Servicenavigation

Project Details

Back

Projekt Print View

3-D-Spectroscopy of a sample of nearby Blue Compact Galaxies: Understanding the star-forming galaxy population in the local Universe and beyond

Subject Area Astrophysics and Astronomy
Term from 2013 to 2023
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 237013364
 
Final Report Year 2023

Final Report Abstract

Blue compact galaxies (BCG) are crucial for understanding galaxy formation, evolution, and the star formation (SF) process. They serve as a unique link to the early Universe in the context of a cold dark matter universe, where structure forms hierarchically, with small objects collapsing first at relatively high redshifts. Also, due to their smaller size and mass relative to normal galaxies, BCGs cannot sustain spiral density waves and are resistant to disk instabilities. This makes them excellent laboratories for studying SF at galactic scales and the impact of massive stellar feedback. In this project, we conducted the first comprehensive analysis of a large sample of BCGs by means of integral field spectroscopy. The main goals were: i) disentangling and characterizing the distinct stellar populations on the sample galaxies, ii) constraining their evolutionary status and star formation histories (SFH) and iii) identifying the mechanism(s) that trigger and sustain the SF in these objects. We collected observations for twenty-six BCGs and generated maps of the galaxy continuum, emission-lines, line ratios, velocity fields, velocity dispersion, and maps of the physical parameters and abundances. This comprehensive information allowed us to spatially distinguish different stellar populations, and by comparing the spectroscopic observables for each spatially resolved cluster/population with the predictions of evolutionary synthesis models, we constrained the ages, initial mass function (IMF) and metallicity of the individual stellar components. Most of the analyzed galaxies showed evidence for at least three different stellar populations: a very young starburst, an intermediate-age component, and an old, mostly regular stellar host several gigayears old. We investigated the excitation mechanims by combining the information derived from spatially resolved diagnostic diagrams with the morphology, ionization pattern and kinematic of the galaxies. We discovered, in remarkable contrast with previous works, that in addition to young massive stars, shocks from the collective action of massive stellar winds and SN remnants, play a crucial role in energizing BCGs. Multiple observational features such as tails, bridges, and filaments in the areas of low surface brightness, the presence of super stellar clusters (SSCs), the velocity dispersion patterns, shocked areas, centrally concentrated SF and substantial amounts of dust, support interactions as the SF triggering mechanism in BCGs. This result opens a very interesting line of research, as mergers and interactions in nearby BCGs would thus provide a unique opportunity to probe the hierarchical scenario under conditions very similar to those prevalent in the high-redshift Universe during the epoch of galaxy formation.

Publications

 
 

Additional Information

© 2025 DFG Disclaimer / Copyright / Privacy Policy

Textvergrößerung und Kontrastanpassung