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
    Electronic Resource
    Electronic Resource
    New window for spectroscopy (1996)
    [s.l.] : Nature Publishing Group
    Nature 382 (1996), S. 588-588 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - We have developed an imaging polarimeter system that can routinely record the Sun's spectrum with a precision of 1(T5 in the degree of polarization. At this level, the whole solar spectrum is linearly polarized, even in the absence of any magnetic fields, due to coherent scattering processes ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/382588a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Resolution of magnetic flux tubes on the Sun (1992)
    [s.l.] : Nature Publishing Group
    Nature 359 (1992), S. 307-308 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] More than 90% of the magnetic flux outside sunspots is concentrated into small flux tubes with field strengths of 1-2 kG (ref. 6). Because these flux tubes have not yet been spatially resolved, our knowledge of their evolution, dynamics and mor-phology is limited. White-light bright points seen in ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/359307a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    X-rays from the Sun (1995)
    Springer
    Cellular and molecular life sciences 51 (1995), S. 710-720 
    Details
    ISSN: 1420-9071
    Keywords: X-rays ; astronomy ; sun ; corona ; solar magnetic fields ; satellites ; detectors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract X-ray astronomy began in 1948 with the first detection of X-rays from the Sun. Astronomical X-ray observations need to be performed from high-altitude rockets and satellites because the Earth's atmosphere absorbs X-rays. Currently about 100,000 X-ray sources are known all over the sky. The Sun is by far the strongest source. The outermost solar atmosphere, the corona, emits X-rays due to its high temperature of a few million K. Solar X-ray emission is highly variable. Eruptions lead to variations of the X-ray flux on time scales of minutes. The average X-ray flux varies with the 11-year sunspot cycle by a factor of about 1000. Solar X-rays have a profound influence on the Earth's upper atmosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01941268
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Imaging coronal emission lines under high sky-background conditions (1996)
    Springer
    Solar physics 166 (1996), S. 311-315 
    Details
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have obtained images in solar coronal emission lines under high sky-background conditions by making precise differential measurements between the coronal emission line and the near-by continuum, which is primarily due to scattered light from the solar disk. Chopping between the two wavelengths was performed at 100 kHz to avoid artifacts from fast-flying dust particles and other aerosols, and also from seeing effects. The differential signal was detected with a novel CCD camera that demodulates signals up to 100 kHz. These preliminary observations show coronal emission at the 0.2% level of the scattered-light background and pave the way to efficient and precise imaging of coronal emission features under less than ideal ‘coronal-sky’ conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00149401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Measurement of the full Stokes vector of He I 10830 Å (1996)
    Springer
    Solar physics 164 (1996), S. 265-275 
    Details
    ISSN: 1573-093X
    Keywords: Chromosphere ; Polarization ; Infrared ; Magnetic Field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract First observations of the full Stokes vector in the upper chromosphere are presented. The He I 10830 Å line, which has been shown to give reliable measurements of the line-of-sight component of the magnetic field vector, has been used for this purpose. It is shown that the difference between the appearance of chromospheric and photospheric magnetic structures observed close to the solar limb is largely due to the difference in height to which they refer and projection effects. The observations do suggest, however, that the magnetic field above sunspot penumbrae is somewhat more vertical in the chromosphere than in the photosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146639
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Recent progress in imaging polarimetry (1996)
    Springer
    Solar physics 164 (1996), S. 243-252 
    Details
    ISSN: 1573-093X
    Keywords: Polarimetry ; Spectroscopy ; Array detectors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Recent instrumental developments in imaging polarimetry allow array detectors to reach a polarimetric sensitivity of 1 × 10−4 of the intensity. New instrumental effects appear at these levels of sensitivity and generate spurious polarization signals with amplitudes of up to 5 × 10−4. Here I discuss these effects and present methods to avoid them. Polarized spectra with an rms noise of 6 × 10−6 may then be obtained. Furthermore a method is brought to the reader's attention that allows polarization measurements at the 1 × 10−4 level with regular array detectors, e.g. in the near-infrared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146637
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Balloon-borne polarimetry (1996)
    Springer
    Solar physics 164 (1996), S. 403-415 
    Details
    ISSN: 1573-093X
    Keywords: Stratospheric balloon ; Antarctica ; Vector polarimetry ; Flares
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract For about two weeks in 1995, the balloon-borne Flare Genesis Experiment will continuously observe the Sun well above the turbulent, image-blurring layers of the Earth's atmosphere. The polarization-free 80 cm telescope will supply images to a liquid-crystal based vector magnetograph, which will measure magnetic features at a resolution of 0.2 arcsec. An electrically tunable lithium-niobate Fabry-Perot provides a spectral resolution of about 0.015 nm. In a follow-up series of Antarctic balloon flights, the Flare Genesis Experiment (FGE) will provide unprecedented details about sunspots, flares, magnetic elements, filaments, and the quiet solar atmosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00146652
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    facet.materialart.
    Unknown
    Balloon-borne polarimetry (1996)
    Springer
    Details
    Publication Date: 1996-03-01
    Print ISSN: 0038-0938
    Electronic ISSN: 1573-093X
    Topics: Physics
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    CS Cha B: A disc-obscured M-type star mimicking a polarised planetary companion (2020)
    EDP Sciences
    Details
    Publication Date: 2020-08-01
    Description: Context. Direct imaging provides a steady flow of newly discovered giant planets and brown dwarf companions. These multi-object systems can provide information about the formation of low-mass companions in wide orbits and/or help us to speculate about possible migration scenarios. Accurate classification of companions is crucial for testing formation pathways. Aims. In this work we further characterise the recently discovered candidate for a planetary-mass companion CS Cha b and determine if it is still accreting. Methods. MUSE is a four-laser-adaptive-optics-assisted medium-resolution integral-field spectrograph in the optical part of the spectrum. We observed the CS Cha system to obtain the first spectrum of CS Cha b. The companion is characterised by modelling both the spectrum from 6300 Å to 9300 Å and the photometry using archival data from the visible to the near-infrared (NIR). Results. We find evidence of accretion and outflow signatures in Hα and OI emission. The atmospheric models with the highest likelihood indicate an effective temperature of 3450 ± 50 K with a log g of 3.6 ± 0.5 dex. Based on evolutionary models, we find that the majority of the object is obscured. We determine the mass of the faint companion with several methods to be between 0.07 M⊙ and 0.71 M⊙ with an accretion rate of Ṁ = 4 × 10−11±0.4 M⊙ yr−1. Conclusions. Our results show that CS Cha B is most likely a mid-M-type star that is obscured by a highly inclined disc, which has led to its previous classification using broadband NIR photometry as a planetary-mass companion. This shows that it is important and necessary to observe over a broad spectral range to constrain the nature of faint companions.
    Print ISSN: 0004-6361
    Electronic ISSN: 1432-0746
    Topics: Physics
    Published by EDP Sciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    X-rays from the Sun (1995)
    Springer
    Details
    Publication Date: 1995-07-01
    Print ISSN: 0014-4754
    Topics: Biology , Medicine
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...