- ID:
- ivo://CDS.VizieR/J/ApJ/504/27
- Title:
- The L_X_-T Relation for Nearby Clusters
- Short Name:
- J/ApJ/504/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The X-ray luminosity-temperature relation for nearby T ~= 3.5-10 keV clusters is rederived using new ASCA temperatures and ROSAT luminosities. Both quantities are derived by directly excluding the cooling flow regions. This correction results in a greatly reduced scatter in the L_X_-T relation; cooling flow clusters are similar to others outside the small cooling flow regions. For a fit of the form L_bol_ {prop.to} T^{alpha}^, we obtain {alpha} = 2.64 +/- 0.27 (90%) and a residual rms scatter in log L_bol_ of 0.10. The derived relation can be directly compared to theoretical predictions that do not include radiative cooling. It also provides an accurate reference point for future evolution searches and comparison to cooler clusters. The new temperatures and L_X_-T relation together with a newly selected cluster sample are used to update the temperature function at z ~ 0.05. The resulting function is generally higher and flatter than, although within the errors of, the previous estimates by Edge and coworkers and Henry and Arnaud (as rederived by Eke and coworkers). For a qualitative estimate of constraints that the new data place on the density fluctuation spectrum, we apply the Press-Schechter formalism for {Omega}_0_ = 1 and 0.3. For {Omega}_0_ = 1, assuming cluster isothermality, the temperature function implies {sigma}_8_ = 0.55 +/- 0.03, while taking into account the observed cluster temperature profiles, {sigma}_8_ = 0.51 +/- 0.03, consistent with the previously derived range. The dependence of {sigma}_8_ on {Omega}_0_ is different from the earlier results because of our treatment of the slope of the fluctuation spectrum, n, as a free parameter. For the considered values of {Omega}_0_, n = -(2.0-2.3) +/- 0.3, somewhat steeper than that derived from the earlier temperature function data, in agreement with the local slope of the galaxy fluctuation spectrum from the Automatic Plate Measuring Facility (APM) survey, and significantly steeper than the standard cold dark matter prediction.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/652/A12
- Title:
- The new X-Class catalogue
- Short Name:
- J/A+A/652/A12
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Cosmological probes based on galaxy clusters rely on cluster number counts and large-scale structure information. X-ray cluster surveys are well suited for this purpose, since they are far less affected than optical surveys by projection effects, and cluster properties can be predicted with good accuracy. The XMM Cluster Archive Super Survey, X-CLASS, is a serendipitous search of X-ray-detected galaxy clusters in 4176 XMM-Newton archival observations until August 2015. All observations are clipped to exposure times of 10 and 20 ks to obtain uniformity and they span ~269 sq. deg. across the high-Galactic latitude sky (|b|>20deg). The main goal of the survey is the compilation of a well-selected cluster sample suitable for cosmological analyses. We describe the detection algorithm, the visual inspection, the verification process and the redshift validation of the cluster sample, as well as the cluster selection function computed by simulations. We also present the various metadata that are released with the catalogue, along with the redshifts of 124 clusters obtained with a dedicated multi-object spectroscopic follow-up programme. With this publication we release the new X-CLASS catalogue of 1646 well-selected X-ray-detected clusters over a wide sky area, along with their selection function. The sample spans a wide redshift range, from the local Universe up to z~1.5, with 982 spectroscopically confirmed clusters, and over 70 clusters above z=0.8. Because of its homogeneous selection and thorough verification, the cluster sample can be used for cosmological analyses, but also as a test-bed for the upcoming eROSITA observations and other current and future large-area cluster surveys. It is the first time that such a catalogue is made available to the community via an interactive database which gives access to a wealth of supplementary information, images, and data.
