Library

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
    Electronic Resource
    Electronic Resource
    Variable X-ray source near Cen X-3 (1975)
    [s.l.] : Nature Publishing Group
    Nature 254 (1975), S. 577-578 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Counting rate of variable source in Centaurus region as a function of time after subtraction of background. The symbol circle with a vertical bar indicates typical ±la values near the maximum intensity; as noted in the text this arises partly from fluctuations in source strength on ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/254577a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Observations of a transient X-ray source with a period of 104 s (1975)
    [s.l.] : Nature Publishing Group
    Nature 256 (1975), S. 628-630 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Figure 1 shows the observed count rate from A05354-26 as a function of time in units of counts s 1 in the 3-7 keV range corrected for the collimator response. Intensities before April 21 were obtained by overlaying several orbits of data together. An approximate ratio between Uhuru counts and the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/256628a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    X-ray outburst from the direction of the galactic centre (1975)
    [s.l.] : Nature Publishing Group
    Nature 257 (1975), S. 291-293 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Figure 1 shows the intensity variation of the new source. Observations were made primarily in the photon energy range 3.0 to 7.5 keV although some data were obtained in the range 4.6-12 keV. Each plotted point represents observations spread over a period of one orbit (101 min). The RMC experiment ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/257291a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Techniques for the analysis of data from coded-mask X-ray telescopes (1987)
    Springer
    Astrophysics and space science 136 (1987), S. 337-349 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Several techniques useful in the analysis of data from coded-mask telescopes are presented. Methods of handling changes in the instrument pointing direction are reviewed and ways of using FFT techniques to do the deconvolution considered. Emphasis is on techniques for optimally-coded systems, but it is shown that the range of systems included in this class can be extended through the new concept of ‘partial cycle averaging’.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00642125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Lasco Observations of Disconnected Magnetic Structures Out to Beyond 28 Solar Radii During Coronal Mass Ejections (1997)
    Springer
    Solar physics 175 (1997), S. 685-698 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Two coronal mass ejections have been well observed by the LASCO coronagraphs to move out into the interplanetary medium as disconnected plasmoids. The first, on July 28, 1996, left the Sun above the west limb around 18:00 UT. As it moved out, a bright V-shaped structure was visible in the C2 coronagraph which moved into the field-of-view of C3 and could be observed out to beyond 28 solar radii. The derived average velocity in the plane of the sky was 110 ± 5 km s-1 out to 5 solar radii, and above 15 solar radii the velocity was 269 ± 10 km s-1. Thus there is evidence of some acceleration around 6 solar radii. The second event occurred on November 5, 1996 and left the west limb around 04:00 UT. The event had an average velocity in the plane of the sky of ∼54 km s-1 below 4 R⊙, and it accelerated rapidly around 5 R⊙ up to 310 ± 10 km s-1. In both events the rising plasmoid is connected back to the Sun by a straight, bright ray, which is probably a signature of a neutral sheet. In the November event there is evidence for multiple plasmoid ejections. The acceleration of the plasmoids around a projected altitude of 5 solar radii is probably a manifestation of the source surface of the solar wind.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004994214697
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Mhd Interpretation of LASCO Observations of a Coronal Mass Ejection as a Disconnected Magnetic Structure (1997)
    Springer
    Solar physics 175 (1997), S. 719-735 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present a qualitative and quantitative comparison of a single coronal mass ejection (CME) as observed by LASCO (July 28–29, 1996) with the results of a three-dimensional axisymmetric time-dependent magnetohydrodynamic model of a flux rope interacting with a helmet streamer. The particular CME considered was selected based on the appearance of a distinct ‘tear-drop’ shape visible in animations generated from both the data and the model. The CME event begins with the brightening of a pre-existing coronal streamer which evolves into a ‘tear-drop’ shaped loop followed by a Y-shaped structure. The brightening moves slowly outward with significant acceleration reaching velocities of ∼450 km s-1 at 30 R⊙. The observed CME characteristics are compared with the model results. On the basis of this comparison, we suggested that the observed features were caused by the evacuation of a flux rope in the closed field region of the helmet streamer (i.e., helmet dome). The flux rope manifests itself as the cavity of the quasi-static helmet streamer and the whole system becomes unstable when the flux rope reaches a threshold strength. The observed ‘tear-drop’ structure is due to the deformed flux rope. The leading edge of the flux rope interacts with the helmet dome to form the typical loop-like CME. The trailing edge of this flux rope interacts with the local bi-polar field to form the observed Y-shaped structure. The model results for the evolution of the magnetic-field configurations, velocity, and polarization brightness are directly compared with observations. Animations have been generated from both the actual data and the model to illustrate the good agreement between the observation and the model. These animations can be found on the CD-ROM which accompanies this volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004923016322
