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The basic characteristics of EUV post-eruptive arcades and their role as tracers of coronal mass ejection source regions
Bothmer, V.; Tripathi, D.; Cremades, H.
The Extreme ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO) spacecraft provides unique observations of dynamic processes in the low corona. The EIT 195 Å data taken from 1997 to the end of 2002 were investigated to study the basic physical properties of post-eruptive arcades (PEAs) and their relationship …
Metallicity in the Galactic Center: The Arches Cluster
Hillier, D. John; Figer, Donald F.; Kudritzki, Rolf P. +1 more
We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties, and, most importantly, metallicity content. The analysis uses a new technique, presented here for the first time, and uses line-blanketed non-LTE wind/atmosphere m…
Average Ultraviolet Quasar Spectra in the Context of Eigenvector 1: A Baldwin Effect Governed by the Eddington Ratio?
Marziani, P.; Zamanov, R.; Bachev, R. +3 more
We present composite UV spectra for low-redshift type 1 active galactic nuclei binned to exploit the information content of the eigenvector 1 (E1) parameter space. Composite spectra show high enough S/N and spectral resolution to permit a decomposition of the C IV λ1549 line profile: one of the strongest high-ionization lines (HILs), and fundament…
The Coronal Heating Mechanism as Identified by Full-Sun Visualizations
Aschwanden, Markus J.; Schrijver, Carolus J.; De Rosa, Marc L. +1 more
We constrain the properties of the mechanism(s) responsible for the bulk of the heating of the corona of the Sun by simulating, for the first time, the appearance of the entire solar corona. Starting from full-sphere magnetic field maps for 2000 December 1 and 8, when the Sun was moderately active, we populate nearly 50,000 coronal field lines wit…
Observations of the helium focusing cone with pickup ions
Geiss, J.; Möbius, E.; Noda, H. +12 more
The helium gravitational focusing cone has been observed using pickup He+, first during the solar minimum in 1984-1985 with the AMPTE/IRM spacecraft, and again in more detail from 1998 to 2002 with ACE and in 2000 with Nozomi. Five traversals of the cone allow us to obtain an accurate determination of the ecliptic longitude of the inter…
Deep Hubble Space Telescope ACS Observations of I Zw 18: a Young Galaxy in Formation
Thuan, Trinh X.; Izotov, Yuri I.
We present V and I photometry of the resolved stars in the most metal-deficient blue compact dwarf galaxy known, I Zw 18 (Zsolar/50), using Hubble Space Telescope/ACS images, the deepest ones ever obtained for this galaxy. The resulting I versus V-I color-magnitude diagram (CMD) reaches limiting magnitudes V=I=29 mag. It reveals a young…
Exploring the X-ray sky with the XMM-Newton bright serendipitous survey
Page, M. J.; Barcons, X.; Carrera, F. J. +11 more
We present here ``The XMM-Newton Bright Serendipitous Survey'', composed of two flux-limited samples: the XMM-Newton Bright Source Sample (BSS, hereafter) and the XMM-Newton ``Hard'' Bright Source Sample (HBSS, hereafter) having a flux limit of f_x≃ 7 × 10-14 erg cm-2 s-1 in the 0.5-4.5 keV and 4.5-7.5 keV energy b…
Contribution of the disk emission to the broad emission lines in AGNs: Two-component model
Bon, E.; Popović, L. Č.; Ilić, D. +1 more
We present an investigation of the structure of the emission line region in a sample of 12 single-peaked Active Galactic Nuclei (AGNs). Using the high resolution Hβ and Hα line profiles observed with the Isaac Newton Telescope (La Palma) we study the substructure in the lines (such as shoulders or bumps) which can indicate a disk or disk-like emis…
On the sizes of stellar X-ray coronae
Schmitt, J. H. M. M.; Audard, M.; Güdel, M. +2 more
Spatial information from stellar X-ray coronae cannot be assessed directly, but scaling laws from the solar corona make it possible to estimate sizes of stellar coronae from the physical parameters temperature and density. While coronal plasma temperatures have long been available, we concentrate on the newly available density measurements from li…
Systematic analysis of equatorial noise below the lower hybrid frequency
Santolík, O.; Cornilleau-Wehrlin, N.; Macúšová, E. +3 more
Available from http://www.copernicus.org/site/EGU/annales/22/7/2587.htm?FrameEngine=false;