- ID:
- ivo://CDS.VizieR/J/A+AS/116/203
- Title:
- The redshift catalogue for galaxy clusters
- Short Name:
- J/A+AS/116/203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An extensive redshift survey has been conducted on a sample of 15 nearby (0.01<~z<~0.05) clusters of galaxies. A total number of 860 redshifts were determined by fitting of emission-lines and/or cross-correlation techniques. Of this sample, 735 galaxies are within 0.2-0.8Mpc (H_0_=50km/s/Mpc) of the center of clusters. Approximate morphological types are available for most of the galaxies. A comparison of the present redshifts with published data allows an extensive error analysis. The agreement is excellent with the most modern data, showing a zero point error of 5km/s and an overall consistency of the measurements and their uncertainties. We estimate our redshifts to have mean random errors around 30km/s. A population analysis of the clusters will be given in a forthcoming paper.
- ID:
- ivo://CDS.VizieR/J/MNRAS/301/881
- Title:
- The ROSAT brightest cluster sample - I.
- Short Name:
- J/MNRAS/301/881
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 90 per cent flux-complete sample of the 201 X-ray-brightest clusters of galaxies in the northern hemisphere ({delta}>=0{deg}), at high Galactic latitudes (|b|>= 20{deg}), with measured redshifts z<=0.3 and fluxes higher than 4.4x10^-12^erg/cm^2^/s in the 0.112.4 keV band. The sample, called the ROSAT Brightest Cluster Sample (BCS), is selected from ROSAT All-Sky Survey data and is the largest X-ray-selected cluster sample compiled to date. In addition to Abell clusters, which form the bulk of the sample, the BCS also contains the X-ray-brightest Zwicky clusters and other clusters selected from their X-ray properties alone. Effort has been made to ensure the highest possible completeness of the sample and the smallest possible contamination by non-cluster X-ray sources. X-ray fluxes are computed using an algorithm tailored for the detection and characterization of X-ray emission from galaxy clusters. These fluxes are accurate to better than 15 per cent (mean 1{sigma} error).
- ID:
- ivo://CDS.VizieR/J/ApJ/690/670
- Title:
- The Sloan lens ACS Survey. VIII.
- Short Name:
- J/ApJ/690/670
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the SLACS Survey. The Sloan Digital Sky Survey (SDSS) database is used to determine two measures of overdensity of galaxies around each lens - the projected number density of galaxies inside the tenth nearest neighbor ({Sigma}_10_) and within a cone of radius 1h^-1^Mpc (D1).
- ID:
- ivo://CDS.VizieR/J/MNRAS/341/1093
- Title:
- The Southern SHARC catalogue
- Short Name:
- J/MNRAS/341/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Southern Serendipitous High-redshift Archival Cluster (SHARC) catalogue is a X-ray selected catalogue of galaxy clusters detected in deep ROSAT observations. The survey area is 17.7deg^2^ and is selected from long (greater than 10ks) ROSAT exposures with a declination <+20deg and excluding the Galactic plane (excluding galactic latitudes within the range [-20,20]deg). Optical follow-up was performed to confirm the presence of a galaxy cluster and measure its redshift. The final catalogue contains 32 galaxy clusters with redshifts between 0.05 and 0.70 and X-ray luminosities between 7x10^35^W and 4x10^37^W. Above a redshift of 0.3 - which forms the primary subsample of the survey - there are 16 clusters; the X-ray luminosities of these clusters are all greater than 2x10^36 W. All X-ray luminosities are quoted in the 0.5-2.0keV band and were calculated using an Einstein-de Sitter cosmology with H_0_ set to 50km/s/Mpc.
