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2961. Clumps in NGC 6334 from 450/850um observations
ID:
ivo://CDS.VizieR/J/AJ/136/2083
Title:
Clumps in NGC 6334 from 450/850um observations
Short Name:
J/AJ/136/2083
Date:
21 Oct 2021
Publisher:
CDS
Description:
NGC 6334 is a galactic star-forming region in Scorpius, heavily obscured by intervening dust. The region consists of several major sites of star formation known previously from far-infrared (IR) and radio-wavelength observations. We present images of NGC 6334 obtained at wavelengths of 850 and 450um with the Submillimeter Common-User Bolometric Array at the James Clerk Maxwell Telescope. These data highlight the distribution of dense cold dust, a particularly striking feature of which is a narrow ridge of emission passing between most of the star-forming centers. We use a clump-finding technique to quantify the distribution of dust emission throughout the region, and we obtain estimates of the sizes, masses, and temperatures of the clump ensemble under simple assumptions.
2962. Clumps in the giant molecular cloud G345.5+1.0
ID:
ivo://CDS.VizieR/J/A+A/534/A131
Title:
Clumps in the giant molecular cloud G345.5+1.0
Short Name:
J/A+A/534/A131
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive condensations in giant molecular clouds (GMCs) are linked to the formation of high mass stars, which are the principal source of heavy elements and UV radiation, playing an important role in the evolution of galaxies. We attemp to make a complete census of massive-star formation within all of GMC G345.5+1.0. This cloud is located one degree above the Galactic plane and at 1.8kpc from the Sun, thus there is little superposition of dust along the line-of-sight, minimizing confusion effects in identifying individual clumps. GMC G345.5+1.0 is located approximately between 344.5{deg} and 346.5{deg} in Galactic longitude, and between 0.2{deg} and 2.0{deg} in Galactic latitude.
2963. Clumps in W31 from CO and 875um observations
ID:
ivo://CDS.VizieR/J/A+A/531/A26
Title:
Clumps in W31 from CO and 875um observations
Short Name:
J/A+A/531/A26
Date:
21 Oct 2021
Publisher:
CDS
Description:
High-mass star formation has been a very active field over the past decade; however, most studies have targeted regions of luminosities between 10^4^ and 10^5^L_{sun}_. In contrast to that, the highest mass stars reside in clusters exceeding 10^5^ or even 10^6^L_{sun}_. We want to study the physical conditions associated with the formation of the highest mass stars. To do this, we selected the W31 star-forming complex with a total luminosity of ~6x10^6^L_{sun}_ (comprised of at least two subregions) for a multiwavelength spectral line and continuum study covering wavelengths from the near- and midinfrared via (sub)mm wavelength observations to radio data in the cm regime.
2964. Clumpy galaxies in CANDELS. II. 0.5<=z<3.0
ID:
ivo://CDS.VizieR/J/ApJ/853/108
Title:
Clumpy galaxies in CANDELS. II. 0.5<=z<3.0
Short Name:
J/ApJ/853/108
Date:
21 Oct 2021
Publisher:
CDS
Description:
Studying giant star-forming clumps in distant galaxies is important to understand galaxy formation and evolution. At present, however, observers and theorists have not reached a consensus on whether the observed "clumps" in distant galaxies are the same phenomenon that is seen in simulations. In this paper, as a step to establish a benchmark of direct comparisons between observations and theories, we publish a sample of clumps constructed to represent the commonly observed "clumps" in the literature. This sample contains 3193 clumps detected from 1270 galaxies at 0.5<=z<3.0. The clumps are detected from rest-frame UV images, as described in our previous paper. Their physical properties (e.g., rest-frame color, stellar mass (M*), star formation rate (SFR), age, and dust extinction) are measured by fitting the spectral energy distribution (SED) to synthetic stellar population models. We carefully test the procedures of measuring clump properties, especially the method of subtracting background fluxes from the diffuse component of galaxies. With our fiducial background subtraction, we find a radial clump U-V color variation, where clumps close to galactic centers are redder than those in outskirts. The slope of the color gradient (clump color as a function of their galactocentric distance scaled by the semimajor axis of galaxies) changes with redshift and M* of the host galaxies: at a fixed M*, the slope becomes steeper toward low redshift, and at a fixed redshift, it becomes slightly steeper with M*. Based on our SED fitting, this observed color gradient can be explained by a combination of a negative age gradient, a negative E(B-V) gradient, and a positive specific SFR gradient of the clumps. We also find that the color gradients of clumps are steeper than those of intra-clump regions. Correspondingly, the radial gradients of the derived physical properties of clumps are different from those of the diffuse component or intra-clump regions.
