- ID:
- ivo://CDS.VizieR/J/A+A/416/537
- Title:
- UBVI and HST photometry of young stellar clusters
- Short Name:
- J/A+A/416/537
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- These tables contain a combination of ground-based and HST archive data for stellar clusters in 18 nearby spiral galaxies. Structural parameters for each cluster are measured on HST images, while UBVI photometry is from ground-based data obtained with the Danish 1.54m telescope at ESO La Silla, the 2.56m Nordic Optical Telescope in La Palma, Canary Islands, and the 3m Shane Telescope at Lick Observatory, California. Photometry in the STMAG system based on the HST data is also given (table 7) for each cluster for the available bandpasses.
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- ID:
- ivo://CDS.VizieR/J/A+A/592/A149
- Title:
- UBVI CCD photometry of Carina region stars
- Short Name:
- J/A+A/592/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies of the Carina region have revealed its complexity and richness as well as a significant number of early-type stars. However, in many cases, these studies only concentrated on the central region (Trumpler 14/16) or were not homogeneous. This latter aspect, in particular is crucial because very different ages and distances for key clusters have been claimed in recent years. The aim of this work is to study in detail an area of the Galactic plane in Carina, east ward Carina. We analyze the properties of different stellar populations and focus on a sample of open clusters and their population of young stellar objects and highly reddened early stars. We also studied the stellar mass distribution in these clusters and the possible scenario of their formation. Finally, we outline the Galactic spiral structure in this direction. We obtained deep and homogeneous photometric data (UBVIKC) for six young open clusters: NGC 3752, Trumpler 18, NGC 3590, Hogg 10, 11, and 12, located in Carina at l~291, and their adjacent stellar fields, which we complemented with spectroscopic observations of a few selected targets. We also culled additional information from the literature, which includes stellar spectral classifications and near-infrared photometry from 2MASS. We finally developed a numerical code that allowed us to perform a homogeneous and systematic analysis of the data. Our results provide more reliable estimates of distances, color excesses, masses, and ages of the stellar populations in this direction. We estimate the basic parameters of the studied clusters and find that they identify two overdensities of young stellar populations located at about 1.8kpc and 2.8kpc, with E_(B-V)_~0.1-0.6. We find evidence of pre-main-sequence populations inside them, with an apparent coeval stellar formation in the most conspicuous clusters. We also discuss apparent age and distance gradients in the direction NW-SE. We study the mass distributions of the covered clusters and several others in the region (which we took form the literature). They consistently show a canonical IMF slope (the Salpeter one). We discover and characterise an abnormally reddened massive stellar population, scattered between 6.6 and 11kpc. Spectroscopic observations of ten stars of this latter population show that all selected targets were massive OB stars. Their location is consistent with the position of the Carina-Sagittarius spiral arm.
- ID:
- ivo://CDS.VizieR/J/AN/325/307
- Title:
- UBVIc photometry of NGC 3077 center
- Short Name:
- J/AN/325/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVIc photometry of starlike objects in the central region of NGC 3077. The colour-colour and colour-magnitude diagrams of the objects are discussed. Many of the objects under consideration, starlike from the ground, are probably dense young star clusters (super star clusters, SSC). Ages spreading over ~4 to ~150Myr are estimated for most of these objects. Sakai and Madore (2001ApJ...555..280S) found enhanced star formation ~30-125Myr ago also in the halo of this galaxy; thus, high star forming activity has occurred within the entire galaxy (centre and halo) since ~130..150Myr. Having ended in the outer regions about 30Myr ago, it is going on near the centre with full vigour.
- ID:
- ivo://CDS.VizieR/J/ApJS/162/49
- Title:
- UBV imaging of irregular galaxies
- Short Name:
- J/ApJS/162/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of UBV imaging of a large sample of irregular galaxies: 94 Im systems, 24 blue compact dwarfs (BCDs), and 18 Sm galaxies. We also include JHK imaging of 42 of these galaxies. The sample spans a large range in galactic parameters. Ellipse fit axial ratios, inclinations, and position angles are derived, integrated photometry and azimuthally averaged surface photometry profiles are determined, and exponential fits give the central surface brightnesses, scale lengths, and isophotal and half-power radii.
