- ID:
- ivo://CDS.VizieR/J/A+A/656/A154
- Title:
- ClG 0217+70 radio images
- Short Name:
- J/A+A/656/A154
- Date:
- 21 Mar 2022 09:15:55
- Publisher:
- CDS
- Description:
- Megaparsec-scale radio sources in the form of halos and relics are often detected in dynamically disturbed galaxy clusters. Although they are associated with merger-induced turbulence and shocks, respectively, their formation is not fully understood. Aims. We aim to identify the mechanisms responsible for particle acceleration and magnetic field amplification in the halo and relics of the galaxy cluster ClG 0217+70. We observed ClG 0217+70 with LOFAR at 141MHz and with VLA at 1.5GHz, and we combined these observations with VLA 1.4GHz archival data to study the morphological and spectral properties of the diffuse sources.We added Chandra archival data to examine the thermal and non-thermal properties of the halo. Our LOFAR and VLA data confirm the presence of a giant radio halo in the cluster centre and multiple relics in the outskirts. The radio and X-ray emission from the halo are correlated, implying a tight relation between the thermal and non-thermal components. The diuse radio structure in the south-east, with a projected size of 3.5Mpc, is the most extended radio relic detected to date. The spectral index across the relic width steepens towards the cluster centre, suggesting electron ageing in the post-shock regions. The shock Mach numbers for the relics derived from the spectral index map range between 2.0 and 3.2. However, the integrated spectral indices lead to increasingly high Mach numbers for the relics farther from the cluster centre. This discrepancy could be because the relation between injection and integrated spectra does not hold for distant shocks, suggesting that the cooling time for the radioemitting electrons is longer than the crossing time of the shocks. The variations in the surface brightness of the relics and the low Mach numbers imply that the radio-emitting electrons are re-accelerated from fossil plasma that could originate in active galactic nuclei.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/458/3443
- Title:
- Cl0939+4713 H{alpha} z~0.4 star-forming galaxies
- Short Name:
- J/MNRAS/458/3443
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cluster star-forming galaxies are found to have an excess of far-infrared emission relative to H{alpha}, when compared to those in the field, which could be caused by intense active galactic nuclei (AGN) activity, dust and/or declining star formation histories. Here we present spectroscopic observations of H{alpha} emitters in the Cl 0939+4713 (Abell 851) super-cluster at z=0.41, using AF2+ WYFFOS on the William Herschel Telescope. We measure [OII], H{beta}, [OIII], H{alpha} and [NII] for a sample of 119 H{alpha} emitters in and around the cluster. We find that 17+/-5 per cent of the H{alpha} emitters are AGN, irrespective of environment. For star-forming galaxies, we obtain Balmer decrements, metallicities and ionization parameters with different methods, individually and by stacking. We find a strong mass-metallicity relation at all environments, with no significant dependence on environment. The ionization parameter declines with increasing stellar mass for low-mass galaxies. H{alpha} emitters residing in intermediate environments show the highest ionization parameters (along with high [OIII]/H{alpha} and high [OIII]/[OII] line ratios, typically twice as large as in the highest and lowest densities), which decline with increasing environmental density. Dust extinction (A_H{alpha}_) correlates strongly with stellar mass, but also with environmental density. Star-forming galaxies in the densest environments are found to be significantly dustier (A_H{alpha}_~=1.5-1.6) than those residing in the lowest density environments (A_H{alpha}_~=0.6), deviating significantly from what would be predicted given their stellar masses.
- ID:
- ivo://CDS.VizieR/J/AJ/116/584
- Title:
- Cl J0023+0423 and Cl J1604+4304 morphology
- Short Name:
- J/AJ/116/584
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed morphological analysis of the galaxy populations in the first two clusters to be completed in an extensive observational study of nine high-redshift clusters of galaxies. These two clusters, Cl 0023+0423 and Cl 1604+4304, are at redshifts of z=0.84 and z=0.90, respectively. The morphological studies are based on high angular resolution imagery taken with Wide Field Planetary Camera 2 aboard the Hubble Space Telescope. These data are combined with deep, ground-based BVRI photometry and spectra taken with the Keck 10m telescopes. The morphological classifications presented in this paper consist of two parts. First, we provide a quantitative description of the structural properties of ~600 galaxies per cluster field using the Medium Deep Survey automated data reduction and object classification software. This analysis includes the galaxy position, photometry, and best-fit bulge+disk model. Second, for the brightest subsample of ~200 galaxies per cluster field, we provide a more detailed morphological description through a visual classification based on the revised Hubble classification scheme.
