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- ID:
- ivo://CDS.VizieR/J/MNRAS/474/3324
- Title:
- Multicomponent matched filter test
- Short Name:
- J/MNRAS/474/3324
- Date:
- 02 Mar 2022 00:06:44
- Publisher:
- CDS
- Description:
- We describe a multicomponent matched filter (MCMF) cluster confirmation tool designed for the study of large X-ray source catalogues produced by the upcoming X-ray all-sky survey mission eROSITA. We apply the method to confirm a sample of 88 clusters with redshifts 0.05<z<0.8 in the recently published 2RXS catalogue from the ROSAT All-Sky Survey (RASS) over the 208 deg^2^ region overlapped by the Dark Energy Survey (DES) Science Verification (DES-SV) data set. In our pilot study, we examine all X-ray sources, regardless of their extent. Our method employs a multicolour red sequence (RS) algorithm that incorporates the X-ray count rate and peak position in determining the region of interest for follow-up and extracts the positionally and colour-weighted optical richness {lambda}_MCMF_ as a function of redshift for each source. Peaks in the {lambda}_MCMF_-redshift distribution are identified and used to extract photometric redshifts, richness and uncertainties. The significances of all optical counterparts are characterized using the distribution of richnesses defined along random lines of sight. These significances are used to extract cluster catalogues and to estimate the contamination by random superpositions of unassociated optical systems. The delivered photometric redshift accuracy is {delta}z/(1+z)=0.010. We find a well-defined X-ray luminosity-{lambda}_MCMF_ relation with an intrinsic scatter of {delta}ln({lambda}_MCMF_|Lx)=0.21. Matching our catalogue with the DES-SV redMaPPer catalogue yields good agreement in redshift and richness estimates; comparing our catalogue with the South Pole Telescope (SPT) selected clusters shows no inconsistencies. SPT clusters in our data set are consistent with the high-mass extension of the RASS-based {lambda}_MCMF_-mass relation.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A29
- Title:
- Multi-frequency galaxy group catalogue
- Short Name:
- J/A+A/590/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To understand the role of the environment in galaxy formation, evolution, and present-day properties, it is essential to study the multi-frequency behavior of different galaxy populations under various environmental conditions. We study the stellar mass functions of different galaxy populations in groups as a function of their large scale environments using multi-frequency observations. We crossmatch the SDSS DR10 group catalogue with GAMA Data Release 2 and Wide-field Survey Explorer (WISE) data to construct a catalogue of 1651 groups and 11436 galaxies containing photometric information in 15 different wavebands ranging from ultraviolet (0.152-micron) to mid-infrared (22-micron). We perform the spectral energy distribution (SED) fitting of galaxies using the MAGPHYS code and estimate the rest frame luminosities and stellar masses. We use the 1/Vmax method to estimate the galaxy stellar mass and luminosity functions, and the luminosity density field of galaxies to define the large scale environment of galaxies. The stellar mass functions of both central and satellite galaxies in groups are different in low and high density large scale environments. Satellite galaxies in high density environments have a steeper low mass end slope compared to low density environments, independently of the galaxy morphology. Central galaxies in low density environments have a steeper low mass end slope but the difference disappears for fixed galaxy morphology. The characteristic stellar mass of satellite galaxies is higher in high density environments and the difference exists only for galaxies with elliptical morphologies. Galaxy formation in groups is more efficient in high density large scale environments. Groups in high density environments have higher abundances of satellite galaxies, irrespective of the satellite galaxy morphology. The elliptical satellite galaxies are generally more massive in high density environments. The stellar masses of spiral satellite galaxies show no dependence on the large scale environment.
- ID:
- ivo://CDS.VizieR/J/ApJ/621/53
- Title:
- Multiple arc systems in A1689
- Short Name:
- J/ApJ/621/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze deep multicolor Advanced Camera images of the largest known gravitational lens, A1689. Radial and tangential arcs delineate the critical curves in unprecedented detail, and many small counterimages are found near the center of mass.
- ID:
- ivo://CDS.VizieR/J/ApJ/749/97
- Title:
- Multiple lensed images in MCS J1206.2-0847
- Short Name:
- J/ApJ/749/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a strong-lensing analysis of the galaxy cluster MACS J1206.2-0847 (z=0.44) using UV, Optical, and IR, HST/ACS/WFC3 data taken as part of the CLASH multi-cycle treasury program, with VLT/VIMOS spectroscopy for some of the multiply lensed arcs. The CLASH observations, combined with our mass model, allow us to identify 47 new multiply lensed images of 12 distant sources. These images, along with the previously known arc, span the redshift range 1<~z<~5.5, and thus enable us to derive a detailed mass distribution and to accurately constrain, for the first time, the inner mass profile of this cluster. We find an inner profile slope of dlog{Sigma}/dlog{theta}=~-0.55+/-0.1 (in the range [1",53"], or 5kpc<~r<~300kpc), as commonly found for relaxed and well-concentrated clusters. Using the many systems uncovered here we derive credible critical curves and Einstein radii for different source redshifts. For a source at z_s_=~2.5, the critical curve encloses a large area with an effective Einstein radius of {theta}_E_=28"+/-3", and a projected mass of (1.34+/-0.15)x10^14^M_{sun}_. From the current understanding of structure formation in concordance cosmology, these values are relatively high for clusters at z~0.5, so that detailed studies of the inner mass distribution of clusters such as MACS J1206.2-0847 can provide stringent tests of the {Lambda}CDM paradigm.
