- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1475
- Title:
- CaT in 903 globular clusters
- Short Name:
- J/MNRAS/426/1475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although the colour distribution of globular clusters in massive galaxies is well known to be bimodal, the spectroscopic metallicity distribution has been measured in only a few galaxies. After redefining the calcium triplet index-metallicity relation, we use our relation to derive the metallicity of 903 globular clusters in 11 early-type galaxies. This is the largest sample of spectroscopic globular cluster metallicities yet assembled. We compare these metallicities with those derived from Lick indices finding good agreement. In six of the eight galaxies with sufficient numbers of high-quality spectra we find bimodality in the spectroscopic metallicity distribution. Our results imply that most massive early-type galaxies have bimodal metallicity as well as colour distributions. This bimodality suggests that most massive early-type galaxies experienced two periods of star formation.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/285/785
- Title:
- 3C 295 BRri photometry
- Short Name:
- J/A+A/285/785
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the cluster Cl 1409+524 (z=0.46) with an imaging Fabry-Perot interferometer. A sequence of Fabry-Perot images (FWHM=1.0-1.3nm) was used to search for redshifted [OII]{lambda}372.7nm- and [OIII]{lambda}500.7nm line emission. We studied 144 galaxies up to a limiting continuum R-band magnitude of 22.5mag within 1 Mpc around the cluster center. Previously known emission-line galaxies in the cluster were confirmed and 17 new members with emission lines were found. Their star formation rate of 1-2M_{sun}_/yr is typical for normal spirals. We have imaged the cluster with broad band B, R and seven intermediate band filters (FWHM=10.0-20.0nm) in order to derive low-resolution spectral energy distributions of cluster galaxies. These were fitted by template spectra to estimate Hubble class and redshifts. Based on this decomposition, we derived a percentage of emission-line galaxies of 40+/-11%.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A107
- Title:
- 3C 129 candidate cluster galaxies
- Short Name:
- J/A+A/644/A107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of 261 new infrared selected members of the 3C 129 galaxy cluster. The cluster, located at z=0.02, forms part of the Perseus-Pisces filament and is obscured at optical wavelengths due to its location in the zone of avoidance. We identified these galaxies using the J- and K-band imaging data provided by the UKIDSS Galactic Plane Survey within an area with a radius of 1.1{deg} centred on the X-ray emission of the cluster at (l, b) = (160.52{deg}, 0.27{deg}). A total of 26 of the identified galaxy members have known redshifts 24 of which are from our 2016 Westerbork HI survey and two are from optical spectroscopy. An analysis of the galaxy density at the core of the 3C 129 cluster shows it to be less dense than the Coma and Norma clusters, but comparable to the galaxy density in the core of the Perseus cluster. From an assessment of the spatial and velocity distributions of the 3C 129 cluster galaxies that have redshifts, we derived a velocity of cz=5227+/-171km/s and=1097+/-252km/s for the main cluster, with a substructure in the cluster outskirts at cz=6923+/-71km/s with {sigma}=422+/-100km/s. The presence of this substructure is consistent with previous claims based on the X-ray analysis that the cluster is not yet virialised and may have undergone a recent merger.
- ID:
- ivo://CDS.VizieR/J/A+A/472/1055
- Title:
- CCD astrometry of visual double stars
- Short Name:
- J/A+A/472/1055
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We measured the angular separations, position angles, Delta(V), Delta(y) and Delta(I) of wide visual double stars during the period 2003-2005. At least one component of the double stars in our sample has an entry in the Hipparcos catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJ/628/729
- Title:
- CCD BVIc photometry of M10 stars
- Short Name:
- J/ApJ/628/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the globular cluster M10 were taken at the Kitt Peak National Observatory (KPNO) 0.9 m telescope on the nights of UT dates 1995 May 6 and 9 using BVI filters. All frames were taken using a 2048x2048 pixel CCD with pixels covering 0.68 arcseconds on a side, for a total field of approximately 23.2 arcminutes on a side. The data were calibrated against Stetson (2000PASP..112..925S) standard stars. Additional high-resolution images were taken at the 3.6 m Canada-France-Hawaii Telescope (CFHT) on the night of UT date 1993 April 13 in BI filters. These observations used a 1200x1200 pixel CCD with pixels covering 0.11 arcseconds on a side, for a total field 2.2 arcminutes on a side, roughly centered on the cluster core. These data were calibrated against the KPNO data.
