- ID:
- ivo://CDS.VizieR/J/MNRAS/429/2264
- Title:
- Galaxies in the UMa cluster complex
- Short Name:
- J/MNRAS/429/2264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A nearby friable cloud in Ursa Majoris contains 270 galaxies with radial velocities 500<V_LG_<1500km/s inside the area of RA=[11.0h,13.0h] and DE=[+40{deg},+60{deg}]. At present, 97 galaxies of them have individual distance estimates. We use these data to clarify the structure and kinematics of the UMa complex. According to Makarov & Karachentsev (2011MNRAS.412.2498M, Cat. J/MNRAS/412/2498), most of the UMa galaxies belong to seven bound groups, which have the following median parameters: velocity dispersion of 58k/s, harmonic projected radius of 300kpc, virial mass of 2x10^12^M{sun} and virial mass-to-K-band luminosity ratio of 27M{sun}/L{sun}. Almost a half of the UMa cloud population are gas-rich dwarfs (Ir, Im, BCD) with active star formation seen in the GALEX UV-survey. The UMa groups reside within 15-19Mpc from us, being just at the same distance as the Virgo cluster. The total virial mass of the UMa groups is 4x10^13^M{sun}, yielding the average density of dark matter in the UMa cloud to be {Omega}m=0.08, i.e. a factor of 3 lower than the cosmic average. This is despite the fact that the UMa cloud resides in a region of the Universe that is an apparent overdensity. A possible explanation for this is that most mass in the Universe lies in the empty space between clusters. Herewith, the mean distances and velocities of the UMa groups follow nearly undisturbed Hubble flow without a sign of the 'Z-wave' effect caused by infall towards a massive attractor. This constrains the total amount of dark matter between the UMa groups within the cloud volume.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/816/98
- Title:
- Galaxies in X-ray clusters with DES. I. Stellar mass
- Short Name:
- J/ApJ/816/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z~1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, m_*_{propto}(M_200_/1.5x10^14^M_{sun}_)^0.24+/-0.08^(1+z)^-0.19+/-0.34, and compare the observed relation to the model prediction. We estimate the average growth rate since z=1.0 for BCGs hosted by clusters of M_200,z_=10^13.8^M_{sun}_; at z=1.0: m_*,BCG_ appears to have grown by 0.13+/-0.11dex, in tension at the ~2.5{sigma} significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z=1.0 may alleviate this tension in BCG growth rates.
383. Galaxies near S1189
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/2578
- Title:
- Galaxies near S1189
- Short Name:
- J/MNRAS/406/2578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radio images of a sample of six wide-angle tail (WAT) radio sources, identified in the Australia Telescope Large Area Survey 1.4-GHz radio survey, and new spectroscopic redshifts for four of these sources. These WATs are in the redshift range of 0.1469-0.3762, and we find evidence of galaxy overdensities in the vicinity of four of the WATs from either spectroscopic or photometric redshifts. We also present follow-up spectroscopic observations of the area surrounding the largest WAT, S1189, which is at a redshift of ~0.22. The spectroscopic observations, taken using the AAOmega spectrograph on the Anglo-Australian Telescope, show an overdensity of galaxies at this redshift. The galaxies are spread over an unusually large area of ~12Mpc with a velocity spread of ~4500km/s. This large-scale structure includes a highly asymmetric Fanaroff-Riley type I radio galaxy and also appears to host a radio relic. It may represent an unrelaxed system with different sub-structures interacting or merging with one another. We discuss the implications of these observations for future large-scale radio surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/514/A60
- Title:
- Galaxies of J0454-0309 lensing fossil group
- Short Name:
- J/A+A/514/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have discovered a strong lensing fossil group (J0454) projected near the well-studied cluster MS0451-0305. Using the large amount of available archival data, we compare J0454 to normal groups and clusters. A highly asymmetric image configuration of the strong lens enables us to study the substructure of the system. We used multicolour Subaru/Suprime-Cam and CFHT/Megaprime imaging, together with Keck spectroscopy to identify member galaxies. A VLT/FORS2 spectrum was taken to determine the redshifts of the brightest elliptical and the lensed arc. Using HST/ACS images, we determined the group's weak lensing signal and modelled the strong lens system. This is the first time that a fossil group is analysed with lensing methods. The X-ray luminosity and temperature were derived from XMM-Newton data.
- ID:
- ivo://CDS.VizieR/J/AJ/132/514
- Title:
- Galaxies of RX J1416.4+2315 cluster
- Short Name:
- J/AJ/132/514
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the properties of the fossil cluster RX J1416.4+2315 through g'- and i'-band imaging and spectroscopy of 25 member galaxies. The system is at a mean redshift of 0.137 and has a velocity dispersion of 584km/s. Superposed onto one quadrant of the cluster field is a group of five galaxies at a mean redshift of 0.131, which, if included as part of the cluster, increases the velocity dispersion to 846km/s. The central object of RX J1416.4+2315 is a normal elliptical galaxy with no cD envelope.
- ID:
- ivo://CDS.VizieR/J/AJ/138/873
- Title:
- Galaxies with H{alpha} emission in A2151
- Short Name:
- J/AJ/138/873
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the first results of an H{alpha} imaging survey of galaxies in the central regions of the A2151 cluster. A total of 50 sources were detected in H{alpha}, from which 41 were classified as secure members of the cluster and 2 as likely members based on spectroscopic and photometric redshift considerations. The remaining seven galaxies were classified as background contaminants and thus excluded from our study on the H{alpha} properties of the cluster.
