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- ID:
- ivo://CDS.VizieR/J/AJ/131/1280
- Title:
- Redshifts of HRS galaxies
- Short Name:
- J/AJ/131/1280
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 118 new optical redshifts for galaxies in 12 clusters in the Horologium-Reticulum supercluster (HRS) of galaxies. For 76 galaxies, the data were obtained with the Dual Beam Spectrograph on the 2.3m telescope of the Australian National University at Siding Spring Observatory. After combining 42 previously unpublished redshifts with our new sample, we determine mean redshifts and velocity dispersions for 13 clusters in which previous observational data were sparse.
- ID:
- ivo://CDS.VizieR/J/ApJ/888/35
- Title:
- Redshifts of lensed systems toward RXCJ2248.7-4431
- Short Name:
- J/ApJ/888/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an iterative method to construct a freeform lens model that self-consistently reproduces the sky positions, geometrically inferred redshifts, and relative brightnesses of all multiply lensed images toward a galaxy cluster. This method is applied to the cluster RXCJ2248.7-4431 (z=0.348) from the Hubble Frontier Fields program, toward which 10 multiply lensed sources with accurate spectroscopic redshifts and 6 others with inexact photometric redshifts have been identified. Using the spectroscopically secure systems to define an initial lens model, we compute the geometric redshifts of the photometric systems. We then iterate the lens model by incorporating the photometric systems at redshifts shifted by incremental amounts toward their geometric redshifts inferred from the previous step; on convergence, we find geometric redshifts in good agreement with the spectroscopically determined redshifts, but they can depart significantly from the photometrically determined redshifts. In the final lens model, all 16 lensed sources tightly follow the cosmological form of the angular diameter distance relation. Furthermore, although they are not used as model constraints, our lens model predicts relative brightnesses between image pairs for a given set of multiply lensed images in reasonable agreement with observations, thus providing independent validation of this model.
- ID:
- ivo://CDS.VizieR/J/MNRAS/316/326
- Title:
- Redshifts of Ophiuchus region galaxies
- Short Name:
- J/MNRAS/316/326
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The large-scale structure around the Ophiuchus cluster of galaxies in the vicinity of the Galactic Centre (l=0.5{deg}, b=9.5{deg}, cz=8500km/s) is investigated on the basis of a galaxy survey and spectroscopic observations made for a 120{deg}x170{deg} area. The galaxy survey was performed using six ESO/SERC Sky Survey Atlas films, and 4021 galaxies were detected in total. Recession velocities were newly obtained for 179 galaxies to make the total number of galaxies in the survey area with known velocities 219. In the distribution of bright galaxies, we identified seven new clumps of galaxies. Comparing the surface number density of bright galaxies with the Galactic extinction, which is estimated from the 100-{mu}m flux density in the IRAS Sky Survey Atlas, we demonstrate that the seven clumps are not spurious as a result of the inhomogeneity of the Galactic extinction. Among the seven clumps, two are found to be clusters and four to be groups on the basis of the histogram of recession velocities and the number of member galaxies. The Ophiuchus cluster, two newly identified clusters, and four groups are all concentrated at 9000km/s. Field galaxies are also distributed centred at 8500km/s. Hence field galaxies occupy a common three-dimensional region with galaxies in the clusters and groups, and altogether they form a large-scale structure of supercluster size. As opposed to the overdensity in the supercluster region, the mean number density of galaxies in the velocity range 0-5000km/s is only 25 per cent of the mean number density of the Universe, comparable with the density of the well-known Bootes void. Hence this nearby three-dimensional region in Ophiuchus is a void of galaxies also.
- ID:
- ivo://CDS.VizieR/J/AJ/123/3018
- Title:
- Redshifts of radio-selected poor clusters
- Short Name:
- J/AJ/123/3018
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Multifiber optical spectroscopy has been performed on galaxies in the vicinity of strong, nearby radio galaxies. These radio galaxies were selected from the 3CR and B2 catalogs based on their exclusion from the Abell catalog, which is puzzling given the hypothesis that an external medium is required to confine the radio plasma of such galaxies. Velocities derived from the spectra were used to confirm the existence of groups and poor clusters in the fields of most of the radio galaxies. We find that all radio galaxies with classical Fanaroff-Riley type I morphologies prove to reside in clusters, whereas the other radio galaxies often appear to be recent galaxy-galaxy mergers in regions of low galaxy density. These findings confirm the earlier result that the existence of extended X-ray emission combined with a statistical excess of neighboring galaxies can be used to identify poor clusters associated with radio galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/96/343
- Title:
- Redshifts of rich clusters of galaxies
- Short Name:
- J/ApJS/96/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic observations and accurate positions for 286 galaxies in clusters taken over several observing sessions, mostly with the DuPont telescope at Las Campanas Observatorv. We derive 165 redshifts of rich clusters of which 130 are apparently new values. Redshifts encompass a wide range out to z=0.27
- ID:
- ivo://CDS.VizieR/J/MNRAS/274/75
- Title:
- Redshifts of ROSAT X-ray brightest clusters
- Short Name:
- J/MNRAS/274/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results from the second stage of an optical follow-up study aimed at determining new redshifts for clusters of galaxies selected from the ROSAT All-Sky Survey. We review the optical properties of all the clusters obtained so far in this programme, which comprises 71 clusters up to a redshift of 0.3. The fraction of central galaxies exhibiting optical line emission and an excess blue continuum is 34%, consistent with smaller, previous, X-ray samples. There is no trend for this fraction to increase with redshift, although we find a clear tendency for the strongest line emitters to have the bluest continua. The probability of the presence of line emission and an excess blue continuum is increased for those galaxies with associated radio sources, although the strength of these features does not appear to be related to the power of the radio emission.
- ID:
- ivo://CDS.VizieR/J/A+AS/101/259
- Title:
- Redshifts of southern rich clusters
- Short Name:
- J/A+AS/101/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/AJ/124/1266
- Title:
- Redshift survey around Abell 2199
- Short Name:
- J/AJ/124/1266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a redshift survey of 1323 galaxies (1092 new or remeasured) in a region of 95deg^2^ centered on the nearby galaxy cluster Abell 2199, we analyze the supercluster containing A2199, A2197, and an X-ray group.
- ID:
- ivo://CDS.VizieR/J/A+A/337/17
- Title:
- Redshift survey between A548 and A3367
- Short Name:
- J/A+A/337/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of a spectroscopic survey of galaxies in an area between the two clusters of galaxies A548 and A3367, suspected to be a close and interacting pair. With the use of multifiber spectroscopy, we measured 180 new velocities of galaxies in the central part of A 3367 and in the external regions of A 548. The redshift histogram shows the presence of three velocity peaks, at v~12000km/s, v~30000km/s and v~40000km/s, respectively. For these we estimate the density excess, the mean velocity, and the velocity dispersion. The first clump corresponds to an elongation of A 548: in particular we found a correspondence between the features of this peak and the substructures of A 548. The second peak has a velocity dispersion which is typical of clusters and the distribution of its members on the plane of the sky corresponds to the highest density peak in A 3367. We therefore suggest that the name A 3367 has to be attributed to this clump. Our general conclusion is that, differently from expected, A 548 and A 3367 do not form a close pair of merging clusters, since the two structures are at significantly different redshifts. Moreover, we found that the complex dynamical structure of A 548 has large coherence, with a projected extension in the range of 1-3h^-1^Mpc.
