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- ID:
- ivo://CDS.VizieR/J/A+A/548/A55
- Title:
- C and O isotopic ratios in Arcturus and Aldebaran
- Short Name:
- J/A+A/548/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We re-analyzed the carbon and oxygen isotopic ratios in the atmospheres of the two bright K giants Arcturus ({alpha} Boo) and Aldebaran ({alpha} Tau). These stars are in the evolutionary stage following the first dredge-up (FDU). Previous determinations (dating back more than 20 years) of their ^16^O/^18^O ratios showed a rough agreement with FDU expectations; however, the estimated ^16^O/^17^O and ^12^C/^13^C ratios were lower than in the canonical predictions for red giants. Today these anomalies are interpreted as signs of the occurrence of non-convective mixing episodes. We therefore re-investigated this problem to verify whether the observed data can be reproduced in this scenario and if the fairly well determined properties of the two stars can help us in fixing the uncertain parameters that characterize non-convective mixing and in constraining its physical nature.
- ID:
- ivo://CDS.VizieR/J/other/RAA/19.127
- Title:
- C- and S-shaped radio galaxies
- Short Name:
- J/other/RAA/19.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the environment of radio galaxies with different morphological types using the Proctor sample, which was built from the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey archive. Among the 15 radio galaxy types classified by Proctor, 199 C-shaped (i.e., wide- or narrow-angle tail) and 203 S-shaped (i.e., S- or Z-shaped) sources are selected in this work, which are located in the redshift range of 0.02<z<1, because these two subsamples are relatively larger than the other subsamples in the Proctor sample. By cross-matching these radio galaxies with the optical sources drawn from the Sloan Digital Sky Survey (SDSS) database and counting the SDSS sources with an r-band absolute magnitude brighter than -19 located within a 0.5Mpc distance around each source (i.e., the richness), we find that the fraction of C-shaped sources with a richness above 10 is larger than that of S-shaped sources. We have also correlated the radio galaxies in our sample with the brightest cluster galaxies (BCGs) defined in the NASA/IPAC Extragalactic Database (NED), and infer that the C-shaped sources are more likely to be BCGs than the S-shaped sources. These results support the idea that C-shaped radio galaxies often reside in a richer environment than radio galaxies with other morphological types.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/8
- Title:
- Cand. young OB stars from GALEX & Gaia DR2
- Short Name:
- J/ApJ/883/8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine Galaxy Evolution Explorer and Gaia DR2 catalogs to track star formation in the outskirts of our Galaxy. Using photometry, proper motions, and parallaxes we identify a structure of ~300 OB-type candidates located between 12 and 15kpc from the Galactic center that are kinematically cold. The structure is located between l=120{deg} and 200{deg}, above the plane up to ~700pc and below the plane to ~1kpc. The bulk motion is disklike; however, we measure a mean upward vertical motion of 5.7+/-0.4km/s, and a mean outward radial motion of between 8 and 16km/s. The velocity dispersion along the least dispersed of its proper-motion axes (perpendicular to the Galactic disk) is 6.0+/-0.3km/s, confirming the young age of this structure. While spatially encompassing the outer spiral arm of the Galaxy, this structure is not a spiral arm. Its explanation as the Milky Way warp is equally unsatisfactory. The structure's vertical extent, mean kinematics, and asymmetry with respect to the plane indicate that its origin is more akin to a wobble generated by a massive satellite perturbing the Galaxy's disk. The mean stellar ages in this outer structure indicate the event took place some 200Myr ago.
- ID:
- ivo://CDS.VizieR/J/MNRAS/496/2663
- Title:
- Canes Venatici I images with LOFAR
- Short Name:
- J/MNRAS/496/2663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dwarf galaxies are dark matter-dominated and therefore promising targets for the search for weakly interacting massive particles (WIMPs), which are well-known candidates for dark matter. Annihilation of WIMPs produce ultra-relativistic cosmic-ray electrons and positrons that emit synchrotron radiation in the presence of magnetic fields. For typical magnetic field strengths (few G) and O(GeV-TeV) WIMP masses (and thus typical electron energies of the same order) this emission peaks at hundreds of MHz. Here, we use the non-detection of 150-MHz radio continuum emission from the dwarf spheroidal galaxy 'Canes Venatici I' with the LOw-Frequency ARray (LO-FAR) to derive constraints on the annihilation cross section of WIMPs into primary electron-positron and other fundamental particle-antiparticle pairs. In this first-of-its-kind LOFAR study, we obtain new constraints on annihilating WIMP dark matter (DM). Using conservative estimates for the magnetic field strengths and diffusion coefficients, we obtain limits that are comparable with those by the Fermi Large Area Telescope (Fermi-LAT) using gamma-ray observations. Assuming s-wave annihilation and WIMPs making up 100% of the DM density, our limits exclude several thermal WIMP realisations in the [2, 20]-GeV mass range. A more ambitious multi-wavelength and multi-target LOFAR study could improve these limits by a few orders of magnitude.
