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Search Results: 1 - 10 of 579903 matches for " G. A. Verdoes Kleijn "
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HST observations of nearby radio-loud early-type galaxies
G. A. Verdoes Kleijn,S. A. Baum,P. T. de Zeeuw,C. P. O'Dea
Physics , 1999, DOI: 10.1086/301135
Abstract: We present and analyse HST/WFPC2 broad- and narrow-band observations of the central regions of 19 nearby radio-loud early-type galaxies. Together with two more galaxies they form a complete sample of Fanaroff & Riley Type I galaxies. We obtained V- and I-band images and narrow-band images centered on the \HalphaNII emission lines. We use archival data for six galaxies. We describe the data reduction, give isophotal fits and analyse the central emission-line gas and dust distributions. Our main conclusions are the following. Although obscuration by dust inhibits a direct determination of central cusp slopes, the data suggest most but not all galaxies have shallow cores. Dust is detected in all but two galaxies. There is a wide variety of central dust morphologies, ranging from central disks to lanes and irregular distributions. The analysis suggests the difference between disks and lanes is intrinsic and not due to different viewing angles. Central emission-line gas is detected in all galaxies. Extended low-surface-brightness emission is always associated with the dust features. In a subsequent paper we will present a detailed analysis of the relation between these central properties and the nuclear activity.
The black hole in IC 1459 from HST observations of the ionized gas disk
G. A. Verdoes Kleijn,R. P. van der Marel,C. M. Carollo,P. T. de Zeeuw
Physics , 2000, DOI: 10.1086/301524
Abstract: The peculiar elliptical galaxy IC 1459 (M_V = -21.19, D = 16.5 Mpc) has a fast counterrotating stellar core, stellar shells and ripples, a blue nuclear point source and strong radio core emission. We present results of a detailed HST study of IC 1459, and in particular its central gas disk, aimed a constraining the central mass distribution. We obtained WFPC2 narrow-band imaging centered on the Halpha+[NII] emission lines to determine the flux distribution of the gas emission at small radii, and we obtained FOS spectra at six aperture positions along the major axis to sample the gas kinematics. We construct different dynamical models for the Halpha+[NII] and Hbeta kinematics that include a supermassive black hole, and in which the stellar mass distribution is constrained by the observed surface brightness distribution and ground-based stellar kinematics. All models are consistent with a black hole mass in the range Mbh=1-4 x 10^8 Msun, and models without a black hole are always ruled out at high confidence.
The Astro-WISE Optical Image Pipeline: Development and Implementation
J. P. McFarland,G. Verdoes-Kleijn,G. Sikkema,E. M. Helmich,D. R. Boxhoorn,E. A. Valentijn
Physics , 2011, DOI: 10.1007/s10686-011-9266-x
Abstract: We have designed and implemented a novel way to process wide-field astronomical data within a distributed environment of hardware resources and humanpower. The system is characterized by integration of archiving, calibration, and post-calibration analysis of data from raw, through intermediate, to final data products. It is a true integration thanks to complete linking of data lineage from the final catalogs back to the raw data. This paper describes the pipeline processing of optical wide-field astronomical data from the WFI (http://www.eso.org/lasilla/instruments/wfi/) and OmegaCAM (http://www.astro-wise.org/~omegacam/) instruments using the Astro-WISE information system (the Astro-WISE Environment or simply AWE). This information system is an environment of hardware resources and humanpower distributed over Europe. AWE is characterized by integration of archiving, data calibration, post-calibration analysis, and archiving of raw, intermediate, and final data products. The true integration enables a complete data processing cycle from the raw data up to the publication of science-ready catalogs. The advantages of this system for very large datasets are in the areas of: survey operations management, quality control, calibration analyses, and massive processing.
