- ID:
- ivo://CDS.VizieR/J/AJ/141/99
- Title:
- BATC and SDSS photometry of A2589 cluster
- Short Name:
- J/AJ/141/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Smooth X-ray morphology and non-detection of a radio source at the center of A2589 indicate that it is a typical case of a well-relaxed regular galaxy cluster. In this paper, we present a multicolor photometry for A2589 (z=0.0414) with 15 intermediate bands in the Beijing-Arizona-Taiwan-Connecticut (BATC) system which covers an optical wavelength range from 3000{AA} to 10000{AA}. The spectral energy distributions (SEDs) for more than 5000 sources are achieved down to V~20mag in about a 1{deg}^2^ field. A2589 has also been covered by the Sloan Digital Sky Survey (SDSS) in photometric mode only. A cross-identification of the BATC-detected galaxies with the SDSS photometric catalog yields 1199 galaxies brighter than i=19.5mag, among which 68 member galaxies with known spectroscopic redshifts are found. After combining the SDSS five-band photometric data and the BATC SEDs, photometric redshift is applied to these galaxies to select faint member galaxies. The color-magnitude relation is taken as a further restriction of early-type cluster galaxies. As a result, 106 galaxies are newly selected as member galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/RAA/10.1
- Title:
- BATC photometry in A98 cluster
- Short Name:
- J/other/RAA/10.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An optical photometric observation with the Beijing-Arizona-Taiwan-Connecticut (BATC) multicolor system is carried out for A98 (z=0.104), a galaxy cluster with two large enhancements in X-ray surface brightness. Spectral energy distributions (SEDs) covering 15 intermediate bands are obtained for all sources detected down to V~20mag in a field of 58'x58'. After star-galaxy separation with color-color diagrams, a photometric redshift technique is applied to the galaxy sample for further membership determination. The color-magnitude relation is taken as a further restriction of the early-type cluster galaxies. As a result, a list of 198 faint member galaxies is achieved. Based
- ID:
- ivo://CDS.VizieR/J/other/RAA/12.1381
- Title:
- BATC photometry on A119
- Short Name:
- J/other/RAA/12.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 (z=0.0442) with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58'x58', there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies (called sample I). Based on the spectral energy distributions of 1376 galaxies brighter than i_BATC_=19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample (called sample II) of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynamically complex cluster with at least three prominent substructures in the central region within 1Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segregations is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A81
- Title:
- Bayesian group finder applied to the 2MRS data
- Short Name:
- J/A+A/618/A81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We propose a probabilistic galaxy group detection algorithm based on marked point processes with interactions. The pattern of galaxy groups in a catalogue is seen as a random set of interacting objects. The positions and the interactions of these objects are governed by a probability density. The parameters of the probability density are chosen using a priori knowledge. The estimator of the unknown cluster pattern is given by the configuration of objects maximising the proposed probability density. Adopting the Bayesian framework, the proposed probability density is maximised using a simulated annealing (SA) algorithm. At fixed temperature, the SA algorithm is a Monte Carlo sampler of the probability density. Hence, the method provides "for free" additional information such as the probabilities that a point or two points in the observation domain belong to the cluster pattern, respectively. These supplementary tools allow the construction of tests and techniques to validate and to refine the detection result. To test the feasibility of the proposed methodology, we applied it to the well-studied 2MASS Redshift Survey (2MRS) data set. Compared to previously published Friends-of-Friends (FoF) group finders, the proposed Bayesian group finder gives overall similar results. However, for specific applications, like the reconstruction of the local Universe, the details of the grouping algorithms are important.
- ID:
- ivo://CDS.VizieR/J/A+A/560/A78
- Title:
- B-Band catalog of sources in Abell 3376
- Short Name:
- J/A+A/560/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The cluster Abell 3376 is a merging cluster of galaxies at redshift z=0.046. It is famous mostly for its giant radio arcs, and shows an elongated and highly substructured X-ray emission, but has not been analysed in detail at optical wavelengths. To improve our understanding of the effects of the major cluster merger on the galaxy properties, we analyse the galaxy luminosity function (GLF) in the B band in several regions as well as the dynamical properties of the substructures.
- ID:
- ivo://CDS.VizieR/J/A+A/430/411
- Title:
- B-band photometry of ellipticals in Virgo
- Short Name:
- J/A+A/430/411
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a complete CCD imaging survey of 226 elliptical galaxies in the North-East quadrant of the Virgo cluster, representative of the properties of giant and dwarf elliptical galaxies in this cluster. We fit their radial light profiles with the Sersic r^1/n^ model of light distribution. We confirm the result of Graham & Guzman (2003AJ....125.2936G) that the apparent dichotomy between E and dE galaxies in the luminosity-<{mu}>_e_ plane no longer appears when other structural parameters are considered and can be entirely attributed to the onset of "core" galaxies at B_T_~-20.5mag. When "core" galaxies are not considered, E and dE form a unique family with n linearly increasing with the luminosity. For 90 galaxies we analyze the B-I color indices, both in the nuclear and in the outer regions. Both indices are bluer toward fainter luminosities. We find also that the outer color gradients do not show any significant correlation with the luminosity. The scatter in all color indicators increases significantly toward lower luminosities, e.g. galaxies fainter than B_T_~-15 have a B-I spread>0.5mag.
