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- ID:
- ivo://CDS.VizieR/J/A+A/503/87
- Title:
- BVI phot. of NGC3370 star cluster candidates
- Short Name:
- J/A+A/503/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the photometric and structural properties of the star cluster system in the late type Sc spiral NGC 3370. BVI observations from the Advanced Camera for Surveys on board of HST are used to analyse in detail the colours, magnitudes and spatial properties of cluster candidates. The final catalogue of sources used for the study is composed by 277 objects.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/33
- Title:
- BVI photometric calatog of star clusters in NGC4589
- Short Name:
- J/ApJ/871/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC4589, a bright E2 merger-remnant galaxy, hosts the peculiar fast and faint calcium-rich supernova SNIb SN2005cz. The progenitor of Ca-rich SNeIb has been controversial: it could be (1) a young, massive star with 6-12M{sun} in a binary system, or (2) an old, low-mass star in a binary system that was kicked out from the galaxy center. Moreover, previous distance estimates for this galaxy have shown a large spread, ranging from 20 to 60Mpc. Thus, using archival Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) F435W, F555W, and F814W images, we search for star clusters in NGC4589 in order to help resolve these issues. We find a small population of young star clusters with 25<V<=27(-7.1<M_V_<-5.1)mag and age <1Gyr in the central region at R<0.5' (<3.8kpc), thus supporting the massive-star progenitor scenario for SN2005cz. In addition to young star clusters, we also find a large population of old globular clusters. In contrast to previous results in the literature, we find that the color distribution of the globular clusters is clearly bimodal. The turnover (Vega) magnitude in the V-band luminosity functions of the blue (metal-poor) globular clusters is determined to be V_0_(max)=24.40{+/-}0.10mag. We derive the total number of globular clusters, N_GC_=640{+/-}50, and the specific frequency, S_N_=1.7{+/-}0.2. Adopting a calibration for the metal-poor globular clusters, M_V_(max) =-7.66{+/-}0.14mag, we derive a distance to this galaxy: (m-M)_0_=32.06{+/-}0.10(ran){+/-}0.15(sys) (d=25.8{+/-}2.2Mpc).
- ID:
- ivo://CDS.VizieR/J/A+AS/114/537
- Title:
- BVI photometric study of NGC 2453
- Short Name:
- J/A+AS/114/537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD observations of the open cluster NGC 2453 have been carried out in B, V and I passbands. A total of 356 stars have been observed in a field of about 4'x6' of the sky centred on the cluster. Colour-magnitude diagrams in V, B-V and V, V-I have been generated down to V=20 and for the first time, the unevolved part of the cluster main sequence has been observed. The mean true distance modulus derived from these diagrams is 13.mag 85+/-0.2 yielding a distance of 5.9+/-0.2kpc. A mean age of 25Myr has been derived for the cluster by fitting isochrones. The distance of approximately 6kpc puts the cluster much beyond the planetary nebula NGC 2452 whose largest estimated distance to date is about 3.5kpc. The two are not physically associated.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1596
- Title:
- BVI photometric variability survey of M3
- Short Name:
- J/AJ/129/1596
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a three-band (BVI) variability survey of the globular cluster M3. This is the first three-band survey of the cluster using modern image subtraction techniques. Observations were made over nine nights in 1998 on the 1.2m telescope at the F. L. Whipple Observatory in Arizona. We present photometry for 180 variable stars in the M3 field, 12 of which are newly discovered. New discoveries include six SX Phoenicis-type variables that all lie in the blue straggler region of the color-magnitude diagram, two new first-overtone RR Lyrae variables, a candidate multimode RR Lyrae variable, a detached eclipsing binary, and two unclassified variables. We also provide revised periods for 52 of the 168 previously known variables that we observe.
- ID:
- ivo://CDS.VizieR/J/A+A/484/609
- Title:
- BVI photometry and proper motions in M67
- Short Name:
- J/A+A/484/609
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The solar-age open cluster M 67 (C0847+ 120, NGC 2682) is a touchstone in studies of the old Galactic disk. Despite its outstanding role, the census of cluster membership for M 67 at fainter magnitudes and their properties are not well-established. Using proprietary and archival ESO data, we have obtained astrometric, photometric, and radial velocities of stars in a 34x33arcmin^2^ field centered on the old open cluster M 67. The two-epoch archival observations separated by 4-years and acquired with the Wide-Field Imager at the 2.2m MPG/ ESO telescope were reduced with our new astrometric techniques, as described in the first paper in this series (Anderson et al., 2006A&A...454.1029A). The same observations served to derive calibrated BVI photometry in M 67. Radial velocities were measured using the archival and new spectroscopic data obtained at the VLT.