- ID:
- ivo://CDS.VizieR/J/A+A/399/813
- Title:
- Multiple merging events in Abell 521
- Short Name:
- J/A+A/399/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed spatial and dynamical analysis of the central ~2.2Mpc(Ho=75km/s/Mpc) region of the galaxy cluster Abell 521 (z=0.247), based on 238 spectra (of which 191 new measurements) obtained at the 3.6m Telescope of the European Southern Observatory and at the Canada-France-Hawaii Telescope. From the analysis of the 125 galaxies that are confirmed members of the cluster, we derive a location ("mean" velocity) of C_BI_=74019^{+112}^_{-125}_km/s and detect a complex velocity distribution with high velocity scale ("dispersion", S_BI_=1325^{+145}^_{-100}_km/s), but clear departure from a single Gaussian component. When excluding a possible background group of four galaxies, the velocity dispersion remains still large (~1200 km/s).
- ID:
- ivo://CDS.VizieR/J/ApJ/668/643
- Title:
- Multiply imaged gravitational lens systems
- Short Name:
- J/ApJ/668/643
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a reconstruction of the mass distribution of galaxy cluster Abell 1689 at z=0.18 using detected strong lensing features from deep ACS observations and extensive ground based spectroscopy. Earlier analyses have reported up to 32 multiply imaged systems in this cluster, of which only 3 were spectroscopically confirmed. In this work, we present a parametric strong lensing mass reconstruction using 34 multiply imaged systems of which 24 have newly determined spectroscopic redshifts, which is a major step forward in building a robust mass model. In turn, the new spectroscopic data allows a more secure identification of multiply imaged systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/114
- Title:
- Multi-wavelength study of clusters of galaxies. II.
- Short Name:
- J/ApJ/761/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy clusters provide powerful laboratories for the study of galaxy evolution, particularly the origin of correlations of morphology and star formation rate (SFR) with density. We construct visible to MIR spectral energy distributions of galaxies in eight low-redshift (z<0.3) clusters and use them to measure stellar masses and SFRs as a function of environment. A partial correlation analysis indicates that the SFRs of star-forming galaxies (SFGs) depend strongly on M_*_ (>99% confidence) with no dependence on R/R_200_ or projected local density at fixed mass. A merged sample of galaxies from the five best measured clusters shows <SFR>{prop.to}(R/R_200_)^1.1+/-0.3^ for galaxies with R/R_200_<=0.4. A decline in the fraction of SFGs toward the cluster center contributes most of this effect, but it is accompanied by a reduction in <SFR> for SFGs with R<=0.1R_200_. The increase in the fraction of SFGs toward larger R/R_200_ and the isolation of SFGs with reduced SFRs near the cluster center are consistent with the truncation of star formation by ram-pressure stripping, as is the tendency for more massive SFGs to have higher SFRs. We conclude that stripping is more likely than slower processes to drive the properties of SFGs with R<0.4R_200_ in clusters. We also find that galaxies near the cluster center are more massive than galaxies farther out in the cluster at ~3.5{sigma}, which suggests that dynamical relaxation significantly impacts the distribution of cluster galaxies as the clusters evolve.
- ID:
- ivo://CDS.VizieR/J/A+A/392/795
- Title:
- Multi-wavelength study of 2 galaxy clusters
- Short Name:
- J/A+A/392/795
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from optical, X-ray and radio observations of two X-ray bright (L_X_~10^45^erg/s) galaxy clusters. Abell 1451 is at redshift z=0.1989 and has line-of-sight velocity dispersion {sigma}_V_=1330km/s as measured from 57 cluster galaxies. It has regular X-ray emission without signs of substructure, a Gaussian velocity distribution, lack of a cooling flow region and significant deviations from the observed scaling laws between luminosity, temperature and velocity dispersion, indicating a possible merging shock. There is only one spectroscopically confirmed cluster radio galaxy, which is close to the X-ray peak. 1RXS J131423.6-251521 (for short RXJ1314-25) has z=0.2474 and {sigma}_V_=1100km/s from 37 galaxies. There are two distinct galaxy groups with a projected separation of ~700kpc. The velocity histogram is bi-modal with a redshift-space separation of ~1700km/s, and the X-ray emission is double peaked. Although there are no spectroscopically confirmed cluster radio galaxies, we have identified a plausible relic source candidate.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/777
- Title:
- Multiwavelength study of RX J1117.4+0743
- Short Name:
- J/ApJ/664/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of the poor cluster RX J1117.4+0743 ([VMF98] 097) at z=0.485, based on GMOS/Gemini South g' and r' photometry and spectroscopy, and XMM-Newton observations. We examine its nature and surroundings by analyzing the projected galaxy distribution, the galaxy velocity distribution, the weak-lensing mass reconstruction, and the X-ray spectroscopy and imaging.
