- ID:
- ivo://CDS.VizieR/J/A+A/628/A60
- Title:
- Star cluster formation in a tidal debris
- Short Name:
- J/A+A/628/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The formation of globular clusters remains an open debate. Dwarf starburst galaxies are efficient at forming young massive clusters with similar masses as globular clusters and may hold the key to understanding their formation. We study star cluster formation in a tidal debris - including the vicinity of three tidal dwarf galaxies - in a massive gas dominated collisional ring around NGC 5291. These dwarfs have physical parameters which differ significantly from local starbursting dwarfs. They are gas-rich, highly turbulent, have a gas metallicity already enriched up to half-solar, and are expected to be free of dark matter. The aim is to study massive star cluster formation in this as yet unexplored type of environment. We use imaging from the Hubble Space Telescope using broadband filters covering the wavelength range from the near- ultraviolet to the near-infrared. We determine the masses and ages of the cluster candidates by using the spectral energy distribution- fitting code CIGALE, carefully considering age-extinction degeneracy effects on the estimation of the physical parameters. Results. We find that the tidal dwarf galaxies in the ring of NGC 5291 are forming star clusters with an average efficiency of about 40%, comparable to blue compact dwarf galaxies. We also find massive star clusters for which the photometry suggests that they were formed at the very birth of the tidal dwarf galaxies and have survived for several hundred million years. Therefore our study shows that extended tidal dwarf galaxies and compact clusters may be formed simultaneously. In the specific case observed here, the young star clusters are not massive enough to survive for a Hubble time. However one may speculate that similar objects at higher redshift, with higher star formation rate, might form some of the long lived globular clusters.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/501/949
- Title:
- Star cluster properties in five spiral galaxies
- Short Name:
- J/A+A/501/949
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Aims: Our goal is to investigate the formation of star clusters in relatively unperturbed environments. To do this, we studied the five nearby spiral galaxies: NGC 45, NGC 1313, NGC 4395, NGC 5236, and NGC 7793. Methods: We obtained images of the galaxies and their star cluster systems in UBVI using the Advanced Camera for Surveys (ACS) and the Wide Field Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. From a comparison of the broad-band colours with simple stellar population (SSP) models, we derived individual properties for each galaxy for the clusters such such as masses, ages, and sizes, as well as global star cluster system properties such as the age distribution, luminosity function, and disruption time for clusters. Results. We identified about 600 star cluster candidates in the five galaxies, typically spanning ages from 3.9Myr up to 1Gyr and masses from 10^2^M_{sun}_ up to 10^5^M_{sun}_. We used the cluster age distribution to reconstruct the recent star formation history of each galaxy and observed significant variations from galaxy to galaxy. We went on to derive the luminosity function of the young star clusters and found slopes around {alpha}~-2 (similar to the ones found in previous studies) and the brightest star cluster magnitudes consistent with a random sampling of the luminosity function without involving an upper luminosity cut off. Finally, the sample includes only a handful of old globular clusters in each galaxy from which we derive low globular cluster specific frequencies.
- ID:
- ivo://CDS.VizieR/J/A+A/647/A135
- Title:
- 35 star clusters and fields in the SMC
- Short Name:
- J/A+A/647/A135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we study 35 stellar clusters in the Small Magellanic Cloud (SMC) in order to provide their mean metallicities and ages. We also provide mean metallicities of the fields surrounding the clusters. We used Stroemgren photometry obtained with the 4.1 m SOAR telescope and take advantage of (b-y) and m1 colors for which there is a metallicity calibration presented in the literature. The spatial metallicity and age distributions of clusters across the SMC are investigated using the results obtained by Stroemgren photometry. We confirm earlier observations that younger, more metal-rich star clusters are concentrated in the central regions of the galaxy, while older, more metal-poor clusters are located farther from the SMC center. We construct the age-metallicity relation for the studied clusters and find good agreement with theoretical models of chemical enrichment, and with other literature age and metallicity values for those clusters. We also provide the mean metallicities for old and young populations of the field stars surrounding the clusters, and find the latter to be in good agreement with recent studies of the SMC Cepheid population. Finally, the Stroemgren photometry obtained for this study is made publicly available.
