Thesis Topic: Study of the stellar populations across the whole Milky Way bulge: age map and star formation history
Thesis Supervisor: Elena Valenti
Abstract
Being one of the major stellar components of the Galaxy, the study of the Milky Way bulge offers a unique opportunity to shed light on the formation and evolution mechanism of our Galaxy and, by extent, of galaxies in general. Indeed, it is only in our bulge that stars in all evolutionary stages can be individually resolved, thus allowing detailed studies of their chemical composition, kinematics and age, to be compared with bulges of other galaxies, and used as template for accurate comparison with the models.
Recent surveys - such as VVV, ARGOS, GIBS, Gaia-ESO - are providing a global view of the Milky Way bulge by producing high quality extinction, metallicity, kinematics and stellar density maps. The next missing key component is the information on the stellar age distribution and gradients. In fact, accurate dating of bulge component allows one to gauge at which lookback time (i.e. redshift) one should look for possible analogs of the Milky Way, when their bulge formation processes were about to start, well on their way, or already concluded.
The project consists in deriving accurate age map of the stellar population across the bulge to be then combined with information on the stellar kinematics and metallicity, with the ultimate goal of reconstructing the star formation history (SFH) of the Milky Way bulge.
In particular, the multi-band photometric dataset obtained by the VVV survey will be used to derive the age map by means of the main-sequence turnoff as age indicator after a careful decontamination of the derived color-magnitude diagrams (CMDs) from foreground disk stars.
Possible additional high-resolution photometric and spectroscopic observations will be acquired along the project evolution to properly calibrate the entire dataset.
The SFH of the bulge will then be constructed by comparing the observed CMDs with synthetic ones.
To get acquainted with the IAC-pop code to be used to simulate synthetic CMDs the student is required to spend some time (up to 3-4 months) at the astrophysics department in Tenerife (IAC).
Because the project requires the comparison between observations and simulations, it offers the opportunity to gain expertiseтАЩs in both research areas, but also to work on the most recent and complete bulge database, as well as to join from the beginning a large collaborations network involving many institutes (i.e. ESO, PUC, IAC).