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Institution

European Southern Observatory

FacilityGarching bei München, Germany
About: European Southern Observatory is a facility organization based out in Garching bei München, Germany. It is known for research contribution in the topics: Galaxy & Stars. The organization has 3594 authors who have published 16157 publications receiving 823095 citations. The organization is also known as: The European Southern Observatory,ESO & ESO.
Topics: Galaxy, Stars, Star formation, Redshift, Population


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors presented L'- and J-band high contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively.
Abstract: We present L'- and J-band high-contrast observations of HD 169142, obtained with the Very Large Telescope/NACO AGPM vector vortex coronagraph and the Gemini Planet Imager, respectively. A source located at 0."156 ± 0.''032 north of the host star (P.A. = 7°.4 ± 11°.3) appears in the final reduced L' image. At the distance of the star (~145 pc), this angular separation corresponds to a physical separation of 22.7 ± 4.7 AU, locating the source within the recently resolved inner cavity of the transition disk. The source has a brightness of L' = 12.2 ± 0.5 mag, whereas it is not detected in the J band (J >13.8 mag). If its L' brightness arose solely from the photosphere of a companion and given the J – L' color constraints, it would correspond to a 28-32 M Jupiter object at the age of the star, according to the COND models. Ongoing accretion activity of the star suggests, however, that gas is left in the inner disk cavity from which the companion could also be accreting. In this case, the object could be lower in mass and its luminosity enhanced by the accretion process and by a circumplanetary disk. A lower-mass object is more consistent with the observed cavity width. Finally, the observations enable us to place an upper limit on the L'-band flux of a second companion candidate orbiting in the disk annular gap at ~50 AU, as suggested by millimeter observations. If the second companion is also confirmed, HD 169142 might be forming a planetary system, with at least two companions opening gaps and possibly interacting with each other.

189 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented multi-passband optical data obtained from observations of the Chandra Deep Field South (CDF-S), located at 3 h 32 m, 2748 0.
Abstract: This paper presents multi-passband optical data obtained from observations of the Chandra Deep Field South (CDF-S), located at 3 h 32 m , 2748 0 . The observations were conducted at the ESO/MPG 2.2 m telescope at La Silla using the 8k 8k Wide-Field Imager (WFI). This data set, taken over a period of one year, represents the rst eld to be completed by the ongoing Deep Public Survey (DPS) being carried out as a part of the ESO Imaging Survey (EIS) project. This paper describes the optical observations, the techniques employed for un-supervised pipeline processing and the general characteristics of the nal data set. Image processing has been performed using multi-resolution image decomposition techniques adapted to the EIS pipeline. The automatic processing steps include standard de-bias and flat-eld, automatic removal of satellite tracks, de-fringing/sky-subtraction, image stacking/mosaicking and astrometry. Stacking of dithered images is carried out using pixel-based astrometry which enables the ecient removal of cosmic rays and image defects, yielding remarkably clean nal images. The nal astrometric calibration is based on a pre-release of the GSC-II catalog and has an estimated intrinsic accuracy of <0.10 arcsec, with all passbands sharing the same solution. The paper includes data taken in six dierent lters (U 0 UBVRI). The data cover an area of about 0.25 square degrees reaching 5 limiting magnitudes of U 0 AB =2 6:0, UAB =2 5:7, BAB =2 6:4, VAB =2 5:4;RAB =2 5: 5a nd IAB = 24.7 mag, as measured within a 2FWHM aperture. The optical data covers an area of 0.1 square degrees for which moderately deep observations in two near-infrared bands are also available, reaching 5 limiting magnitudes of JAB 23: 4a ndKAB 22:6. The current optical/infrared data also fully encompass the region of the deep X-ray observations recently completed by the Chandra telescope. The optical data presented here, as well as the infrared data released earlier, are publicly available world-wide in the form of fully calibrated pixel and associated weight maps and source lists extracted in each passband. These data can be requested through the URL \http://www.eso.org/eis".

189 citations

Journal ArticleDOI
TL;DR: In this paper, the authors found that the solar lithium abundance normal for a star of its age, mass, and metallicity, and that the presence of giant planets is not related to low lithium abundances.
Abstract: We have determined precise stellar parameters and lithium abundances in a sample of 117 stars with basic properties very similar to the Sun. This sample selection reduces biasing effects and systematic errors in the analysis. We estimate the ages of our sample stars mainly from isochrone fitting but also from measurements of rotation period and X-ray luminosity and test the connection between lithium abundance, age, and stellar parameters. We find strong evidence for increasing lithium depletion with age. Our sample includes 14 stars that are known to host planets and it does not support recent claims that planet-host stars have experienced more lithium depletion than stars without planets. We find the solar lithium abundance normal for a star of its age, mass, and metallicity. Furthermore, we analyze published data for 82 stars that were reported to support an enhanced lithium depletion in planet hosts. We show that those stars in fact follow an age trend very similar to that found with our sample and that the presence of giant planets is not related to low lithium abundances. Finally, we discuss the systematic biases that led to the incorrect conclusion of an enhanced lithium depletion in planet-host stars.

189 citations

Journal ArticleDOI
TL;DR: The internal dynamics of ultra-compact dwarf galaxies (UCDs) has attracted increasing attention, with most of the UCDs studied to date located in the Virgo cluster as mentioned in this paper.
Abstract: Context. The internal dynamics of ultra-compact dwarf galaxies (UCDs) has attracted increasing attention, with most of the UCDs studied to date located in the Virgo cluster.

188 citations

Journal ArticleDOI
TL;DR: In this article, the authors present new mid-infrared spectroscopy of the emission from warm circumstellar dust grains in Herbig Ae/Be stars and find a correla- tion between the strength of the silicate feature and its shape.
Abstract: We present new mid-infrared spectroscopy of the emission from warm circumstellar dust grains in Herbig Ae/Be stars. Our survey significantly extends the sample that was studied by Bouwman et al. (2001). We find a correla- tion between the strength of the silicate feature and its shape. We interpret this as evidence for the removal of small (0.1m) grains from the disk surface while large (1-2m) grains persist. If the evolution of the grain size distribution is dominated by gravitational settling, large grains are expected to disappear first, on a timescale which is much shorter than the typical age of our programme stars. Our observations thus suggest a continuous replenishment of micron sized grains at the disk surface. If the grain replenishment is due to the dredge-up of dust from the disk interior, the mineralogy we observe is representative of the bulk composition of dust in these stars.

188 citations


Authors

Showing all 3617 results

NameH-indexPapersCitations
Robert C. Nichol187851162994
Richard S. Ellis169882136011
Rob Ivison1661161102314
Alvio Renzini16290895452
Timothy C. Beers156934102581
Krzysztof M. Gorski132380105912
Emanuele Daddi12958163187
P. R. Christensen12731388445
Mark Dickinson12438966770
Christopher W. Stubbs122622109429
Eva K. Grebel11886383915
Martin Asplund11861252527
Jesper Sollerman11872653436
E. F. van Dishoeck11574249190
Jørgen Christensen-Dalsgaard11458548272
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20233
202231
2021557
2020920
2019759
2018941