The counterrotating core and the black hole mass of IC1459
M. Cappellari,E. K. Verolme,R. P. van der Marel,G. A. Verdoes Kleijn,G. D. Illingworth,M. Franx,C. M. Carollo,P. T. de Zeeuw
Physics , 2002, DOI: 10.1086/342653
Abstract: The E3 giant elliptical galaxy IC1459 is the prototypical galaxy with a fast counterrotating stellar core. We obtained one HST/STIS long-slit spectrum along the major axis of this galaxy and CTIO spectra along five position angles. We present self-consistent three-integral axisymmetric models of the stellar kinematics, obtained with Schwarzschild's numerical orbit superposition method. We study the dynamics of the kinematically decoupled core (KDC) in IC1459 and we find it consists of stars that are well-separated from the rest of the galaxy in phase space. The stars in the KDC counterrotate in a disk on orbits that are close to circular. We estimate that the KDC mass is ~0.5% of the total galaxy mass or ~3*10^9 Msun. We estimate the central black hole mass M_BH of IC1459 independently from both its stellar and its gaseous kinematics. Some complications probably explain why we find rather discrepant BH masses with the different methods. The stellar kinematics suggest that M_BH = (2.6 +/- 1.1)*10^9 Msun (3 sigma error). The gas kinematics suggests that M_BH ~ 3.5*10^8 Msun if the gas is assumed to rotate at the circular velocity in a thin disk. If the observed velocity dispersion of the gas is assumed to be gravitational, then M_BH could be as high as ~1.0*10^9 Msun. These different estimates bracket the value M_BH = (1.1 +/- 0.3)*10^9 Msun predicted by the M_BH-sigma relation. It will be an important goal for future studies to assess the reliability of black hole mass determinations with either technique. This is essential if one wants to interpret the correlation between the BH mass and other global galaxy parameters (e.g. velocity dispersion) and in particular the scatter in these correlations (believed to be only ~0.3 dex). [Abridged]
The jet-cloud interacting radio galaxy PKS B2152-699. I. Structures revealed in new deep radio and X-ray observations
D. M. Worrall,M. Birkinshaw,A. J. Young,K. Momtahan,R. A. E. Fosbury,R. Morganti,C. N. Tadhunter,G. Verdoes Kleijn
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.21320.x
Abstract: PKS B2152-699 has radio power characteristic of sources that dominate radio feedback. We present new deep ATCA, Chandra and optical observations, and test the feedback model. We report the first high-resolution observations of the radio jet. The inner jet extends ~8.5 kpc towards an optical emission-line High Ionization Cloud (HIC) before taking a zig-zag path to an offset position. Jet X-ray synchrotron radiation is seen. The HIC is associated with 0.3 keV X-ray gas of anomalously low metallicity. On larger scales the radio galaxy displays all three X-ray features that together confirm supersonic expansion of the lobes into the external medium: gas cavities, inverse-Compton emission showing excess internal lobe pressure, and high-contrast arms of temperature above the ~1 keV ambient medium. The well-formed S lobe on the counterjet side is expanding with a Mach number 2.2-3. We estimate a cavity power ~3x10^43 ergs/s, which falls well below previously reported correlations with radio power. The total inferred time-averaged jet power, ~4x10^44 ergs/s, is dominated by the kinetic and thermal energy of shocked gas, and if used instead would bring the source into better agreement with the correlations. The S hotspot is the more complex, with a spiral polarization structure. Its bright peak emits synchrotron X-rays. The fainter N hotspot is particularly interesting, with X-rays offset in the direction of the incoming jet by ~1 arcsec relative to the radio peak. Here modest (delta ~ 6) relativistic beaming and a steep radio spectrum cause the jet to be X-ray bright through inverse-Compton scattering before it decelerates. With such beaming, a modest proton content or small departure from minimum energy in the jet will align estimates of the instantaneous and time-averaged jet power. The hotspots suggest acceleration of electrons to a maximum energy ~10^13 eV in the jet termination shocks.
