- ID:
- ivo://CDS.VizieR/J/AJ/116/1573
- Title:
- Redshift Survey Compact Groups
- Short Name:
- J/AJ/116/1573
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Redshift Survey Compact Groups (RSCGs) are tight knots of N>=3 galaxies selected from the CfA2+SSRS2 redshift survey. The selection is based on physical extent and association in redshift space alone. We measured 300 new redshifts of fainter galaxies within 1h^-1^Mpc of 14 RSCGs to explore the relationship between RSCGs and their environments. Thirteen of 14 RSCGs are embedded in overdense regions of redshift space. The systems range from a loose group of five members to an Abell cluster. The remaining group, RSCG 64, appears isolated. RSCGs are isolated and distinct from their surroundings to varying degrees, as are the Hickson compact groups. Among the 13 embedded RSCGs, three are distinct from their general environments (RSCG 9, RSCG 11, and RSCG 85).
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/665/921
- Title:
- Redshift survey in the field of A1689
- Short Name:
- J/ApJ/665/921
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of the HST Advanced Camera for Surveys spectroscopic ground-based redshift survey in the field of A1689. We measure 98 redshifts, increasing the number of spectroscopically confirmed objects sixfold. We present two spectra from this catalog of the Sextet Arcs, images that arise from a strongly lensed Lyman break galaxy (LBG) at a redshift of z=3.038. Gravitational lensing by the cluster magnifies its flux by a factor of ~16 and produces six separate images with a total r-band magnitude of r_625_=21.7. The two spectra, each of which represents emission from different regions of the LBG, show HI and interstellar metal absorption lines at the systemic redshift.
- ID:
- ivo://CDS.VizieR/J/ApJ/750/168
- Title:
- Redshift survey in the Subaru GTO2deg^2^ field
- Short Name:
- J/ApJ/750/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a dense redshift survey in the foreground of the Subaru GTO2deg^2^ weak-lensing field (centered at 16:04:44+43:11'24 (2000) to assess the completeness and comment on the purity of massive halo identification in the weak-lensing map. The redshift survey (published here) includes 4541 galaxies; 4405 are new redshifts measured with the Hectospec on the MMT. Among the weak-lensing peaks with a signal to noise greater than 4.25, 2/3 correspond to individual massive systems; this result is essentially identical to the Geller et al. (2010ApJ...709..832G) test of the Deep Lens Survey (DLS) field F2. The Subaru map, based on images in substantially better seeing than the DLS, enables detection of less massive halos at fixed redshift as expected. We demonstrate that the procedure adopted by Miyazaki et al. (2002ApJ...580L..97M) for removing some contaminated peaks from the weak-lensing map improves agreement between the lensing map and the redshift survey in the identification of candidate massive systems.
- ID:
- ivo://CDS.VizieR/J/AJ/162/193
- Title:
- Redshift survey nearby galaxy cluster A2626
- Short Name:
- J/AJ/162/193
- Date:
- 16 Mar 2022 00:18:57
- Publisher:
- CDS
- Description:
- New MMT/Hectospec spectroscopy centered on the galaxy cluster A2626 and covering a ~1.8deg^2^ area out to z~0.46 more than doubles the number of galaxy redshifts in this region. The spectra confirm four clusters previously identified photometrically. A2625, which was previously thought to be a close neighbor of A2626, is in fact much more distant. The new data show six substructures associated with A2626 and five more associated with A2637. There is also a highly collimated collection of galaxies and galaxy groups between A2626 and A2637 having at least three and probably four substructures. At larger scales, the A2626-A2637 complex is not connected to the Pegasus-Perseus filament.
- ID:
- ivo://CDS.VizieR/J/MNRAS/312/540
- Title:
- Redshift survey of intercluster galaxies
- Short Name:
- J/MNRAS/312/540
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a redshift survey of intercluster galaxies in the central region of the Shapley Concentration supercluster, aimed at determining the distribution of galaxies in between obvious overdensities. Our sample is formed by 442 new redshifts, mainly in the b_J_ magnitude range 17-18.8. Adding the data from our redshift surveys on the A3558 and A3528 complexes, which are close to the geometrical centre of this supercluster, we obtain a total sample of ~2000 radial velocities. The average velocity of the observed intercluster galaxies in the Shapley Concentration appears to be a function of their ({alpha}, {delta} position, and it can be fitted by a plane in the three dimensional space ({alpha}, {delta}, v): the distribution of the galaxy distances around the best-fitting plane is described by a Gaussian with dispersion 3.8h^-1^Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/607/202
- Title:
- Redshift survey of nearby galaxy groups
- Short Name:
- J/ApJ/607/202
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We constrain the mass profile and orbital structure of nearby groups and clusters of galaxies. Our method yields the joint probability distribution of the density slope n, the velocity anisotropy {beta}, and the turnover radius r_0_ for these systems. The measurement technique does not use results from N-body simulations as priors. We incorporate 2419 new redshifts (included here) in the fields of 41 systems of galaxies with z<0.04.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/124
- Title:
- Redshift survey of the nearby galaxy cluster A2107
- Short Name:
- J/ApJ/869/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the rotational motion of the galaxy cluster A2107 at redshift z=0.04 and its connection to nearby large-scale structures using a large amount of spectroscopic redshift data. By combining 978 new redshifts from the MMT/Hectospec observations with data in the literature, we construct a large sample of 1968 galaxies with measured redshifts at clustercentric radius R<60'. Our sample has high (80%) and spatially uniform completeness at r-band apparent magnitude m_r,Petro,0_<19.1. We first apply the caustic method to the sample and identify 285 member galaxies of A2107 at R<60'. Then the rotation amplitude and the position angle of the rotation axis are measured. We find that the member galaxies show strong global rotation at R<20' (v_rot_/{sigma}_v_~0.6) with a significance of >3.8{sigma}, which is confirmed by two independent methods. The rotation becomes weaker in outer regions. There are at least five filamentary structures that are connected to the cluster and that consist of known galaxy groups. These structures are smoothly connected to the cluster, which seem to be inducing the global rotation of the cluster through inflow of galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/425/367
