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NASA NTRS1973

Hypermass generalization of Einstein's gravitation theory

The curvilinear invariant quaternion formalism is examined for curved space time. Einstein's gravitation equation is shown to have a simple and natural form in this notation. The hypermass generalization of particle mass, which was generated in our studies of the Dirac equation, is incorporated in gravitation by generalizing Einstein's equation. Covariance requires that the gravitational constant be generalized to an invariant quaternion when the mass is. The modification appears minor and of no importance cosmologically, unless one begins considering time and mass dependence of G.

Edmonds, J. D., Jr.↗

NASA NTRS1979

The Einstein /HEAO 2/ X-ray Observatory

The Einstein (HEAO 2) X-ray Observatory, launched in 1978, includes a fully imaging focusing X-ray telescope with an angular resolution of a few arc sec, a field of view of up to one deg, and a sensitivity several hundred times greater than previously available in any X-ray astronomy experiment. A high-resolution imager, an imaging proportional counter, a focal plane crystal spectrometer, and a monitor proportional counter are among the principal instruments on board the Einstein X-ray Observatory. About 20% of the total effective observing time in the first year of the X-ray astronomy experiment has been reserved for guest observers.

Giacconi, R.↗

NASA NTRS1979

X-ray studies of quasars with the Einstein Observatory

Results of an investigation of the X-ray properties of quasars conducted using the Einstein Observatory (HEAO 2) are reported. The positions, fluxes and luminosities of 35 known quasars were observed by the Einstein high-resolution imaging detector and the imaging proportional counter. Assuming optical redshifts as valid distance indicators, 0.5-4.5 keV X-ray luminosities ranging from 10 to the 43rd to 10 to the 47 ergs/sec are obtained, with evidence of very little cold gas absorption. Flux variability on a time scale of less than 10,000 sec is observed for the quasar OX 169, which implies a mass between 8 x 10 to the 5th and 2 x 10 to the 8th solar masses for the black hole assumed to be responsible for the emission. Preliminary results of the quasar survey also indicate that quasars contribute significantly to the diffuse X-ray background.

Tananbaum, H.↗

NASA NTRS1980

Stellar coronae from Einstein - Observations and theory

Einstein Observatory observations of stellar X-ray emission are presented and their implications for the formation of stellar coronae and the problem of stellar angular momentum loss are discussed. Solar coronal X-ray observations and observations of stellar coronae made prior to Einstein are reviewed, and it is noted that they already suggest that the standard theory of acoustic coronal heating is inadequate. The principal results of the Einstein/CfA stellar survey are summarized, with attention given to variations of the level of X-ray flux detected along the main sequence, the decline of X-ray flux with increasing age of giants and supergiants, and indications of a large range of X-ray emission levels within a given type, which are clearly incompatible with models for acoustic flux generation. A new theory to explain stellar coronae and hence X-ray emission from them is then proposed in which stellar magnetic fields play the key role in determining the level of coronal emission, and the modulation of the surface magnetic flux level and the level of stressing of surface magnetic fields essentially determine the variation of mean coronal activity in the H-R diagram.

Rosner, R.↗

NASA NTRS1981

Einstein imaging observations of clusters with a bimodal mass distribution

Einstein imaging observations of four X-ray clusters of galaxies characterized by a double X-ray surface brightness and thus mass distribution are presented. The clusters A98, A115, A1750 and SC 0627-54 were found to exhibit two enhancements in their X-ray surface brightness distributions in observations made with the Einstein Imaging Proportional Counter. Calculations of the probability that the clusters represent chance superpositions indicate that the double clusters are physically associated. The radial distributions of the components are inconsistent with those of single point sources, and have been used to derive cluster luminosities which are typical of rich clusters. Masses of the subclusters are also found to be typical of bound and virialized clusters with gas contributing 10%. Within the framework of the hierarchical theory of galactic clustering, the double clusters are suggested to represent an intermediate evolutionary stage before the merger of subclusters into a relaxed Coma-type cluster.

Forman, W.↗

NASA NTRS1982

Einstein observations of cool stars

Observations of cool stars with the Einstein Observatory (HEAO-2) have brought about a fundamental change in our knowledge and understanding of stellar coronae. The existence of X-ray emission from stars throughout the H-R diagram, the wide range of X-ray luminosity within a given spectral and luminosity class, and the strong correlation of X-ray luminosity with stellar age and rotation are among the more significant Einstein results. These results are strong evidence for the influence of stellar dynamo action on the formation and heating of stellar coronae. A discussion of relevant consortium and guest observations is given. The Hyades cluster, in particular, serves as an example to demonstrate the usefulness of X-ray observations in the study of stellar activity and coronal evolution.

