Search Publications
High-frequency slowly drifting structures and X-ray sources observed by RHESSI
Krucker, S.; Karlický, M.; Fárník, F.
Three solar flares (April 4, 2002, May 17, 2002, and August 30, 2002) with the 0.4-2.0 GHz slowly drifting structures were selected and analyzed together with RHESSI X-ray observations. Two events (April 4, 2002 and May 17, 2002) were observed above and one event (August 30, 2002) close to the solar limb. While in April 4, 2002 and August 30, 2002…
Network boundary origins of fast solar wind seen in the low transition region?
Doyle, J. G.; Xia, L. D.; Popescu, M. D.
We present a study of a high spatial resolution raster acquired on-disk with the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) grating spectrograph on SoHO (the Solar and Heliospheric Observatory) in a polar Coronal Hole (CH) region. We analyse two EUV emission lines, representing the properties of solar plasma in the low transition …
The Sun as an X-ray star: Active region evolution, rotational modulation, and implications for stellar X-ray variability
Orlando, S.; Peres, G.; Reale, F.
We study the contribution of an active region and its core to the luminosity and the spectrum of the Sun in the X-ray band and to the relevant solar emission measure vs. temperature distribution, EM(T). We also study the relevant changes in the course of four solar rotations, and the solar rotational modulation due to this active region, the only …
Variability of the EUV quiet Sun emission and reference spectrum using SUMER
Kretzschmar, M.; Lilensten, J.; Aboudarham, J.
This paper aims to build a quiet Sun EUV reference spectrum from the SOHO - SUMER database. We make use of 750 quiet Sun spectra spread over a large range of solar activity. They are carefully calibrated both in terms of frequency and intensity. The data do not show any noticeable variations versus the solar activity. This allows us to build a qui…
ISO deep far-infrared survey in the ``Lockman Hole''. III. Catalogs and source counts at 90 & 170 µm
Sanders, D. B.; Kawara, K.; Taniguchi, Y. +7 more
We present the catalogs and source counts for the C90 (reference wavelength of 90 µm) and C160 (170 µm) bands, which were extracted from our analysis of an ISO deep far-infrared survey conducted as part of the Japan/UH ISO cosmology project. The total survey area is ∼0.9 deg2 in two fields within the Lo…
Radio observations of HD 93129A: The earliest O star with the highest mass loss?
Benaglia, P.; Koribalski, B.
We present the results of radio continuum observations towards the open cluster Tr 14, where our main targets are the early-type O stars HD 93129A/B and HD 93128. The observations were carried out at 3 cm (8.64 GHz) and 6 cm (4.80 GHz) with the Australia Telescope Compact Array. Only HD 93129A (type O2 If*) was detected; we measure flux densities …
X-ray emitting class I protostars in the Serpens dark cloud
Preibisch, T.
We analyze a set of three individual XMM-Newton X-ray observation of the Serpens dark cloud. In addition to the 45 sources already reported in the analysis of the first of these XMM-Newton observations by Preibisch (\cite{Preibisch2003), the complete combined data set leads to the detection of X-ray emission from four of the 19 known class I proto…
Complexity of magnetic structures: Flares and cycle phase dependence
Meunier, N.
A long data set of MDI/SOHO full-disk magnetograms is analyzed to provide a large sample of active regions. The objective is to study the variations of the fractal dimension of these structures on different time scales: in relation to their activity level (spots, flares) and during the solar cycle. First, the variations of the fractal dimension of…
Photospheric and stellar wind variability in ɛ Ori (B0 Ia)
Stahl, O.; Rivinius, Th.; Orlando, S. +4 more
We provide direct observational evidence for a link between photospheric activity and perturbations in the dense inner-most stellar wind regions of the B supergiant star ɛ Ori. The results, which are relevant to our understanding of the origin of wind structure, are based on a multi-spectral line analysis of optical time-series data secured in 199…
Solar type II and type IV radio bursts observed during 1998-2000 with the ARTEMIS-IV radiospectrograph
Hillaris, A.; Preka-Papadema, P.; Moussas, X. +9 more
A catalogue of the type II and type IV solar radio bursts in the 110-687 MHz range, observed with the radio spectrograph ARTEMIS-IV operated by the University of Athens at Thermopylae, Greece from 1998-2000 is presented. These observations are compared with the LASCO archives of Coronal Mass Ejections and the Solar Geophysical Reports of solar fla…