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- ID:
- ivo://CDS.VizieR/J/AJ/108/2087
- Title:
- Globular Clusters in Ellipticals
- Short Name:
- J/AJ/108/2087
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present VRI photometry for the globular cluster systems (GCS's) of ten elliptical and S0 galaxies in Virgo and Leo. We find that the V-I color (metallicity) distributions are quite different from galaxy to galaxy. One extreme is represented by NGC 4374 with a narrow, blue distribution. NGC 4472 has a very broad, uniform distribution in color, corresponding to -1.8 < [Fe/H] < +0.47. At the other extreme is NGC 4365, which is weighted towards red colors, and possibly has a peculiar luminosity function. We suggest that this variation of GCS metallicity depends on environment, with formation of high metallicity globular clusters inhibited in higher density environments. We compare color-color plots of the GCS's of these galaxies with the Milky Way GCS and with integrated isochrones. We find good agreement with the galaxies studied here except that the isochrones predict colors which are slightly too bright in the I band for metal-rich clusters. We also consider the radial GC color distributions in these galaxies. We find evidence for a V-I color gradient only in NGC 4374, in the sense of redder clusters toward the center of the galaxy but warn that possible systematic effects must be ruled out with the new data. Lastly, using the surface brightness fluctuation distances to these galaxies, we find supporting evidence for the universality of the globular cluster luminosity function.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/155
- Title:
- Globular clusters in five early-type galaxies
- Short Name:
- J/MNRAS/416/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present deep high-quality photometry of globular cluster systems (GCSs) belonging to five early-type galaxies, covering a range of mass and environment. Photometric data were obtained with the Gemini North and Gemini South telescopes in the filter passbands g', r' and i'. The combination of these filters with good seeing conditions allows an excellent separation between globular cluster (GC) candidates and unresolved field objects.
2274. Globular clusters in M87
- ID:
- ivo://CDS.VizieR/J/AJ/106/493
- Title:
- Globular clusters in M87
- Short Name:
- J/AJ/106/493
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep integrated Washington CCD photometry of the extremely populous globular cluster system of NGC 4486 (M87) in Virgo. The metallicities of 407 of the best candidates with T1 < 22 have been estimated from the (C-T1) color. These values are internally precise to ~0.15dex and accurate to ~0.25dex. The mean metallicity of the globular clusters is [Fe/H] = -0.86dex, with a formal standard error of the mean of 0.03dex but a more realistic uncertainty of about 0.2dex. This value is higher than that of the corresponding means of the globular clusters in the Galaxy and M31, but similar to those of the globular clusters in NGC 1399 and NGC 5128, as expected from the relative parent galaxy luminosities. Approximately 10% of the clusters exceed solar abundance, similar to the case for the globular clusters in NGC 1399 and NGC 5128. As found by Couture et al. [ApJS, 73, 671 (1990)], there is a large metallicity dispersion at any radius, with a sigma ~ 0.65dex. However, in contrast to their result and that of previous small-field CCD studies, the globular clusters display a marked gradient in both mean (M-T1) and (C-T1) color with galactocentric distance. The mean metallicity decreases by some 0.6dex over the radial extent of the cluster sample. This result is consistent with the early photographic study by Strom et al. [ApJ, 245, 416 (1981)]. The metallicity distribution function is remarkably similar to that of NGC 1399 found by Ostrov et al. [AJ, 105, 1762 (1993)] using the same technique. The two central cluster ellipticals show significant peaks at very similar metallicities, indicating similar formation and enrichment histories. We also find that this structure in the metallicity distribution function persists to radii where the halo light is dominated by the cD envelope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/401/1965
- Title:
- Globular clusters in M104
- Short Name:
- J/MNRAS/401/1965
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images from the Hubble Space Telescope Advanced Camera for surveys are used to carry out a new photometric study of the globular clusters (GCs) in M104, the Sombrero galaxy. The primary focus of our study is the characteristic distribution function of linear sizes [size distribution function (SDF)] of the GCs. We measure the effective radii for 652 clusters with point spread function-convolved King and Wilson dynamical model fits. The SDF is remarkably similar to those measured for other large galaxies of all types, adding strong support to the view that it is a 'universal' feature of GC systems. We use the Sombrero and Milky Way data and the formation models of Baumgardt & Kroupa (2007MNRAS.380.1589B) to develop a more general interpretation of the SDF for GCs.
