- ID:
- ivo://CDS.VizieR/J/A+A/659/A59
- Title:
- Structural parameters of 389 local open clusters
- Short Name:
- J/A+A/659/A59
- Date:
- 07 Mar 2022 05:56:37
- Publisher:
- CDS
- Description:
- The distribution of member stars in the surroundings of an Open Cluster (OC) can shed light on the process of its formation, evolution and dissolution. The analysis of structural parameters of OCs as a function of their age and position in the Galaxy brings constraints on theoretical models of cluster evolution. The Gaia catalogue is very appropriate to find members of OCs at large distance from their centers. We aim at revisiting the membership lists of OCs from the solar vicinity, in particular by extending these membership lists to the peripheral areas thanks to Gaia EDR3. We then take advantage of these new lists of members to study the morphological properties and the mass segregation levels of the clusters. We used the clustering algorithm HDBSCAN on Gaia parallaxes and proper motions to systematically look for members up to 50pc from the cluster centers. We fitted a King's function on the radial density profile of these clusters and a Gaussian Mixture Model (GMM) on their two dimensional distribution of members to study their shape. We also evaluated the degree of mass segregation of the clusters and the correlations of these parameters with the age and Galactic position of the clusters. Our methodology performs well on 389 clusters out of the 467 selected ones, including several recently discovered clusters that were poorly studied until now. We report the detection of vast coronae around almost all the clusters and report the detection of 71 OCs with tidal tails, multiplying by more than four the number of such structures identified. We find the size of the cores to be on average smaller for old clusters than for young ones. Also, the overall size of the clusters seems to slightly increase with age while the fraction of stars in the halo seems to decrease. As expected the mass segregation is more pronounced in the oldest clusters but a clear trend with age is not seen. OCs are more extended than previously expected, regardless of their age. The decrease in the proportion of stars populating the clusters halos highlights the different cluster evaporation processes and the short timescales they need to affect the clusters. Reported parameters like cluster sizes or mass segregation levels all depend on cluster ages but can not be described as single functions of time.
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- ID:
- ivo://CDS.VizieR/J/ApJ/787/24
- Title:
- Structural parameters of true edge-on galaxies
- Short Name:
- J/ApJ/787/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS, Cat. II/294). A visual inspection of the g, r, and i images of about 15000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-on galaxies, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects either show signs of interaction and warps, or nearby bright stars project on it. We added more candidate galaxies from RFGC, EFIGI, RC3, and Galaxy Zoo catalogs found in the SDSS footprints. Our final sample consists of 5747 genuine edge-on galaxies. We estimate the structural parameters of the stellar disks (the stellar disk thickness, radial scale length, and central surface brightness) in the galaxies by analyzing photometric profiles in each of the g, r, and i images. We also perform simplified three-dimensional modeling of the light distribution in the stellar disks of edge-on galaxies from our sample. Our large sample is intended to be used for studying scaling relations in the stellar disks and bulges and for estimating parameters of the thick disks in different types of galaxies via the image stacking. In this paper, we present the sample selection procedure and general description of the sample.
- ID:
- ivo://CDS.VizieR/J/AJ/129/682
- Title:
- Structural properties of S+S galaxies
- Short Name:
- J/AJ/129/682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a structural analysis of nearby galaxies in spiral-spiral pairs in optical BVRI bands and compare them with the structures of isolated spiral galaxies and galaxies in ongoing mergers. We use these comparisons to determine how galaxy structure changes during galaxy interactions and mergers. We analyze light concentration (C), asymmetry (A), and clumpiness (S) parameters, and use the projections of CAS parameter space to compare these samples.
- ID:
- ivo://CDS.VizieR/J/AJ/136/773
- Title:
- Structure of classical bulges and pseudobulges
- Short Name:
- J/AJ/136/773
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we study the properties of pseudobulges (bulges that appear similar to disk galaxies) and classical bulges (bulges which appear similar to E-type galaxies) in bulge-disk decompositions. We show that the distribution of bulge Sersic indices, n_b_, is bimodal, and this bimodality correlates with the morphology of the bulge. Pseudobulges have n_b_~<2 and classical bulges have n_b_>~2 with little to no overlap. Also, pseudobulges do not follow the correlations of Sersic index with structural parameters or the photometric projections of the fundamental plane in the same way that classical bulges and elliptical galaxies do. We find that pseudobulges are systematically flatter than classical bulges and thus more disk-like in both their morphology and shape.
