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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 a complete picture of hot stellar systems ranging from faint galaxies and star clusters of only a few hundred solar masses up to giant ellipticals (gEs) with 10 12 M �, in particular including large samples of compact elliptical (cEs), ultra-compact dwarf galaxies (UCDs), dwarf ellipticals(dEs) of nearby galaxy clusters and Local Group ultra-faint dwarf spheroidals (dSphs).
Abstract: Dynamically hot stellar systems, whether star clusters or early-type galaxies, follow well-defined scaling relations over many orders of magnitudes in mass. These fundamental plane relations have been subject of several studies, which have been mostly confined to certain types of galaxies and/or star clusters so far. Here, we present a complete picture of hot stellar systems ranging from faint galaxies and star clusters of only a few hundred solar masses up to giant ellipticals (gEs) with 10 12 M � , in particular including – for the first time – large samples of compact ellipticals (cEs), ultra-compact dwarf galaxies (UCDs), dwarf ellipticals (dEs) of nearby galaxy clusters and Local Group ultra-faint dwarf spheroidals (dSphs). For all those stellar systems we show the effective radius–luminosity, effective radius–stellar mass, and effective mass surface density–stellar mass plane. Two clear families of hot stellar systems can be differentiated: the ’galaxian’ family, ranging from gEs over Es and dEs to dSphs, and the ’star cluster’ family, comprising globular clusters (GCs), UCDs and nuclear star clusters (NCs). Interestingly, massive ellipticals have a similar size–mass relation as cEs, UCDs and NCs, with a clear common boundary towards minimum sizes, which can be approximated by Reff > 2:24 �10 6 �M 4=5

204 citations

Journal ArticleDOI
TL;DR: In this article, the authors detect extended ionised outflows in luminous quasars, where they expect the highest activity both in star formation and in black-hole accretion.
Abstract: Aims. Outflows driven by active galactic nuclei (AGN) are invoked by galaxy evolutionary models to quench star formation and to explain the origin of the relations observed locally between super-massive black holes and their host galaxies. We here aim to detect extended ionised outflows in luminous quasars, where we expect the highest activity both in star formation and in black-hole accretion. Currently, there are only a few studies based on spatially resolved observations of outflows at high redshift, z > 2.Methods. We analysed a sample of six luminous (L > 1047 erg/s) quasars at z ~ 2.4, observed in H -band using the near-IR integral field spectrometer SINFONI at the VLT. We performed a kinematic analysis of the [Oiii] emission line at λ = 5007 A.Results. We detect fast, spatially extended outflows in five out of six targets. [Oiii]λ 5007 has a complex gas kinematic, with blue-shifted velocities of a few hundreds of km s-1 and line widths up to 1500 km s-1 . Using the spectroastrometric method, we infer a size of the ionised outflows of up to ~2 kpc. The properties of the ionised outflows, mass outflow rate, momentum rate, and kinetic power, are correlated with the AGN luminosity. The increase in outflow rate with increasing AGN luminosity is consistent with the idea that a luminous AGN pushes away the surrounding gas through fast outflows that are driven by radiation pressure, which depends on the emitted luminosity.Conclusions. We derive mass outflow rates of about 6−700 M ⊙ yr-1 for our sample, which are lower than those observed in molecular outflows. The physical properties of ionised outflows show dependences on AGN luminosity that are similar to those of molecular outflows, but indicate that the mass of ionised gas is lower than that of molecular outflows. Alternatively, this discrepancy between ionised and molecular outflows could be explained with different acceleration mechanisms.

204 citations

Journal ArticleDOI
TL;DR: In this paper, the absolute I magnitude of the tip of the Red Giant Branch M_I(TRGB) is estimated to be −4.04 ± 0.12.
Abstract: The absolute I magnitude of the Tip of the Red Giant Branch M_I(TRGB) is one of the most promising Standard Candles actually used in astrophysics as a fundamental pillar for the Cosmological Distance Scale. With the aim of improving the observational basis of its calibration, we have obtained an accurate estimate of the M_I(TRGB) for the globular cluster Omega Centauri, based (a) on the largest photometric database ever assembled for a globular, by Pancino et al.(2000), and (b) on a direct distance estimate for Omega Cen, recently obtained by Thompson et al.(2001) from a detached eclipsing binary. The derived value M_I(TRGB) =-4.04\pm 0.12 provides, at present, the most accurate empirical zero-point for the calibration of the M_I(TRGB) - [Fe/H] relation, at [Fe/H] ~ -1.7. We also derived a new empirical M_I(TRGB) - [Fe/H] relation, based on the large IR dataset of red giants in Galactic Globular Clusters recently presented by Ferraro et al.(2000). This database (extending up to [Fe/H]=-0.2) covers a more appropriate metallicity range, for extragalactic applications, than previous empirical calibrations (limited to [Fe/H]<= -0.7). The proposed relation is in excellent agreement with the newly determined zero-point.

204 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the radii of 7 low and very low-mass stars using long baseline interferometry with the VLTI interferometer and its VINCI and AMBER near-infrared recombiners.
Abstract: We measured the radii of 7 low and very low-mass stars using long baseline interferometry with the VLTI interferometer and its VINCI and AMBER near-infrared recombiners. We use these new data, together with literature measurements, to examine the luminosityradius and mass-radius relations for K and M dwarfs. The precision of the new interferometric radii now competes with what can be obtained for double-lined eclipsing binaries. Interferometry provides access to much less active stars, as well as to stars with much better measured distances and luminosities, and therefore complements the information obtained from eclipsing systems. The radii of magnetically quiet late-K to M dwarfs match the predictions of stellar evolution models very well, providing direct confirmation that magnetic activity explains the discrepancy that was recently found for magnetically active eclipsing systems. The radii of the early K dwarfs are reproduced well for a mixing length parameter that approaches the solar value, as qualitatively expected.

204 citations

Journal ArticleDOI
TL;DR: In this article, the authors present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368).
Abstract: We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 1998bu in the Leo I Group galaxy M96 (NGC 3368). The data set consists of 356 photometric measurements and 29 spectra of SN 1998bu between UT 1998 May 11 and July 15. The well-sampled light curve indicates the supernova reached maximum light in B on UT 1998 May 19.3 (JD 2450952.8 ± 0.8) with B = 12.22 ± 0.03 and V = 11.88 ± 0.02. Application of a revised version of the Multicolor Light Curve Shape (MLCS) method yields an extinction toward the supernova of AV = 0.94 ± 0.15 mag, and indicates the supernova was of average luminosity compared to other normal Type Ia supernovae. Using the HST Cepheid distance modulus to M96 and the MLCS fitted parameters for the supernova, we derive an extinction-corrected absolute magnitude for SN 1998bu at maximum, MV = -19.42 ± 0.22. Our independent results for this supernova are consistent with those of Suntzeff et al. Combining SN 1998bu with three other well-observed local calibrators and 42 supernovae in the Hubble flow yields a Hubble constant, H0 = 64 -->img1.gif km s-1 Mpc-1, where the error estimate incorporates possible sources of systematic uncertainty including the calibration of the Cepheid period-luminosity relation, the metallicity dependence of the Cepheid distance scale, and the distance to the LMC.

204 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