- ID:
- ivo://CDS.VizieR/J/MNRAS/365/110
- Title:
- CCD BVI photometry of 3 open clusters
- Short Name:
- J/MNRAS/365/110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVI photometry for poorly known southern hemisphere open clusters: NGC 2425, Haffner 10 and Czernik 29. We have calculated the density profile and established the number of stars in each cluster. The colour-magnitude diagrams of the objects show a well-defined main sequence. However, the red giant clump is present only in NGC 2425 and Haffner 10. For these two clusters we estimated the age as 2.5+/-0.5Gyr assuming metallicity of Z=0.008. The apparent distance moduli are in the ranges 13.2<(m-M)_V<13.6 and 14.3<(m-M)_V<14.7, while heliocentric distances are estimated to be 2.9<d<3.8kpc and 3.1<d<4.3kpc, respectively for NGC 2425 and Haffner 10. The angular separation of 2.4deg (150pc at mean distance) may indicate a common origin of the two clusters.
- 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/A+A/395/823
- Title:
- CCD {Delta}a-photometry of 5 open clusters
- Short Name:
- J/A+A/395/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The time scale on which chemical peculiarity in upper main sequence stars begins is unknown. Results from the Hipparcos measurements indicate that the classical chemically peculiar (CP) stars occupy the whole area from the zero age main sequence to the terminal age main sequence. Hubrig et al. (2000ApJ...539..352H) reported that the magnetic fields appear only in stars that have already completed at least approximately 30% of their main sequence life time. Previous observations in the very young Orion OB1 and Scorpio Centaurus associations reveal a percentage of chemically peculiar stars that is significantly smaller (less than 5%) than that of the galactic field (up to 25%). This already indicates that the phenomenon needs at least several Myr to appear. Since no further observations have been published since then, we have observed the five very young (1Myr<Age<25Myr) open clusters Collinder 272, Pismis 20, Lynga 14, NGC 6396 and NGC 6611. Photometry from 250 CCD frames in the three filter Delta a-system results in very low detection limits (0.008 to 0.015mag). We find no single photometrically chemically peculiar candidate in approximately 460 observed cluster members in the five program clusters. From the number of observed objects we deduce upper limits between 0.6% and 2.4% for the incidence of CP stars for the five observed aggregates.The tables presented here include all photometric observations of these five clusters. For a description of the (Delta a) photometric system, see e.g. <GCPD/75>: a = g2 - (g1+y)/2 g1 and g2 centered at 502 and 524nm.
- ID:
- ivo://CDS.VizieR/J/A+A/385/867
- Title:
- CCD {Delta}a-photometry of 5 open clusters
- Short Name:
- J/A+A/385/867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In total, more than 550 objects within the fields of five open clusters (NGC 2439, NGC 3960, NGC 6134, NGC 6192 and NGC 6451) were investigated in order to find classical chemically peculiar stars. One bona-fide CP candidate was detected in each of the open clusters NGC 3960, NGC 6192 and NGC 6451. All three objects seem to be members of the corresponding cluster taking the results from our photometry as well as from the literature. For NGC 6192 and NGC 6451 we found widely different interstellar reddening values and therefore distances and ages in the literature. From an analysis of published Johnson UBVRI photometry, we were able to rule out a rather old age for NGC 6451. This is also supported by the finding of one peculiar object in this cluster with spectral type of about A2. Five variable objects within the field of NGC 6134 were detected. The variability exceeds 10 times (or typically 0.03 mag) the standard deviation of the weighted individual measurements. But since our observations were obtained mostly during one hour (typical integration times of five minutes per filter) on several nights within 45 days, no light curves could yet be derived. For this cluster some Am candidates were reported for which we were not able to detect a significant positive {Delta} a-value. For a description of the {Delta}a photometric system, see e.g. <GCPD/75>
- ID:
- ivo://CDS.VizieR/J/A+A/454/171
- Title:
- CCD {Delta}a-photometry of 8 open clusters
- Short Name:
- J/A+A/454/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of magnetic chemically peculiar (CP2) stars in open clusters of the Milky Way can be used to study the influence of different galactic environments on the (non-)presence of peculiarities, which has to be taken into account in stellar evolution models. Furthermore it is still unknown if the CP2 phenomenon evolves, i.e. does the strength of the peculiarity feature at 5200{AA} increase or decrease with age. Methods. We have observed eight young to intermediate age open clusters in the {Delta}a photometric system.
