- ID:
- ivo://CDS.VizieR/J/MNRAS/441/1230
- Title:
- RRLyr stars in the Catalina Sky Survey (CS2)
- Short Name:
- J/MNRAS/441/1230
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of RR Lyrae stars distributed across ~14000deg^2^ of the sky from the combined data of the Sloan Digital Sky Survey (SDSS, http://www.sdss.org), the Panoramic Survey Telescope and Rapid Response System 1 (PS1, Kaiser et al., 2002, SPIE, 4836, 154), and the second photometric catalogue from the Catalina Survey (CS2, http://nesssi.cacr.caltech.edu/DataRelease), out of these, ~2021 RRL stars (~572 RRab and 1449 RRc) are new discoveries. The RRL stars have heliocentric distances in the 4-28kpc distance range. Our catalog has a completeness level of ~50 per cent for both RRab and RRc stars, and an efficiency of ~99 and ~87 per cent for RRab and RRc stars, respectively. We provide the positions, CSDR2 mean magnitudes, CSDR2 amplitudes, subtypes, periods, ephemeris, and the heliocentric distances of our RRab and RRc stars.
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- ID:
- ivo://CDS.VizieR/J/AJ/140/1337
- Title:
- RV of 111 Galactic halo stars in Virgo
- Short Name:
- J/AJ/140/1337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-slit radial velocity measurements for 111 stars in the direction of the Virgo Stellar Stream (VSS). The stars were photometrically selected to be probable main-sequence stars in the Galactic halo. When compared with the radial velocity distribution expected for the halo of the Milky Way, as well as the distribution seen in a control field, we observe a significant excess of negative velocity stars in the field, which can likely be attributed to the presence of a stellar stream.
- ID:
- ivo://CDS.VizieR/J/A+A/631/A72
- Title:
- SABOCA 350um view of ATLASGAL-selected massive clumps
- Short Name:
- J/A+A/631/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The structure formation of the dense interstellar material and the fragmentation of clumps into cores is a fundamental step to understand how stars and stellar clusters form. We aim to establish a statistical view of clump fragmentation at sub-parsec scales based on a large sample of massive clumps selected from the ATLASGAL survey. We used the APEX/SABOCA camera at 350um to image clumps at a resolution of 8.5", corresponding to physical scales of <0.2pc at a distance <5kpc. The majority of the sample consists of massive clumps that are weak or in absorption at 24um. We resolve spherical and filamentary structures and identify the population of compact sources. Complemented with archival Herschel data, we derive the physical properties, such as dust temperature, mass and bolometric luminosity of clumps and cores. We use association with mid-infrared 22-24 m and 70 m point sources to pin down the star formation activity of the cores. We then statistically assess their physical properties, and the fragmentation characteristics of massive clumps. We detect emission at 350um towards all targets and find that it typically exhibits a filamentary(-like) morphology and hosts a population of compact sources. Using Gaussclumps we identify 1120 compact sources and derive the physical parameters and star formation activity for 971 of these, 874 of which are associated with 444 clumps. We find a moderate correlation between the clump fragmentation levels with the clump gas density and the predicted number of fragments with pure Jeans fragmentation scenario. We find a strong correlation between the mass of the most massive fragment and the total clump mass, suggesting that the self-gravity may play an important role in the clumps' small scale structure formation. Finally, due to the improved angular resolution compared to ATLASGAL, we are able to identify 27 massive quiescent cores with M_core_>100M_{sun}_ within 5kpc; these are massive enough to be self-gravitating but do not yet show any sign of star-formation. This sample comprises, therefore, promising candidates of massive pre-stellar cores, or deeply embedded high-mass protostars. The submillimeter observations of the massive clumps that are weak or completely dark at 24um reveal rich filamentary structures and an embedded population of compact cores. The maximum core mass is likely determined by the self-gravity of the clump. The rarity of massive pre-stellar core candidates implies short collapse time-scales for dense structures.
