The emission line near 1319 A in solar and stellar spectra

An emission line near 1319 A is one of the strongest unidentified lines in the ultraviolet spectra of cool dwarf stars. In most line lists it is identified as a transition in N I, although its intensity would then be anomalous and the observed wavelength does not fit precisely that expected for N I. The line is also observed in cool giant stars. The measured wavelength of the line in stellar spectra is 1318.94 (+,- 0.01) A. Observations of giant stars provide further evidence that this line is not due to N I. It is proposed that this line is a decay from a previously unknown level in S I, which lies above the first ionization limit. This is identified with the 3d singlet D (odd parity) term. The previous tentative assignment of this term to the S I line at 1309.3 A then needs to be revised. The 1309.3 A line has been identified here for the first time in an astrophysical source. The singlet D (odd parity) level could, in principle, be populated by collisions from nearby autoionizing levels that have large number-densities, through population by di-electronic capture. Spin-orbit interaction with the autoionizing triplet D (odd parity) term might also lead to di-electronic capture into the singlet D (odd parity) level. A line at 1309.87 A observed in cool giant stars is identified as a transition in P II, pumped by the O I resonance lines.Comment: 9 pages, 3 figures, to be published in Monthly Notices of the Royal Astronomical Societ

Das Lößprofil von Ahlshausen und weitere tiefe Quartäraufschlüsse entlang der Bundesbahn-Neubaustrecke bei Northeim, Südniedersachsen

In der Subrosionssenke von Ahlshausen wurde eine 25 m mächtige Lößlehm-Fließerde-Folge mit bis zu 9 Parabraunerden (fBt- und Bleichhorizonte) untersucht. Unter dem 3. fBt fanden sich Reste eines Glaziärvorkommens, das eine elsterzeitliche Inlandvereisung belegt. Ein mächtiger Beckenschluff bis -ton im Liegenden der Lößfolge gehört vermutlich bereits in die Matuyama-Periode. In den Bahnprofilen und in Bohrungen der begleitenden Geologischen Kartierung wurden Kiesvorkommen mehrerer prä-holsteinzeitlicher Rhumeläufe nachgewiesen. Ihre Verstellung um viele Zehnermeter wird auf Hebung des Ahlshausener Gewölbes (über einem Zechstein-Salzkissen) zurückgeführt, unterbrochen durch lokale subrosive Absenkung.researc

Concert recording 2013-04-27b

[Track 01]. Fantasia di concerto / Eduardo Boccalari -- [Track 02]. Apres un reve / Gabriel Faure -- [Track 03]. Arabesque / Joseph Turrin -- [Track 04]. Gabriel\u27s oboe / Ennio Morricone ; arranged by David Werden -- [Track 05]. Believe me if all those endearing young charms / Simone Mantia ; arranged by David Werden -- [Track 06]. St. James Infirmary / Joe Primrose ; arranged by Mike Forbes

Lebenslanges „Lernen, Lehren und Forschen” mit brauchwiki.de! Der interdisziplinäre Einsatz einer Web 2.0-Anwendung in einem geisteswissenschaftlichen Kooperationsprojekt an der Universität Augsburg

An Terminen wie Weihnachten, Halloween oder Ostern wird in den Medien oftmals die Frage nach der Bedeutung und dem Ursprung von bestimmten Bräuchen aufgeworfen. Hat Halloween beispielsweise etwas mit den Kelten zu tun oder wurde der Brauch aus dem anglo-amerikanischen Kulturfeld nach Deutschland importiert?1 Eine wissenschaftlich fundierte Antwort darüber zu liefern, ist oftmals schwieriger als es auf den ersten Blick erscheint. Der hohe Innovationscharakter von Bräuchen und Festen, die gesamtgesellschaftlichen Wandlungsprozessen unterliegen, macht eine verbindliche und damit starre Definition zu bestimmten Brauchelementen und einer Gesamtdeutung schwierig oder fast unmöglich (Döring 2007, S. 26). Die Antwort auf die Frage, wie Bräuche aktuell ausgeübt und vollzogen werden, bedarf also einer reflektierten Materialbasis, die zeitnah und beständig und vor allem mit neuesten Erkenntnissen zur Verfügung steht. Klassische Lexika und Einzeldarstellungen in Monographien können diesen Bedarf in der Regel nicht abdecken. Durch die Zeitspanne zwischen dem Schreiben und dem Erscheinen von Texten können Innovationsprozesse nur bedingt erfasst werden (Mezger 2008, S. 184f.). (...

