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A catalog of bright calibrator stars for 200-m baseline near-infrared stellar interferometry
We present in this paper a catalog of reference stars suitable forcalibrating infrared interferometric observations. In the K band,visibilities can be calibrated with a precision of 1% on baselines up to200 meters for the whole sky, and up to 300 meters for some part of thesky. This work, extending to longer baselines a previous catalogcompiled by Bordé et al. (2002, A&A, 393, 183), isparticularl y well adapted to hectometric-class interferometers such asthe Very Large Telescope Interferometer (VLTI, Glindemann et al. 2003,Proc. SPIE, 4838, 89) or the CHARA array (ten Brummelaar et al. 2003,Proc. SPIE, 4838, 69) when one is observing well-resolved, high-surfacebrightness objects (K 8). We use the absolute spectro-photometriccalibration method introduced by Cohen et al. (1999, AJ, 117, 1864) toderive the angular diameters of our new set of 948 G8-M0 calibratorstars extracted from the IRAS, 2MASS and MSX catalogs. Angular stellardiameters range from 0.6 mas to 1.8 mas (median is 1.1 mas) with amedian precision of 1.35%. For both the northern and southernhemispheres, the closest calibrator star is always less than 10°away.
| CHARM2: An updated Catalog of High Angular Resolution Measurements
We present an update of the Catalog of High Angular ResolutionMeasurements (CHARM, Richichi & Percheron \cite{CHARM}, A&A,386, 492), which includes results available until July 2004. CHARM2 is acompilation of direct measurements by high angular resolution methods,as well as indirect estimates of stellar diameters. Its main goal is toprovide a reference list of sources which can be used for calibrationand verification observations with long-baseline optical and near-IRinterferometers. Single and binary stars are included, as are complexobjects from circumstellar shells to extragalactic sources. The presentupdate provides an increase of almost a factor of two over the previousedition. Additionally, it includes several corrections and improvements,as well as a cross-check with the valuable public release observationsof the ESO Very Large Telescope Interferometer (VLTI). A total of 8231entries for 3238 unique sources are now present in CHARM2. Thisrepresents an increase of a factor of 3.4 and 2.0, respectively, overthe contents of the previous version of CHARM.The catalog is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/431/773
| Line-strength indices and velocity dispersions for 148 early-type galaxies in different environments
We have derived high quality line-strength indices and velocitydispersions for a sample of 148 early-type galaxies in differentenvironments. The wavelength region covered by the observations (lambda=~ 4600 to 6600 Å) includes the Lick/IDS indices Hβ,Mg1, Mg2, Mgb, Fe5015, Fe5270, Fe5335, Fe5406,Fe5709, Fe5782, NaD, TiO1 and TiO2. The data areintended to address possible differences of the stellar populations ofearly-type galaxies in low- and high-density environments. This paperdescribes the sample properties, explains the data reduction andpresents the complete list of all the measurements. Most galaxies of thesample (85%) had no previous measurements of any Lick/IDS indices andfor 30% of the galaxies we present first-time determinations of theirvelocity dispersions. Special care is taken to identify galaxies withemission lines. We found that 62 per cent of the galaxies in the samplehave emission lines, as measured by the equivalent width of the [OIII]5007Å line, EW[OIII] > 0.3 Å. Tables 5 and 6 are onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/ A+A/395/431. They are also available via ftp atftp.mpe.mpg.de in the directory people/dthomas/Beuing02 or via WWW atftp://ftp.mpe.mpg.de/people/dthomas/Beuing02.
| Starlight polarization and CO observations towards the Lupus clouds
We performed an observational study of the dark filaments Lupus 1 andLupus 4 using both polarimetric observations of 190 stars and a sampleof 72 ^12CO profiles towards these clouds. We have estimated lowerlimits to the distances of Lupus 1 and Lupus 4 (>~ 140 and >~ 125pc, respectively). The observational strategy of the survey allows us tocompare the projected magnetic field in an extended area around eachcloud with the magnetic field direction observed to prevail along theclouds. Lupus 4 could have collapsed along the magnetic field lines,while in Lupus 1 the magnetic field appears to be less ordered, havingthe major axis of the filaments parallel to the large-scale projectedmagnetic field. These differences would imply that both filaments havedifferent pattern evolutions. From the CO observations we have probedthe velocity fields of the filaments and the spatial extension of themolecular gas with respect to the dust.
