Institute of Astrophysics and Space Sciences (IA) | University of Porto | 2018 Jul 05
Using Integral Field Spectroscopy (IFS) and advanced modeling tools, Instituto de Astrofísica e Ciências do Espaço (IA) researchers Iris Breda and Polychronis Papaderos have achieved an important milestone towards solving a long standing enigma in extragalactic astronomy – the nature and formation of the central spherical component in spiral galaxies like the Milky Way.
The bulge is thought to form through two distinct routes: Classical bulges consist of ancient stars, older than the disk, because they assembled rapidly more than 10 billion years ago, prior to disks. Pseudo-bulges have stars of similar age as the disk, because they assembled gradually through a combination of dynamical processes, with continuous star formation fed by inflow of gas from the disk.
These two scenarios imply that classical bulges and pseudo-bulges have strikingly different characteristics, but this sharp contrast was never observed, despite numerous studies over the past years.
To solve this riddle, the team has carried out an unprecedented spectral modeling analysis of more than half a million individual spectra, to spatially resolve the star formation history of bulge and disk components of 135 galaxies from the CALIFA IFS survey. ...
The Continuous Rise of Bulges Out of Galactic Disks - I. Breda, P. Papaderos