- ID:
- ivo://CDS.VizieR/J/A+A/442/841
- Title:
- High-redshift galaxy clusters
- Short Name:
- J/A+A/442/841
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic data in the field of five high-redshift (z>~0.6) candidate galaxy clusters, drawn from the EIS Cluster Candidate Catalog. A total of 327 spectra were obtained using FORS1 at the VLT, out of which 266 are galaxies with secure redshifts. In this paper, we use these data for confirming the existence of overdensities in redshift space at the approximate same location as the matched-filter detections in the projected distribution of galaxies from the EIS I-band imaging survey. The spectroscopic redshifts, associated to these overdensities, are consistent but, in general, somewhat lower than those predicted by the matched-filter technique. Combining the systems presented here with those analyzed earlier, we have spectroscopically confirmed a total of nine overdensities in the redshift range 0.6<z<1.3, providing an important first step in building an optically-selected, high-redshift sample for more detailed studies, complementing those based on the few available X-ray selected systems.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/734/68
- Title:
- High redshift galaxy clusters in deep fields
- Short Name:
- J/ApJ/734/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Identification of high-redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada-France-Hawaii Telescope (CFHT) wide field, 202 clusters from the CFHT deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) field, and 737 clusters from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) field. The redshifts of these clusters are in the range 0.1<~z<~1.6. Merging these cluster samples gives 1644 clusters in the four survey fields, of which 1088 are newly identified and more than half are from the large SWIRE field. Among 228 clusters of z>=1, 191 clusters are newly identified, and most of them from the SWIRE field. With this large sample of high-redshift clusters, we study the color evolution of the brightest cluster galaxies (BCGs).
- ID:
- ivo://CDS.VizieR/J/ApJ/862/156
- Title:
- High-z galaxy candidates in the HFF cluster fields
- Short Name:
- J/ApJ/862/156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Acting as powerful gravitational lenses, the strong lensing galaxy clusters of the deep Hubble Frontier Fields (HFF) program permit access to lower-luminosity galaxies lying at higher redshifts than hitherto possible. We analyzed the HFF to measure the volume density of Lyman-break galaxies at z>4.75 by identifying a complete and reliable sample up to z~10. A marked deficit of such galaxies was uncovered in the highly magnified regions of the clusters relative to their outskirts, implying that the magnification of the sky area dominates over additional faint galaxies magnified above the flux limit. This negative magnification bias is consistent with a slow rollover at the faint end of the UV luminosity function and it indicates a preference for Bose-Einstein condensate dark matter with a light boson mass of m_B_~10^-22^eV over standard cold dark matter. We emphasize that measuring the magnification bias requires no correction for multiply-lensed images (with typically three or more images per source), whereas directly reconstructing the luminosity function will lead to an overestimate unless such images can be exhaustively matched up, especially at the faint end that is only accessible in the strongly lensed regions. In addition, we detected a distinctive downward transition in galaxy number density at z>~8, which may be linked to the relatively late reionization reported by Planck. Our results suggests that JWST will likely peer into an "abyss" with essentially no galaxies detected in deep NIR imaging at z>10.
- ID:
- ivo://CDS.VizieR/J/ApJ/655/814
- Title:
- HII regions in IC 342/Maffei group
- Short Name:
- J/ApJ/655/814
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectra of HII regions in the heavily obscured spiral galaxy Maffei 2. The observations have allowed for a determination of the Galactic extinction of this galaxy using a correlation between extinction and hydrogen column density observed among spiral galaxies.
- ID:
- ivo://CDS.VizieR/J/A+AS/112/429
- Title:
- HI observations in Her Supercluster
- Short Name:
- J/A+AS/112/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This part of the HI redshift survey in the region of the Hercules Supercluster presents HI spectra of 84 galaxies selected from the UGC and CGCG with extends in the previously begun survey of late-type spiral galaxies in that region. Measured HI parameters from the spectra are given.
- ID:
- ivo://CDS.VizieR/J/A+A/449/929
- Title:
- HI observations of Coma Supercluster
- Short Name:
- J/A+A/449/929
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High sensitivity 21-cm HI line observations with an rms noise level of ~0.5mJy were made of 35 spiral galaxies in the Coma Supercluster, using the refurbished Arecibo telescope, leading to detection of 25 objects. These data, combined with the measurements available in the literature, provide the set of HI data for 94% of all late-type galaxies in the Coma Supercluster with an apparent photographic magnitude m_p_<=15.7mag. We confirm that the typical scale of HI deficiency around the Coma cluster is 2Mpc, i.e. one virial radius. Comparing the HI mass function (HIMF) of cluster with non-cluster members of the Coma Supercluster we detected a shortage of high HI mass galaxies among cluster members that can be attributed to the pattern of HI deficiency found in rich clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/352/478
- Title:
- HI obs. of low surface brightness dwarf gal.