- ID:
- ivo://CDS.VizieR/J/AJ/116/560
- Title:
- Cl J0023+0423 and Cl J1604+4304 spectroscopy
- Short Name:
- J/AJ/116/560
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive photometric and spectroscopic study of two high-redshift clusters of galaxies based on data obtained from the Keck 10m telescopes and the Hubble Space Telescope. The clusters Cl 0023+0423 (z=0.84) and Cl 1604+4304 (z=0.90) are part of a multiwavelength program of Oke, Postman & Lubin (1998AJ....116..549O, Paper I) to study nine candidate clusters at z>~0.6. Based on these observations, we study in detail both the field and cluster populations. From the confirmed cluster members, we find that Cl 0023+0423 actually consists of two components separated by ~2900km/s. A kinematic analysis indicates that the two components are a poor cluster with ~3x10^14^M_{sun}_ and a less massive group with ~10^13^M_{sun}_. Cl 1604+4304 is a centrally concentrated, rich cluster at z=0.8967 with a velocity dispersion of 1226km/s and a mass of ~3x10^15^M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2644
- Title:
- CL 0024+1654 UBVI photometry
- Short Name:
- J/AJ/126/2644
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Wide-field (20x20arcmin^2^) UBVI images of intermediate-redshift (z=0.39), Butcher-Oemler cluster CL0024+1654 are being distributed. These data probe the rest-frame mid-UV properties over a much larger area than previous studies of CL0024+1654. These images were obtained with the 0.9m telescope at the NOAO Kitt Peak National Observatory in 1991-1992. The resolution is 0.68 arcsec/pix, and the field-of-view is 20arcmin^2^. The standard KPNO Harris filter set was used. We are distributing the individual U, B, V and I frames, as well as the combined U+B+V+I image. Using these data, SExtractor was used to construct a multi-color catalog of approximately 6000 objects in this field. We present both isophotal and aperture photometry in the catalog to be complete. We cross-matched the objects in our catalog with three other CL0024 datasets, and list the matching results in the distributed catalog. Our catalog includes the cross-references to data from Czoske et al., 2001, Cat. <J/A+A/372/391>; from Smail et al., 1997, Cat. <J/ApJS/110/213>; and from Dressler et al., 1999, Cat. <J/ApJS/122/51>.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A122
- Title:
- Cluster and field elliptical galaxies at z~1.3
- Short Name:
- J/A+A/597/A122
- Date:
- 04 Feb 2022 00:04:27
- Publisher:
- CDS
- Description:
- The aim of this work is twofold: first, to assess whether the population of elliptical galaxies in cluster at z~1.3 differs from the population in the field and whether their intrinsic structure depends on the environment where they belong; second, to constrain their properties 9Gyr back in time through the study of their scaling relations. We compared a sample of 56 cluster elliptical galaxies selected from three clusters at 1.2<z<1.4 with elliptical galaxies selected at comparable redshift in the GOODS-South field (~30), in the COSMOS area (~180), and in the CANDELS fields (~220). To single out the environmental effects, we selected cluster and field elliptical galaxies according to their morphology. We compared physical and structural parameters of galaxies in the two environments and we derived the relationships between effective radius, surface brightness, stellar mass, and stellar mass density {Sigma}_R_e__ within the effective radius and central mass density {Sigma}_1kpc_, within 1kpc radius. We find that the structure and the properties of cluster elliptical galaxies do not differ from those in the field: they are characterized by the same structural parameters at fixed mass and they follow the same scaling relations. On the other hand, the population of field elliptical galaxies at z~1.3 shows a significant lack of massive (M_*_>2x10^11^M_{sun}_) and large (R_e_>4-5kpc) elliptical galaxies with respect to the cluster. Nonetheless, at M_*_<2x10^11^M_{sun}_, the two populations are similar. The size-mass relation of cluster and field ellipticals at z~1.3 clearly defines two different regimes, above and below a transition mass m_t_~=2-3x10^10^M_{sun}_ at lower masses the relation is nearly flat (R_e_{prop}M*^-0.1+/-0.2^), the mean radius is nearly constant at ~1kpc and, consequently, {Sigma}_Re_~={Sigma}_1kpc_ while, at larger masses, the relation is R_e_{prop}M*^0.64+/-0.09^. The transition mass marks the mass at which galaxies reach the maximum stellar mass density. Also the {Sigma}_1kpc_-mass relation follows two different regimes, above and below the transition mass ({Sigma}_1kpc_{prop}M*_1.07<mt_^0.64>mt^) defining a transition mass density {Sigma}_1kpc_~=2-3x10^3^M_{sun}_/pc^2^. The effective stellar mass density {Sigma}_Re_ does not correlate with mass; dense/compact galaxies can be assembled over a wide mass regime, independently of the environment. The central stellar mass density, {Sigma}_1kpc_, besides being correlated with the mass, is correlated to the age of the stellar population: the higher the central stellar mass density, the higher the mass, the older the age of the stellar population. While we found some evidence of environmental effects on the elliptical galaxies as a population, we did not find differences between the intrinsic properties of cluster and field elliptical galaxies at comparable redshift. The structure and the shaping of elliptical galaxies at z~1.3 do not depend on the environment. However, a dense environment seems to be more efficient in assembling high-mass large ellipticals, much rarer in the field at this redshift. The correlation found between the central stellar mass density and the age of the galaxies beside the mass shows the close connection of the central regions to the main phases of mass growth.
