- ID:
- ivo://CDS.VizieR/J/MNRAS/367/156
- Title:
- C-T1 photometry in NGC 1374, 1379 and 1387
- Short Name:
- J/MNRAS/367/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of the globular cluster systems (GCSs) of the Fornax cluster galaxies NGC 1374, NGC 1379 and NGC 1387. The data consist of images from the wide-field MOSAIC imager of the Cerro Tololo Inter-American Observatory (CTIO) 4-m telescope, obtained with Washington C and Kron-Cousins R filters. The images cover a field of 36x36arcmin^2^, corresponding to 200x200kpc^2^ at the Fornax distance. Two of the galaxies, NGC 1374 and NGC 1379, are low-luminosity ellipticals while NGC 1387 is a low-luminosity lenticular. Their cluster systems are still embedded in the cluster system of NGC 1399. Therefore, the use of a large field is crucial and some differences to previous work can be explained by this. The colour distributions of all GCSs are bimodal. NGC 1387 presents a particularly distinct separation between red and blue clusters and an over-proportionally large population of red clusters. The radial distribution is different for blue and red clusters, red clusters being more concentrated towards the respective galaxies. The different colour and radial distributions point to the existence of two globular cluster subpopulations in these galaxies. Specific frequencies are in the range S_N_=1.4-2.4, smaller than the typical values for elliptical galaxies. These galaxies might have suffered tidal stripping of blue globular clusters by NGC 1399.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/2311
- Title:
- CT1 photometry of Antlia early-type galaxies
- Short Name:
- J/MNRAS/386/2311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first colour-magnitude relation (CMR) of early-type galaxies in the central region of the Antlia cluster, obtained from CCD wide-field photometry in the Washington photometric system. Integrated (C-T1) colours, T1 magnitudes, and effective radii have been measured for 93 galaxies (i.e. the largest galaxies sample in the Washington system till now) from the FS90 Antlia Group catalogue. Membership of 37 objects can be confirmed through new radial velocities and data collected from the literature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/425/477
- Title:
- Dark matter annihilation in galaxy clusters
- Short Name:
- J/MNRAS/425/477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Clusters of galaxies are potentially important targets for indirect searches for dark matter (DM) annihilation. Here we reassess the detection prospects for annihilation in massive haloes, based on a statistical investigation of 1743 clusters in the new Meta-Catalogue of X-ray Clusters (MCXC). We derive a new limit for the extragalactic DM annihilation background of at least 20 per cent of that originating from the Galaxy for an integration angle of 0.1{deg}.
- ID:
- ivo://CDS.VizieR/VII/87A
- Title:
- Data on 1889 Abell's clusters of galaxies
- Short Name:
- VII/87A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 1889 clusters from Abell's catalogue of Rich Clusters of Galaxies (1958, ApJS 3, 211) have been classified in the Bautz-Morgan system
- ID:
- ivo://CDS.VizieR/J/A+A/546/A79
- Title:
- 400d Cluster Survey Weak Lensing Programme II
- Short Name:
- J/A+A/546/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Evolution in the mass function of galaxy clusters sensitively traces both the expansion history of the Universe and cosmological structure formation. Robust cluster mass determinations are a key ingredient for a reliable measurement of this evolution, especially at high redshift. Weak gravitational lensing is a promising tool for, on average, unbiased mass estimates. This weak lensing project aims at measuring reliable weak lensing masses for a complete X-ray selected sample of 36 high redshift (0.35<z<0.9) clusters. The goal of this paper is to demonstrate the robustness of the methodology against commonly encountered problems, including pure instrumental effects, the presence of bright (8-9mag) stars close to the cluster centre, ground based measurements of high-z (z~0.8) clusters, and the presence of massive unrelated structures along the line-sight.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A64
- Title:
- 3D density & temp. profiles of 5 clusters
- Short Name:
- J/A+A/617/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the integrated total hydrostatic mass profiles of the five most massive (M_500_^SZ^>5x10^14^M_{sun}_) galaxy 500 clusters selected at z~1 via the Sunyaev-Zel'dovich effect. These objects represent an ideal laboratory to test structure formation models where the primary driver is gravity. Optimally exploiting spatially-resolved spectroscopic information from XMM-Newton and Chandra observations, we used both parametric (forward, backward) and non-parametric methods to recover the mass profiles, finding that the results are extremely robust when density and temperature measurements are both available. Our X-ray masses at R_500_ are higher than the weak lensing masses obtained from the Hubble Space Telescope (HST), with a mean ratio of 1.39^+0.47^_-0.35_. This offset goes in the opposite direction to that expected in a scenario where the hydrostatic method yields a biased, underestimated, mass. We investigated halo shape parameters such as sparsity and concentration, and compared to local X-ray selected clusters, finding hints for evolution in the central regions (or for selection effects). The total baryonic content is in agreement with the cosmic value at R_500_. Comparison with numerical simulations shows that the mass distribution and concentration are in line with expectations. These results illustrate the power of X-ray observations to probe the statistical properties of the gas and total mass profiles in this high-mass, high-redshift regime.