- ID:
- ivo://CDS.VizieR/J/AJ/157/12
- Title:
- Star clusters, associations, & candidates in the MW
- Short Name:
- J/AJ/157/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of Galactic star clusters, associations and candidates with 10978 entries. This multi-band catalog was constructed over 20 years, starting with visual inspections on the Digital Sky Survey and incremented with the 2MASS, WISE, VVV, Spitzer, and Herschel surveys. Large and small catalogs, as well as papers on individual objects have been systematically cross-identified. The catalog provides Galactic and equatorial coordinates, angular diameters, and chronologically ordered designations, making it simple to assign discoveries and verify how often the objects were cataloged by different authors, search methods, and/or surveys. Detection in a single band is the minimum constraint to validate an entry. About 3200 objects have measured parameters in the literature. A fundamental contribution of the present study is to present an additional ~7700 objects for the first analyses of nature, photometry, spectroscopy and structure. The present focus is not to compile or determine fundamental parameters, but to provide a catalog uniformly characterizing the entries. A major result is that now 4234 embedded clusters are cataloged, a factor of ~1.5 larger than open clusters. In addition to cross-identifications in different references and wavelength domains, we also communicate the discovery of 638 star clusters and similar objects. The present general catalog provides previously studied objects and thousands of additional entries in a homogeneous way, a timely contribution to Gaia-related works.
3515. Star clusters in IC 10
- ID:
- ivo://CDS.VizieR/J/ApJ/804/123
- Title:
- Star clusters in IC 10
- Short Name:
- J/ApJ/804/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of star clusters in the halo of IC 10, a starburst galaxy in the Local Group, based on Subaru R-band images and NOAO Local Group Survey UBVRI images. We find five new star clusters. All of these star clusters are located far from the center of IC 10, while previously known star clusters are mostly located in the main body. Interestingly, the distribution of these star clusters shows an asymmetrical structure elongated along the east and southwest directions. We derive UBVRI photometry of 66 star clusters, including these new star clusters, as well as previously known star clusters. Ages of the star clusters are estimated from a comparison of their UBVRI spectral energy distribution with the simple stellar population models. We find that the star clusters in the halo are all older than 1Gyr, while those in the main body have various ages, from very young (several Myr) to old (>1Gyr). The young clusters (<10Myr) are mostly located in the H{alpha} emission regions and are concentrated on a small region at 2" in the southeast direction from the galaxy center, while the old clusters are distributed in a wider area than the disk. Intermediate-age clusters (~100 Myr) are found in two groups. One is close to the location of the young clusters and the other is at ~ 4" from the location of the young clusters. The latter may be related to past mergers or tidal interaction.
3516. Star clusters in IC 10
- ID:
- ivo://CDS.VizieR/J/PAZh/35/829
- Title:
- Star clusters in IC 10
- Short Name:
- J/PAZh/35/829
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on our observations with the 6-m BTA telescope at the Special Astrophysical Observatory, the Russian Academy of Sciences, and archival Hubble Space Telescope images, we have performed stellar photometry for several regions of the irregular galaxy IC 10, a member of the Local Group. Distance moduli with a median value of m-M=24.47, D=780+/-4kpc, have been obtained by the TRGB method for several regions of IC 10. We have revealed 57 star clusters with various masses and ages within the fields used. Comparison of the Hertzsprung-Russell diagrams for star clusters in IC 10 with theoretical isochrones has shown that this galaxy has an enhanced metallicity, which probably explains the high ratio of the numbers of carbon and nitrogen Wolf-Rayet stars (WC/WN). The size of the galaxy's thick disk along its minor axis is 10.5' and a more extended halo is observed outside this disk.