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/L50
- Title:
- Structure of the Upper Scorpius association
- Short Name:
- J/MNRAS/477/L50
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using new proper motion data from recently published catalogs, we revisit the membership of previously identified members of the Upper Scorpius association. We confirmed 750 of them as cluster members based on the convergent point method, compute their kinematic parallaxes and combined them with Gaia parallaxes to investigate the 3D structure and geometry of the association using a robust covariance method. We find a mean distance of 146+/-3+/-6pc and show that the morphology of the association defined by the brightest (and most massive) stars yields a prolate ellipsoid with dimensions of 74x38x32pc^3^, while the faintest cluster members define a more elongated structure with dimensions of 98x24x18pc^3^. We suggest that the different properties of both populations is an imprint of the star formation history in this region.
- ID:
- ivo://CDS.VizieR/J/MNRAS/369/1131
- Title:
- Structures in the GA region
- Short Name:
- J/MNRAS/369/1131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To further our understanding of the Great Attractor (GA), we have undertaken a redshift survey using the 2dF on the AAT. Clusters and filaments in the GA region were targeted with 25 separate pointings resulting in approximately 2600 new redshifts. Targets included poorly studied X-ray clusters from the CIZA catalogue as well as the Cen-Crux and PKS 1343-601 clusters, both of which lie close to the classic GA centre. For nine clusters in the region, we report velocity distributions as well as virial and projected mass estimates. The virial mass of CIZA J1324.75736, now identified as a separate structure from the Cen-Crux cluster, is found to be ~3x10^14^M_{sun}_ in good agreement with the X-ray inferred mass. In the PKS 1343-601 field, five redshifts are measured of which four are new. An analysis of redshifts from this survey, in combination with those from the literature, reveals the dominant structure in the GA region to be a large filament, which appears to extend from Abell S0639 (l=281{deg}, b=+11{deg}) to (l~5{deg}, b~-50{deg}), encompassing the Cen-Crux, CIZA J1324.75736, Norma and Pavo II clusters. Behind the Norma Cluster at cz~15000km/s, the masses of four rich clusters are calculated. These clusters (Triangulum-Australis, Ara, CIZA J1514.64558 and CIZA J1410.44246) may contribute to a continued large- scale flow beyond the GA. The results of these observations will be incorporated into a subsequent analysis of the GA flow.
- ID:
- ivo://CDS.VizieR/J/AZh/77/3
- Title:
- Studies of Bright Steep-Spectrum Radio Sources
- Short Name:
- J/AZh/77/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of studies of bright radio sources in the constellation Cetus are presented. More than 50% of the sources have radio spectral indices steeper than 0.9. Optical identifications have been determined for 35 sources. A large fraction of the radio sources are identified with weak blue galaxies. Given their spectral indices, it is likely that these objects have redshift z=0.4-1.0. More than 20% of the steep-spectrum sources do not have optical identifications and appear to be weak galaxies with z>2.
- ID:
- ivo://CDS.VizieR/III/147
- Title:
- Studies of LMC stellar content
- Short Name:
- III/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spectral survey has been made during the period 1971 to 1975 with the ESO 40cm astrograph at La Silla, equipped with its normal prism, giving an intermediate dispersion of 95Angstroem/mm at 4026Angstroem. Long exposure plates taken directly or with an interference filter enabled us to obtain spectral types for nearly 1600 stars. In parallel, a V photographic survey has been carried out during the same period with the same astrograph and has led to the determination of V magnitudes for more that 700 stars having no previous photometric data. New spectroscopic and photometric results as well as previous photoelectric UBV values are given in the catalogue together with additional remarks concerning peculiarities of spectra, V magnitudes, and details on double and multiple systems.
- ID:
- ivo://CDS.VizieR/J/ApJ/659/1176
- Title:
- Study of bars in 180 spiral galaxies
- Short Name:
- J/ApJ/659/1176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Critical insights on galaxy evolution stem from the study of bars. With the advent of HST surveys that trace bars in the rest-frame optical out to z~1, it is critical to provide a reference baseline for bars at z~0 in the optical band. We present results on bars at z~0 in the optical and NIR based on 180 spirals from OSUBSGS (Eskridge et al., 2002, Cat. J/ApJS/143/73).
- ID:
- ivo://CDS.VizieR/J/A+A/390/179
- Title:
- Study of FK Comae Berenices. IV.
- Short Name:
- J/A+A/390/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Doppler imaging techniques have earlier been used to study the starspots and their evolution over a four year period in a single, late-type star FK Com. In the present work we publish new photometric observations of FK Com for the year 2001 and analyse them together with the previously published photometry obtained since 1966. The observations for 2001 have been carried out at the Phoenix 10 automatic photometric telescope in Arizona, USA. Observations contain measurements at the Johnson U, B and V bands. The observations are differential photometry in respect to the primary comparison star HD 117567. In table1, 99.000 means that no observations were available at that time at that band or that the error in the magnitude was larger than 0.02.
