Interacting Galaxies in the A901/902 Supercluster with STAGES

Abstract

We present a study of galaxy mergers and the influence of environment in the Abell 901/902 supercluster at z~0.165. We use HST ACS F606W data from the STAGES survey, COMBO-17, Spitzer 24um, and XMM-Newton X-ray data. Our analysis utilizes both a visual classification system, and quantitative CAS parameters to identify systems which show evidence of a recent or ongoing merger of mass ratio >1/10. Our results are: (1) After visual classification and minimizing the contamination from false projection pairs, we find that the merger fraction f_merge is 0.023+/-0.007. The estimated fractions of likely major mergers, likely minor mergers, and ambiguous cases are 0.01+/-0.004, 0.006+/-0.003, and 0.007+/-0.003, respectively. (2) The mergers lie outside the cluster core of radius R < 0.25 Mpc: the lack of mergers in the core is likely due to the large galaxy velocity dispersion in the core. Mergers populate the region (0.25 Mpc < R <= 2 Mpc) between the core and outskirt. In this region, the estimated frequency of mergers is similar to those seen at typical group overdensities. This suggests ongoing growth of the clusters via accretion of group and field galaxies. (3) We compare our observed merger fraction with those reported in other clusters and groups out to z~0.4. Existing data points on the merger fraction for L<= L* galaxies in clusters allow for a range of evolutionary scenarios. (4) The fraction of mergers, which lie on the blue cloud is 80%+/-18% versus 34%+/-7% for non-interacting galaxies, implying that interacting galaxies are preferentially blue. (5) The average SFR, based on UV or UV+IR data, is enhanced by a factor of ~1.5 to 2 in mergers compared to non-interacting galaxies. However, mergers in the clusters contribute only a small fraction (between 10% and 15%) of the total SFR density.(Abridged)

Accepted for publication in ApJ. 34 pages, 16 figures. Version with full resolution figures available at: http://www.as.utexas.edu/~alh/apj/int/ ; updated abridged abstract

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Cited by in corpus (25)

• Galaxy Pairs in the Sloan Digital Sky Survey - II: The Effect of Environment on Interactions
• Galaxy Pairs in the Sloan Digital Sky Survey - III: Evidence of Induced Star Formation from Optical Colours
• Resolving the Discrepancy of Galaxy Merger Fraction Measurements at z ~ 0 - 3
• The merger-driven evolution of massive galaxies
• The Pair Fraction of Massive Galaxies at 0 < z < 3
• Bars in early- and late-type disks in COSMOS
• The Dynamics of Galaxy Pairs in a Cosmological Setting
• Integral field spectroscopy of nearby QSOs II. The molecular gas content and condition for star formation
• The environmental dependence of the structure of outer galactic discs in STAGES spiral galaxies
• The minor role of gas-rich major mergers in the rise of intermediate-mass early types at z <~ 1
• The HST/ACS Coma Cluster Survey. VIII. Barred Disk Galaxies in the Core of the Coma Cluster
• Ram pressure and dusty red galaxies - key factors in the evolution of the multiple cluster system Abell 901/902
• Spectro-photometric close pairs in GOODS-S: major and minor companions of intermediate-mass galaxies
• A New Automatic Method to Identify Galaxy Mergers I. Description and Application to the STAGES Survey
• Evolution of the Major Merger Galaxy Pair Fraction at z < 1
• The environmental dependence of the structure of galactic discs in STAGES S0 galaxies: implications for S0 formation
• The HST/ACS Coma Cluster Survey - VII. Structure and Assembly of Massive Galaxies in the Center of the Coma Cluster
• HST/WFC3 grism observations of $z\sim 1$ clusters: evidence for evolution in the mass-size relation of quiescent galaxies from poststarburst galaxies
• Relating basic properties of bright early-type dwarf galaxies to their location in Abell 901/902
• The Zurich Environmental Study (ZENS) of Galaxies in Groups along the Cosmic Web. V. Properties and Frequency of Merging Satellites and Centrals in Different Environments
• A minor merger scenario for the ultraluminous X-ray source ESO 243-49 HLX-1 - II. Constraints from photometry
• Galaxy interactions in filaments and sheets: effects of the large-scale structures versus the local density
• The Double Galaxy Cluster Abell 2465 I. Basic Properties: Optical Imaging and Spectroscopy
• Linking the Structural Properties of Galaxies and their Star Formation Histories with STAGES
• Do minor interactions trigger star formation in galaxy pairs?