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961. Close binary systems from SDSS DR4
ID:
ivo://CDS.VizieR/J/AJ/131/1674
Title:
Close binary systems from SDSS DR4
Short Name:
J/AJ/131/1674
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a spectroscopic sample of 746 detached close binary systems from the Sloan Digital Sky Survey (SDSS) Fourth Data Release (2006ApJS..162...38A). The majority of these binaries consist of a white dwarf primary and a low-mass secondary (typically M dwarf) companion. We have determined the temperature and gravity for 496 of the white dwarf primaries and the spectral type and magnetic activity properties for 661 of the low-mass secondaries. We have estimated the distances for each of the white dwarf-main-sequence star binaries and use white dwarf evolutionary grids to establish the age of each binary system from the white dwarf cooling times.
962. Close pairs of galaxies
ID:
ivo://CDS.VizieR/J/AJ/132/197
Title:
Close pairs of galaxies
Short Name:
J/AJ/132/197
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study star formation in a sample of 345 galaxies in 167 pairs and compact groups drawn from the original CfA2 Redshift Survey and from a follow-up search for companions. We construct our sample with attention to including pairs with luminosity contrast |{Delta}m_R_|>=2. These 57 galaxies with |{Delta}m_R_|>=2 provide a set of nearby representative cases of minor interactions, a central feature of the hierarchical galaxy formation model. Here we report the redshifts and positions of the 345 galaxies in our sample and of 136 galaxies in apparent pairs that are superpositions.
963. Close visual companions in Scorpius OB2
ID:
ivo://CDS.VizieR/J/A+A/430/137
Title:
Close visual companions in Scorpius OB2
Short Name:
J/A+A/430/137
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a near-infrared adaptive optics survey with the aim to detect close companions to Hipparcos members in the three subgroups of the nearby OB association Sco OB2: Upper Scorpius (US), Upper Centaurus Lupus (UCL) and Lower Centaurus Crux (LCC). We have targeted 199 A-type and late B-type stars in the K_S band, and a subset also in the J and H band. We find 151 stellar components other than the target stars. A brightness criterion is used to separate these components into 77 background stars and 74 candidate physical companion stars. Out of these 74 candidate companions, 41 have not been reported before (14 in US; 13 in UCL; 14 in LCC).
964. Cloud Atlas: HST/WFC3 NIR spectral library
ID:
ivo://CDS.VizieR/J/AJ/157/101
Title:
Cloud Atlas: HST/WFC3 NIR spectral library
Short Name:
J/AJ/157/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
Bayesian atmospheric retrieval tools can place constraints on the properties of brown dwarfs' and hot Jupiters' atmospheres. To fully exploit these methods, high signal-to-noise spectral libraries with well-understood uncertainties are essential. We present a high signal-to-noise spectral library (1.10-1.69 {mu}m) of the thermal emission of 76 brown dwarfs and hot Jupiters. All our spectra have been acquired with the Hubble Space Telescope's Wide Field Camera 3 instrument and its G141 grism. The near-infrared spectral types of these objects range from L4 to Y1. Eight of our targets have estimated masses below the deuterium-burning limit. We analyze the database to identify peculiar objects and/or multiple systems, concluding that this sample includes two very-low-surface-gravity objects and five intermediate-surface-gravity objects. In addition, spectral indices designed to search for composite-atmosphere brown dwarfs indicate that eight objects in our sample are strong candidates to have such atmospheres. None of these objects are overluminous, so their composite atmospheres are unlikely to be companion-induced artifacts. Five of the eight confirmed candidates have been reported as photometrically variable, suggesting that composite atmospheric indices are useful in identifying brown dwarfs with strongly heterogeneous cloud covers. We compare hot Jupiters and brown dwarfs in a near-infrared color-magnitude diagram. We confirm that the coldest hot Jupiters in our sample have spectra similar to mid-L dwarfs, and the hottest hot Jupiters have spectra similar to those of M-dwarfs. Our sample provides a uniform data set of a broad range of ultracool atmospheres, allowing large-scale comparative studies and providing an HST legacy spectral library.
