- ID:
- ivo://CDS.VizieR/J/A+A/547/A57
- Title:
- Swift X-ray Telescope Cluster Survey
- Short Name:
- J/A+A/547/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new sample of X-ray selected galaxy groups and clusters serendipitously observed with Swift and the X-ray Telescope (XRT). We searched the XRT archive for extended sources among 336 GRB fields with galactic latitude |b|>20{deg}. Our selection algorithm yields a flux-limited sample of 72 X-ray groups and clusters with a well defined selection function and negligible contamination. The sky coverage of the survey goes from the total 40deg^2^ to 1deg^2^ at a flux limit of 10^-14^erg/s/cm^-2 (0.5-2keV). All the X-ray sources are detected in the Swift-XRT soft (0.5-2keV) band.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/567/A89
- Title:
- Swift X-ray Telescope Cluster Survey. II.
- Short Name:
- J/A+A/567/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectral analysis of a new, flux-limited sample of 72 X-ray selected clusters of galaxies identified with the X-ray Telescope (XRT) on board the Swift satellite down to a flux limit of ~10^-14^erg/s/cm2 (SWXCS). We carry out a detailed X-ray spectral analysis with the twofold aim of measuring redshifts and characterizing the properties of the intracluster medium (ICM) for the majority of the SWXCS sources. Optical counterparts and spectroscopic or photometric redshifts for some of the sources are obtained with a cross-correlation with the NASA/IPAC Extragalactic Database. Additional photometric redshifts are computed with a dedicated follow-up program with the Telescopio Nazionale Galileo and a cross-correlation with the SDSS. In addition, we also blindly search for the Hydrogen-like and He-like iron K_{alpha}_ emission line complex in the X-ray spectrum. We detect the iron emission lines in 35% of the sample, and hence obtain a robust measure of the X-ray redshift z_X_ with typical rms error 1-5%. We use z_X_ whenever the optical redshift is not available. Finally, for all the sources with measured redshift, background-subtracted spectra are fitted with a single-temperature mekal model to measure global temperature, X-ray luminosity and iron abundance of the ICM. We perform extensive spectral simulations to accounts for fitting bias, and to assess the robustness of our results. We derive a criterion to select reliable best-fit models and an empirical formula to account for fitting bias. The bias-corrected values are then used to investigate the scaling properties of the X-ray observables.
- ID:
- ivo://CDS.VizieR/J/ApJS/216/28
- Title:
- SWXCS III. Cluster catalog from 2005-2012 Swift data
- Short Name:
- J/ApJS/216/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Swift X-ray Cluster Survey (SWXCS) catalog obtained using archival data from the X-ray telescope (XRT) on board the Swift satellite acquired from 2005 February to 2012 November, extending the first release of the SWXCS. The catalog provides positions, soft fluxes, and, when possible, optical counterparts for a flux-limited sample of X-ray group and cluster candidates. We consider the fields with Galactic latitude |b|>20{deg} to avoid high H I column densities. We discard all of the observations targeted at groups or clusters of galaxies, as well as particular extragalactic fields not suitable to search for faint extended sources. We finally select ~3000 useful fields covering a total solid angle of ~400deg^2^. We identify extended source candidates in the soft-band (0.5-2keV) images of these fields using the software EXSdetect, which is specifically calibrated for the XRT data. Extensive simulations are used to evaluate contamination and completeness as a function of the source signal, allowing us to minimize the number of spurious detections and to robustly assess the selection function. Our catalog includes 263 candidate galaxy clusters and groups down to a flux limit of 7x10^-15^erg/cm2/s in the soft band, and the logN-logS is in very good agreement with previous deep X-ray surveys. The final list of sources is cross-correlated with published optical, X-ray, and Sunyaev-Zeldovich catalogs of clusters. We find that 137 sources have been previously identified as clusters in the literature in independent surveys, while 126 are new detections. Currently, we have collected redshift information for 158 sources (60% of the entire sample).