- ID:
- ivo://CDS.VizieR/J/AcA/48/455
- Title:
- Globular Clusters in M31 and M33
- Short Name:
- J/AcA/48/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the data from the DIRECT project to search for new globular cluster candidates in the M31 and M33 galaxies. We have found 67 new objects in M31 and 35 in M33 and confirmed 38 and 16 previously discovered ones. A VI and BVI photometry has been obtained for all clusters in M31 and M33, respectively. Luminosity functions have been constructed for the clusters in each galaxy and compared with that of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1043
- Title:
- Globular clusters in M31 and the Galaxy
- Short Name:
- J/AJ/140/1043
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Milky Way system and the Andromeda galaxy experienced radically different evolutionary histories. Nevertheless, it is found that these two galaxies ended up with globular cluster systems in which individual clusters have indistinguishable distributions of half-light radii. Furthermore, globulars in both M31 and the Galaxy are found to have radii that are independent of their luminosities. In this respect, globular clusters differ drastically from early-type galaxies in which half-light radius and luminosity are tightly correlated. Metal-rich globular clusters in M31 occupy a slightly larger volume than do those in the Galaxy. The specific globular cluster frequency in the Andromeda galaxy is found to be significantly higher than it is in the Milky Way system. The present discussion is based on the 107 Galactic globular clusters, and 200 putative globulars in M31, for which UBV photometry was available.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/879
- Title:
- Globular clusters in nearby dwarf galaxies
- Short Name:
- J/MNRAS/392/879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the old globular cluster (GC) population of 68 faint (M_V_>−16mag) dwarf galaxies located in the halo regions of nearby (<~12Mpc) loose galaxy groups and in the field environment based on archival Hubble Space Telescope (HST)/Advanced Camera for Surveys (ACS) images in F606W and F814W filters.
- ID:
- ivo://CDS.VizieR/J/ApJS/150/367
- Title:
- Globular clusters in NGC 5128
- Short Name:
- J/ApJS/150/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a photometric and spectroscopic survey of the globular cluster (GC) system of NGC 5128 (Centaurus A), a galaxy whose proximity makes it an important target for early-type galaxy studies. We imaged three fields in UBVRI that extend 50 and 30kpc along the major and minor axes, respectively. We used both color and size information to develop efficient selection criteria for differentiating between star clusters and foreground stars. In total, we obtained new velocities for 138 globular clusters, nearly tripling the number of known clusters, and bringing the confirmed total in NGC 5128 to 215. We present a full catalog of all known GCs, with their positions, photometry, and velocities. In addition, we present catalogs of other objects observed, such as foreground stars, background galaxies, three Galactic white dwarfs, seven background QSOs, and 52 optical counterparts to known X-ray point sources. We also report an observation of the cluster [HGH92] G169, in which we confirm the existence of a bright emission line object. This object, however, is unlikely to be a planetary nebula, but may be a supernova remnant.
- ID:
- ivo://CDS.VizieR/J/ApJ/835/123
- Title:
- Globular clusters in NGC 474 from CFHT obs.
- Short Name:
- J/ApJ/835/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Globular clusters (GCs) are some of the most visible tracers of the merging and accretion histories of galaxy halos. Metal-poor GCs, in particular, are thought to arrive in massive galaxies largely through dry, minor merging events, but it is rare to see a direct connection between GCs and visible stellar streams. NGC 474 is a post-merger early-type galaxy with dramatic fine structures made of concentric shells and radial streams that have been more clearly revealed by deep imaging. We present a study of GCs in NGC 474 to better establish the relationship between merger-induced fine structure and the GC system. We find that many GCs are superimposed on visible streams and shells, and about 35% of GCs outside 3R_e,galaxy_ are located in regions of fine structure. The spatial correlation between GCs and fine structure is significant at the 99.9% level, which shows that this correlation is not coincidental. The colors of GCs on fine structures are mostly blue, and we also find an intermediate-color population that is dominant in the central region and that will likely passively evolve to have colors consistent with a traditional metal-rich GC population. The association of the blue GCs with fine structures is direct confirmation that many metal-poor GCs are accreted onto massive galaxy halos through merging events and that the progenitors of these mergers are sub-L^*^ galaxies.
