- ID:
- ivo://CDS.VizieR/VII/169
- Title:
- Optical Identifications of IRAS Point Sources
- Short Name:
- VII/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical identifications are given of IRAS point sources: 312 sources in a 304 square deg area centred on the South Galactic Pole, of which 148 are identified with stars, 154 with galaxies and 10 are unidentified down to 21st magnitude; 206 point sources in a 113 square deg area centred on the Virgo cluster, of which 54 are identified with stars, 113 with optically bright (B_J<16) galaxies, 32 with faint galaxies, and 7 are apparently empty fields; (66, 114, 61) sources in the regions of (Fornax, Hydra I, Coma) cluster of galaxies, of which (35, 48, 18) are identified with stars, (43, 58, 41) with galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/495/379
- Title:
- Optical radial velocities in A85
- Short Name:
- J/A+A/495/379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this series of papers we explore the evolution of late-type galaxies in the rich cluster Abell 85. In this first paper we revisit the complex dynamical state of A 85 by using independent methods. First, we analyze the galaxy redshift distribution towards A 85 in the whole range 0-40000km/s, and determine the mean redshifts of the background clusters A 87 and A 89, very close in projection to A 85. Then we search for substructures in A 85 by considering the 2D galaxy distribution of its members (13000-20000km/s) and by applying the kinematical 3D {Delta}-test to both projected positions and radial velocities.
- ID:
- ivo://CDS.VizieR/J/AJ/109/14
- Title:
- Optical spectroscopy of Abell clusters. I.
- Short Name:
- J/AJ/109/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a program of optical spectroscopy of radio galaxies in rich clusters. Redshifts are reported for 268 radio galaxies or close companions in Abell clusters and 36 objects which turned out to be foreground or background objects. Absolute line strengths are also reported for the 3727{AA} [OII] line and the [NII]/H{alpha} complex. We find no evidence that the radio activity in our sample of mostly FR I radio galaxies is associated with emission-line luminosities above those found in "normal" galaxies of the same absolute magnitude and optical type. We also find that the radial velocity differences between radio galaxies and the cluster mean seem mainly to be a function of galaxy absolute magnitude rather than radio properties.
- ID:
- ivo://CDS.VizieR/J/A+A/489/11
- Title:
- Optical view of Abell 85 filament region
- Short Name:
- J/A+A/489/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an optical investigation of the Abell 85 cluster filament (z=0.055) previously interpreted in X-rays as groups falling on to the main cluster. We compare the distribution of galaxies with the X-ray filament, and investigate the galaxy luminosity functions in several bands and in several regions. We search for galaxies where star formation may have been triggered by interactions with intracluster gas or tidal pressure due to the cluster potential when entering the cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/985
- Title:
- Orientation of galaxies in galaxy clusters
- Short Name:
- J/ApJ/723/985
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the spatial orientations of galaxies in 247 optically selected rich Abell clusters which have at least 100 members in the considered area. We investigated the relation between angles that give information about galaxy angular momenta and the number of members in each structure. The position angles of the galaxies' major axes, as well as two angles describing the spatial orientation of the galaxy plane, were tested for isotropy by applying three different statistical tests. It is found that the values of the statistics increase with the amount of the galaxies' members, which is equivalent to the existence of a relation between anisotropy and the number of galaxies in a cluster. The search for connection between the galaxies' alignments and Bautz-Morgan (BM) morphological types of examined clusters showed a weak dependence. A statistically marginal relation between velocity dispersion and cluster richness was observed. In addition, it was found that the velocity dispersion decreases with BM type at almost 3{sigma} level. These results show the dependence of alignments with respect to clusters' richness, which can be regarded as an environmental effect.