2965. Cluster and field elliptical galaxies at z~1.3
ID:
ivo://CDS.VizieR/J/A+A/597/A122
Title:
Cluster and field elliptical galaxies at z~1.3
Short Name:
J/A+A/597/A122
Date:
04 Feb 2022 00:04:27
Publisher:
CDS
Description:
The aim of this work is twofold: first, to assess whether the population of elliptical galaxies in cluster at z~1.3 differs from the population in the field and whether their intrinsic structure depends on the environment where they belong; second, to constrain their properties 9Gyr back in time through the study of their scaling relations. We compared a sample of 56 cluster elliptical galaxies selected from three clusters at 1.2<z<1.4 with elliptical galaxies selected at comparable redshift in the GOODS-South field (~30), in the COSMOS area (~180), and in the CANDELS fields (~220). To single out the environmental effects, we selected cluster and field elliptical galaxies according to their morphology. We compared physical and structural parameters of galaxies in the two environments and we derived the relationships between effective radius, surface brightness, stellar mass, and stellar mass density {Sigma}_R_e__ within the effective radius and central mass density {Sigma}_1kpc_, within 1kpc radius. We find that the structure and the properties of cluster elliptical galaxies do not differ from those in the field: they are characterized by the same structural parameters at fixed mass and they follow the same scaling relations. On the other hand, the population of field elliptical galaxies at z~1.3 shows a significant lack of massive (M_*_>2x10^11^M_{sun}_) and large (R_e_>4-5kpc) elliptical galaxies with respect to the cluster. Nonetheless, at M_*_<2x10^11^M_{sun}_, the two populations are similar. The size-mass relation of cluster and field ellipticals at z~1.3 clearly defines two different regimes, above and below a transition mass m_t_~=2-3x10^10^M_{sun}_ at lower masses the relation is nearly flat (R_e_{prop}M*^-0.1+/-0.2^), the mean radius is nearly constant at ~1kpc and, consequently, {Sigma}_Re_~={Sigma}_1kpc_ while, at larger masses, the relation is R_e_{prop}M*^0.64+/-0.09^. The transition mass marks the mass at which galaxies reach the maximum stellar mass density. Also the {Sigma}_1kpc_-mass relation follows two different regimes, above and below the transition mass ({Sigma}_1kpc_{prop}M*_1.07<mt_^0.64>mt^) defining a transition mass density {Sigma}_1kpc_~=2-3x10^3^M_{sun}_/pc^2^. The effective stellar mass density {Sigma}_Re_ does not correlate with mass; dense/compact galaxies can be assembled over a wide mass regime, independently of the environment. The central stellar mass density, {Sigma}_1kpc_, besides being correlated with the mass, is correlated to the age of the stellar population: the higher the central stellar mass density, the higher the mass, the older the age of the stellar population. While we found some evidence of environmental effects on the elliptical galaxies as a population, we did not find differences between the intrinsic properties of cluster and field elliptical galaxies at comparable redshift. The structure and the shaping of elliptical galaxies at z~1.3 do not depend on the environment. However, a dense environment seems to be more efficient in assembling high-mass large ellipticals, much rarer in the field at this redshift. The correlation found between the central stellar mass density and the age of the galaxies beside the mass shows the close connection of the central regions to the main phases of mass growth.
2966. Cluster And Infall Region Nearby Survey. I
ID:
ivo://CDS.VizieR/J/AJ/126/2152
Title:
Cluster And Infall Region Nearby Survey. I
Short Name:
J/AJ/126/2152
Date:
21 Oct 2021
Publisher:
CDS
Description:
The CAIRNS (Cluster and Infall Region Nearby Survey) project is a spectroscopic survey of the infall regions surrounding eight nearby, rich, X-ray-luminous clusters of galaxies. We have collected 15654 redshifts (3471 new or remeasured) within ~5-10h^-1^Mpc of the centers of the clusters, making it the largest study of the infall regions of clusters. We determine cluster membership and the mass profiles of the clusters based on the phase-space distribution of the galaxies. All of the clusters display decreasing velocity dispersion profiles. The mass profiles are fitted well by functional forms based on numerical simulations but exclude an isothermal sphere. Specifically, Navarro et al. (1997ApJ...490..493N) and Hernquist (1990ApJ...356..359H) models provide good descriptions of cluster mass profiles to their turnaround radii. Our sample shows that the predicted infall pattern is ubiquitous in rich, X-ray-luminous clusters over a large mass range. The caustic mass estimates are in excellent agreement with independent X-ray estimates at small radii and with virial estimates at intermediate radii. The mean ratio of the caustic mass to the X-ray mass is 1.03+/-0.11, and the mean ratio of the caustic mass to the virial mass (when corrected for the surface pressure term) is 0.93+/-0.07. We further demonstrate that the caustic technique provides reasonable mass estimates even in merging clusters.
2967. Cluster and Infall Region Nearby Survey. II
ID:
ivo://CDS.VizieR/J/AJ/128/1078
Title:
Cluster and Infall Region Nearby Survey. II
Short Name:
J/AJ/128/1078
Date:
21 Oct 2021
Publisher:
CDS
Description:
CAIRNS (Cluster and Infall Region Nearby Survey) is a spectroscopic survey of the infall regions surrounding nine nearby rich clusters of galaxies. In our previous paper (Cat. <J/AJ/126/2152>), we used redshifts within ~10h_-1_ Mpc of the centers of the clusters to determine the mass profiles of the clusters based on the phase-space distribution of the galaxies. Here, we use Two Micron All Sky Survey (Cat. <II/246>) photometry and an additional 515 redshifts to investigate the environmental dependence of near-infrared mass-to-light ratios.
