Compact star clusters in M81. II. Two populations

Rupali Chandar, Zlatan Tsvetanov, Holland C. Ford

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

We present the color and magnitude distributions of compact star clusters discovered in the early-type spiral galaxy M81, from Hubble Space Telescope Wide Field Planetary Camera 2 B, V, and I-band imaging. These clearly show the presence of two cluster populations - a typical red globular cluster system, as well as a young population, which was not previously known to exist in M81. While the young clusters in M81 are not as massive as those found in merging and starburst galaxies (for example, its neighbor M82), they more closely resemble the populous clusters in the Magellanic Clouds and M33 and similarly are found in all environments of M81. Further, the young clusters are more compact than their counterparts in M82, with core radii between 0.4 and 4.3 pc. The color-color diagram indicates that young cluster formation may have "turned on" ∼600 Myr ago and continued until 6 Myr ago. The timescale of continued cluster formation in M81 coincides both with independent dynamical estimates for the last tidal encounter between M81 and M82, as well as with a peak in cluster formation recently discovered in the fossil starburst region B in M82. This suggests that interactions may have sparked the recent cluster formation in M81.

Original languageEnglish
Pages (from-to)1342-1349
Number of pages8
JournalAstronomical Journal
Volume122
Issue number3
DOIs
Publication statusPublished - Sep 2001
Externally publishedYes

Fingerprint

star clusters
young population
diagram
fossil
timescale
color-color diagram
young
starburst galaxies
fossils
Magellanic clouds
spiral galaxies
globular clusters
Hubble Space Telescope
encounters
cameras
galaxies
color
radii
estimates

Keywords

  • Galaxies: individual (M81)
  • Galaxies: star clusters
  • Galaxies: stellar content

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Compact star clusters in M81. II. Two populations. / Chandar, Rupali; Tsvetanov, Zlatan; Ford, Holland C.

In: Astronomical Journal, Vol. 122, No. 3, 09.2001, p. 1342-1349.

Research output: Contribution to journalArticle

Chandar, Rupali ; Tsvetanov, Zlatan ; Ford, Holland C. / Compact star clusters in M81. II. Two populations. In: Astronomical Journal. 2001 ; Vol. 122, No. 3. pp. 1342-1349.
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