Hubble Space Telescope discovery of candidate young globular clusters in the merger remnant NGC 7252

Whitmore, Bradley C.; Schweizer, F.; Leitherer, Claus; Borne, K. D.; Robert, Carmelle

doi:10.1086/116732

Cited by 272 publications

(254 citation statements)

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“…Such gaseous disks have been confirmed observationally (e.g., Wang et al 1992;Whitmore et al 1993) in some mergers. If these disks can form stars, it may explain both the disky isophotal shapes and the apparent rotation observed in many of the merger remnants.…”

Section: Summary and Discussionmentioning

confidence: 78%

“…This feature was later observed in one-third of the merger remnants in Rothberg & Joseph (2004, hereafter Paper I). Both numerical simulations (Barnes & Hernquist 1996;Barnes 2002) and observations (Wang et al 1992;Whitmore et al 1993) show that dissipation can lead to the formation of central gaseous disks that could later form stellar disks. The effects of gaseous dissipation were observationally inferred from the results in Rothberg & Joseph (2006, hereafter Paper II).…”

Section: Introductionmentioning

confidence: 99%

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A Survey of Merger Remnants. III. Are Merger Remnants Supported by Rotation or Anisotropy?

Rothberg¹,

Joseph²

2006

Astron J

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A growing body of observational evidence suggests that the luminosity, photometric shape, and amount of rotational or anisotropic support in elliptical galaxies may provide vital clues to how they formed. Elliptical galaxies appear to fall into two distinct categories based on these parameters: bright, boxy-shaped, and having little or no rotation, and less luminous, disky-shaped, and having significant rotation. One viable formation scenario is the ''merger hypothesis,'' in which two disk galaxies merge to form a new elliptical galaxy. A comparison of the luminosity, photometric shape, and amount of rotation in advanced merger remnants may shed more light on the possible formation scenarios of elliptical galaxies. Yet little observational data exist for such merger remnants. This paper is the third in a series investigating the photometric and kinematic properties of a sample of 51 optically selected advanced merger remnants. Presented here are K-band isophotal shapes and spatially resolved kinematics for a subsample of 37 merger remnants. The results show that $11% of the sample is boxy and anisotropically supported, while $47% is disky and rotationally supported. The remainder of the sample shows variations among expected correlations between shape and rotation. This may suggest that the isophotal shapes are still ''in flux.'' There does appear to be a lower limit to the amount of anisotropy observed in the merger remnants. This may provide an observational diagnostic for discriminating among formation scenarios in elliptical galaxies.

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Section: Summary and Discussionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

A Survey of Merger Remnants. III. Are Merger Remnants Supported by Rotation or Anisotropy?

Rothberg¹,

Joseph²

2006

Astron J

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“…While their older and usually more massive counterparts, the classic globular clusters, are found around almost every type of galaxy (Harris 2001), rich populations of luminous blue star clusters are found predominantly in starburst and interacting systems (Holtzman et al 1992;Whitmore et al 1993;Whitmore & Schweizer 1995;Bastian et al 2005, among many others). However, the facts that individual young clusters have been found in several nearby dwarf galaxies (e.g., Conti & Vacca 1994;O'Connell et al 1994;Billett et al 2002) and that small populations are found in several nearby spiral galaxies (Maoz et al 1996;Larsen 2000Larsen , 2002Larsen et al 2001) suggest that massive star cluster formation is a relatively widespread phenomenon, although it seems to occur with high efficiency only in the most active star-forming systems.…”

Section: Introductionmentioning

confidence: 99%

Two Populations of Young Massive Star Clusters in Arp 220

Wilson

Harris

Longden

et al. 2006

ApJ

103

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We present new optical observations of young massive star clusters in Arp 220, the nearest ultraluminous infrared galaxy, taken in UBVI with the Hubble Space Telescope ACS HRC camera. We find a total of 206 probable clusters whose spatial distribution is centrally concentrated toward the nucleus of Arp 220. We use model star cluster tracks to determine ages, luminosities, and masses for 14 clusters with complete UBVI indices or previously published nearinfrared data. We estimate rough masses for 24 additional clusters with I < 24 mag from BVI indices alone. The clusters with useful ages fall into two distinct groups: a ''young'' population (<10 Myr) and an intermediate-age population ('300 Myr). There are many clusters with masses clearly above 10 6 M and possibly even above 10 7 M in the most extreme instances. These masses are high enough that the clusters being formed in the Arp 220 starburst can be considered to be genuine young globular clusters. In addition, this study allows us to extend the observed correlation between global star formation rate and maximum cluster luminosity by more than 1 order of magnitude in star formation rate.

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“…One is the metal-poor GCs of the progenitor spirals and other is the metal-rich GCs formed in the collision of high velocity gas. One of the most noteworthy success of this model is the discovery of the protoglobular clusters in the currently merging galaxies (Whitmore et al 1993;Schweizer et al 1996). In the merger model the high S N galaxies said to be created by the merger of several normal S N galaxies.…”

Section: Introductionmentioning

confidence: 99%

Globular clusters of the Local Group – statistical classification

Chattopadhyay¹,

Chattopadhyay²

2007

A&A

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Aims. To find an objective classification of the globular clusters in our Galaxy, M 31, and LMC. Methods. A new method of Cluster Analysis (CA)was carried out and the set of parameters for this method was selected through an objective process, Principal Component Analysis (PCA). Robustness of the classification was established using bootstrap samples.Results. In every case they exhibit multi-population structure instead of bimodality as is found in many spirals and giant elliptical galaxies. The kinematics of MW and M 31 GCs are examined in support of these sub-populations in the cluster system. It is found that for MW and M 31 GCs a disc, inner halo, and outer halo populations of GCs are more likely to exist than only the disc and halo populations of GCs in MW as concluded by Zinn (1985, ApJ, 293, 424). This supports the existence of three populations more firmly explained by Zinn (1993, Globular Cluster-Galaxy Connection, 38) and Mackey & Gilmore (2004, MNRAS, 355, 504) whereas only two populations are found for LMC GCs. The new multivariate analysis increases the importance of the inclusion of many parameters while at the same time it eliminates less significant parameters and helps to enunciate a unique theory of galaxy formation.

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Hubble Space Telescope discovery of candidate young globular clusters in the merger remnant NGC 7252

Cited by 272 publications

References 0 publications

A Survey of Merger Remnants. III. Are Merger Remnants Supported by Rotation or Anisotropy?

A Survey of Merger Remnants. III. Are Merger Remnants Supported by Rotation or Anisotropy?

Two Populations of Young Massive Star Clusters in Arp 220

Globular clusters of the Local Group – statistical classification

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