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The primordial binary population. I. A near-infrared adaptive optics search for close visual companions to A star members of Scorpius OB2
Kaper, L.; Brown, A. G. A.; Zinnecker, H. +2 more
We present the results of a near-infrared adaptive optics survey with the aim to detect close companions to Hipparcos members in the three subgroups of the nearby OB association Sco OB2: Upper Scorpius (US), Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC). We have targeted 199 A-type and late B-type stars in the KS band, and …
Molecular gas in NUclei of GAlaxies (NUGA). IV. Gravitational torques and AGN feeding
Hunt, L. K.; Schinnerer, E.; Combes, F. +2 more
We discuss the efficiency of stellar gravity torques as a mechanism to account for the feeding of the central engines of four low luminosity Active Galactic Nuclei (AGN): NGC 4321 (HII nucleus/LINER), NGC 4826 (HII nucleus/LINER), NGC 4579 (LINER 1.9/Seyfert 1.9) and NGC 6951 (Seyfert 2). These galaxies have been observed as part of the NUclei of …
Properties of Lyα emitters around the radio galaxy MRC 0316 257,
Pentericci, L.; Röttgering, H. J. A.; Miley, G. K. +9 more
Observations of the radio galaxy MRC 0316 257 at z = 3.13 and the surrounding field are presented. Using narrow- and broad-band imaging obtained with the VLT, 77 candidate Lyα emitters with a rest-frame equivalent width of >15 Å were selected in a ∼ 7´ × 7´ field around the radio galaxy. Spectroscopy of 40 candidate emitters resulted in the dis…
Sub-arcsec imaging of the AB Aur molecular disk and envelope at millimeter wavelengths: a non Keplerian disk
Guilloteau, S.; Dutrey, A.; Piétu, V.
We present sub-arcsecond images of AB Auriga obtained with the IRAM Plateau de Bure interferometer in the isotopologues of CO, and in continuum at 3 and 1.3 mm. These observations allow us to trace the structure of the circumstellar material of
Interplanetary flux rope ejected from an X-ray bright point. The smallest magnetic cloud source-region ever observed
Mandrini, C. H.; van Driel-Gesztelyi, L.; Démoulin, P. +5 more
Using multi-instrument and multi-wavelength observations (SOHO/MDI and EIT, TRACE and Yohkoh/SXT), as well as computing the coronal magnetic field of a tiny bipole combined with modelling of Wind in situ data, we provide evidences for the smallest event ever observed which links a sigmoid eruption to an interplanetary magnetic cloud (MC). The tiny…
Direction of the interstellar H atom inflow in the heliosphere: Role of the interstellar magnetic field
Izmodenov, V.; Alexashov, D.; Myasnikov, A.
Recently Lallement et al. (2005, Science, 307, 1447) reported that the direction of the flow of interstellar neutral hydrogen in the heliosphere is deflected by ~4° from the direction of the pristine local interstellar gas flow. The most probable physical phenomenon responsible for such a deviation is the interstellar magnetic field inclined to th…
Abundance trends in kinematical groups of the Milky Way's disk
Soubiran, C.; Girard, P.
We have compiled a large catalogue of metallicities and abundance ratios from the literature in order to investigate abundance trends of several alpha and iron peak elements in the thin disk and the thick disk of the Galaxy. The catalogue includes 743 stars with abundances of Fe, O, Mg, Ca, Ti, Si, Na, Ni and Al in the metallicity range -1.30 <…
Discovery of 10 µm silicate emission in quasars. Evidence of the AGN unification scheme
Siebenmorgen, R.; Schulz, B.; Haas, M. +1 more
According to the unified scheme, AGN are surrounded by a dust-torus, and the observed diversity of AGN properties results from the different orientations relative to our line of sight. The strong resonance of silicate dust at 10 µm is therefore, as expected, seen in absorption towards many type-2 AGN. In type-1 AGN, it should be seen in emis…
VLT spectroscopy of globular cluster systems. II. Spectroscopic ages, metallicities, and [ α/Fe] ratios of globular clusters in early-type galaxies
Saglia, R. P.; Thomas, D.; Bender, R. +5 more
An analysis of ages, metallicities, and [ α/Fe] ratios of globular cluster systems in early-type galaxies is presented, based on Lick index measurements summarized in Puzia et al. (2004, A&A, 415, 123, Paper I of this series). In the light of calibration and measurement uncertainties, age-metallicity degeneracy, and the relative dynamic range …
The CME-flare relationship: Are there really two types of CMEs?
Vršnak, B.; Sudar, D.; Ruždjak, D.
We present a statistical analysis of 545 flare-associated CMEs and 104 non-flare CMEs observed in the heliocentric distance range 2-30 solar radii. We found that both data sets show quite similar characteristics, contradicting the concept of two distinct (flare/non-flare) types of CMEs. In both samples there is a significant fraction of CMEs showi…