SUMER: Solar Ultraviolet Measurements of Emitted Radiation

The SUMER (solar ultraviolet measurements of emitted radiation) experiment is described. It will study flows, turbulent motions, waves, temperatures and densities of the plasma in the upper atmosphere of the Sun. Structures and events associated with solar magnetic activity will be observed on various spatial and temporal scales. This will contribute to the understanding of coronal heating processes and the solar wind expansion. The instrument will take images of the Sun in EUV (extreme ultra violet) light with high resolution in space, wavelength and time. The spatial resolution and spectral resolving power of the instrument are described. Spectral shifts can be determined with subpixel accuracy. The wavelength range extends from 500 to 1600 angstroms. The integration time can be as short as one second. Line profiles, shifts and broadenings are studied. Ratios of temperature and density sensitive EUV emission lines are established

Enhancement of the helium resonance lines in the solar atmosphere by suprathermal electron excitation II: non-Maxwellian electron distributions

In solar EUV spectra the He I and He II resonance lines show unusual behaviour and have anomalously high intensities compared with other transition region lines. The formation of the helium resonance lines is investigated through extensive non-LTE radiative transfer calculations. The model atmospheres of Vernazza, Avrett & Loeser are found to provide reasonable matches to the helium resonance line intensities but significantly over-estimate the intensities of other transition region lines. New model atmospheres have been developed from emission measure distributions derived by Macpherson & Jordan, which are consistent with SOHO observations of transition region lines other than those of helium. These models fail to reproduce the observed helium resonance line intensities by significant factors. The possibility that non-Maxwellian electron distributions in the transition region might lead to increased collisional excitation rates in the helium lines is studied. Collisional excitation and ionization rates are re-computed for distribution functions with power law suprathermal tails which may form by the transport of fast electrons from high temperature regions. Enhancements of the helium resonance line intensities are found, but many of the predictions of the models regarding line ratios are inconsistent with observations. These results suggest that any such departures from Maxwellian electron distributions are not responsible for the helium resonance line intensities.Comment: 23 pages, 11 figures, accepted to appear in MNRAS, LaTeX uses mn.st

Concert recording 2013-04-25a

[Track 01]. English madrigal suite. Late in my rash accounting ; [Track 02]. Rest, sweet nymphs ; [Track 03]. My bonny lass / Weelkes ; Pilkington ; Morley ; arranged by Michael Forbes -- [Track 04]. Auburn is the colour... / Michael Forbes -- [Track 05]. Royal garden blues / traditional ; arranged by Michael Forbes -- [Track 06]. Tuba juba duba / Terry Hutchinson -- [Track 07]. Allegro / Roger Jones -- [Track 08]. Now hear this! / Ray Dempsey -- [Track 09]. Pari intervallo / Arvo Part -- [Track 10]. To a wild rose / Edward MacDowell ; arranged by Lockhart -- [Track 11]. Kierkegaard / Meyer Kupferman -- [Track 12]. Bill Bailey / Hughie Cannon ; arranged by James Garrett