2968. Cluster candidates for joint X-rays and SZ surveys
ID:
ivo://CDS.VizieR/J/A+A/614/A82
Title:
Cluster candidates for joint X-rays and SZ surveys
Short Name:
J/A+A/614/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
The combination of X-ray and Sunyaev-Zeldovich (SZ) observations can potentially improve the cluster detection efficiency, when compared to using only one of these probes, since both probe the same medium, the hot ionized gas of the intra-cluster medium. We present a method based on matched multifrequency filters (MMF) for detecting galaxy clusters from SZ and X-ray surveys. This method builds on a previously proposed joint X-ray-SZ extraction method and allows the blind detection of clusters, that is finding new clusters without knowing their position, size, or redshift, by searching on SZ and X-ray maps simultaneously. The proposed method is tested using data from the ROSAT all-sky survey and from the Planck survey. The evaluation is done by comparison with existing cluster catalogues in the area of the sky covered by the deep SPT survey. Thanks to the addition of the X-ray information, the joint detection method is able to achieve simultaneously better purity, better detection efficiency, and better position accuracy than its predecessor Planck MMF, which is based on SZ maps alone. For a purity of 85%, the X-ray-SZ method detects 141 confirmed clusters in the SPT region; to detect the same number of confirmed clusters with Planck MMF, we would need to decrease its purity to 70%. We provide a catalogue of 225 sources selected by the proposed method in the SPT footprint, with masses ranging between 0.7 and 14.5x10^14^M_{sun}_ and redshifts between 0.01 and 1.2.
2969. Cluster formation toward Be87/ON2. I.
ID:
ivo://CDS.VizieR/J/A+A/650/A156
Title:
Cluster formation toward Be87/ON2. I.
Short Name:
J/A+A/650/A156
Date:
22 Feb 2022
Publisher:
CDS
Description:
Disentangling line-of-sight alignments of young stellar populations is crucial for observational studies of star-forming complexes. This task is particularly problematic in a Cygnus-X subregion where several components, located at different distances, overlap: the Berkeley 87 young massive cluster, the poorly known [DB2001] Cl05 embedded cluster, and the ON2 star-forming complex, which in turn is composed of several HII regions. We provide a methodology for building an exhaustive census of young objects that can consistently treat large differences in extinction and distance. OMEGA2000 near-infrared observations of the Berkeley 87 / ON2 field were merged with archival data from Gaia, Chandra, Spitzer, and Herschel, and with cross-identifications from the literature. To address the incompleteness effects and selection biases that arise from the line-of-sight overlap, we adapted existing methods for extinction estimation and young object classification. We also defined the intrinsic reddening index, R_int_, a new tool for separating intrinsically red sources from those whose infrared color excess is caused by extinction. Finally, we introduce a new method for finding young stellar objects based on R_int_. We find 571 objects whose classification is related to recent or ongoing star formation. Together with other point sources with individual estimates of distance or extinction, we compile a catalog of 3005 objects to be used for further membership work. A new distance for Berkeley 87, (1673+/-17)pc, is estimated as a median of 13 spectroscopic members with accurate Gaia EDR3 parallaxes. The flexibility of our approach, especially regarding the R_int_ definition, allows overcoming photometric biases caused by large variations in extinction and distance, in order to obtain homogeneous catalogs of young sources. The multiwavelength census that results from applying our methods to the Berkeley 87 / ON2 field will serve as a basis for disentangling the overlapped populations.
2970. Cluster galaxy circular velocity function
ID:
ivo://CDS.VizieR/J/MNRAS/351/265
Title:
Cluster galaxy circular velocity function
Short Name:
J/MNRAS/351/265
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present galaxy circular velocity functions (GCVFs) for 34 low-redshift (z<~0.15) clusters identified in the Sloan Digital Sky Survey (SDSS, Cat. <J/AJ/123/567>), for 15 clusters drawn from dark matter simulations of hierarchical structure growth in a {LAMBDA}CDM cosmology, and for ~22000 SDSS field galaxies. We find that the simulations successfully reproduce the shape, amplitude and scatter in the observed distribution of cluster galaxy circular velocities. The power-law slope of the observed cluster GCVF is ~-2.4, independent of cluster velocity dispersion. The average slope of the simulated GCVFs is somewhat steeper, although formally consistent given the errors. We find that the effects of baryons on galaxy rotation curves is to flatten the simulated cluster GCVF into better agreement with observations. The cumulative GCVFs of the simulated clusters are very similar across a wide range of cluster masses, provided individual subhalo circular velocities are scaled by the circular velocities of the parent cluster. The scatter is consistent with that measured in the cumulative, scaled observed cluster GCVF. Finally, the observed field GCVF deviates significantly from a power law, being flatter than the cluster GCVF at circular velocities less than 200km/s.

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