Stern, R. A.↗

NASA NTRS1983

Einstein X-ray observations of optical-radio selected areas

Einstein Observatory Imaging Proportional Counter X-ray observations of fields in SA 57, SA 68, and U Mi that possess deep optical and radio coverage have been conducted with a sensitivity comparable to that of the Einstein Observatory's medium sensitivity survey of serendipitous X-ray sources. The number of X-ray sources detected is consistent with a log N(greater than S) - log S slope of about -1.5. The fraction of active galactic nuclei in the X-ray sample is less than about 50 percent, with the rest being composed of clusters and normal galaxies, consistent with the medium sensitivity survey.

Katgert, P.↗

NASA NTRS1988

The Einstein observatory stellar X-ray database - An overview

The paper presents the motivations for and the methodology followed in building the 'Einstein Observatory Stellar X-ray Database' based on the uniform analysis of all Einstein Observatory Imaging Proportional Counter fields obtained during the life of the HEAO-2 mission. The database has been implemented using the INGRES database system, so that statistical analyses of the properties of the full detection catalog are relatively easily and flexibly accomplished. Some illustrative examples will furnish a general view both of the kind and the amount of the archived information, and of the statistical approach used in analyzing the global properties of the data.

Sciortino, S.↗

NASA NTRS1989

Spatial and spectral features of soft diffuse X ray background seen by the Einstein observatory

A survey of the diffuse soft X-ray background as seen directly by the Einstein Observatory Imaging Proportional Counter (IPC) is presented. A source free region of the detector 1 by 1 degree field is used. The background in the 0.16 to 3.5 keV spectral region is viewed. The data covers roughly 5 percent of the sky, with some bias in coverage towards the galactic plane. The moderate energy resolution of the IPC enables the characterization and the production of maps of the background as a function of energy within the Einstein passband. The results are compared with previous observations of the diffuse X-ray background. The implications for galactic structure and for the soft component of the extragalactic X-ray background are discussed.

Micela, G.↗

NASA NTRS1989

The soft X ray excess in Einstein quasar spectra

The soft X-ray excess component is studied for a signal to noise limited subsample of 14 quasars from the WE87 sample observed with the Einstein Imaging Proportional Counter (IPC). Detailed analysis of the IPC data, combined with Einstein Monitor Proportional Counter (MPC) data where possible, and use of accurate galactic N sub H values allows estimation of the strength of any excess and improvement of constraints on the spectral slope at higher X-ray energies. A significant excess in 9 of the 14 objects is found. It is confined in all but one case to below 0.6 keV and variable in the two cases where there are multiple observations. The relation of the soft excess to other continuum properties of the quasars is investigated.

Wilkes, Belinda J.↗

NASA NTRS1990

H + O3 Fourier-transform infrared emission and laser absorption studies of OH(X2Pi) radical - An experimental dipole moment function and state-to-state Einstein A coefficients

FTIR emission/absorption spectroscopy is used to measure the relative intensities of 88 pairs of rovibrational transitions of OH(X2Pi) distributed over 16 vibrational bands. The experimental technique used to obtain the Einstein A ratios is discussed. The dipole moment function which follows from the intensity ratios along with Einstein A coefficients calculated from mu(r) is presented.

Nelson, David D., Jr.↗

NASA NTRS1991

The diffuse soft X-ray background as seen with the Einstein Observatory

A systematic survey of the diffuse soft X-ray background as seen directly with the Einstein Observatory is presented. With the aid of 1633 selected 1 x 1 deg fields of view obtained by the IPC to provide about 5-percent sky coverage, with some bias toward the Galactic plane, the background in the 0.16-3.5 keV spectral region was spatially resolved on this angular scale. Maps of the background are characterized and produced at different energies within the Einstein passband. It is confirmed that the Galactic ridge is not present at energies below 0.33 keV and it is demonstrated that the appearance of the ridge above this energy is not due to hard Galactic sources with a flux above 10 exp -13 ergs/sq cm/s. A southern Galactic region is identified, with l between 80 and 180 deg and b less than -5 deg, where the mean background intensity has the lowest value and is homogeneous within better than 9 percent. The implications of these results for the Galactic structure and for the nature of the extragalactic X-ray background are discussed.

Micela, G.↗

NASA NTRS1992

Einstein coefficients for rotational lines of the (0,0) band of the NO A2sigma(+)-X2Pi system

A summary of the spectroscopic equations necessary for prediction of the molecular transition energies and the Einstein A and B coefficients for rovibronic lines of the gamma(0,0) band of nitric oxide (NO) is presented. The calculated molecular transition energies are all within 0.57/cm of published experimental values; in addition, over 95 percent of the calculated energies give agreement with measured results within 0.25/cm. Einstein coefficients are calculated from the band A00 value and the known Hoenl-London factors and are tabulated for individual rovibronic transitions in the NO A2sigma(+)-X2Pi(0,0) band.

Reisel, John R.↗

NASA NTRS1993

The Einstein Observatory catalog of IPC x ray sources. Volume 4E: Right ascension range 08h 00m to 11h 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 documentaion 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 5E: Right ascension range 12h 00m to 15h 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 6E: Right ascension range 16h 00m to 19h 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 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

Harris, D. E.↗