- ID:
- ivo://CDS.VizieR/J/MNRAS/403/2063
- Title:
- SXDF X-ray groups and galaxy clusters
- Short Name:
- J/MNRAS/403/2063
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for galaxy clusters in the Subaru-XMM Deep Field (SXDF). We reach a depth for a total cluster flux in the 0.5-2keV band of 2x10^-15^erg/cm^2^/s over one of the widest XMM-Newton contiguous raster surveys, covering an area of 1.3deg^2^. Cluster candidates are identified through a wavelet detection of extended X-ray emission. The red-sequence technique allows us to identify 57 cluster candidates. We report on the progress with the cluster spectroscopic follow-up and derive their properties based on the X-ray luminosity and cluster scaling relations.
- ID:
- ivo://CDS.VizieR/J/A+A/445/819
- Title:
- Systems of galaxies in Shapley supercluster
- Short Name:
- J/A+A/445/819
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the largest compilation of galaxies with redshift in the region of the Shapley Supercluster (Proust et al., 2004 in prep., 2006A&A...447..133P), we identified 122 galaxy systems, 60 of which are new systems. Using the SuperCOSMOS catalogue, we have assigned b_j_ magnitudes to each galaxy in our compilation. The sample of galaxy systems was used to estimate the mass function of systems in the range 10^13^ to 10^15^M_{sun}/h^-1^. We computed a lower value to the total mass in the region of the Shapley Supercluster with this mass function. Using 15 mock catalogues we derived the mean mass that these kinds of systems have before comparing it with that obtained from the real data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/248
- Title:
- 44 SZ-selected galaxy clusters ACT observations
- Short Name:
- J/MNRAS/461/248
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present galaxy velocity dispersions and dynamical mass estimates for 44 galaxy clusters selected via the Sunyaev-Zel'dovich (SZ) effect by the Atacama Cosmology Telescope. Dynamical masses for 18 clusters are reported here for the first time. Using N-body simulations, we model the different observing strategies used to measure the velocity dispersions and account for systematic effects resulting from these strategies. We find that the galaxy velocity distributions may be treated as isotropic, and that an aperture correction of up to 7 per cent in the velocity dispersion is required if the spectroscopic galaxy sample is sufficiently concentrated towards the cluster centre. Accounting for the radial profile of the velocity dispersion in simulations enables consistent dynamical mass estimates regardless of the observing strategy. Cluster masses M_200_ are in the range (1-15)x10^14^M_{sun}_. Comparing with masses estimated from the SZ distortion assuming a gas pressure profile derived from X-ray observations gives a mean SZ-to-dynamical mass ratio of 1.10+/-0.13, but there is an additional 0.14 systematic uncertainty due to the unknown velocity bias; the statistical uncertainty is dominated by the scatter in the mass-velocity dispersion scaling relation. This ratio is consistent with previous determinations at these mass scales.
1037. The A3528 complex
- ID:
- ivo://CDS.VizieR/J/MNRAS/320/387
- Title:
- The A3528 complex
- Short Name:
- J/MNRAS/320/387
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a redshift survey of galaxies in the A3528 complex, a chain of interacting clusters in the core of the Shapley Concentration. The spectroscopic observations were performed at the 3.6-m ESO telescope at La Silla, equipped with the OPTOPUS multifibre spectrograph, on the nights of 1991 March 8-9 (for the Field 10) and from 1993 February 23-27.