Charge fluctuations in open chaotic cavities

We present a discussion of the charge response and the charge fluctuations of mesoscopic chaotic cavities in terms of a generalized Wigner-Smith matrix. The Wigner-Smith matrix is well known in investigations of time-delay of quantum scattering. It is expressed in terms of the scattering matrix and its derivatives with energy. We consider a similar matrix but instead of an energy derivative we investigate the derivative with regard to the electric potential. The resulting matrix is then the operator of charge. If this charge operator is combined with a self-consistent treatment of Coulomb interaction, the charge operator determines the capacitance of the system, the non-dissipative ac-linear response, the RC-time with a novel charge relaxation resistance, and in the presence of transport a resistance that governs the displacement currents induced into a nearby conductor. In particular these capacitances and resistances determine the relaxation rate and dephasing rate of a nearby qubit (a double quantum dot). We discuss the role of screening of mesoscopic chaotic detectors. Coulomb interaction effects in quantum pumping and in photon assisted electron-hole shot noise are treated similarly. For the latter we present novel results for chaotic cavities with non-ideal leads.Comment: 29 pages, 13 figures;v.2--minor changes; contribution for the special issue of J. Phys. A on "Trends in Quantum Chaotic Scattering

HST/STIS High Resolution Echelle Spectra of alpha Centauri A (G2 V)

We describe and analyze HST/STIS observations of the G2 V star alpha Centauri A (alpha Cen A, HD 128620), a star similar to the Sun. The high resolution echelle spectra obtained with the E140H and E230H gratings cover the complete spectral range 1133-3150 Angstrom with a resolution of 2.6 km/s, an absolute flux calibration accurate to +/-5%, and an absolute wavelength accuracy of 0.6-1.3 km/s. We present here a study of the E140H spectrum covering the 1140-1670 Angstrom spectral range, which includes 671 emission lines representing 37 different ions and the molecules CO and H_2. For alpha Cen A and the quiet and active Sun, we intercompare the redshifts, nonthermal line widths, and parameters of two Gaussian representations of transition region lines (e.g., Si IV, C IV), infer the electron density from the O IV intersystem lines, and compare their differential emission measure distributions. One purpose of this study is to compare the alpha Cen A and solar UV spectra to determine how the atmosphere and heating processes in alpha Cen A differ from the Sun as a result of the small differences in gravity, age, and chemical composition of the two stars. A second purpose is to provide an excellent high resolution UV spectrum of a solar-like star that can serve as a proxy for the Sun observed as a point source when comparing other stars to the Sun.Comment: A&A in pres

Response of the solar atmosphere to magnetic field evolution in a coronal hole region

Methods. We study an equatorial CH observed simultaneously by HINODE and STEREO on July 27, 2007. The HINODE/SP maps are adopted to derive the physical parameters of the photosphere and to research the magnetic field evolution and distribution. The G band and Ca II H images with high tempo-spatial resolution from HINODE/BFI and the multi-wavelength data from STEREO/EUVI are utilized to study the corresponding atmospheric response of different overlying layers. Results. We explore an emerging dipole locating at the CH boundary. Mini-scale arch filaments (AFs) accompanying the emerging dipole were observed with the Ca II H line. During the separation of the dipolar footpoints, three AFs appeared and expanded in turn. The first AF divided into two segments in its late stage, while the second and third AFs erupted in their late stages. The lifetimes of these three AFs are 4, 6, 10 minutes, and the two intervals between the three divisions or eruptions are 18 and 12 minutes, respectively. We display an example of mixed-polarity flux emergence of IN fields within the CH and present the corresponding chromospheric response. With the increase of the integrated magnetic flux, the brightness of the Ca II H images exhibits an increasing trend. We also study magnetic flux cancellations of NT fields locating at the CH boundary and present the obvious chromospheric and coronal response. We notice that the brighter regions seen in the 171 A images are relevant to the interacting magnetic elements. By examining the magnetic NT and IN elements and the response of different atmospheric layers, we obtain good positive linear correlations between the NT magnetic flux densities and the brightness of both G band (correlation coefficient 0.85) and Ca II H (correlation coefficient 0.58).Comment: 9 pages, 9 figures. A&A, in pres