| Ca II H and K Filter Photometry on the UVBY System. II. The Catalog of Observations
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2828T&db_key=AST
| Colours Line Strengths and Stellar Kinematics of NGC2663 and NGC5018
Results of the analysis of broad-band optical images and long-slitspectra of the two elliptical galaxies NGC 2663 and 5018 are presented.Line-strength profiles of Mg_2_, Fe_5270_ and Fe_5335_ have been derivedfor both galaxies, together with rotational velocity and velocitydispersion curves at three and four position angles (PAs) for NGC 2663and 5018, respectively. The measurements extend to about 1.8 effectiveradii for NGC 2663, and to about 3 effective radii for NGC 5018.Axisymmetric dynamical models with distribution function f= f(E, J_z_)(i.e. depending only on the energy E and the angular momentum along thesymmetry axis J_z_) have been fitted to the kinematic profiles of bothgalaxies, to derive information about the intrinsic shapes of theluminous galaxies and the sizes and shapes of possible dark haloes. Inagreement with what has been found for other ellipticals: (i) versus Mg_2_ shows, within both galaxies, a steeper slope than thatshown by galactic nuclei, and (ii) the slope is approximately equal inthe two galaxies and constant within each galaxy (over the whole radialrange, to ~2R_e_). A shift is observed between the two galaxies,implying different [Mg/Fe] abundance ratios. In NGC 2663, the derived[Mg/Fe] abundance ratio is (as is normally found in ellipticals) largerthan solar; its colour [d(B - R )/d log r = - 0.08] and Mg_2_ (dMg_2_/dlog r = - 0.06) gradients are consistent with each other and with achange in metallicity only. The galaxy shows a hint of counter-rotationwithin the innermost 20 arcsec and minor axis rotation. Any oblate orprolate model fitting its kinematics along any two position angles failsto fit the third position angle available, the discrepancy with the databeing a systematic shift. Most probably, this galaxy is a triaxialobject (observed V_rot_/σ~ 0.15 with e~0.3, anisotropy parameterδ >= 0.2-0.3); alternatively, it might be prolate but alwayswith an anisotropic velocity dispersion tensor. In NGC 5018, an almostflat velocity dispersion profile is observed out to the last measuredpoint. Assuming that the galaxy is an axisymmetric rotator, such a flata profile can be reproduced at a confidence level >~ 5 sigma only ifa very massive dark matter halo surrounds the luminous component (M_D_ ~6 M_lum_). A rather strong (B-R) colour gradient is observed in NGC 5018[d(B- R)/dlog r= -0.13], despite its shallow Mg_2_ gradient (dMg_2_/dlogr= - 0.04). Although the whole galaxy is blue, its central (B - R)colour and the observed patchy structure in the (B - R) colour mapsuggest a considerable amount of extinction in its central regions. Ifthe dust follows the Galactic extinction law, at 1550 A one could evenexpect ~2 mag of extinction. This might hide a younger stellarpopulation diluting the Mg_2_ line strength, and might explain the lackof UV flux reported by other authors. The dilution of Mg_2_ would alsoexplain the solar [Mg/Fe] abundance ratio.
| Radial velocities of southern stars obtained with the photoelectric scanner CORAVEL. III - 790 late-type bright stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1985A&AS...59...15A&db_key=AST
| Observations of double stars - Summer 1950.
Not Available
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Besorolás csoportokba:
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Pozíciós és asztrometriai adatok
| Csillagkép: | Szögmérő |
| Rektaszcenzió: | 16h15m24.00s |
| Deklináció: | -42°53'59.0" |
| Vizuális fényesség: | 6.14 |
| Távolság: | 75.019 parszek |
| RA sajátmozgás: | -25.2 |
| Dec sajátmozgás: | -5.8 |
| B-T magnitude: | 7.581 |
| V-T magnitude: | 6.261 |
Katalógusok és elnevezések:
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INHABITED SKY
