Contents
Images
Upload your image
DSS Images Other Images
Related articles
Host Dynamics and Origin of Palomar-Green QSOs
We present host galaxy velocity dispersions of 12 local (mainlyPalomar-Green) QSOs measured directly from the stellar CO absorptionfeatures in the H band. The mean bulge dispersion of the QSOs in oursample is 186 km s-1 with a standard deviation of 24 kms-1. The measurement of the stellar dispersion in QSOsenables us to place them on observational diagrams such as the localblack hole mass-bulge velocity dispersion relation and the fundamentalplane of early-type galaxies. Concerning the former relation, these QSOshave higher black hole masses than most Seyfert 1 AGNs with similarvelocity dispersions. On the fundamental plane, PG QSOs are locatedbetween the regions occupied by moderate-mass and giant ellipticals. TheQSO bulge and black hole masses, computed from the stellar velocitydispersions, are of order 1011 and 108Msolar, respectively. The Eddington efficiency of their blackholes is on average 0.25, assuming that all of the bolometric luminosityoriginates from the active nucleus. Our data are consistent with otherlines of evidence that Palomar-Green QSOs are related to galaxy mergerswith gas-rich components and that they are formed in a manner similar tothe most massive ultraluminous infrared galaxies, regardless of theirfar-infrared emission. However, PG QSOs seem to have smaller hostdispersions and different formation mechanisms than QSOs withsupermassive black holes of 5×108-109Msolar that accrete at low rates and reside in massivespheroids.Based on observations at the European Southern Observatory, Chile(171.B-0442).
| Dynamical Properties of Ultraluminous Infrared Galaxies. II. Traces of Dynamical Evolution and End Products of Local Ultraluminous Mergers
We present results from our Very Large Telescope large program to studythe dynamical evolution of local ultraluminous infrared galaxies(ULIRGs) and QSOs. This paper is the second in a series presenting thestellar kinematics of 54 ULIRGs, derived from high-resolution, long-slitH- and K-band spectroscopy. The data presented here, includingobservations of 17 new targets, are mainly focused on sources that havecoalesced into a single nucleus. The stellar kinematics, extracted fromthe CO ro-vibrational band heads in our spectra, indicate that ULIRGremnants are dynamically heated systems with a mean dispersion of 161 kms-1. The combination of kinematic, structural, andphotometric properties of the remnants indicate that they mostlyoriginate from major mergers and that they result in the formation ofsystems supported by random motions, i.e., elliptical galaxies. The peakof the velocity dispersion distribution and the locus of ULIRGs on thefundamental plane of early-type galaxies indicate that the end productsof ultraluminous mergers are typically moderate-mass ellipticals (ofstellar mass ~1010-1011 Msolar).Converting the host dispersion into black hole mass with the aid of theMBH-σ relation yields black hole mass estimates of theorder 107-108 Msolar and high accretionrates with Eddington efficiencies often >0.5.Based on observations at the European Southern Observatory (ESO)(171.B-044).
| Dynamical Properties of Ultraluminous Infrared Galaxies. I. Mass Ratio Conditions for ULIRG Activity in Interacting Pairs
We present first results from our Very Large Telescope large program tostudy the dynamical evolution of ultraluminous infrared galaxies(ULIRGs), which are the products of mergers of gas-rich galaxies. Thefull data set consists of high-resolution long-slit H- and K-bandspectra of 38 ULIRGs and 12 QSOs (in the range 0.0423:1 typically do not force enough gas into the center togenerate ULIRG luminosities.
| Hipparcos red stars in the HpV_T2 and V I_C systems
For Hipparcos M, S, and C spectral type stars, we provide calibratedinstantaneous (epoch) Cousins V - I color indices using newly derivedHpV_T2 photometry. Three new sets of ground-based Cousins V I data havebeen obtained for more than 170 carbon and red M giants. These datasetsin combination with the published sources of V I photometry served toobtain the calibration curves linking Hipparcos/Tycho Hp-V_T2 with theCousins V - I index. In total, 321 carbon stars and 4464 M- and S-typestars have new V - I indices. The standard error of the mean V - I isabout 0.1 mag or better down to Hp~9 although it deteriorates rapidly atfainter magnitudes. These V - I indices can be used to verify thepublished Hipparcos V - I color indices. Thus, we have identified ahandful of new cases where, instead of the real target, a random fieldstar has been observed. A considerable fraction of the DMSA/C and DMSA/Vsolutions for red stars appear not to be warranted. Most likely suchspurious solutions may originate from usage of a heavily biased color inthe astrometric processing.Based on observations from the Hipparcos astrometric satellite operatedby the European Space Agency (ESA 1997).}\fnmsep\thanks{Table 7 is onlyavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/397/997
| Ultraluminous Infrared Mergers: Elliptical Galaxies in Formation?
We report high-quality near-IR spectroscopy of 12 ultraluminous infraredgalaxy mergers (ULIRGs). Our new VLT and Keck data provide ~0.5"resolution, stellar and gas kinematics of these galaxies, most of whichare compact systems in the last merger stages. We confirm that ULIRGmergers are ``ellipticals in formation.'' Random motions dominate theirstellar dynamics, but significant rotation is common. Gasdynamics andstellar dynamics are decoupled in most systems. ULIRGs fall on or nearthe fundamental plane of hot stellar systems, and especially on its lessevolution-sensitive, reff-σ projection. The ULIRGvelocity dispersion distribution, their location in the fundamentalplane, and their distribution of vrotsini/σ closelyresemble those of intermediate-mass (~L*), ellipticalgalaxies with moderate rotation. As a group ULIRGs do not resemble giantellipticals with large cores and little rotation. Our results are ingood agreement with other recent studies indicating that diskyellipticals with compact cores or cusps can form through dissipativemergers of gas-rich disk galaxies while giant ellipticals with largecores have a different formation history. Based on observations at theEuropean Southern Observatory, Chile (ESO 65.N-0266, 65.N-0289), and onobservations at the W. M. Keck Observatory, which is operated as ascientific partnership among the California Institute of Technology, TheUniversity of California, and the National Aeronautics and SpaceAdministration. The Keck Observatory was made possible by the generalfinancial support by the W. M. Keck Foundation.
|
Submit a new article
Related links
Submit a new link
Member of following groups:
|
Observation and Astrometry data
| Constellation: | Netz |
| Right ascension: | 03h58m45.77s |
| Declination: | -63°50'05.8" |
| Apparent magnitude: | 9.198 |
| Proper motion RA: | 3.9 |
| Proper motion Dec: | 2.1 |
| B-T magnitude: | 11.287 |
| V-T magnitude: | 9.371 |
Catalogs and designations:
|
