- ID:
- ivo://CDS.VizieR/J/AJ/131/2959
- Title:
- Candidate low-mass PMS in 25 Orionis group
- Short Name:
- J/AJ/131/2959
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar group surrounding the Be (B1Vpe) star 25 Ori was discovered to be a pre-main-sequence (PMS) population by the CIDA Variability Survey of Orion (Cat. J/AJ/129/907) and subsequent spectroscopy. We analyze Sloan Digital Sky Survey multiepoch photometry to map the southern extent of the 25 Ori group and characterize its PMS population. We compare this group to the neighboring Orion OB1a and OB1b subassociations and to active star formation sites (NGC 2068/NGC 2071) within the LDN 1630 dark cloud. We find that the 25 Ori group has a radius of 1.4{deg}, corresponding to 8-11pc at the distances of Orion OB1a and OB1b.
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- ID:
- ivo://CDS.VizieR/J/A+A/571/A43
- Title:
- Candidate red supergiants in Galactic clusters
- Short Name:
- J/A+A/571/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Clear identifications of Galactic young stellar clusters farther than a few kpc from the Sun are rare, despite the large number of candidate clusters. We aim to improve the selection of candidate clusters rich in massive stars with a multiwavelength analysis of photometric Galactic data that range from optical to mid-infrared wavelengths. We present a photometric and spectroscopic analysis of five candidate stellar clusters, which were selected as overdensities with bright stars (K_s_<7mag) in GLIMPSE and 2MASS images. A total of 48 infrared spectra were obtained. The combination of photometry and spectroscopy yielded six new red supergiant stars with masses from 10M_{sun}_ to 15M_{sun}_. Two red supergiants are located at Galactic coordinates (l,b)=(16.7{deg}, -0.63{deg}) and at a distance of about ~3.9kpc; four other red supergiants are members of a cluster at Galactic coordinates (l,b)=(49.3{deg}, +0.72{deg}) and at a distance of ~7.0kpc. Spectroscopic analysis of the brightest stars of detected overdensities and studies of interstellar extinction along their line of sights are fundamental to distinguish regions of low extinction from actual stellar clusters. The census of young star clusters containing red supergiants is incomplete; in the existing all-sky near-infrared surveys, they can be identified as overdensities of bright stars with infrared color-magnitude diagrams characterized by gaps.
- ID:
- ivo://CDS.VizieR/J/A+A/506/711
- Title:
- Canis Major R1 X-ray sources
- Short Name:
- J/A+A/506/711
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CMa R1 star-forming region contains several compact clusters as well as many young early-B stars. It is associated with a well-known bright rimmed nebula, the nature of which is unclear (fossil HII region or supernova remnant). To help elucidate the nature of the nebula, our goal was to reconstruct the star-formation history of the CMa R1 region, including the previously unknown older, fainter low-mass stellar population, using X-rays. We analyzed images obtained with the ROSAT satellite, covering ~5deg^2^. Complementary VRI photometry was performed with the Gemini South telescope. Colour-magnitude and colour-colour diagrams were used in conjunction with pre-main sequence evolutionary tracks to derive the masses and ages of the X-ray sources.
- ID:
- ivo://CDS.VizieR/J/AJ/134/447
- Title:
- Catalog of star cluster candidates in M 33
- Short Name:
- J/AJ/134/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new catalog of star cluster candidates in the nearby spiral galaxy M33. It is based on eight existing catalogs wherein we have cross-referenced identifications and endeavored to resolve inconsistencies between them. Our catalog contains 451 candidates, of which 255 are confirmed clusters based on Hubble Space Telescope and high-resolution ground-based imaging. The catalog contains precise cluster positions (right ascension and declination), magnitudes and colors in the UBVRIJHKS filters, metallicities, radial velocities, masses and ages, where available, and galactocentric distances for each cluster.
- ID:
- ivo://CDS.VizieR/III/244
- Title:
- Catalog of Stellar Rotational Velocities
- Short Name:
- III/244
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a compilation of the observed projected rotational velocities, V_rot_*sin(i), for 28179 stars from 166 open clusters, globular clusters and associations. The catalog.dat file contains 39351 individual V_rot_*sin(i) data, together with the error and the method of determination. Because of the possible confusion with the use of different names for stars belonging to clusters we have included alternative names using SIMBAD nomenclature. Rotational velocities from CDS catalogue III/226 (Glebocki+ 2000) are included. Information about the number of stars in each cluster as well as other cluster names can be found in the "clusters.dat" file. The bibliographical references are provided in the "refs.dat" file. The file "mean.dat" contains mean V*sin(i) values for each star. The individual v*sin(i) measurements were reduced to a uniform standard (to remove the systematic errors) and a weighted average of V*sin(i) was calculated. The V*sin(i) values used as standards are presented in the "standards.dat" file.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/678
- Title:
- Catalogue of extended objects in Magellanic Clouds
- Short Name:
- J/MNRAS/389/678
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We update the Small Magellanic Cloud (SMC), Bridge and Large Magellanic Cloud (LMC) catalogues of extended objects that were constructed by members of our group from 1995 to 2000. In addition to the rich subsequent literature for the previous classes, we now also include HI shells and supershells. A total of 9305 objects were cross-identified, while our previous catalogues amounted to 7900 entries, an increase of ~12 per cent. We present the results in subcatalogues containing 1445 emission nebulae, 3740 star clusters, 3326 associations and 794 HI shells and supershells. Angular and apparent size distributions of the extended objects are analysed. We conclude that the objects, in general, appear to respond to tidal effects arising from the LMC, SMC and Bridge. Number-density profiles extracted along directions parallel and perpendicular to the LMC bar, can be described by two exponential-discs. A single exponential-disc fits the equivalent SMC profiles. Interestingly, when angular-averaged number-densities of most of the extended objects are considered, the profiles of both Clouds do not follow an exponential-disc. Rather, they are best described by a tidally truncated, core/halo profile, despite the fact that the Clouds are clearly disturbed discs. On the other hand, the older star clusters taken isolately, distribute as an exponential disc. The present catalogue is an important tool for the unambiguous identification of previous objects in current CCD surveys and to establish new findings.
