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The Central Parsecs of Centaurus A: High-excitation Gas, a Molecular Disk, and the Mass of the Black Hole
We present two-dimensional gas-kinematic maps of the central region inCentaurus A. The adaptive optics (AO) assisted SINFONI data from the VLThave a resolution of 0.12" in K band. The ionized gas species(Brγ, [Fe II], [Si VI]) show a rotational pattern that isincreasingly overlaid by nonrotational motion for higher excitationlines in the direction of Cen A's radio jet. The emission lines ofmolecular hydrogen (H2) show regular rotation and nodistortion due to the jet. The molecular gas seems to be well settled inthe gravitational potential of the stars and the central supermassiveblack hole, and we thus use it as a tracer to model the mass in thecentral +/-1.5". These are the first AO integral-field observations onthe nucleus of Cen A, enabling us to study the regularity of therotation around the black hole, well inside the radius of influence, andto determine the inclination angle of the gas disk in a robust way. Thegas kinematics are best modeled through a tilted-ring model thatdescribes the warped gas disk; its mean inclination angle is ~34°and the mean position angle of the major axis is ~155°. The best-fitblack hole mass isMBH=(4.5+1.7-1.0)×107Msolar (3 σ error), based on a kinematically hot diskmodel where the velocity dispersion is included through the Jeansequation. This black hole mass estimate is somewhat lower than, butconsistent with, the mass values previously derived from ionized gaskinematics. It is also consistent with the stellar dynamical measurementfrom the same AO observations, which we present in a separate paper. Itbrings Cen A into agreement with the MBH-σ relation.Based on observations collected at the European Southern Observatory,Paranal, Chile, ESO Programs 74.A-9011(A), 75.B-0490(A).
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| A homogeneous catalog of new UBV and H-beta photometry of B- and A-type stars in and around the Scorpius-Centaurus OB association
B- and A-type stars in and near the Sco-Cen OB association areinvestigated with UBV and H-beta photometry to acquire data relevant tothe luminosity function of Sco-Cen. The measurements generally consistof two 10-s integrations of U, B, V, (W, N) filters, and theobservations are corrected iteratively for atmospheric extinction andinstrumental response. The data presented give the mean V magnitude,mean B-V, mean U-B, and the estimated uncertainties for these values.The catalog provides a homogeneous catalog of data for a large fieldwith stellar objects delineating membership to the association Sco-Cenand that affect the luminosity function of the aggregate.
| The local system of early type stars - Spatial extent and kinematics
Published uvby and H-beta photometric data and proper motions arecompiled and analyzed to characterize the structure and kinematics ofthe bright early-type O-A0 stars in the solar vicinity, with a focus onthe Gould belt. The selection and calibration techniques are explained,and the data are presented in extensive tables and graphs and discussedin detail. The Gould belt stars of age less than 20 Myr are shown togive belt inclination 19 deg to the Galactic plane and node-lineorientation in the direction of Galactic rotation, while the symmetricaldistribution about the Galactic plane and kinematic properties (purecircular differential rotation) of the belt stars over 60 Myr oldresemble those of fainter nonbelt stars of all ages. The unresolveddiscrepancy between the expansion observed in the youngest nearby starsand the predictions of simple models of expansion from a point isattributed to the inhomogeneous distribution of interstellar matter.
| Radial velocities for early type stars in six galactic regions
Coudespectroscopy has been carried out for 353 stars of spectral typesB0-A0 and V magnitudes between 6.5 and 10.8 m, selected in six regions(three northern and three southern) close to the galactic plane at thegalactic longitudes 135, 175, 315 and 350 deg. The radial velocitieswere obtained by cross-correlating each spectrogram with a referencespectrogram giving an internal error of 1.4 km/s.
| Four-colour and H-beta photometry for early type stars in three southern galactic regions
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980A&AS...41...85L&db_key=AST
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Observation and Astrometry data
| Constellation: | Zentaur |
| Right ascension: | 13h59m34.79s |
| Declination: | -49°01'02.7" |
| Apparent magnitude: | 8.941 |
| Distance: | 245.7 parsecs |
| Proper motion RA: | -7.4 |
| Proper motion Dec: | -5.2 |
| B-T magnitude: | 8.92 |
| V-T magnitude: | 8.94 |
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