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

• Applicant: Dr. Luz-Marina Cairós Barreto
• Subject Area: Astrophysics and Astronomy
• Term: from 2013 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 237013364

This proposal aims to extend and conclude the project “3-D-Spectroscopy of a sample of nearby blue compact galaxies: understanding the star-forming galaxy population in the local Universe and beyond”, devoted to the study of a sample of Blue Compact Galaxies (BCG) by means of Integral Field Spectroscopy (IFS). BCGs are key objects in contemporary extragalactic research: being small, they offer an unparalleled link to the early Universe --- in the framework of a Cold Dark Matter Universe, high mass systems form by hierarchical mergers of smaller ones ---, and their lack of density waves and strong shear forces permits to probe the star formation (SF) in a simple environment. To investigate these intriguing objects, we have performed IFS observations for a sample of 36 galaxies. The data have been already reduced and the bulk of the analysis done: we have built emission-line, continuum, diagnostic-line and velocity maps of the whole sample and, using these maps, identified the major HII regions and derived their physical parameters and chemical abundances. We are working now in the interpretation of these results, which comprises i) to disentangle the distinct stellar populations of the sample galaxies; ii) to probe their evolutionary status and devise their star formation history; iii) to search for abundance inhomogeneities; iv) to look into the nebula ionization mechanism and search for AGNs and/or shocked regions and, v) to constraint, by means of cosmological simulations, the formation process and evolution of dwarf galaxies. In addition, the recent advent of wide field, high spatial resolution IFS instruments at large telescopes, as the Multi Unit Spectroscopic Explorer (MUSE) at the VLT, opens new possibilities in our understanding of the SF at galactic scales. We propose now, taking advantage of the large experience acquired in the IFS data processing and analysis, to exploit the unique capabilities of MUSE to investigate the SF process and the interplay between massive stars and the interstellar medium in BCGs. It is well known that the combined action of stellar winds and multiple supernova explosions strongly impacts their surroundings; the effects being particularly dramatic when they take place within the shallow gravitational potential of a low mass galaxy. Stellar feedback can trigger (positive feedback or star induced SF) or suppress (negative feedback) SF, and can accelerate the interstellar gas to velocities larger than the galaxy escape velocity, polluting the intergalactic medium. But how exactly, and to what extend, this affects the evolution and chemical enrichment of a low mass galaxy is still unknown. MUSE observations, providing high spatial resolution and high sensitivity data up to galactocentric distances of kpc, are essential and will contribute in this project to tackle these questions.

• DFG Programme: Research Grants
• Cooperation Partners: Dr. José Nicolás González Pérez; Dr. Rafael Manso Sainz