- ID:
- ivo://CDS.VizieR/J/A+A/442/917
- Title:
- BVI photometry in Berkeley 73, 75 and 25
- Short Name:
- J/A+A/442/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD BVI photometry of the faint open clusters Berkeley 73, Berkeley 75 and Berkeley 25 are presented. The two latter are previously unstudied clusters to our knowledge. While Berkeley 73 is found to be of intermediate-age (about 1.5Gyr old), Berkeley 75 and Berkeley 25 are old clusters, with ages greater than 3.0Gyr. We provide also estimates of the clusters size. All these clusters lie far away from the Galactic Center, at R_GC_>=16kpc, and quite high on the Galactic plane, at |Z_{sun}_|>=1.5kpc. They are therefore important targets to probe the properties of the structure of the Galaxy in this direction, where the Canis Major over-density has been discovered to be located.
- ID:
- ivo://CDS.VizieR/J/MNRAS/344/188
- Title:
- BVI photometry in Fornax cluster galaxies
- Short Name:
- J/MNRAS/344/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVI photometry of 190 galaxies in the central 4x3deg^2^ region of the Fornax cluster observed with the Michigan Curtis Schmidt Telescope. Results from the Fornax Cluster Spectroscopic Survey (FCSS) and the Flair-II Fornax Surveys have been used to confirm the membership status of galaxies in the Fornax Cluster Catalogue (FCC, Cat. <VII/180>). In our catalogue of 213 member galaxies, 92 (43 per cent) have confirmed radial velocities.
- ID:
- ivo://CDS.VizieR/J/MNRAS/299/1
- Title:
- BVI photometry in four open clusters
- Short Name:
- J/MNRAS/299/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD observations for the distant northern open star clusters Berkeley 81, Berkeley 99, NGC 6603 and NGC 7044 in BVI photometric passbands. A total of 9900 stars have been observed in fields of about 6x6arcmin^2^ of the sky around the clusters. Colour-magnitude diagrams in V, (B-V) and V, (V-I) have been generated down to V=22mag and, for the first time, such diagrams have been produced for the clusters Berkeley 81 and Berkeley 99. The data serve as a base for the study of mass functions and for comparison with theoretical models. Analysis of the radial distribution of stellar surface density indicates that the radius values for Berkeley 81, Berkeley 99, NGC 6603 and NGC 7044 are 2.7, 2.8, 2.8 and 2.2arcmin respectively. By fitting the latest convective core overshooting isochrones to the colour-magnitude diagram and using its morphological features, reddenings, distances and ages of the star clusters have been determined. Broad but well-defined main sequences with stellar evolutionary effects in the brighter stars are clearly visible in colour-magnitude diagrams of all the clusters under study. Some blue stragglers along with well-developed giant branches and red giant clumps are also clearly seen in all of them. The clusters studied here are located at a distance of ~3 kpc, except for Berkeley 99 which is located at a distance of 4.9kpc. Their linear sizes lie between 3.8 and 8.0pc; E(B-V) values range from 0.3 to 1.0mag, while their ages are between 0.5 and 3.2Gyr. Thus the star clusters studied here are of intermediate and high age but are compact and distant objects.
- ID:
- ivo://CDS.VizieR/J/AJ/108/555
- Title:
- BVI photometry in globular cluster M68
- Short Name:
- J/AJ/108/555
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A total of 363 CCD frames in the B, V, and I passbands have been used to study the color-magnitude diagram (CMD) and the variable-star population of the metal-poor galactic globular cluster M68 (NGC 4590, C1236-264). Light curves have been prepared for 40 RR Lyrae variables, five of which are new discoveries, and for two probable SX Phe stars. The RR Lyraes have <V>=15.64+/-0.01, and via several methods E(B-V)=0.07+/-0.01. [Fe/H]=-2.1 is adopted. From a comparison with Sandage's data for M3 (NGC 5272, C1339+286), a period shift of Delta(logP)/Delta([Fe/H])=-0.11+/-0.02 is derived, and the mass-to-light parameter is found to be <A>=1.90. RR Lyrae masses are derived from Fourier fits to the light curves, from the RRd variables, and by comparison with HB (horizontal branch) evolutionary models calculated by Dorman. The light-curve structure agrees qualitatively with recent theoretical models. From short exposures, CMDs have been prepared that are complete from the tip of the red giant branch (RGB) to below the level of the HB, while from the long exposures a CMD to V~23 is provided for 7298 stars more than 158 arcsec distant from the cluster center. The HB is skewed to the blue with the eight bluest stars clearly separated from the remainder of the HB stars. This HB gap is at the identical color to that in M15 (NGC 7078, C2127+119), but M68 lacks the extensive population of the very blue HB stars present in M15. The total number of HB stars is deficient with respect to the RGB population, with the ratio of RGB to HB stars R=0.99. There are several likely blue stragglers identified on CMDs of inner annuli, but near to the cluster center photometric errors scatter stars off the main sequence (MS) into this region. The deep CMDs are in excellent agreement with existing CCD CMDs for M68, with the MS turnoff Delta(V)=3.42+/-0.10mag below the HB. Matching the M68 CMD to that for M15 in the subgiant-MS turnoff region shows that the age of M68 is identical to that for M15 to within +/-0.4Gyr.