3517. Star Clusters in M33
- ID:
- ivo://CDS.VizieR/J/ApJS/122/431
- Title:
- Star Clusters in M33
- Short Name:
- J/ApJS/122/431
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the discovery of 60 star clusters in 20 multiband Hubble Space Telescope (HST) WFPC2 fields in M33. The fields sample a variety of environments, from outer regions to spiral arms and central regions, as well as a range of galactocentric distances. The HST spatial resolution allowed us to penetrate the crowded, spiral arm regions of M33 yielding the first unbiased, representative sample of star clusters for this galaxy. We discuss the separation of clusters from stellar sources, and from other extended sources such as star-forming regions, H II regions, and supernova remnants. For the clusters we present multiband images and discuss morphology, location, and integrated photometry. Measured cluster colors and magnitudes are presented. The cluster density in our sample as a function of galactocentric distance yields an estimate of 690 total clusters in M33.
3518. Star clusters in M31
- ID:
- ivo://CDS.VizieR/J/ApJS/177/174
- Title:
- Star clusters in M31
- Short Name:
- J/ApJS/177/174
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new survey of star clusters in the southwest field of the M31 disk based on the high-resolution Subaru Suprime-Cam observations is presented. The UBVRI aperture CCD photometry catalog of 285 objects (V<~20.5mag; 169 of them identified for the first time) is provided. Each object is supplemented with multiband color maps presented in the electronic edition of the Astrophysical Journal Supplement. Seventy-seven star cluster candidates from the catalog are located in the Hubble Space Telescope archive frames.
3519. Star clusters in M33
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/3400
- Title:
- Star clusters in M33
- Short Name:
- J/MNRAS/451/3400
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present precision radial velocities and stellar population parameters for 77 star clusters in the Local Group galaxy M33. Our Gran Telescopio de Canarias and William Herschel Telescope observations sample both young, massive clusters and known/candidate globular clusters (GCs), spanning ages ~10^6-10^10yr, and metallicities, [M/H]~-1.7 to solar. The cluster system exhibits an age-metallicity relation; the youngest clusters are the most metal rich. When compared to HI data, clusters with [M/H]~-1.0 and younger than ~4Gyr are clearly identified as a disc population. The clusters show evidence for strong time evolution in the disc radial metallicity gradient (d[M/H]dt/dR=0.03dex/kpc/Gyr). The oldest clusters have stronger, more negative gradients than the youngest clusters in M33. The clusters also show a clear age-velocity dispersion relation. The line-of-sight velocity dispersions of the clusters increases with age similar to Milky Way open clusters and stars. The general shape of the relation is reproduced by disc heating simulations, and the similarity between the relations in M33 and the Milky Way suggests that heating by substructure and cooling of the interstellar medium both play a role in shaping this relation. We identify 12 'classical' GCs, six of which are newly identified GC candidates. The GCs are more metal rich than Milky Way halo clusters, and show weak rotation. The inner (R<4.5kpc) GCs exhibit a steep radial metallicity gradient (d[M/H]/dR=-0.29+/-0.11dex/kpc) and an exponential-like surface density profile. We argue that these inner GCs are thick disc rather than halo objects.
3520. Star clusters in M31
- ID:
- ivo://CDS.VizieR/J/AJ/137/94
- Title:
- Star clusters in M31
- Short Name:
- J/AJ/137/94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an updated catalog of 1300 objects in the field of M31, including 670 likely star clusters of various types, the rest being stars or background galaxies once thought to be clusters. The coordinates in the catalog are accurate to 0.2", and are based on images from the Local Group Survey (LGS) or from the Digitized Sky Survey (DSS). Archival Hubble Space Telescope (HST) images and the LGS were inspected to confirm cluster classifications where possible, but most of the classifications are based on spectra taken of ~1000 objects with the Hectospec fiber positioner and spectrograph on the 6.5m MMT.