- ID:
- ivo://CDS.VizieR/J/MNRAS/425/3085
- Title:
- CCD CT1 data of stars in the field of B119
- Short Name:
- J/MNRAS/425/3085
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present for the first time Washington CT_1_ photometry for 11 unstudied or poorly studied candidate star clusters. The selected objects are of small angular size, contain a handful of stars, and are projected towards the innermost regions of the Small Magellanic Cloud (SMC). The respective colour-magnitude diagrams (CMDs) were cleaned of the unavoidable star field contamination by taking advantage of a procedure which makes use of variable size CMD cells. This method has shown to be able to eliminate stochastic effects in the cluster CMDs caused by the presence of isolated bright stars, as well as to make a finer cleaning in the most populous CMD regions. Our results suggest that nearly one-third of the studied candidate star clusters would appear to be genuine physical systems.
- ID:
- ivo://CDS.VizieR/J/AJ/144/100
- Title:
- CCD Washington CT1T2 photometry of stars in LMC
- Short Name:
- J/AJ/144/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry for an unprecedented database of some 5.5million stars distributed throughout the Large Magellanic Cloud main body, from 21 fields covering a total area of 7.6deg^2^, obtained from Washington CT_1_T_2_ CTIO 4m MOSAIC data. Extensive artificial star tests over the whole mosaic image data set and the observed behavior of the photometric errors with magnitude demonstrate the accuracy of the morphology and clearly delineate the position of the main features in the color-magnitude diagrams (CMDs). The representative T_1_(MS TO) mags are on average ~0.5mag brighter than the T_1_ mags for the 100% completeness level of the respective field, allowing us to derive an accurate age estimate. We have analyzed the CMD Hess diagrams and used the peaks in star counts at the main sequence turnoff and red clump (RC) locations to age date the most dominant sub-population (or "representative" population) in the stellar population mix. The metallicity of this representative population is estimated from the locus of the most populous red giant branch track. We use these results to derive age and metallicity estimates for all of our fields. The analyzed fields span age and metallicity ranges covering most of the galaxy's lifetime and chemical enrichment, i.e., ages and metallicities between ~1 and 13Gyr and ~-0.2 and -1.2dex, respectively. We show that the dispersions associated with the mean ages and metallicities represent in general a satisfactory estimate of the age/metallicity spread (~1-3 Gyr/0.2-0.3 dex), although a few subfields have a slightly larger age/metallicity spread. Finally, we revisit the study of the vertical structure (VS) phenomenon, a striking feature composed of stars that extend from the bottom, bluest end of the RC to ~0.45mag fainter. We confirm that the VS phenomenon is not clearly seen in most of the studied fields and suggest that its occurrence is linked to some other condition(s) in addition to the appropriate age, metallicity, and the necessary red giant star density.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/1674
- Title:
- CFHT M33 extended sources catalog
- Short Name:
- J/ApJ/720/1674
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of 2990 extended sources in a 1x1{deg} area centered on M33 using the MegaCam camera on the 3.6m Canada-France-Hawaii Telescope. The catalog includes 599 new candidate stellar clusters, 204 previously confirmed clusters, 1969 likely background galaxies, and 218 unknown extended objects. We present ugriz integrated magnitudes of the candidates and confirmed star clusters (SCs) as well as the full width at half maximum, ellipticity, and stellarity. Based on the properties of the confirmed SCs, we select a sub-sample of highly probable clusters composed of 246 objects. The integrated photometry of the complete cluster catalog reveals a wide range of colors of -0.4<(g-r)<1.5 and -1.0<(r-i)<1.0 with no obvious cluster subpopulations. Comparisons with models of simple stellar populations suggest a large range of ages some as old as ~10Gyr.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A46
- Title:
- Chamaeleon DANCe. Stellar population with Gaia-DR2
- Short Name:
- J/A+A/646/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kinematic properties and stellar parameters of the Chamaeleon stars selected in our membership analysis using Gaia-DR2 data. We provide for each star its identifier, position, proper motion, parallax, radial velocity, distance, spatial velocity, SED classification, age and membership probability. We also provide the membership probabilities for all sources in the fields surveyed by our study and the empirical isochrone of the Cha I and Cha II subgroups.
