles selected for this years annual science report exemplify the range of Hubble research from the Solar System, across our Milky Way, and on to distant galaxies. The objects of study include a new feature on Jupiter, binaries in the Kuiper Belt, Cepheid variable stars, the Orion Nebula, distant transiting planets, lensing galaxies, active galactic nuclei, red-and-dead galaxies, and galactic outflows and jets. Each narrative strives to construct the readers understanding of the topics and issues, and to place the latest research in historical, as well as scientific, context. These essays reveal trends in the practice of astronomy. More powerful computers are permitting astronomers to study ever larger data sets, enabling the discovery of subtle effects and rare objects. (Two investigations created mosaic images that are among the largest produced to date.) Multiwavelength data sets from ground-based telescopes, as well as other great observatories Spitzer and Chandraare increasingly important for holistic interpretations of Hubble results. This yearbook also presents profiles of 12 individuals who work with Hubble, or Hubble data, on a daily basis. They are representative of the many students, scientists, engineers, and other professions who are proudly associated with Hubble. Their stories collectively communicate the excitement and reward of careers related to space science and technology.

Hubble space telescope↗
NASA NTRS1980

The Einstein Observatory - New perspectives in astronomy

The impact of high-resolution, high-sensitivity X-ray measurements obtained by the Einstein Observatory (HEAO-2) on various areas of astronomical research is discussed. Following a review of the Einstein instruments based on grazing incidence focusing X-ray optics, including the telescope, imaging detectors and spectrometers, consideration is given to observations of X-ray emission from stellar systems, galaxies, and clusters of galaxies. Einstein results concerning the X-ray luminosities of young O, B and A stars and late K and M stars, the temperature, composition and distribution of material ejected in supernova explosions and comprising the interstellar medium, the formation and evolution of stellar systems and galaxies, the energy source of quasars and active galactic nuclei and the mass distribution in galactic clusters are indicated. Substantial progress made possible by the high-resolution observations of the diffuse X-ray background in cosmological research is also noted.

Giacconi, R.↗
DOE OSTI2025

The Kangaroo’s First Hop: The Early Fast Cooling Phase of EP250108a/SN 2025kg

Fast X-ray transients are a rare and poorly understood population of events. Previously difficult to detect in real time, the launch of the Einstein Probe with its Wide-field X-ray Telescope has led to a rapid expansionof the sample and allowed the exploration of these transients across the electromagnetic spectrum. EP250108a is a recently detected example linked to an optical counterpart, SN 2025kg, or “the kangaroo.” Together with a companion Letter we present our observing campaign and analysis of this event. In this letter, we focus on the early evolution of the optical counterpart over the first 6 days, including our measurement of the redshift of z = 0.17641. We compare to other supernovae and fast transients showing similar features, finding significant similarities with SN 2006aj and SN 2020bvc, and show that the source is well modelled by a rapidly expanding cooling blackbody. We show the observed X-ray and radio properties are consistent with a collapsar-powered jet that is low energy (≲10 51 erg) and/or fails to break out of the dense material surrounding it. While we examine the possibility that the optical emission emerges from the shock produced as the supernova ejecta expand into a dense shell of circumstellar material, due to our X-ray and radio inferences, we favour a model where it arises from a shocked cocoon resulting from a trapped jet. This makes SN 2025 one of the few examples of this currently observationally rare event.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1983

Optical and X-ray observations of faint quasars in an optically selected sample

The confirmation of six quasars from spectrographic observations made in 1981 using the Multiple Mirror Telescope, and the characterization of 10 quasars from 1980 Einstein-Observatory X-ray observations (using both imaging proportional counter and high-resolution imager), are reported. The candidates had been selected by Formiggini et al. (1980) in a 1.72-sq-deg region centered on 13h 6 deg, on the basis of ultraviolet excess and a limiting B magnitude of 19.20. A total sample of 10 UV-excess quasars of this magnitude has now been confirmed, for an integral surface density of 5.8 + or - 1.8 per sq deg. Confirmation of three objects from another sample with B less than 18.25 as quasars yielded a surface density of 0./59 + or - 0.13 per sq deg at that magnitude. Data from the complete samples were used to compute the number-flux relation, found to be described by a power law with a 2.25 index for quasars with B between 17.0 and 19.2. From the X-ray observations it was determined that quasars with z less than 2.2 and B less than 19.20 contribute about 15 percent to the cosmic 2-keV background.

Marshall, H. L.↗
DOE OSTI2026

Constraining axion properties with radio telescopes

Axion dark matter or any ultralight bosonic dark matter can go through Bose-Einstein condensation due to the large phase density, leading to the formation of axion stars or solitons in dark matter halo centers. The formation rate is enhanced in the presence of the substructures expected in the postinflationary scenario for the QCD axion or axionlike particles. An axion star will continue to grow until a critical mass is reached, after which it collapses and then explodes, with the emission of relativistic axions, in a process called an “axinovae.” There can also be accompanying photon emission due to the stimulated decay of axions in the coherent compact axion star. In axion models with a modest enhancement (𝜅 ∼𝒪⁡(10)) of the axion-photon coupling 𝑔 𝑎⁢𝛾 = 𝜅⁢𝛼/(2⁢𝜋⁢𝑓 𝑎 ) axinovae will contain a significant flux of radio photons. We determine the range of parameters over which axinovae can be detectable with radio transient searches.

Fox, Patrick J. [Fermi National Accelerator Labora↗
NASA NTRS1982

High resolution large area modular array of reflectors /LAMAR/ Wolter type I X-ray telescope for Spacelab

The Spacelab Wolter type I X-ray telescope, which is intended for both astronomical observations and the functional verification of the future Large Area Modular Array of Reflectors (LAMAR) concept, comprises five mirrors and is designed to have a blur circle radius of 20 arcsec, with effective areas of (1) 400 sq cm at 0.25 keV, (2) 200 sq cm in the 0.5-2.0 keV range, and (3) 50 sq cm between 2 and 5 keV. A rotary interchange mechanism allows either of two imaging proportional counters to be placed at the telescope focus. The telescope's primary objective is the observational study of galactic and extragalactic X-ray sources, extending the work of the Einstein Observatory to fainter sources and higher energies. Secondarily, the costs and performance to be expected from the use of this telescope type in the LAMAR mission will be assessed.

Catura, R. C.↗
NASA NTRS1997

Cluster-Induced Fluctuations in the Microwave Background Radiation

The research proposed was to detect, map and interpret the Sunyaev-Zel dovich (SZ) effects in two samples of distant clusters of galaxies with the OVRO 40-m telescope: an optically selected sample of 26 clusters at the North Ecliptic Pole, and an X-ray selected sample of clusters based on the Einstein Medium Sensitivity Survey, to make small maps of the strongest cluster SZ effects using the OVRO 40-m telescope, to combine the SZ and X-ray data for well-detected clusters to determine the value of the Hubble constant and set limits to the value of the deceleration parameter, and to study the properties of cluster atmospheres using the SZ effect.

Birkinshaw, Mark↗