- ID:
- ivo://CDS.VizieR/J/A+A/396/397
- Title:
- Deep cluster survey in Chandra archival data
- Short Name:
- J/A+A/396/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I present the first results of a search for clusters of galaxies in Chandra ACIS pointed observations at high galactic latitude with exposure times larger than 10ks. The survey is being carried out using the Voronoi Tessellation and Percolation technique, which is particularly suited for the detection and accurate quantification of extended and/or low surface brightness emission in X-ray imaging observations. A new catalogue of 36 cluster candidates has been created from 5.55deg^2^ of surveyed area. Five of these candidates have already been associated to visible enhancements of the projected galaxy distribution in low deepness DSS-II fields and are probably low-to moderate redshift systems. Three of the candidates have been identified in previous ROSAT-based surveys. I show that a significative fraction (30-40%) of the candidate clusters are probably intermediate to high redshift systems. In this paper I publish the catalogue of these first candidate clusters. I also derive the number counts of clusters and compare it with the results of deep ROSAT-based cluster surveys.
- ID:
- ivo://CDS.VizieR/J/ApJS/190/43
- Title:
- Deep GALEX observations of the Coma cluster
- Short Name:
- J/ApJS/190/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a source catalog from a deep 26ks Galaxy Evolution Explorer (GALEX) observation of the Coma cluster in the far-UV (FUV; 1530{AA}) and near-UV (NUV; 2310{AA}) wavebands. The observed field is centered ~0.9{deg} (1.6Mpc) southwest of the Coma core in a well-studied region of the cluster known as "Coma-3". The entire field is located within the apparent virial radius of the Coma cluster, and has optical photometric coverage with Sloan Digital Sky Survey (SDSS) and deep spectroscopic coverage to r~21. We detect GALEX sources to NUV=24.5 and FUV=25.0, which corresponds to a star formation rate of ~10^-3^M_{sun}_/yr for galaxies at the distance of Coma. We have assembled a catalog of 9700 galaxies with GALEX and SDSS photometry, including 242 spectroscopically confirmed Coma member galaxies (in fig. 1) that span a large range of galaxy types from giant spirals and elliptical galaxies to dwarf irregular and early-type galaxies. The full multi-wavelength catalog (cluster plus background galaxies) is ~80% complete to NUV=23 and FUV=23.5. The GALEX images presented here are very deep and include detections of many resolved cluster members superposed on a dense field of unresolved background galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/612/A26
- Title:
- Deep HI observations of Leo T with WSRT
- Short Name:
- J/A+A/612/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Leo T is the lowest mass gas-rich galaxy currently known and studies of its gas content help us understand how such marginal galaxies survive and form stars. We present deep neutral hydrogen (HI) observations from the Westerbork Synthesis Radio Telescope in order to understand its HI distribution and potential for star formation. We find a larger HI line flux than the previously accepted value, resulting in a 50% larger HI mass of 4.1x10^5^M_{sun}_. The additional HI flux is from low surface brightness emission that was previously missed; with careful masking this emission can be recovered even in shallower data.We perform a Gaussian spectral decomposition to find a cool neutral medium component (CNM) with a mass of 3.7x10^4^M_{sun}_, or almost 10% of the total HI mass. Leo T has no HI emission extending from the main HI body, but there is evidence of interaction with the Milky Way circumgalactic medium in both a potential truncation of the HI body and the offset of the peak HI distribution from the optical center. The CNM component of Leo T is large when compared to other dwarf galaxies, even though Leo T is not currently forming stars and has a lower star formation efficiency than other gas-rich dwarf galaxies. However, the HI column density associated with the CNM component in Leo T is low. One possible explanation is the large CNM component is not related to star formation potential but rather a recent, transient phenomenon related to the interaction of Leo T with the Milky Way circumgalactic medium.
- ID:
- ivo://CDS.VizieR/J/ApJ/518/69
- Title:
- Deep Optical Catalog of galaxy systems
- Short Name:
- J/ApJ/518/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We assemble and observe a sample of poor galaxy systems that is suitable for testing N-body simulations of hierarchical clustering and other dynamical halo models. We (1) determine the parameters of the density profile {Rho}(r) and the velocity dispersion profile {sigma}_p_(R), (2) separate emission-line galaxies from absorption-line galaxies, examining the model parameters, {beta}, and as a function of spectroscopic type, and (3) for the best-behaved subsample, constrain the velocity anisotropy parameter, {beta}, which determines the shapes of the galaxy orbits. Our sample consists of 20 systems, 12 of which have extended X-ray emission in the ROSAT All-Sky Survey. We measure the 877 optical spectra of galaxies brighter than m_R_~15.4 within 1.5h^-1^Mpc of the system centers (we take H_0_=100h*km/s/Mpc). Thus, we sample the system membership to a radius typically three times larger than other recent optical group surveys. The average system population is 30 galaxies, and the average line-of-sight velocity dispersion is ~300km/s. The Navarro, Frenk, & White universal profile and the Hernquist model both provide good descriptions of the spatial data. In most cases an isothermal sphere is ruled out. Systems with declining {sigma}_p_(R) are well-matched by theoretical profiles in which the star-forming galaxies have predominantly radial orbits ({beta}>0); many of these galaxies are probably falling in for the first time. There is significant evidence for spatial segregation of the spectroscopic classes regardless of {sigma}_p_(R).