- ID:
- ivo://CDS.VizieR/J/AJ/157/81
- Title:
- The Arecibo PPS Survey. I. Harvesting ALFALFA
- Short Name:
- J/AJ/157/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a multi-objective campaign of targeted 21 cm H I line observations of sources selected from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey and galaxies identified by their morphological and photometric properties in the Sloan Digital Sky Survey. The aims of this program have been (1) to confirm the reality of some ALFALFA sources whose enigmatic nature suggest additional multiwavelength observations; (2) to probe the low signal-to-noise ratio (S/N) regime, below the ALFALFA reliability limit; and (3) to explore the feasibility of using optical morphology, color, and surface brightness to identify gas-rich objects in the region of the Pisces-Perseus Supercluster (PPS) whose H I fluxes are below the ALFALFA sensitivity limit at that distance. As expected, the reliability of ALFALFA detections depends strongly on the S/N of the H I line signal and its coincidence with a probable stellar counterpart identified by its optical properties, suggestive of ongoing star formation. The identification of low-mass, star-forming populations enables targeted H I line observations to detect galaxies with H I line fluxes below the ALFALFA sensitivity limits in fixed local volumes (D<100 Mpc). The method explored here serves as the basis for extending the sample of gas-bearing objects as part of the ongoing Arecibo Pisces-Perseus Supercluster Survey (APPSS).
- ID:
- ivo://CDS.VizieR/J/ApJ/746/178
- Title:
- The augmented maxBCG cluster catalog
- Short Name:
- J/ApJ/746/178
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Reducing the scatter between cluster mass and optical richness is a key goal for cluster cosmology from photometric catalogs. We consider various modifications to the red-sequence-matched filter richness estimator of Rozo et al. (Paper I, 2009ApJ...703..601R) implemented on the maxBCG cluster catalog and evaluate the impact of these changes on the scatter in X-ray luminosity (L_X_) at fixed richness, using L_X_ from the ROSAT All-Sky Catalog as the best mass proxy available for the large area required. Most significantly, we find that deeper luminosity cuts can reduce the recovered scatter, finding that {sigma}_lnLx|{lambda}_=0.63+/-0.02 for clusters with M_500c_>~1.6x10^14^h^-1^_70_M_{sun}_. The corresponding scatter in mass at fixed richness is {sigma}_lnM|{lambda}_~0.2-0.3 depending on the richness, comparable to that for total X-ray luminosity. We find that including blue galaxies in the richness estimate increases the scatter, as does weighting galaxies by their optical luminosity. We further demonstrate that our richness estimator is very robust. Specifically, the filter employed when estimating richness can be calibrated directly from the data, without requiring a priori calibrations of the red sequence. We also demonstrate that the recovered richness is robust to up to 50% uncertainties in the galaxy background, as well as to the choice of photometric filter employed, so long as the filters span the 4000{AA} break of red-sequence galaxies. Consequently, our richness estimator can be used to compare richness estimates of different clusters, even if they do not share the same photometric data. Appendix A includes "easy-bake" instructions for implementing our optimal richness estimator, and we are releasing an implementation of the code that works with Sloan Digital Sky Survey data, as well as an augmented maxBCG catalog with the {lambda} richness measured for each cluster.
1040. The BAX Database
- ID:
- ivo://CDS.VizieR/B/bax
- Title:
- The BAX Database
- Short Name:
- B/bax
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BAX, Base de Donnees Amas de Galaxies X (http://bax.ast.obs-mip.fr), a multi-wavelength database dedicated to X-ray clusters and groups of galaxies allowing detailed information retrieval. BAX is designed to support astronomical research by providing access to published measurements of the main physical quantities and to the related bibliographic references: basic data stored in the database are cluster/group identifiers, equatorial coordinates, redshift, flux, X-ray luminosity (in the ROSAT band) and temperature, and links to additional linked parameters (in X-rays, such as spatial profile parameters, as well as SZ parameters of the hot gas, lensing measurements, and data at other wavelengths, such as optical and radio). The clusters and groups in BAX can be queried by the basic parameters as well as the linked parameters or combinations of these. We expect BAX to become an important tool for the astronomical community. BAX will optimize various aspects of the scientific analysis of X-ray clusters and groups of galaxies, from proposal planning to data collection, interpretation and publication, from both ground based facilities like MEGACAM (CFHT), VIRMOS (VLT) and space missions like XMM-Newton, Chandra and Planck.