- ID:
- ivo://CDS.VizieR/J/MNRAS/379/867
- Title:
- BCG C4 cluster catalog
- Short Name:
- J/MNRAS/379/867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the Sloan Digital Sky Survey (SDSS) to construct a sample of 625 brightest group and cluster galaxies (BCGs) together with control samples of non-BCGs matched in stellar mass, redshift and colour. We investigate how the systematic properties of BCGs depend on stellar mass and on their privileged location near the cluster centre. The groups and clusters that we study are drawn from the C4 catalogue of Miller et al. (2005, Cat. <J/AJ/130/968>) but we have developed improved algorithms for identifying the BCG and for measuring the cluster velocity dispersion. Since the SDSS photometric pipeline tends to underestimate the luminosities of large galaxies in dense environments, we have developed a correction for this effect which can be readily applied to the published catalogue data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1223
- Title:
- BCG high radio-frequency properties
- Short Name:
- J/MNRAS/453/1223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We consider the high radio-frequency (15-353GHz) properties and variability of 35 brightest cluster galaxies (BCGs). These are the most core-dominated sources drawn from a parent sample of more than 700 X-ray selected clusters, thus allowing us to relate our results to the general population. We find that >=6.0 percent of our parent sample (>=15.1 percent if only cool-core clusters are considered) contain a radio source at 150GHz of at least 3mJy (~1x10^23^W/Hz at our median redshift of z~0.13). Furthermore, >=3.4 percent of the BCGs in our parent sample contain a peaked component (Gigahertz Peaked Spectrum, GPS) in their spectra that peaks above 2GHz, increasing to >=8.5 percent if only cool-core clusters are considered. We see little evidence for strong variability at 15GHz on short (week-month) time-scales although we see variations greater than 20 percent at 150GHz over six-month time frames for 4 of the 23 sources with multi-epoch observations. Much more prevalent is long-term (year-decade time-scale) variability, with average annual amplitude variations greater than 1 percent at 15GHz being commonplace. There is a weak trend towards higher variability as the peak of the GPS-like component occurs at higher frequency. We demonstrate the complexity that is seen in the radio spectra of BCGs and discuss the potentially significant implications of these high-peaking components for Sunyaev-Zel'dovich cluster searches.
- ID:
- ivo://CDS.VizieR/J/ApJ/704/1586
- Title:
- BCGs with radio AGN
- Short Name:
- J/ApJ/704/1586
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The radio active galactic nucleus (AGN) feedback in X-ray cool cores has been proposed as a crucial ingredient in the evolution of baryonic structures. However, it has long been known that strong radio AGNs also exist in "noncool core" clusters, which brings up the question whether an X-ray cool core is always required for the radio feedback. In this work, we present a systematic analysis of brightest cluster galaxies (BCGs) and strong radio AGNs in 152 groups and clusters from the Chandra archive. All 69 BCGs with radio AGN more luminous than 2x10^23^W/Hz at 1.4GHz are found to have X-ray cool cores. BCG cool cores can be divided into two classes: the large cool core (LCC) class and the corona class. As examples of the corona class, we also present detailed analyses of a BCG corona associated with a strong radio AGN (ESO 137-006 in A3627) and one of the faintest coronae known (NGC 4709 in the Centaurus cluster).
- ID:
- ivo://CDS.VizieR/J/A+A/649/A42
- Title:
- BCG up to z=1.80 physical properties
- Short Name:
- J/A+A/649/A42
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Brightest cluster galaxies (BCGs) have grown by accreting numerous smaller galaxies and can be used as tracers of cluster formation and evolution in the cosmic web. However, there is still a controversy on the main epoch of formation of BCGs, since some authors believe they have already formed before redshift z=2, while others still find them to evolve at more recent epochs. We aim to analyse the physical properties of a large sample of BCGs covering a wide redshift range up to z=1.8 and analysed in a homogeneous way, to see if their characteristics vary with redshift. As a first step, we also present a new tool to define for each cluster which galaxy is the BCG. For a sample of 137 clusters with HST images in the optical and/or infrared, we analyse the BCG properties by applying GALFIT with one or two Sersic components. For each BCG, we compute the Sersic index, effective radius, major axis position angle, surface brightness. We then search for correlations of these quantities with redshift. We find that BCGs follow the Kormendy relation (between the effective radius and the mean surface brightness), with a slope that remains constant with redshift, but with a variation with redshift of the ordinate at the origin. Although the trends are faint, we find that both the absolute magnitudes and effective radii tend to become respectively brighter and bigger with decreasing redshift. On the other hand, we find no significant correlation of the mean surface brightnesses or Sersic indices with redshift. The major axes of the cluster elongations and of the BCGs agree within 30 degrees for 73% of our clusters at redshift z<=0.9. Our results agree with the BCGs being mainly formed before redshift z=2. The alignment of the major axes of BCGs with their clusters agree with the general idea that BCGs form at the same time as clusters by accreting matter along the filaments of the cosmic web.
