ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Gravitational theories with nonzero divergence of the energy-momentum tensor (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Assuming that the divergence of the energy-momentum tensor is nonzero leads to a class of theories with consistent field equations and gauge conditions as well as compatibility with the Newtonian limit of the conservation laws. Both the Einstein and the Brans-Dicke theories are used as models, but the extension to other viable theories such as vector-metric and two-metric theories is possible. One particularly interesting theory emerges that agrees with the ordinary Brans-Dicke theory except for the post-Newtonian parameter zeta sub 2, which predicts nonconservation of total momentum. Unfortunately, no accurate experimental limits for this parameter are known. It thus remains for future experiments in lunar-laser ranging to test this theory.
    Keywords: ASTROPHYSICS
    Type: Physical Review D - Particles and Fields; vol. 12
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    Radio detection of interstellar sulfur dioxide (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Interstellar sulfur dioxide (SO2) has been detected in emission from the direction of the Orion Nebula molecular cloud and from Sgr B2. SO2 is the heaviest interstellar molecule detected to date, and the only nonlinear triatomic molecule which does not contain hydrogen. The remarkable Orion emission profiles suggest that two components are supporting the SO2 emission: a dense circumstellar-type envelope, which may be in maser emission, and a warm galactic cloud component.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 198; June 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    The infrared excess of cool giant stars - A chromospheric contribution (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: The idea that the infrared excesses of evolved M stars may contain a contribution from a chromosphere is explored using alpha Ori and W Hya as test cases. The spectrum of alpha Ori between 8 and 30 millimicrons can be interpreted satisfactorily in terms of three components: a photosphere, a silicate dust cloud, and a cool chromosphere (temperature about 5000 K), which is optically thick at 14 millimicrons. A similar modelling for W Hya suggests a hotter chromosphere (temperature about 8000 K), with unit optical depth at 30 millimicrons. Some consequences of these chromospheres are briefly discussed.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 172
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Relativistic astrophysics (1975)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The coordinate independence of gravitational radiation and the parameterized post-Newtonian approximation from which it is extended are described. The general consistency of the field equations with Bianchi identities, gauge conditions, and the Newtonian limit of the perfect fluid equations of hydrodynamics are studied. A technique of modification is indicated for application to vector-metric or double metric theories, as well as to scalar-tensor theories.
    Keywords: ASTROPHYSICS
    Type: NASA-CR-142988 , FR-4
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Motion of shocks through interplanetary streams (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: A model for the motion of flare-generated shocks through interplanetary streams is presented which illustrates the effects of a stream-shock interaction on the shock strength and geometry. It is a gasdynamic calculation based on Whitham's (1958) method and on an empirical approximation for the relevant characteristics of streams. The results show that the Mach number of a shock can decrease appreciably to near unity in the interaction region ahead of streams and that the interaction of a spherically symmetric shock with a spiral-shaped corotating stream can cause significant distortions of the initial shock-front geometry. The geometry of a shock discussed by Lepping and Chao (1972) is qualitatively explained by this model.
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 80; Oct. 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Observations of a new transition in the emission from Cyg X-1 (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Data from the all-sky X-ray monitor aboard Ariel V were used to establish that a sudden transition had occurred in emissions from Cyg X-1 on April 22, 1975. Cyg X-1 has been observed almost continuously since around November 1, 1974, and has been relatively constant in apparent magnitude until the reported effect. The results of these observations are discussed.
    Keywords: ASTROPHYSICS
    Type: Nature; 256; July 10
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Investigation of low-latitude hydrogen emission in terms of a two-component interstellar gas model (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: High-resolution 21-cm hydrogen line observations at low galactic latitude are analyzed to determine the large-scale distribution of galactic hydrogen. Distribution parameters are found by model fitting, optical depth effects are computed using a two-component gas model suggested by the observations, and calculations are made for a one-component uniform spin-temperature gas model to show the systematic departures between this model and data obtained by incorrect treatment of the optical depth effects. Synthetic 21-cm line profiles are computed from the two-component model, and the large-scale trends of the observed emission profiles are reproduced together with the magnitude of the small-scale emission irregularities. Values are determined for the thickness of the galactic hydrogen disk between half density points, the total observed neutral hydrogen mass of the galaxy, and the central number density of the intercloud hydrogen atoms. It is shown that typical hydrogen clouds must be between 1 and 13 pc in diameter and that optical thinness exists on large-scale despite the presence of optically thin gas.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 198; June 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Ultraviolet observations of classical Cepheids by OAO-2 (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: OAO-2 observations of eight bright classical Cepheids in the wavelength region 1910 A to 4250 A are presented. The data for RT Aurigae, alpha Ursa Minoris, delta Cephei, and gamma Ophiuchi show excellent agreement with ground based photometry in the wavelength region of overlap and are consistent with a simple extrapolation of light curve properties from the visible region. However, in the ultraviolet, the light curve of beta Doradus shows two small flux bumps, at phases of 0.75 and 0.85, in addition to the well known bump at phase 0.0. All three bumps should probably be associated with the arrival of shocks at the stellar surface.
    Keywords: ASTROPHYSICS
    Type: NASA. Goddard Space Flight Center Cepheid Modeling; p 5-30
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unknown
    Ultraviolet observations of cool stars. III - Chromospheric and coronal lines in alpha Tauri, beta Geminorum, and alpha Bootis (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 202; Nov. 15
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unknown
    Spectral variability of Cygnus X-3 (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Spectra of Cyg X-3 from 1.7 to 40 keV, obtained about a year apart using the same rocket payload, show large spectral differences. The two observations suggest that while the luminosity of this source remains roughly the same, its spectrum can vary from a featureless blackbody distribution to a flat spectrum which includes strong iron line emission at approximately 6.7 keV. The flux in the line is 0.018 (plus or minus 0.004) photons per sq cm/sec, corresponding to an equivalent continuum width of 1.2 keV.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 201; Oct. 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...