STIS spectroscopy of gas disks in the nuclei of nearby, radio-loud, early-type galaxies
J. Noel-Storr,C. M. Carollo,S. A. Baum,R. P. van der Marel,C. P. O'Dea,G. A. Verdoes Kleijn,P. T. de Zeeuw
Physics , 2001,
Abstract: We present initial results of our analysis of line emission produced in gas disks found at the centers of a sample of nearby, radio galaxies with radio jets. We obtained data using STIS (The Space Telescope Imaging Spectrograph) at three parallel slit positions on the nucleus of each galaxy. This allows us to map the H$\alpha$ + [NII] flux, the gas radial velocity and the velocity dispersion. We find evidence of rotating disks in 11 of the sample galaxies and we can not currently rule out a rotating disk model for the remaining eight. For rotating systems, we find that the minimum central enclosed mass is greater than or similar to the predicted black hole mass based on ground-based stellar velocity dispersions. By modeling the gas dynamics we will go on to constrain the masses of the black holes. We will also investigate the properties of the gas disks themselves, giving us an insight into fueling, ionization mechanisms and the structure of the central regions.
Monitoring the photometric behavior of OmegaCAM with Astro-WISE
Gijs A. Verdoes Kleijn,Konrad H. Kuijken,Edwin A. Valentijn,Danny R. Boxhoorn,Kor G. Begeman,Erik R. Deul,Ewout M. Helmich,Roeland Rengelink
Physics , 2012, DOI: 10.1007/s10686-012-9325-y
Abstract: The OmegaCAM wide-field optical imager is the sole instrument on the VLT Survey Telescope at ESO's Paranal Observatory. The instrument, as well as the telescope, have been designed for surveys with very good, natural seeing-limited image quality over a 1 square degree field. OmegaCAM was commissioned in 2011 and has been observing three ESO Public Surveys in parallel since October 15, 2011. We use the Astro-WISE information system to monitor the calibration of the observatory and to produce the Kilo Degree Survey (KiDS). Here we describe the photometric monitoring procedures in Astro-WISE and give a first impression of OmegaCAM's photometric behavior as a function of time. The long-term monitoring of the observatory goes hand in hand with the KiDS survey production in Astro-WISE. KiDS is observed under partially non-photometric conditions. Based on the first year of OmegaCAM operations it is expected that a $\sim 1%-2%$ photometric homogeneity will be achieved for KiDS.
Strong lens search in the ESO public Survey KiDS
N. R. Napolitano,G. Covone,N. Roy,C. Tortora,F. La Barbera,M. Radovich,F. Getman,M. Capaccioli,A. Colonna,M. Paolillo,G. A. Verdoes Kleijn,L. V. E. Koopmans,KiDS collaboration
Physics , 2015,
Abstract: We have started a systematic search of strong lens candidates in the ESO public survey KiDS based on the visual inspection of massive galaxies in the redshift range $0.1
The Nuclei of Nearby Radio-Loud Ellipticals
G. A. Verdoes Kleijn,P. T. de Zeeuw,S. A. Baum,C. P. O'Dea,R. P. van der Marel,C. Xu,C. M. Carollo,J. Noel-Storr
Physics , 2000,
Abstract: We have observed a complete sample of 21 nearby (D < 70h^{-1} Mpc) Fanaroff & Riley Type I galaxies with HST/WFPC2 and detected dust disks and lanes in 19 of them. The radio jets are roughly perpendicular to the dust which is used to constrain the Doppler boosting factors of the radio jet and cores. The VLBA core flux correlates with the central Halpha+[NII] flux which might indicate that the VLBA core is dominated by an isotropic component. Twelve galaxies show nuclear optical sources. We discuss various possible origins for this emission.
The Data Zoo in Astro-WISE
Gijs A. Verdoes Kleijn,Andrey N. Belikov,John P. McFarland
Physics , 2012, DOI: 10.1007/s10686-012-9314-1
Abstract: In this paper we describe the way the Astro-WISE information system (or simply Astro-WISE) supports the data from a wide range of in- struments and combines multiple surveys and their catalogues. Astro-WISE allows ingesting of data from any optical instrument, survey or catalogue, pro- cessing of this data to create new catalogues and bringing in data from di?erent surveys into a single catalogue, keeping all dependencies back to the original data. Full data lineage is kept on each step of compiling a new catalogue with an ability to add a new data source recursively. With these features, Astro- WISE allows not only combining and retrieving data from multiple surveys, but performing scientific data reduction and data mining down to the rawest data in the data processing chain within a single environment.
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