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    First View of the Extended Green-Line Emission Corona At Solar Activity Minimum Using the Lasco-C1 Coronagraph on Soho (1997)
    Springer
    Solar physics 175 (1997), S. 667-684 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The newly developed C1 coronagraph as part of the Large-Angle Spectroscopic Coronagraph (LASCO) on board the SOHO spacecraft has been operating since January 29, 1996. We present observations obtained in the first three months of operation. The green-line emission corona can be made visible throughout the instrument's full field of view, i.e., from 1.1 R⊙ out to 3.2 R⊙ (measured from Sun center). Quantitative evaluations based on calibrations cannot yet be performed, but some basic signatures show up even now: (1) There are often bright and apparently closed loop systems centered at latitudes of 30° to 45° in both hemispheres. Their helmet-like extensions are bent towards the equatorial plane. Farther out, they merge into one large equatorial ‘streamer sheet’ clearly discernible out to 32 R⊙. (2) At mid latitudes a more diffuse pattern is usually visible, well separated from the high-latitude loops and with very pronounced variability. (3) All high-latitude structures remain stable on time scales of several days, and no signature of transient disruption of high-latitude streamers was observed in these early data. (4) Within the first 4 months of observation, only one single ‘fast’ feature was observed moving outward at a speed of 70 km s-1 close to the equator. Faster events may have escaped attention because of data gaps. (5) The centers of high-latitude loops are usually found at the positions of magnetic neutral lines in photospheric magnetograms. The large-scale streamer structure follows the magnetic pattern fairly precisely. Based on our observations we conclude that the shape and stability of the heliospheric current sheet at solar activity minimum are probably due to high-latitude streamers rather than to the near-equatorial activity belt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004948913883
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    A search for neutrons of solar origin using balloon borne detectors 1967–69 (1972)
    Springer
    Solar physics 24 (1972), S. 483-497 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A series of telescopes having approximately a 30° half opening angle and responding to neutrons in the energy range 50 MeV to 350 MeV has been flown to the top of the atmosphere on balloons released from an equatorial launching site at Kampala, Uganda, between 1967 and 1969. The aim of the experiment was to attempt to detect solar neutrons during periods of enhanced solar activity. No neutrons of solar origin were detected, but an upper limit of the order of 30 neutrons m−2 s−1 at the Earth has been placed on the continuous solar neutron flux in the above energy range, and a limit of four photons m−2 s−1 has also been placed on the corresponding γ-ray flux above 80 MeV. Limits have likewise been placed on the total emission from various flares. For a 1B flare the values were 23 × 104 neutrons m−2 and 6 × 104 photons m−2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00153390
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The Large Angle Spectroscopic Coronagraph (LASCO) (1995)
    Springer
    Solar physics 162 (1995), S. 357-402 
    Details
    ISSN: 1573-093X
    Keywords: Sun ; Corona ; Coronagraph
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The Large Angle Spectroscopic Coronagraph (LASCO) is a three coronagraph package which has been jointly developed for the Solar and Heliospheric Observatory (SOHO) mission by the Naval Research Laboratory (USA), the Laboratoire d'Astronomie Spatiale (France), the Max-Planck-Institut für Aeronomie (Germany), and the University of Birmingham (UK). LASCO comprises three coronagraphs, C1, C2, and C3, that together image the solar corona from 1.1 to 30 R⊙ (C1: 1.1 – 3 R⊙, C2: 1.5 – 6 R⊙, and C3: 3.7 – 30 R⊙). The C1 coronagraph is a newly developed mirror version of the classic internally-occulted Lyot coronagraph, while the C2 and C3 coronagraphs are externally occulted instruments. High-resolution imaging spectroscopy of the corona from 1.1 to 3 R⊙ can be performed with the Fabry-Perot interferometer in C1. High-volume memories and a high-speed microprocessor enable extensive on-board image processing. Image compression by a factor of about 10 will result in the transmission of 10 full images per hour.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00733434
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The distribution of iron in the Perseus cluster (1990)
    [s.l.] : Nature Publishing Group
    Nature 347 (1990), S. 450-452 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The coarse component of the dual X-ray telescope on Spacelab 2 (ref. 1) used coded-mask imaging2 to achieve angular resolution of 12' over a 6° field together with proportional-counter energy resolution covering the 2-32 keVband, recording ~7 x 105 photons from the Perseus cluster during an ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/347450a0
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...