965. CL 0024+1654 UBVI photometry
ID:
ivo://CDS.VizieR/J/AJ/126/2644
Title:
CL 0024+1654 UBVI photometry
Short Name:
J/AJ/126/2644
Date:
21 Oct 2021
Publisher:
CDS
Description:
Wide-field (20x20arcmin^2^) UBVI images of intermediate-redshift (z=0.39), Butcher-Oemler cluster CL0024+1654 are being distributed. These data probe the rest-frame mid-UV properties over a much larger area than previous studies of CL0024+1654. These images were obtained with the 0.9m telescope at the NOAO Kitt Peak National Observatory in 1991-1992. The resolution is 0.68 arcsec/pix, and the field-of-view is 20arcmin^2^. The standard KPNO Harris filter set was used. We are distributing the individual U, B, V and I frames, as well as the combined U+B+V+I image. Using these data, SExtractor was used to construct a multi-color catalog of approximately 6000 objects in this field. We present both isophotal and aperture photometry in the catalog to be complete. We cross-matched the objects in our catalog with three other CL0024 datasets, and list the matching results in the distributed catalog. Our catalog includes the cross-references to data from Czoske et al., 2001, Cat. <J/A+A/372/391>; from Smail et al., 1997, Cat. <J/ApJS/110/213>; and from Dressler et al., 1999, Cat. <J/ApJS/122/51>.
966. 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.
967. 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.
968. Clustering of high-redshift QSOs from SDSS
ID:
ivo://CDS.VizieR/J/AJ/133/2222
Title:
Clustering of high-redshift QSOs from SDSS
Short Name:
J/AJ/133/2222
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the two-point correlation function of a uniformly selected sample of 4426 luminous optical quasars with redshift 2.9<=z<=5.4 selected over 4041deg^2^ from the Fifth Data Release of the Sloan Digital Sky Survey. We fit a power-law to the projected correlation function w_p_(r_p_) to marginalize over redshift-space distortions and redshift errors.
969. Clusters and groups of galaxies in 2dF
ID:
ivo://CDS.VizieR/J/AN/327/365
Title:
Clusters and groups of galaxies in 2dF
Short Name:
J/AN/327/365
Date:
21 Oct 2021
Publisher:
CDS
Description:
We create a new catalogue of groups and clusters, applying the friends-to-friends method to the 2dF GRS final release. We investigate various selection effects due to the use of a magnitude limited sample. For this purpose we follow the changes in group sizes and mean galaxy number densities within the groups when shifting nearby observed groups to larger distances. We study the distribution of sizes of dark matter haloes in N-body simulations and compare properties of these haloes and the 2dF groups.
970. Cluster SC2008-57(A3667)
ID:
ivo://CDS.VizieR/J/MNRAS/259/233
Title:
Cluster SC2008-57(A3667)
Short Name:
J/MNRAS/259/233
Date:
21 Oct 2021
Publisher:
CDS
Description:
(Abstract of the paper) We present the results of photometric and spectroscopic observations of the cluster of galaxies SC2008-57 (A3667). The observations have resulted in a catalogue with positions and magnitudes for 203 galaxies, complete at b_25 = 18.0, and radial velocities for 128 galaxies, 91 per cent complete at b_25 = 17.5. The cluster can be classified as type L because its galaxy distribution is highly flattened. It shows two strong concentrations: a main concentration, centred on the cluster brightest galaxy (a D galaxy) and coincident with the peak of X-ray emission, and a substructure around the second brightest galaxy (also a D galaxy). Most of the galaxies in this substructure seem to be bound to the second-brightest galaxy, forming a dynamical subunit inside the cluster. The extreme flattening of the cluster may at least partially be due to the presence of the substructure. The cluster also shows evidence for luminosity segregation, with the brightest galaxies being preferentially found in high galaxy density regions. Most of the luminosity segregation, however, is produced by galaxies associated with the two clumps around the D galaxies, suggesting that dynamical friction is effective in subclusters with low velocity dispersions and may be associated with the formation of D galaxies. The velocity dispersion of SC2008-57 is high, about 1200 km/s, but consistent with the observed X-ray luminosity. The cluster mass, derived using several estimators, is about 2.6 x 10^15 M_solar. Both the cluster mass and velocity dispersion may be overestimates due to the presence of the substructure.