- ID:
- ivo://CDS.VizieR/J/AJ/114/2381
- Title:
- UBVI photometry of NGC 7252
- Short Name:
- J/AJ/114/2381
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new U, B, V, and I images of the prototypical merger remnant NGC 7252 obtained with the WFPC2 instrument of the Hubble Space Telescope. The photometry reaches about 3 mag deeper than the previous observations with WF/PCI and we detect 499 cluster candidates, most of them previously undiscovered. We can distinguish three populations of star clusters. We confirm the existence of a very luminous, blue population of clusters with a narrow range in color. Comparisons with Bruzual & Charlot (1996, in preparation) models incorporating a Salpeter stellar IMF show that the mean ages of these clusters are 650Myr for [Fe/H]=0.0 and 750 Myr if [Fe/H]=-0.3. Therefore, these are the clusters that formed during the merger event. The upper limit to the effective radii of these objects is 4.8+/-0.4pc (for D=64.4Mpc, H_0_=75), suggesting that they have physical properties like Galactic globular clusters. The second population of clusters is associated with the inner disk. Their (U-B) colors and reddening-free Q values indicate that their light is dominated by O stars and that they have ages less than 10Myr. However, with <R_eff_>=8.3+/-0.6pc, these objects may be more like stellar associations and they may not survive for a significant time. Finally, there is also evidence for the presence of the most luminous of the old, metal-poor globular clusters that belonged to the progenitor galaxies. The cluster luminosity function is a single power law with slope {alpha}~-1.8 down to a limiting magnitude of V=26. The current specific cluster frequency is S_N_=0.6+/-0.3 for old clusters and young clusters with M>10^5^M_{sun}_, but after the remnant has faded for about 15Gyr S_N_ will have increased to about 2.5. The central disk is now resolved into much finer detail than in earlier WF/PCI observations and the light profile of the nuclear region is consistent with a single power law with slope {gamma}=-1.26+/-0.03. After both the main body and the cluster system of NGC 7252 have aged, for several Gyr it may have the properties of a field elliptical.
- ID:
- ivo://CDS.VizieR/J/A+A/464/495
- Title:
- UBVI photometry of NGC 45 star clusters
- Short Name:
- J/A+A/464/495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Star clusters are present in almost all types of galaxies. Here we investigate the star cluster population in the low-luminosity, unperturbed spiral galaxy NGC 45, which is located in the nearby Sculptor group. Both the old (globular) and young star-cluster populations are studied. Previous ground-based observations have suggested that NGC 45 has few if any "massive" young star clusters. We aim to study the population of lower-mass "open" star clusters and also identify old globular clusters that could not be distinguished from foreground stars in the ground-based data. Star clusters were identified using UBVI imaging from the Advanced Camera for Surveys (ACS) and the Wide Field Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. From broad band colors and comparison with simple stellar population (SSP) models assuming a fixed metallicity, we derived the age, mass, and extinction. We also measured the radius for each star cluster candidate.
- ID:
- ivo://CDS.VizieR/J/AN/329/418
- Title:
- UBVRcIc photometry in fields of Seyfert galaxies
- Short Name:
- J/AN/329/418
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVRcIc magnitudes of 49 comparison stars in the fields of the Seyfert galaxies Mrk 335, Mrk 79, Mrk 279, Mrk 506, 3C 382, 3C 390.3, NGC 6814, Mrk 304, Ark 564, and NGC 7469 in order to facilitate the photometric monitoring of these objects; 36 of the stars have not been calibrated before. The comparison stars are situated in 5x5arcmin fields centred on the Seyfert galaxies, their V band flux ranges from 11.7 to 18.2mag with a median value of 16.3mag, and their B-V colour index ranges from 0.4 to 1.6mag with a median value of 0.8mag. The median errors of the calibrated UBVRCIC magnitudes are 0.08, 0.04, 0.03, 0.04, and 0.06mag, respectively. Comparison stars were calibrated for the first time in three of the fields (Mrk 506, 3C 382, and Mrk 304). The comparison sequences in the other fields were improved in various aspects. Extra stars were calibrated in four fields (Mrk 335, Mrk 79, NGC 6814, and NGC 7469) most of these stars are fainter and are situated closer to the Seyfert galaxies compared to the existing comparison stars. The passband coverage of the sequences in five fields (Mrk 335, Mrk 79, Mrk 279, NGC 6814, and Ark 564) was complemented with the U band.
- ID:
- ivo://CDS.VizieR/J/A+A/441/905
- Title:
- UBVRI from the Garching-Bonn Deep Survey
- Short Name:
- J/A+A/441/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present first results of our search for high-redshift galaxies in deep CCD mosaic images. As a pilot study for a larger survey, very deep images of the Chandra Deep Field South (CDFS), taken with WFI@MPG/ESO2.2m, are used to select large samples of 1070 U-band and 565 B-band dropouts with the Lyman-break method.
- ID:
- ivo://CDS.VizieR/J/A+A/441/451
- Title:
- UBVRIJHK photometry of E-type galaxies
- Short Name:
- J/A+A/441/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Colour gradients are considered for a sample of circa 50 E-type galaxies in the Local Supercluster. The new data includes isophotal colour profiles in J-H, J-K, V-J and V-K, measured using 2MASS frames mostly from the Large Galaxies Atla s, V frames from previous work and V profiles from the literature. This is supplemented by U-B, B-V, B-R, V-I colour gradients obtained anew from published photometric data. The here available file gives our zero-point colours at r_e_/2 and the measured gradients for 54 objects, but for missing data.
- ID:
- ivo://CDS.VizieR/J/AJ/133/2393
- Title:
- UBVRI phot. in seven Local Group dwarfs galaxies
- Short Name:
- J/AJ/133/2393
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained UBVRI images with the Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory 4m telescopes and Mosaic cameras of seven dwarfs in (or near) the Local Group, all of which have known evidence of recent star formation: IC 10, NGC 6822, WLM, Sextans B, Sextans A, Pegasus, and Phoenix. We construct color-magnitude diagrams (CMDs) of these systems, as well as neighboring regions that can be used to evaluate the degree of foreground contamination by stars in the Milky Way.
