Astronomy & Astrophysics
using multiwavelength data
Rainbow over the Anglo-Australian Telescope in Siding Spring Observatory, NSW, Australia © Á.R.L-S.
I will propose to supervise at least one Honours Student to work with me in the multiwavelength analysis of local star-forming galaxies. Some ideas I have for these projects are these:
IC 10 is the nearest starburst. Our 2D spectroscopical analysis using PMAS @ 3.5m CAHA suggests the existence of a probable localized chemical pollution of nitrogen and helium from the fresh material released by a single Wolf-Rayet star. © Á.R.L-S., Adel Mesa-Delgado, Luis López-Martín & César Esteban
The new observational technique of 2D spectroscopy using Integrated Field Units (IFU) is providing amazing new results about the kinematics and the chemical composition of galaxies. In particular, Blue Compact Dwarf Galaxies (BCDGs) are excellent targets to perform such studies, because their modest sizes allow that all the galaxy can be observed in just some few pointings. During the last year we have collected some 2D spectroscopy data of a sample of BCDGs using the new WiFeS instrument available at the 2.3m ANU telescope at Siding Spring Observatory, and the preliminary results are quite promising. We are offering the opportunity of study one or two of the BCDGs for which we already have good-quality data. In particular, this project will give to the Honours student an introduction to 2D spectroscopy techniques (we expect to continue the observations using both WiFeS @ 2.3m ANU and SPIRAL @ 3.9m AAT) and to gain some expertise in the reduction and analysis of this kind of data. The aims of this project is to perform an analysis of the physical (mass, star-formation rate, extinction, electron temperature and density, excitation), chemical (ionic and total abundances of helium, oxygen, nitrogen, sulphur, neon, argon...) and kinematical properties of the ionized gas within these galaxies, which may be compared with the properties of the neutral gas from our own ATCA observations. Finally, the student will also learn to write up the results not only for his/her Honours Thesis but for a subsequent publication. As an example of this project, please consult the 2D spectroscopical analysis of the brightest star-forming region of the local BCDG IC10, López-Sánchez et al. (2011) and this research image.
Near-infrared (NIR) observations at 1.65 microns (H-band) traces the old stellar population (and hence, the dominant stellar mass distribution) of galaxies, while dust attenuation is dramatically reduced. Although 2MASS surveys the entire sky, it failed to detect almost all dwarf systems and underestimates the fluxes of those it did detect by as much as 70% (Kirby et al. 2008). We are obtaining very deep H-band observations of local dwarf galaxies using the instrument IRIS2 at the 3.9m AAT at the Siding Spring Observatory. The target galaxies belong to the The Local Volume HI Survey (LVHIS), and hence we already know their neutral gas distribution, as well as many other multi-wavelength properties. The aim of this Honour project is to reduce and analyse the H-band images of a sub-sample of these galaxies. Many of the observations will be carried out in the next months, and hence the student will have the possibility of participate in them. This project will give to the Honours student a very good knowledge of NIR observations. Using the new images, the candidate will be able to derive the Sersic parameters that best describe the observed surface brightness profiles of the galaxies, as well as estimate their stellar masses from their absolute H-band luminosity. The derived stellar mass will be compared with the total neutral gas mass and the dynamical mass derived from the HI observations, as well as with other properties such as the extinction, the metallicity, or the star-formation rate, to constrain the nature and evolution of each galaxy. Comparing the new results with those already available, the student will also analyze the classical (using the B-band absolute magnitude) and the baryonic (stellar plus gas masses) Tully-Fisher relations. This study will provide powerful constraints to the nature and evolution of dwarf galaxies. Finally, the student will also learn to write up the results not only for his/her Honours Thesis but for a subsequent publication.
Other interesting projects I have in mind are these:
| Updated: 10.02.2011 | Released: 25.01.2011 |