- ID:
- ivo://CDS.VizieR/J/ApJ/820/98
- Title:
- Galaxy candidates in the Hubble Frontier Fields
- Short Name:
- J/ApJ/820/98
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of our search for and study of z>~6 galaxy candidates behind the third Frontier Fields (FFs) cluster, MACS J0717.5+3745, and its parallel field, combining data from Hubble and Spitzer. We select 39 candidates using the Lyman break technique, for which the clear non-detection in optical make the extreme mid-z interlopers hypothesis unlikely. We also take benefit from z>~6 samples selected using the previous FF data sets of Abell 2744 and MACS 0416 to improve the constraints on the properties of very high redshift objects. We compute the redshift and the physical properties such emission lines properties, star formation rate, reddening, and stellar mass for all FF objects from their spectral energy distribution using templates including nebular emission lines. We study the relationship between several physical properties and confirm the trend already observed in previous surveys for evolution of star formation rate with galaxy mass and between the size and the UV luminosity of our candidates. The analysis of the evolution of the UV luminosity function with redshift seems more compatible with an evolution of density. Moreover, no robust z>=8.5 object is selected behind the cluster field and few z~9 candidates have been selected in the two previous data sets from this legacy survey, suggesting a strong evolution in the number density of galaxies between z~8 and 9. Thanks to the use of the lensing cluster, we study the evolution of the star formation rate density produced by galaxies with L>0.03 L_{star}_, and confirm the strong decrease observed between z~8 and 9.
- ID:
- ivo://CDS.VizieR/J/ApJS/246/2
- Title:
- Galaxy cluster cat. from SDSS-DR13 (GalWCat19)
- Short Name:
- J/ApJS/246/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Utilizing the SDSS-DR13 spectroscopic data set, we create a new publicly available catalog of 1800 galaxy clusters (GalWeight cluster catalog, GalWCat19) and a corresponding catalog of 34,471 identified member galaxies. The clusters are identified from overdensities in redshift phase space. The GalWeight technique introduced by Abdullah+ (2018ApJ...861...22A) is then applied to identify cluster members. The completeness of the cluster catalog (GalWCat19) and the procedure followed to determine cluster mass are tested on the Bolshoi N-body simulations. The 1800 GalWCat19 clusters range in redshift between 0.01 and 0.2 and have masses in the range of (0.4-14)x10^14^h^-1^M_{sun}_. The cluster catalog provides a large number of cluster parameters, including sky position, redshift, membership, velocity dispersion, and mass at overdensities {Delta}=500, 200, 100, and 5.5. The 34471 member galaxies are identified within the radius at which the density is 200 times the critical density of the universe. The galaxy catalog provides the coordinates of each galaxy and the ID of the cluster that the galaxy belongs to. The cluster velocity dispersion scales with mass as log({sigma}_200_)=log(946+/-52km/s)+ (0.349+/-0.142)log[h(z)M_200_/10^1 5^M_{sun}], with a scatter of {delta}log{sigma}=0.06+/-0.04.
- ID:
- ivo://CDS.VizieR/J/MNRAS/455/892
- Title:
- Galaxy cluster concentration-mass relation
- Short Name:
- J/MNRAS/455/892
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Scaling relations of clusters have made them particularly important cosmological probes of structure formation. In this work, we present a comprehensive study of the relation between two profile observables, concentration (cvir) and mass (Mvir). We have collected the largest known sample of measurements from the literature which make use of one or more of the following reconstruction techniques: weak gravitational lensing (WL), strong gravitational lensing (SL), weak+strong lensing (WL+SL), the caustic method (CM), line-of-sight velocity dispersion (LOSVD), and X-ray. We find that the concentration-mass (c-M) relation is highly variable depending upon the reconstruction technique used. We also find concentrations derived from dark matter-only simulations (at approximately Mvir~10^14^M_{sun}_) to be inconsistent with the WL and WL+SL relations at the 1{sigma} level, even after the projection of triaxial haloes is taken into account. However, to fully determine consistency between simulations and observations, a volume-limited sample of clusters is required, as selection effects become increasingly more important in answering this. Interestingly, we also find evidence for a steeper WL+SL relation as compared to WL alone, a result which could perhaps be caused by the varying shape of cluster isodensities, though most likely reflects differences in selection effects caused by these two techniques. Lastly, we compare concentration and mass measurements of individual clusters made using more than one technique, highlighting the magnitude of the potential bias which could exist in such observational samples.
- ID:
- ivo://CDS.VizieR/J/AJ/141/88
- Title:
- Galaxy cluster environments of radio sources
- Short Name:
- J/AJ/141/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the Sloan Digital Sky Survey (SDSS) and the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) catalogs, we examined the optical environments around double-lobed radio sources. Previous studies have shown that multi-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD-type galaxy at the center of a cluster. We cross-correlated the SDSS and FIRST catalogs and measured the richness of the cluster environments surrounding both bent and straight multi-component radio sources. This led to the discovery and classification of a large number of galaxy clusters out to a redshift of z~0.5.
