Diameters of Galactic globular clusters

Bergh, Sidney van den; Morbey, C. L.; Pazder, John

doi:10.1086/170220

Cited by 140 publications

(79 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the Milky Way, we see the well‐known trend for the mean r h to increase gradually with R GC (e.g. van den Bergh, Morbey & Pazder 1991; Jordán et al 2005) and for the range in r h to increase at larger R GC as well. The NGC 891 data hint barely at the same increase amidst the large scatter.…”

Section: Discussionsupporting

confidence: 59%

Globular cluster candidates in NGC 891

Harris¹,

Mouhcine²,

Rejkuba³

et al. 2009

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We use deep images taken with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope of the disc galaxy NGC 891 to search for globular cluster (GC) candidates. This galaxy has long been considered to be a close analogue in size and structure to the Milky Way and is nearly edge‐on, facilitating studies of its halo population. These extraplanar ACS images, originally intended to study the halo field‐star populations, reach deep enough to reveal even the faintest GCs that would be similar to those in the Milky Way. From the three pointings, we have identified a total of 43 candidates after culling by object morphology, magnitude and colour. We present (V, I) photometry for all of these, along with measurements of their effective radius and ellipticity. The 16 highest‐rank candidates within the whole sample are found to fall in very much the same regions of parameter space occupied by the classic Milky Way GCs. Our provisional conclusion from this survey is that the total GC population in NGC 891 as a whole may be almost as large as that of the Milky Way.

show abstract

Section: Discussionsupporting

confidence: 59%

Globular cluster candidates in NGC 891

Harris¹,

Mouhcine²,

Rejkuba³

et al. 2009

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Peculiar object S923, at a projected distance of 3.6 arcmin (17 kpc) from M87, with the same field of view as the sub-panels in Figure 1. Its line-ofsight velocity is 2777 ± 26 km s −1 (S+11), which is barely within the standard range for the Virgo cluster (Trentham & Tully 2002), suggesting a highly radial orbit near its closest approach to M87. The image is from HST/WFPC2 in the F606W band; the object has a core with a size of ∼2 pc, and two asymmetric protuberances extending out to distances of ∼35-60 pc from the center.…”

Section: The Stripping Scenariomentioning

confidence: 87%

The Relationships Among Compact Stellar Systems: A Fresh View of Ultracompact Dwarfs

Brodie

Romanowsky

Strader

et al. 2011

The Astronomical Journal

206

311

View full text Add to dashboard Cite

We use a combined imaging and spectroscopic survey of the nearby central cluster galaxy, M87, to assemble a sample of 34 confirmed ultracompact dwarfs (UCDs) with half-light radii of 10 pc measured from Hubble Space Telescope images. This doubles the existing sample in M87, making it the largest such sample for any galaxy, while extending the detection of UCDs to unprecedentedly low luminosities (M V = −9). With this expanded sample, we find no correlation between size and luminosity, in contrast to previous suggestions, and no general correlation between size and galactocentric distance. We explore the relationships between UCDs, less luminous extended clusters (including faint fuzzies), globular clusters (GCs), as well as early-type galaxies and their nuclei, assembling an extensive new catalog of sizes and luminosities for stellar systems. Most of the M87 UCDs follow a tight color-magnitude relation, offset from the metal-poor GCs. This, along with kinematical differences, demonstrates that most UCDs are a distinct population from normal GCs, and not simply a continuation to larger sizes and higher luminosities. The UCD color-magnitude trend couples closely with that for Virgo dwarf elliptical nuclei. We conclude that the M87 UCDs are predominantly stripped nuclei. The brightest and reddest UCDs may be the remnant nuclei of more massive galaxies while a subset of the faintest UCDs may be tidally limited and related to more compact star clusters. In the broader context of galaxy assembly, blue UCDs may trace halo build-up by accretion of low-mass satellites, while red UCDs may be markers of metal-rich bulge formation in larger galaxies.

show abstract

“…For G1 a σ 0 ∼ 27.8 km s −1 is provided by Meylan et al (2001), and from their dynamical model we estimate R eff ∼ 4.47 pc. For ωCen σ 0 ∼ 16 km s −1 (from Pryor & Meylan 1993), and R eff ∼ 4.85 pc is from van den Bergh et al (1991). It should be noted that both G1 and ωCen have been argued to be the remnant nuclei of stripped galaxies (Meylan et al 2001;Freeman 1993), because they show a metallicity spread, in other words they both are not simple stellar populations as all other galactic GCs.…”

Section: Clues From the κ Spacementioning

confidence: 99%

The dynamical mass of the young cluster W3 in NGC 7252

Maraston

Bastian

Saglia

et al. 2004

A&A

164

193

View full text Add to dashboard Cite

Abstract.We have determined the dynamical mass of the most luminous stellar cluster known to date, i.e. object W3 in the merger remnant galaxy NGC 7252. The dynamical mass is estimated from the velocity dispersion measured with the highresolution spectrograph UVES on VLT. Our result is the astonishingly high velocity dispersion of σ = 45 ± 5 km s −1 . Combined with the large cluster size R eff = 17.5 ± 1.8 pc, this translates into a dynamical virial mass for W3 of (8 ± 2) × 10 7 M . This mass is in excellent agreement with the value (∼7.2 × 10 7 M ) we previously estimated from the cluster luminosity (M V = −16.2) by means of stellar M/L ratios predicted by Simple Stellar Population models (with a Salpeter IMF) and confirms the heavyweight nature of this object. This results points out that the NGC 7252-type of mergers are able to form stellar systems with masses up to ∼10 8 M . We find that W3, when evolved to ∼10 Gyr, lies far from the typical Milky Way globular clusters, but appears to be also separated from ωCen in the Milky Way and G1 in M 31, the most massive old stellar clusters of the Local Group, because it is too extended for a given mass, and from dwarf elliptical galaxies because it is much more compact for its mass. Instead the aged W3 is amazingly close to the compact objects named ultracompact dwarf galaxies (UCDGs) found in the Fornax cluster (Hilker et al. 1999;Drinkwater et al. 2000), and to a miniature version of the compact elliptical M 32. These objects start populating a previously deserted region of the fundamental plane.

show abstract

Diameters of Galactic globular clusters

Cited by 140 publications

References 0 publications

Globular cluster candidates in NGC 891

Globular cluster candidates in NGC 891

The Relationships Among Compact Stellar Systems: A Fresh View of Ultracompact Dwarfs

The dynamical mass of the young cluster W3 in NGC 7252

Contact Info

Product

Resources

About