- ID:
- ivo://CDS.VizieR/J/AJ/126/2152
- Title:
- Cluster And Infall Region Nearby Survey. I
- Short Name:
- J/AJ/126/2152
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CAIRNS (Cluster and Infall Region Nearby Survey) project is a spectroscopic survey of the infall regions surrounding eight nearby, rich, X-ray-luminous clusters of galaxies. We have collected 15654 redshifts (3471 new or remeasured) within ~5-10h^-1^Mpc of the centers of the clusters, making it the largest study of the infall regions of clusters. We determine cluster membership and the mass profiles of the clusters based on the phase-space distribution of the galaxies. All of the clusters display decreasing velocity dispersion profiles. The mass profiles are fitted well by functional forms based on numerical simulations but exclude an isothermal sphere. Specifically, Navarro et al. (1997ApJ...490..493N) and Hernquist (1990ApJ...356..359H) models provide good descriptions of cluster mass profiles to their turnaround radii. Our sample shows that the predicted infall pattern is ubiquitous in rich, X-ray-luminous clusters over a large mass range. The caustic mass estimates are in excellent agreement with independent X-ray estimates at small radii and with virial estimates at intermediate radii. The mean ratio of the caustic mass to the X-ray mass is 1.03+/-0.11, and the mean ratio of the caustic mass to the virial mass (when corrected for the surface pressure term) is 0.93+/-0.07. We further demonstrate that the caustic technique provides reasonable mass estimates even in merging clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1078
- Title:
- Cluster and Infall Region Nearby Survey. II
- Short Name:
- J/AJ/128/1078
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CAIRNS (Cluster and Infall Region Nearby Survey) is a spectroscopic survey of the infall regions surrounding nine nearby rich clusters of galaxies. In our previous paper (Cat. <J/AJ/126/2152>), we used redshifts within ~10h_-1_ Mpc of the centers of the clusters to determine the mass profiles of the clusters based on the phase-space distribution of the galaxies. Here, we use Two Micron All Sky Survey (Cat. <II/246>) photometry and an additional 515 redshifts to investigate the environmental dependence of near-infrared mass-to-light ratios.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A82
- Title:
- Cluster candidates for joint X-rays and SZ surveys
- Short Name:
- J/A+A/614/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The combination of X-ray and Sunyaev-Zeldovich (SZ) observations can potentially improve the cluster detection efficiency, when compared to using only one of these probes, since both probe the same medium, the hot ionized gas of the intra-cluster medium. We present a method based on matched multifrequency filters (MMF) for detecting galaxy clusters from SZ and X-ray surveys. This method builds on a previously proposed joint X-ray-SZ extraction method and allows the blind detection of clusters, that is finding new clusters without knowing their position, size, or redshift, by searching on SZ and X-ray maps simultaneously. The proposed method is tested using data from the ROSAT all-sky survey and from the Planck survey. The evaluation is done by comparison with existing cluster catalogues in the area of the sky covered by the deep SPT survey. Thanks to the addition of the X-ray information, the joint detection method is able to achieve simultaneously better purity, better detection efficiency, and better position accuracy than its predecessor Planck MMF, which is based on SZ maps alone. For a purity of 85%, the X-ray-SZ method detects 141 confirmed clusters in the SPT region; to detect the same number of confirmed clusters with Planck MMF, we would need to decrease its purity to 70%. We provide a catalogue of 225 sources selected by the proposed method in the SPT footprint, with masses ranging between 0.7 and 14.5x10^14^M_{sun}_ and redshifts between 0.01 and 1.2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/351/265
- Title:
- Cluster galaxy circular velocity function
- Short Name:
- J/MNRAS/351/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present galaxy circular velocity functions (GCVFs) for 34 low-redshift (z<~0.15) clusters identified in the Sloan Digital Sky Survey (SDSS, Cat. <J/AJ/123/567>), for 15 clusters drawn from dark matter simulations of hierarchical structure growth in a {LAMBDA}CDM cosmology, and for ~22000 SDSS field galaxies. We find that the simulations successfully reproduce the shape, amplitude and scatter in the observed distribution of cluster galaxy circular velocities. The power-law slope of the observed cluster GCVF is ~-2.4, independent of cluster velocity dispersion. The average slope of the simulated GCVFs is somewhat steeper, although formally consistent given the errors. We find that the effects of baryons on galaxy rotation curves is to flatten the simulated cluster GCVF into better agreement with observations. The cumulative GCVFs of the simulated clusters are very similar across a wide range of cluster masses, provided individual subhalo circular velocities are scaled by the circular velocities of the parent cluster. The scatter is consistent with that measured in the cumulative, scaled observed cluster GCVF. Finally, the observed field GCVF deviates significantly from a power law, being flatter than the cluster GCVF at circular velocities less than 200km/s.
