Linking the Structural Properties of Galaxies and their Star Formation Histories with STAGES

Abstract

We study the links between star formation history and structure for a large mass-selected galaxy sample at 0.05 < z_phot < 0.30. The galaxies inhabit a very broad range of environments, from cluster cores to the field. Using HST images, we quantify their structure following Hoyos et al. (2012), and divide them into disturbed and undisturbed. We also visually identify mergers. Additionally, we provide a quantitative measure of the degree of disturbance for each galaxy ("roughness"). The majority of elliptical and lenticular galaxies have relaxed structure, showing no signs of ongoing star formation. Structurally-disturbed galaxies, which tend to avoid the lowest-density regions, have higher star-formation activity and younger stellar populations than undisturbed systems. Cluster spirals with reduced/quenched star formation have somewhat less disturbed morphologies than spirals with "normal" star-formation activity, suggesting that these "passive" spirals have started their morphological transformation into S0s. Visually identified mergers and galaxies not identified as mergers but with similar roughness have similar specific star formation rates and stellar ages. The degree of enhanced star formation is thus linked to the degree of structural disturbance, regardless of whether it is caused by major mergers or not. This suggests that merging galaxies are not special in terms of their higher-than-normal star-formation activity. Any physical process that produces "roughness", or regions of enhanced luminosity density, will increase the star-formation activity in a galaxy with similar efficiency. An alternative explanation is that star formation episodes increase the galaxies' roughness similarly, regardless of whether they are merger-induced or not.

16 pages, 6 figures, accepted for publication in MNRAS

References in corpus (12)

• The hierarchical formation of the brightest cluster galaxies
• The stellar masses of 25000 galaxies at 0.2<z<1.0 estimated by the COMBO-17 survey
• On the frequency, intensity and duration of starburst episodes triggered by galaxy interactions and mergers
• Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks
• The STAGES view of red spirals and dusty red galaxies: Mass-dependent quenching of star-formation in cluster infall
• The relation between star formation, morphology and local density in high redshift clusters and groups
• The Tully-Fisher relation for S0 galaxies
• STAGES: the Space Telescope A901/2 Galaxy Evolution Survey
• Calibration update of the COMBO-17 CDFS catalogue
• The role of thermal evaporation in galaxy formation
• 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

Cited by in corpus (6)

• The role of mergers in driving morphological transformation over cosmic time
• The role of mergers and interactions in driving the evolution of dwarf galaxies over cosmic time
• The limited role of galaxy mergers in driving stellar mass growth over cosmic time
• The effect of the environment on the structure, morphology and star-formation history of intermediate-redshift galaxies
• Galaxy kinematics across different environments in the RXJ1347-1145 cluster complex
• Analysis of the Intrinsic Mid-Infrared L-band to Visible--Near-Infrared Flux Ratios in Spectral Synthesis Models of Composite Stellar Populations