- ID:
- ivo://CDS.VizieR/J/AJ/155/188
- Title:
- Origin of nuclear activity in low-power radio galaxies
- Short Name:
- J/AJ/155/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using large samples containing nearly 2300 active galaxies of low radio luminosity (1.4 GHz luminosity between 2x10^23^ and 3x10^25^ W/Hz, essentially low-excitation radio galaxies) at z~<0.3, we present a self-contained analysis of the dependence of the nuclear radio activity on both intrinsic and extrinsic properties of galaxies, with the goal of identifying the best predictors of the nuclear radio activity. While confirming the established result that stellar mass must play a key role on the triggering of radio activities, we point out that for the central, most massive galaxies, the radio activity also shows a strong dependence on halo mass, which is not likely due to enhanced interaction rates in denser regions in massive, cluster-scale halos. We thus further investigate the effects of various properties of the intracluster medium (ICM) in massive clusters on the radio activities, employing two standard statistical tools, principle component analysis and logistic regression. It is found that ICM entropy, local cooling time, and pressure are the most effective in predicting the radio activity, pointing to the accretion of gas cooling out of a hot atmosphere to be the likely origin in triggering such activities in galaxies residing in massive dark matter halos. Our analysis framework enables us to logically discern the mechanisms responsible for the radio activity separately for central and satellite galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/610/A77
- Title:
- Orion Integral Filament ALMA+IRAM30m N2H+(1-0) data
- Short Name:
- J/A+A/610/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the gas organization within the paradigmatic Integral Shape Filament (ISF) in Orion in order to decipher whether or not all filaments are bundles of fibers. We combined two new ALMA Cycle 3 mosaics with previous IRAM 30m observations to produce a high-dynamic range N2H+ (1-0) emission map of the ISF tracing its high-density material and velocity structure down to scales of 0.009pc (or ~2000AU). From the analysis of the gas kinematics, we identify a total of 55 dense fibers in the central region of the ISF. Independently of their location in the cloud, these fibers are characterized by transonic internal motions, lengths of ~0.15pc, and masses per unit length close to those expected in hydrostatic equilibrium. The ISF fibers are spatially organized forming a dense bundle with multiple hub-like associations likely shaped by the local gravitational potential. Within this complex network, the ISF fibers show a compact radial emission profile with a median FWHM of 0.035pc systematically narrower than the previously proposed universal 0.1pc filament width. Our ALMA observations reveal complex bundles of fibers in the ISF, suggesting strong similarities between the internal substructure of this massive filament and previously studied lower-mass objects. The fibers show identical dynamic properties in both low- and high-mass regions, and their widespread detection in nearby clouds suggests a preferred organizational mechanism of gas in which the physical fiber dimensions (width and length) are self-regulated depending on their intrinsic gas density. Combining these results with previous works in Musca, Taurus, and Perseus, we identify a systematic increase of the surface density of fibers as a function of the total mass per-unit-length in filamentary clouds. Based on this empirical correlation, we propose a unified star-formation scenario where the observed differences between low- and high-mass clouds, and the origin of clusters, emerge naturally from the initial concentration of fibers.
- ID:
- ivo://CDS.VizieR/J/A+A/486/755
- Title:
- Parameters of galaxies in 8 Abell clusters
- Short Name:
- J/A+A/486/755
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is a continuation of an ongoing study of the evolutionary processes affecting cluster galaxies. Both CCD R band and Halpha narrow-band imaging was used to determine photometric parameters (m_r_, r_24_, Halpha flux, and equivalent width) and derive star formation rates for 227 CGCG galaxies in 8 low-redshift clusters. The galaxy sample is a subset of CGCG galaxies in an objective prism survey (OPS) of cluster galaxies for Halpha emission. It is found that detection of emission-line galaxies in the OPS is 85%, 70%, and 50% complete at the mean surface brightness values of 1.25x10^-19^, 5.19x10^-20^, and 1.76x10^-20^W/m^2^/arcsec^2^, respectively, measured within the R band isophote of 24mag/arcsec^2^ for the galaxy. The CCD data, together with matched data from a recent Halpha galaxy survey of UGC galaxies within 3000km/s, will be used for a comparative study of R band and Halpha surface photometry between cluster and field spirals.
- ID:
- ivo://CDS.VizieR/J/MNRAS/459/4450
- Title:
- Peculiar compact stellar systems in Fornax
- Short Name:
- J/MNRAS/459/4450
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We search for hints to the origin and nature of compact stellar systems in the magnitude range of ultracompact dwarf galaxies in deep wide-field imaging data of the Fornax cluster core. We visually investigate a large sample of 355 spectroscopically confirmed cluster members with V-band equivalent magnitudes brighter than -10mag for faint extended structures. Our data reveal peculiar compact stellar systems, which appear asymmetric or elongated from their outer light distribution. We characterize the structure of our objects by quantifying their core concentration, as well as their outer asymmetry and ellipticity. For the brighter objects of our sample we also investigate their spatial and phase-space distribution within the cluster. We argue that the distorted outer structure alone that is seen for some of our objects, is not sufficient to decide whether these systems have a star cluster or a galaxy origin. However, we find that objects with low core concentration and high asymmetry (or high ellipticity) are primarily located at larger cluster-centric distances as compared to the entire sample. This supports the hypothesis that at least some of these objects may originate from tidally stripped galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/239/459
- Title:
- Photographic study of A2197 and A2199
- Short Name:
- J/MNRAS/239/459
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radii, b26 magnitudes, (b-r) colors, position angles, and ellipticities have been measured on the plates of Palomar 48-inch Schmidt telescope taken in May 1976, for 6925 galaxies in a 5-sq deg field enclosing the close pair of rich clusters A2197 and A2199.