- Title:
- REFLEX Galaxy Cluster Survey catalogue
- Short Name:
- J/A+A/425/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the catalogue of the REFLEX Cluster Survey providing information on the X-ray properties, redshifts, and some identification details of the clusters in the REFLEX sample. The catalogue describes a statistically complete X-ray flux-limited sample of 447 galaxy clusters above an X-ray flux of 3x10^-12^erg/s/cm^2^ (0.1 to 2.4keV) in an area of 4.24ster in the southern sky. The cluster candidates were first selected by their X-ray emission in the ROSAT-All Sky Survey and subsequently spectroscopically identified in the frame of an ESO key programme. Previously described tests have shown that the sample is more than 90% complete and there is a conservative upper limit of 9% on the fraction of clusters with a dominant X-ray contamination from AGN. In addition to the cluster catalogue we also describe the complete selection criteria as a function of the sky position and the conversion functions used to analyse the X-ray data. These are essential for the precise statistical analysis of the large-scale cluster distribution. This data set is at present the largest, statistically complete X-ray galaxy cluster sample. Together with these data set we also provide for the first time the full three-dimensional selection function. The sample forms the basis of several cosmological studies, one of the most important applications being the assessment of the statistics of the large-scale structure of the universe and the test of cosmological models. Part of these cosmological results have already been published.
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/3272
- Title:
- REFLEX II flux-limited supercluster sample
- Short Name:
- J/MNRAS/429/3272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first supercluster catalogue constructed with the extended ROSAT-ESO Flux-Limited X-ray (REFLEX II) Galaxy Cluster survey data, which comprises 919 X-ray selected galaxy clusters with a flux limit of 1.8x10^-12^erg/s/cm2. Based on this cluster catalogue we construct a supercluster catalogue using a friends-of-friends algorithm with a linking length depending on the (local) cluster density, which thus varies with redshift. The resulting catalogue comprises 164 superclusters at redshift z<=0.4. The choice of the linking length in the friends-of-friends method modifies the properties of the superclusters. We study the properties of different catalogues such as the distributions of the redshift, extent and multiplicity by varying the choice of parameters. In addition to the supercluster catalogue for the entire REFLEX II sample, we compile a large volume-limited cluster sample from REFLEX II with the redshift and luminosity constraints of z<=0.1 and L_X_>=5x10^43^erg/s. With this catalogue we construct a volume-limited sample of superclusters. This sample is built with a homogeneous linking length, and hence selects effectively the same type of superclusters. By increasing the luminosity cut we can build a hierarchical tree structure of the volume-limited samples, where systems at the top of the tree are only formed via the most luminous clusters. This allows us to test if the same superclusters are found when only the most luminous clusters are visible, comparable to the situation at higher redshift in the REFLEX II sample. We find that the selection of superclusters is very robust, independent of the luminosity cut, and the contamination of spurious superclusters among cluster pairs is expected to be small. Numerical simulations and observations of the substructure of clusters suggest that regions of high cluster number density provide an astrophysically different environment for galaxy clusters, where the mass function and X-ray luminosity function are shifted to higher cut-off values and an increased merger rate may also boost some of the cluster X-ray luminosities. We therefore compare the X-ray luminosity function for the clusters in superclusters with that for the field clusters with the flux- and volume-limited catalogues. The results mildly support the theoretical suggestion of a top-heavy X-ray luminosity function of galaxy clusters in regions of high cluster density.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A30
- Title:
- REFLEX II. Properties of the survey
- Short Name:
- J/A+A/555/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters provide unique laboratories to study astrophysical processes on large scales and are important probes for cosmology. X-ray observations are currently the best means of detecting and characterizing galaxy clusters. Therefore X-ray surveys for galaxy clusters are one of the best ways to obtain a statistical census of the galaxy cluster population. In this paper we describe the construction of the REFLEX II galaxy cluster survey based on the southern part of the ROSAT All-Sky Survey. REFLEX II extends the REFLEX I survey by a factor of about two down to a flux limit of 1.8x10^-12^erg/s/cm^2^ (0.1-2.4keV). We describe the determination of the X-ray parameters, the process of X-ray source identification, and the construction of the survey selection function. The REFLEX II cluster sample comprises currently 915 objects. A standard selection function is derived for a lower source count limit of 20 photons in addition to the flux limit. The median redshift of the sample is z=0.102. Internal consistency checks and the comparison to several other galaxy cluster surveys imply that REFLEX II is better than 90% complete with a contamination less than 10%. With this publication we give a comprehensive statistical description of the REFLEX II survey and provide all the complementary information necessary for a proper modelling of the survey for astrophysical and cosmological applications.