- ID:
- ivo://cadc.nrc.ca/youcat
- Title:
- CANFAR User Catalogue Query Service
- Short Name:
- YouCat
- Date:
- 06 Nov 2024 23:59:00
- Publisher:
- Canadian Astronomy Data Centre
- Description:
- YouCat is a query service for catalogues hosted by CANFAR. This service provides Table Access Protocol (TAP) API access to catalogues created by project teams. YouCat also implements a prototype VOSI-tables extension that allows users to create, update table metadata add table content (rows), create indices, and delete tables in the database. Users can also control access to their own tables (public to allow anonymous querying, protected so only members of specified groups can query, and private where only the owner can query). Users who want to create tables must request an allocation (schema) by email to support@canfar.net. Currently available catalogues include: VLASS, CFHTLS, KiDS, PAndAS, RCSLens.
- 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/I/219
- Title:
- Cape AC Zone Data Reduced to ACRS
- Short Name:
- I/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The U.S. Naval Observatory is in the process of making new reductions of the Astrographic Catalogue (AC) using a modern reference system, the ACRS, which represents the system of the FK5. The data from the Cape Zone, whose plates are centered between declinations -41 and -51 degrees (eq. 1900), have been analyzed for scale, rotation, tilt, coma, magnitude equation, radial distortion and distortions introduced by the use of reseaux in the Carte du Ciel program. The result is a positional catalog of over 544,000 stars on eq. J2000.0, epoch of observation. Additionally, all stars have been matched with the Tycho Input Catalog (revised); those numbers have been added for additional identification purposes.
- ID:
- ivo://CDS.VizieR/I/6
- Title:
- Cape Catalog of 20554 Faint Stars, -40 to -52{deg}
- Short Name:
- I/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains positions, precessions, proper motions, and photographic magnitudes for 20,554 stars. These were derived from photographs taken at the Royal Observatory, Cape of Good Hope between 1923 and 1928. It covers the astrographic zones -40 degrees to -52 degrees of declination. The positions are given for epoch 1900 (1900.0). It includes spectral types for many of the stars listed. It extends the earlier catalogs derived from the same plates to fainter magnitudes. The computer-readable version consists of a single data table. The stated probable error for the star positions is 0.024 seconds of time (R.A.) and 0.25 seconds of arc (Dec.) for stars with one determination, 0.017 seconds of time, and 0.18 seconds of arc for two determinations, and 0.014 / 0.15 for stars with three determinations. The precession and secular variations were derived from Newcomb's constants. The authors quote probable errors of the proper motions in both coordinates of 0.008 seconds of arc for stars with one determination, 0.0055 seconds for stars with two determinations, and 0.0044 for stars with three. The photographic magnitudes were derived from the measured diameters on the photographic plates and from the magnitudes given in the Cape Photographic Durchmusterung. The spectral classification of the catalogued stars was done with the assistance of Annie Jump Cannon of the Harvard College Observatory. The user should consult the source reference for more details of the measurements and reductions. See also the notes in this document for additional information on the interpretation of the entries.
- ID:
- ivo://CDS.VizieR/I/116
- Title:
- Cape Photographic Catalog 1950.0 (CPC)
- Short Name:
- I/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog includes most of the stars from the 1900.0 Cordoba Zone Catalogues B and C in the zone -30 deg. -35 deg. at the equinox of 1925.0. Some of the fainter Cordoba stars have been omitted in the rather crowded regions in the Milky Way. The aim was to provide accurate places for an average of 9 to 10 stars per square degree as a reference for a rereduction of the AG positions. Most of the stars have visual magnitudes between 7 and 10. Positions and proper motions have been supplied from the General Catalogue for those stars that were too bright for accurate measurement on photographic plates. The positions are on the FK3 system for the equinox of 1950.0. The probable errors of the positions are nominally +/- 0.15" in both right ascension and declination. That of the proper motions should not exceed +/- 1.4"/century, or +/-14 in the units in which the proper motions expressed in arc are given in the catalog.