- ID:
- ivo://CDS.VizieR/J/ApJS/247/25
- Title:
- The SPTpol Extended Cluster Survey
- Short Name:
- J/ApJS/247/25
- Date:
- 18 Jan 2022 14:48:55
- Publisher:
- CDS
- Description:
- We describe the observations and resultant galaxy cluster catalog from the 2770deg^2^ SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance {xi}>=5 and an additional 204 systems at 4<{xi}<5. The confirmed sample has a median mass of M_500c_~4.4x10^14^M_{sun}_h_70_^-1^ and a median redshift of z=0.49, and we have identified 44 strong gravitational lenses in the sample thus far. Radio data are used to characterize contamination to the SZ signal; the median contamination for confirmed clusters is predicted to be ~1% of the SZ signal at the {xi}>4 threshold, and <4% of clusters have a predicted contamination >10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass ({lambda}-M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4{sigma} level-with the relations intersecting at {lambda}=60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/917
- Title:
- The Super-CLASS GMRT catalogue - SCG
- Short Name:
- J/MNRAS/462/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 325MHz Giant Metrewave Radio Telescope observations of a supercluster field, known to contain five Abell clusters at redshift z~0.2. We achieve a nominal sensitivity of 34uJy/beam towards the phase centre. We compile a catalogue of 3257 sources with flux densities in the range 183uJy-1.5Jy within the entire ~6.5deg^2^ field of view. Subsequently, we use available survey data at other frequencies to derive the spectral index distribution for a sub-sample of these sources, recovering two distinct populations - a dominant population which exhibit spectral index trends typical of steep-spectrum synchrotron emission, and a smaller population of sources with typically flat or rising spectra. We identify a number of sources with ultrasteep spectra or rising spectra for further analysis, finding two candidate high-redshift radio galaxies and three gigahertz-peaked-spectrum radio sources. Finally, we derive the Euclidean-normalized differential source counts using the catalogue compiled in this work, for sources with flux densities in excess of 223uJy. Our differential source counts are consistent with both previous observations at this frequency and models of the low-frequency source population. These represent the deepest source counts yet derived at 325MHz. Our source counts exhibit the well-known flattening at mJy flux densities, consistent with an emerging population of star-forming galaxies; we also find marginal evidence of a downturn at flux densities below 308uJy, a feature so far only seen at 1.4GHz.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/119
- Title:
- The supercluster-void network. I.
- Short Name:
- J/A+AS/123/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a compilation of redshifts of rich clusters by Andernach, Tago and Stengler-Larrea (1996, in preparation) to determine superclusters of rich clusters up to a redshift of z=0.12. Superclusters were searched for with a clustering algorithm, using a neighbourhood radius of 24h^-1^Mpc (h is the Hubble constant in units of 100km/s/Mpc). The catalogue contains 220 superclusters of rich clusters, of which 90 superclusters have been determined for the first time. Table A2 gives the supercluster number, its multiplicity, centre coordinates, a list of member clusters and identifications with the catalogue by Einasto et al. (1994MNRAS.269..301E).
- ID:
- ivo://CDS.VizieR/J/A+A/642/L13
- Title:
- The Toothbrush relic 14.25GHz image
- Short Name:
- J/A+A/642/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radio relics trace shock fronts generated in the intracluster medium (ICM) during cluster mergers. The particle acceleration mechanism at the shock fronts is not yet completely understood. We observed the Toothbrush relic with the Effelsberg and Sardinia Radio Telescope at 14.25GHz and 18.6GHz, respectively. Unlike previously claimed, the integrated spectrum of the relic closely follows a power law over almost three orders of magnitude in frequency, with a spectral index of {alpha}_58MHz_^18.6GHz^=-1.16+/-0.03. Our finding is consistent with a power-law injection spectrum, as predicted by diffusive shock acceleration theory. The result suggests that there is only little magnetic field strength evolution downstream of the shock. From the lack of spectral steepening, we find that either the Sunyaev-Zeldovich decrement produced by the pressure jump is less extended than ~600kpc along the line of sight or, conversely, that the relic is located far behind in the cluster. For the first time, we detect linearly polarized emission from the "brush" at 18.6GHz. Compared to 8.3GHz, the degree of polarization across the brush increases at 18.6GHz, suggesting a strong Faraday depolarization toward lower frequencies. The observed depolarization is consistent with an intervening magnetized screen that arises from the dense ICM containing turbulent magnetic fields. The depolarization, corresponding to a standard deviation of the rotation measures as high as {sigma}_RM_=212+/-23rad/m^2^, suggests that the brush is located in or behind the ICM. Our findings indicate that the Toothbrush relic can be consistently explained by the standard scenario for relic formation.
