- ID:
- ivo://CDS.VizieR/J/A+A/409/147
- Title:
- J magnitude of IC 348 brown dwarfs
- Short Name:
- J/A+A/409/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a deep near-infrared census of the young stellar cluster IC 348 to construct and analyze its luminosity function. Our mosaic image of IC 348 covers the full extent of the cluster with a completeness limit of J~19.5 and is therefore sensitive for 2Myr old cluster members with masses as low as M>=0.005M_{sun}_ or the mean extinction of the known cluster members (A_V_~3.5mag).
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/II/300
- Title:
- JMMC Stellar Diameters Catalogue - JSDC
- Short Name:
- II/300
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains stellar angular diameter estimate for bright stars, complete for all stars with Hipparcos parallaxes. The JMMC Calibrator Workgroup has long developed methods to estimate the angular diameter of stars, and provides this expertise in the SearchCal software (http://www.jmmc.fr/searchcal). "SearchCal" creates a dynamical catalogue of stars suitable to calibrate Optical Long-Baseline Interferometry (OLBI) observations from on-line queries of CDS catalogues, according to observational parameters. In essence, SearchCal is limited only by the completeness of the stellar catalogues it uses, and in particular is not limited in magnitude. SearchCal being an application centered on OLBI peculiar purposes, it appeared useful to publish the estimated angular diameters of all stars with known parallaxes in a static catalogue. The present catalogue of stellar angular diameters has been obtained from an automated SearchCal results aggregation on the whole celestial sphere. For each star, the value of the limb-darkened angular diameters are computed using a surface brightness method and calibrations for (B-V), (V-R) and (V-K) color indexes. Stars whose angular diameters estimated from the various color indexes are not comparable, are rejected, and a reliable error on the estimated diameter is computed (1). For details of the method see Bonneau et al. (2006A&A...456..789B). To avoid specific confusion problems, spectroscopic binaries in the 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix et al., 2009, Cat. B/sb9) or close visual binaries with a separation of less than 2 arc seconds in the Washington Visual Double Star Catalog (Mason et al., 2001, Cat. B/wds) have been filtered out.
- ID:
- ivo://CDS.VizieR/II/346
- Title:
- JMMC Stellar Diameters Catalogue - JSDC. Version 2
- Short Name:
- II/346
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains stellar angular diameter estimates for nearly all the stars of the Hipparcos and Tycho catalogue that have an associated spectral type in Simbad/CDS. The median error on the diameters is around 1.5%, with possible biases of around ~2%. For each object, the limb-darkened diameter retained is the mean value of several estimates performed using different couples of photometries. The chi-square representing the dispersion between these values is also given (it is below 2 for ~400000 stars). An additional flag signals stars that could represent a risk if chosen as calibrators for Optical Long-Baseline Interferometry, independently of the correctness of their apparent diameter estimate. This catalog replaces the catalog II/300/jsdc .
- ID:
- ivo://CDS.VizieR/J/A+A/568/A22
- Title:
- Joint analysis of the SDSS-II and SNLS SNe Ia
- Short Name:
- J/A+A/568/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We deliver luminosity-distance measurements from a joint analysis of 740 type-Ia supernovae from the SDSS and SNLS supernova surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A181
- Title:
- J-PLUS DR1 stellar param, and abundances
- Short Name:
- J/A+A/659/A181
- Date:
- 25 Mar 2022 09:03:05
- Publisher:
- CDS
- Description:
- The Javalambre Photometric Local Universe Survey (J-PLUS) has obtained precise photometry in twelve specially designed filters for large numbers of Galactic stars. Deriving their precise stellar atmospheric parameters and individual elemental abundances is crucial for studies of Galactic structure, and the assembly history and chemical evolution of our Galaxy. Our goal is to estimate not only stellar parameters (effective temperature, Teff, surface gravity, logg, and metallicity, [Fe/H]), but also [{alpha}/Fe] and four elemental abundances ([C/Fe], [N/Fe], [Mg/Fe], and [Ca/Fe]) using data from J-PLUS DR1. By combining recalibrated photometric data from J-PLUS DR1, Gaia DR2, and spectroscopic labels from LAMOST, we design and train a set of cost-sensitive neural networks, the CSNet, to learn the non-linear mapping from stellar colors to their labels. We have achieved precisions of {delta}Teff~55K, {delta}logg~0.15dex, and {delta}[Fe/H]~0.07dex, respectively, over a wide range of temperature, surface gravity, and metallicity. The uncertainties of the abundance estimates for [{alpha}/Fe] and the four individual elements are in the range 0.04-0.08 dex. We compare our parameter and abundance estimates with those from other spectroscopic catalogs such as APOGEE and GALAH, and find an overall good agreement. Conclusions. Our results demonstrate the potential of well-designed, high-quality photometric data for determinations of stellar parameters as well as individual elemental abundances. Applying the method to J-PLUS DR1, we have obtained the aforementioned parameters for about two million stars, providing an outstanding data set for chemo-dynamic analyses of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/659/A144
- Title:
- J-PLUS. STAR-GALAXY-QSO Classification
- Short Name:
- J/A+A/659/A144
- Date:
- 18 Mar 2022 08:13:24
- Publisher:
- CDS
- Description:
- In modern astronomy, machine learning has proved to be efficient and effective in mining big data from the newest telescopes. In this study, we construct a supervised machine-learning algorithm to classify the objects in the Javalambre Photometric Local Universe Survey first data release (J-PLUS DR1). The sample set is featured with 12-waveband photometry and labeled with spectrum-based catalogs, including Sloan Digital Sky Survey (SDSS) spectroscopic data, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), and VERON- CAT - the Veron Catalog of Quasars & AGN (VV13. Cat. VII/258). The performance of the classifier is presented with the applications of blind test validations based on RAdial Velocity Extension (RAVE), the Kepler Input Catalog (KIC), the 2 MASS (the Two Micron All Sky Survey) Redshift Survey (2MRS), and the UV-bright Quasar Survey (UVQS). A new algorithm was applied to constrain the potential extrapolation that could decrease the performance of the machine-learning classifier. The accuracies of the classifier are 96.5% in the blind test and 97.0% in training cross-validation. The F1-scores for each class are presented to show the balance between the precision and the recall of the classifier. We also discuss different methods to constrain the potential extrapolation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/341/534
- Title:
- J-type carbon stars in LMC
- Short Name:
- J/MNRAS/341/534
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 1497 carbon stars in the Large Magellanic Cloud (LMC) has been observed in the red part of the spectrum with the 2dF facility on the Anglo-Australian Telescope. Of these, 156 have been identified as J-type (i.e. ^13^C-rich) carbon stars using a technique which provides a clear distinction between J stars and the normal N-type carbon stars that comprise the bulk of the sample, and yields few borderline cases. A simple two-dimensional classification of the spectra, based on their spectral slopes in different wavelength regions, has been constructed and found to be related to the more conventional c and j indices, modified to suit the spectral regions observed. Most of the J stars form a photometric sequence in the K-(J-K) colour-magnitude diagram, parallel to and 0.6mag fainter than the N-star sequence. A subset of the J stars (about 13 per cent) are brighter than this J-star sequence; most of these are spectroscopically different from the other J stars. The bright J stars have stronger CN bands than the other J stars and are found strongly concentrated in the central regions of the LMC. Most of the rather few stars in common with Hartwick and Cowley's sample (1988ApJ...334..135H) of suspected CH stars are J stars. Overall, the proportion of carbon stars identified as J stars is somewhat lower than has been found in the Galaxy. The Na D lines are weaker in the LMC J stars than in either the Galactic J stars or the LMC N stars, and do not seem to depend on temperature.
2468. K and M stars photometry
- ID:
- ivo://CDS.VizieR/J/AJ/105/1962
- Title:
- K and M stars photometry
- Short Name:
- J/AJ/105/1962
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Broadband UBVRI photometry is presented for 687 stars from among the dwarf K and M stars found spectroscopically by Vyssotsky [1958AJ.....63..211V]. Of these, 211 are without previous photometry.
- ID:
- ivo://CDS.VizieR/J/ApJS/237/14
- Title:
- KASI-Yonsei Deep Imaging Survey of Clusters (KYDISC)
- Short Name:
- J/ApJS/237/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the KASI-Yonsei Deep Imaging Survey of Clusters targeting 14 clusters at 0.015<~z<~0.144 using the Inamori Magellan Areal Camera and Spectrograph on the 6.5m Magellan Baade telescope and the MegaCam on the 3.6m Canada-France-Hawaii Telescope. We provide a catalog of cluster galaxies that lists magnitudes, redshifts, morphologies, bulge-to-total ratios, and local density. Based on the 1409 spectroscopically confirmed cluster galaxies brighter than -19.8 in the r band, we study galaxy morphology, color, and visual features generated by galaxy mergers. We see a clear trend between morphological content and cluster velocity dispersion, which was not presented by previous studies using local clusters. Passive spirals are preferentially found in a highly dense region (i.e., cluster center), indicating that they have gone through environmental quenching. In deep images ({mu}_r'_~27mag/arcsec^2^), 20% of our sample shows signatures of recent mergers, which is not expected from theoretical predictions and a low frequency of ongoing mergers in our sample (~4%). Such a high fraction of recent mergers in the cluster environment supports a scenario that the merger events that made the features have preceded the galaxy accretion into the cluster environment. We conclude that mergers affect a cluster population mainly through the preprocessing of recently accreted galaxies.
- ID:
- ivo://CDS.VizieR/VII/254
- Title:
- Kazarian galaxies catalog
- Short Name:
- VII/254
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The entire KG (KG) catalog is presented which combines extensive new measurements of their optical parameters with a literature and database search. The measurements were made using images extracted from the STScI Digitized Sky Survey (DSS) of Jpg(blue), Fpg(red) and Ipg(NIR) band photographic sky survey plates obtained by the Palomar and UK Schmidt telescopes. We provide accurate coordinates, morphological type, spectral and activity classes, blue apparent diameters, axial ratios, position angles, red, blue and NIR apparent magnitudes, as well as counts of neighboring objects in a circle of radius 50kpc from centers of KG. Special attention was paid to the individual descriptions of the galaxies in the original Kazarian lists, which clarified many cases of misidentifications of the objects, particularly among interacting systems. The total number of individual Kazarian objects in the database is now 706. We also include the redshifts which are now available for 404 galaxies, and the 2MASS infrared magnitudes for 598 KG. The database also includes extensive notes, which summarize information about the membership of KG in different systems of galaxies, and about revised activity classes and redshifts. An atlas of several interesting subclasses of KG is also presented.