- Short Name:
- J/MNRAS/352/478
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- According to the cold dark matter (CDM) hierarchical clustering theory of galaxy and large-scale structure formation, there should be numerous low-mass dark matter haloes present in the Universe today. If these haloes contain sufficient stars, they should be detectable as low-luminosity stellar systems or dwarf galaxies. We have previously described a new detection method for faint low surface brightness objects and we have shown that there are relatively large numbers of very faint dwarf galaxies in the nearby Virgo cluster. In this paper, we present results from a similar survey carried out on the Millennium Galaxy strip (MGS, cat. <VII/240>), which runs along the celestial equator and samples a very different galaxy environment.
488. HIPASS in Fornax
- ID:
- ivo://CDS.VizieR/J/MNRAS/337/641
- Title:
- HIPASS in Fornax
- Short Name:
- J/MNRAS/337/641
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the HI Parkes All Sky Survey (HIPASS), we have searched for neutral hydrogen in galaxies in a region <25x25{deg}^2^ centred on NGC 1399, the nominal centre of the Fornax cluster. Within a velocity search range of 300-3700km/s and to a 3 lower flux limit of ~40mJy, 110 galaxies with HI emission were detected, one of which is previously uncatalogued. None of the detections has early-type morphology. Previously unknown velocities for 14 galaxies have been determined, with a further four velocity measurements being significantly dissimilar to published values. Identification of an optical counterpart is relatively unambiguous for more than ~90 per cent of our HI galaxies. The galaxies appear to be embedded in a sheet at the cluster velocity which extends for more than 30across the search area. At the nominal cluster distance of ~20Mpc, this corresponds to an elongated structure more than 10Mpc in extent. A velocity gradient across the structure is detected, with radial velocities increasing by ~500km/s from south-east to north-west. The clustering of galaxies evident in optical surveys is only weakly suggested in the spatial distribution of our HI detections. Of 62 HI detections within a 10{deg} projected radius of the cluster centre, only two are within the core region (projected radius <1{deg}) and less than 30 per cent are within 3.5{deg}, suggesting a considerable deficit of HI-rich galaxies in the centre of the cluster. However, relative to the field, there is a 3(+/-1)-fold excess of HI-rich galaxies in the outer parts of the cluster where galaxies may be infalling towards the cluster for the first time.
- ID:
- ivo://CDS.VizieR/J/A+A/370/765
- Title:
- HI synthesis observations in UMa cluster
- Short Name:
- J/A+A/370/765
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this data paper we present the results of an extensive 21 cm-line synthesis imaging survey of 43 spiral galaxies in the nearby Ursa Major cluster using the Westerbork Synthesis Radio Telescope. Detailed kinematic information in the form of position-velocity diagrams and rotation curves is presented in an atlas together with HI channel maps, 21 cm continuum maps, global HI profiles, radial HI surface density profiles, integrated HI column density maps, and HI velocity fields. The relation between the corrected global HI linewidth and the rotational velocities Vmax and Vflat as derived from the rotation curves is investigated. Inclination angles obtained from the optical axis ratios are compared to those derived from the inclined HI disks and the HI velocity fields. The galaxies were not selected on the basis of their HI content but solely on the basis of their cluster membership and inclination which should be suitable for a kinematic analysis. The observed galaxies provide a well-defined, volume limited and equidistant sample, useful to investigate in detail the statistical properties of the Tully-Fisher relation and the dark matter halos around them.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1289
- Title:
- H magnitude and radial velocities of A1644
- Short Name:
- J/AJ/122/1289
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss H-band (1.65{mu}m) near-infrared photometry of the central 9h^-2^Mpc^2^ of Abell 1644 (A1644) to a limiting M_H_~M*_H_+3 (throughout this paper H_0_=100h*km/s/Mpc). here are 861 galaxies in the photometric survey region. We also measured radial velocities of 155 galaxies; 141 of these are cluster members within 2.44h^-1^Mpc of the cluster center.
