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61.
Aschwanden Markus J. De Pontieu Bart Schrijver Carolus J. Title Alan M. 《Solar physics》2002,206(1):99-132
Solar Physics - We measure geometric and physical parameters oftransverse oscillations in 26 coronal loops, out of the 17 events described in Paper I by Schrijver, Aschwanden, and Title (2002).... 相似文献
62.
Claudia Maraston Markus Kissler-Patig Jean Brodie Pauline Barmby John Huchra 《Astrophysics and Space Science》2002,281(1-2):137-138
A new method to detect and study young star clusters is presented. This is based on the knowledge that the light of stellar
populations with ages between ∼ 200 Myr and ∼ 1/2 Gyr is dominated by very red, bright AGB stars. Star clusters undergoing this so-called ‘AGB phase transition’ are featured by very red V-K colours, like those of Magellanic
Clouds clusters, while optical colours like B-V remain blue typical for young populations. The best channel for detecting
star clusters in this age range is therefore the near IR. From the theoretical side, SSP models including properly the contribution
of the bright AGB are required (Maraston, 1998). Using this strategy, we succesfully detected the AGB phase transition among
the clusters of the merger remnant galaxy NGC 7252 (see Maraston etal., 2001).
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
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Geotechnical and Geological Engineering - This paper proposes a new design method for the axial capacity of driven piles in glacial deposits with the standard penetration test (SPT) based on a... 相似文献
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Compared to other phytoplankton groups, nitrogen-fixing cyanobacteria generally prefer high water temperatures for growth and are therefore expected to benefit from global warming. We use a coupled biological-physical model with an advanced cyanobacteria life cycle model to compare the abundance of cyanobacteria in the Baltic Sea during two different time periods (1969–1998; 2069–2098). For the latter, we find prolonged growth and a more than twofold increase in the climatologically (30 years) averaged cyanobacteria biomass and nitrogen fixation. Additional sensitivity experiments indicate that the biological-physical feedback mechanism through light absorption becomes more important with global warming. In general, we find a nonlinear response of cyanobacteria to changes in the atmospheric forcing fields as a result of life-cycle related feedback mechanisms. Overall, the sensitivity of the cyanobacteria-driven system suggests that biological-physical and life-cycle related feedback mechanisms are important and must therefore be included in future projection studies. 相似文献
70.
Daniel F. Ryan Aidan M. O’Flannagain Markus J. Aschwanden Peter T. Gallagher 《Solar physics》2014,289(7):2547-2563
We test the compatibility and biases of multi-thermal flare DEM (differential emission measure) peak temperatures determined with AIA with those determined by GOES and RHESSI using the isothermal assumption. In a set of 149 M- and X-class flares observed during the first two years of the SDO mission, AIA finds DEM peak temperatures at the time of the peak GOES 1?–?8 Å flux to have an average of T p=12.0±2.9 MK and Gaussian DEM widths of log10(σ T )=0.50±0.13. From GOES observations of the same 149 events, a mean temperature of T p=15.6±2.4 MK is inferred, which is systematically higher by a factor of T GOES/T AIA=1.4±0.4. We demonstrate that this discrepancy results from the isothermal assumption in the inversion of the GOES filter ratio. From isothermal fits to photon spectra at energies of ?≈6?–?12 keV of 61 of these events, RHESSI finds the temperature to be higher still by a factor of T RHESSI/T AIA=1.9±1.0. We find that this is partly a consequence of the isothermal assumption. However, RHESSI is not sensitive to the low-temperature range of the DEM peak, and thus RHESSI samples only the high-temperature tail of the DEM function. This can also contribute to the discrepancy between AIA and RHESSI temperatures. The higher flare temperatures found by GOES and RHESSI imply correspondingly lower emission measures. We conclude that self-consistent flare DEM temperatures and emission measures require simultaneous fitting of EUV (AIA) and soft X-ray (GOES and RHESSI) fluxes. 相似文献