The origin of bulges and discs in the CALIFA survey - I. Morphological evolution
Abstract
This series of papers aims at understanding the formation and evolution of non-barred disc galaxies. We use the new spectro-photometric decomposition code, C2D, to separate the spectral information of bulges and discs of a statistically representative sample of galaxies from the CALIFA survey. Then, we study their stellar population properties analysing the structure-independent datacubes with the PIPE3D algorithm. We find a correlation between the bulge-to-total (B/T) luminosity (and mass) ratio and galaxy stellar mass. The B/T mass ratio has only a mild evolution with redshift, but the bulge-to-disc (B/D) mass ratio shows a clear increase of the disc component since redshift z < 1 for massive galaxies. The mass-size relation for both bulges and discs describes an upturn at high galaxy stellar masses (log (M⋆/M⊙) > 10.5). The relation holds for bulges but not for discs when using their individual stellar masses. We find a negligible evolution of the mass-size relation for both the most massive ($\log {(M_{\star \rm ,b,d}/{\rm M}_{\odot })} \gt 10$) bulges and discs. For lower masses, discs show a larger variation than bulges. We also find a correlation between the Sérsic index of bulges and both galaxy and bulge stellar mass, which does not hold for the disc mass. Our results support an inside-out formation of nearby non-barred galaxies, and they suggest that (i) bulges formed early-on and (ii) they have not evolved much through cosmic time. However, we find that the early properties of bulges drive the future evolution of the galaxy as a whole, and particularly the properties of the discs that eventually form around them.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2021
- DOI:
- 10.1093/mnras/stab1064
- arXiv:
- arXiv:2104.07743
- Bibcode:
- 2021MNRAS.504.3058M
- Keywords:
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- galaxies: bulges;
- galaxies: evolution;
- galaxies: formation;
- galaxies: structure;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 16 pages, 11 figures. Accepted for publication in MNRAS