- ID:
- ivo://CDS.VizieR/J/A+A/604/A128
- Title:
- S abundances for 1301 stars from GES
- Short Name:
- J/A+A/604/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Due to their volatile nature, when sulphur and zinc are observed in external galaxies, their determined abundances represent the gas-phase abundances in the interstellar medium. This implies that they can be used as tracers of the chemical enrichment of matter in the Universe at high redshift. Comparable observations in stars are more difficult and, until recently, plagued by small number statistics. We wish to exploit the Gaia ESO Survey (GES) data to study the behaviour of sulphur and zinc abundances of a large number of Galactic stars, in a homogeneous way. By using the UVES spectra of the GES sample, we are able to assemble a sample of 1301 Galactic stars, including stars in open and globular clusters in which both sulphur and zinc were measured. We confirm the results from the literature that sulphur behaves as an alpha-element. We find a large scatter in [Zn/Fe] ratios among giant stars around solar metallicity. The lower ratios are observed in giant stars at Galactocentric distances less than 7.5kpc. No such effect is observed among dwarf stars, since they do not extend to that radius. Given the sample selection, giants and dwarfs are observed at different Galactic locations, and it is plausible, and compatible with simple calculations, that Zn-poor giants trace a younger population more polluted by SN Ia yields. It is necessary to extend observations in order to observe both giants and dwarfs at the same Galactic location. Further theoretical work on the evolution of zinc is also necessary.
- ID:
- ivo://CDS.VizieR/V/132
- Title:
- SAI Open Clusters Catalog
- Short Name:
- V/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The automated search for star clusters of J,H,K_s data from the Two Micron All-Sky Survey (2MASS) was made using a new method based on the convolution with density functions (Koposov et al. 2008A&A...486..771K). In two papers (this one and Koposov et al. 2008A), 168 new clusters were found and verified in the range of galactic latitude |b|<24 degrees. The new method to estimate main physical parameters of clusters was developed, which involves three different techniques: Hess-diagram, color-magnitude diagrams in (J,J-H) and (K_s,J-K_s), and radial density distribution. Color excesses E(B-V), distance moduli and ages were determined for 141 new and 27 known, but poorly studied clusters. We present the Sternberg Astronomical Institute Open Clusters Catalog (SAI OCL Catalog) of coordinates, diameters and main physical parameters of these clusters. The parameters for 9 clusters were determined using J,H,K data from UKIDSS GPS. For 26 new embedded clusters, we publish the coordinates and diameters only. To facilitate the access to these data and its scientific analysis, we have developed a dedicated web-site of the catalog available at http://ocl.sai.msu.ru/
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/250
- Title:
- SCUBA-2 Ambitious Sky Survey
- Short Name:
- J/MNRAS/468/250
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The SCUBA-2 Ambitious Sky Survey (SASSy) is composed of shallow 850-{mu}m imaging using the Submillimetre Common-User Bolometer Array 2 (SCUBA-2) on the James Clerk Maxwell Telescope. Here we describe the extraction of a catalogue of beam-sized sources from a roughly 120deg^2^ region of the Galactic plane mapped uniformly (to an rms level of about 40mJy), covering longitude 120{deg}<l<140{deg} and latitude |b|<2.9{deg}. We used a matched-filtering approach to increase the signal-to-noise ratio (S/N) in these noisy maps and tested the efficiency of our extraction procedure through estimates of the false discovery rate, as well as by adding artificial sources to the real images. The primary catalogue contains a total of 189 sources at 850{mu}m, down to an S/N threshold of approximately 4.6. Additionally, we list 136 sources detected down to S/N=4.3, but recognize that as we go lower in S/N, the reliability of the catalogue rapidly diminishes. We perform follow-up observations of some of our lower significance sources through small targeted SCUBA-2 images and list 265 sources detected in these maps down to S/N=5. This illustrates the real power of SASSy: inspecting the shallow maps for regions of 850-{mu}m emission and then using deeper targeted images to efficiently find fainter sources. We also perform a comparison of the SASSy sources with the Planck Catalogue of Compact Sources and the IRAS Point Source Catalogue, to determine which sources discovered in this field might be new, and hence potentially cold regions at an early stage of star formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/738/79
- Title:
- SDSS-DR8 BHB stars in the Milky Way's halo
- Short Name:
- J/ApJ/738/79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and analyze the positions, distances, and radial velocities for over 4000 blue horizontal-branch (BHB) stars in the Milky Way's halo, drawn from SDSS DR8. We search for position-velocity substructure in these data, a signature of the hierarchical assembly of the stellar halo. Using a cumulative "close pair distribution" as a statistic in the four-dimensional space of sky position, distance, and velocity, we quantify the presence of position-velocity substructure at high statistical significance among the BHB stars: pairs of BHB stars that are close in position on the sky tend to have more similar distances and radial velocities compared to a random sampling of these overall distributions. We make analogous mock observations of 11 numerical halo formation simulations, in which the stellar halo is entirely composed of disrupted satellite debris, and find a level of substructure comparable to that seen in the actually observed BHB star sample. This result quantitatively confirms the hierarchical build-up of the stellar halo through a signature in phase (position-velocity) space. In detail, the structure present in the BHB stars is somewhat less prominent than that seen in most simulated halos, quite possibly because BHB stars represent an older sub-population. BHB stars located beyond 20kpc from the Galactic center exhibit stronger substructure than at r_gc_<20kpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/794/60
- Title:
- SDSS RGB stars distances
- Short Name:
- J/ApJ/794/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present distance determinations for a large and clean sample of red giant branch stars selected from the ninth data release of the Sloan Digital Sky Survey (Adelman-McCarthy et al. 2012ApJS..203...21A, Cat. V/139). The distances are calculated based on both observational cluster fiducials and theoretical isochrones. Distributions of distances from the two methods are very similar with peaks at about 10 kpc and tails extending to more than 70 kpc. We find that distances from the two methods agree well for the majority of the sample stars; though, on average, distances based on isochrones are 10% higher than those based on fiducials. We test the accuracy of our distance determinations using 332 stars from 10 Galactic globular and open clusters. The average relative deviation from the literature cluster distances is 4% for the fiducial-based distances and 8% for the isochrone-based distances, both of which are within the uncertainties. We find that the effective temperature and surface gravity derived from low-resolution spectra are not accurate enough to essentially improve the performance of distance determinations. However, for stars with significant extinction, effective temperature may help to better constrain their distances to some extent. We make our sample stars and their distances available from an online catalog. The catalog comprises 17941 stars with reasonable distance estimations reaching to more than 70 kpc, which is suitable for the investigation of the formation and evolution of the Galaxy, especially the Galactic halo.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A30
- Title:
- Seismology and spectroscopy of CoRoGEE red giants
- Short Name:
- J/A+A/597/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the CoRoGEE dataset -- obtained from CoRoT lightcurves for 606 red giant stars in two fields of the Galactic disc which have been co-observed for an ancillary project of the Apache Point Observatory Galactic Evolution Experiment (APOGEE). The CoRoGEE stars cover a large radial range of the Milky Way's disc (5kpc<RGal<14kpc) and thus provide a valuable dataset for Galactic Archaeology studies. We have used the Bayesian parameter estimation code PARAM to calculate distances, extinctions, masses, and ages for these stars in a homogeneous analysis, resulting in relative statistical uncertainties of 2% in distance, 4% in radius, ~9% in mass and ~25% in age. We also assess systematic age uncertainties due to different input physics and mass loss.
- ID:
- ivo://CDS.VizieR/J/MNRAS/460/1131
- Title:
- Selection function of Milky Way field stars
- Short Name:
- J/MNRAS/460/1131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Gaia-ESO Survey was designed to target all major Galactic components (i.e. bulge, thin and thick discs, halo and clusters), with the goal of constraining the chemical and dynamical evolution of the Milky Way. This paper presents the methodology and considerations that drive the selection of the targeted, allocated and successfully observed Milky Way field stars. The detailed understanding of the survey construction, specifically the influence of target selection criteria on observed Milky Way field stars is required in order to analyse and interpret the survey data correctly. We present the target selection process for the Milky Way field stars observed with Very Large Telescope/Fibre Large Array Multi Element Spectrograph and provide the weights that characterize the survey target selection. The weights can be used to account for the selection effects in the Gaia-ESO Survey data for scientific studies. We provide a couple of simple examples to highlight the necessity of including such information in studies of the stellar populations in the Milky Way.
