We study the rest-frame optical mass-size relation of bulges and discs from z~2 to z~0 for a complete sample of massive galaxies in the CANDELS fields using 2 component S\'ersic models (Dimauro et a. 2018). Discs and star forming galaxies follow similar mass-size relations. The mass-size relation of bulges is less steep than the one of quiescent galaxies (best fit slope of ~ 0.7 for quiescent galaxies against ~ 0.4 for bulges). We find little dependence of the structural properties of massive bulges and discs with the global morphology of galaxies (disc vs. bulge dominated) and the star formation activity (star-forming vs. quiescent). This result suggests similar bulge formation mechanisms for most massive galaxies and also that the formation of the bulge component does not significantly affect the disc structure. Our findings pose a challenge to models envisioning multiple channels for massive bulge growth, such as disc instabilities and mergers.
@article{arxiv.1902.04089,
title = {The structural properties of classical bulges and discs from z~2},
author = {Paola Dimauro and Marc Huertas-Company and Emanuele Daddi and Pablo G. Pérez-González and Mariangela Bernardi and Fernando Caro and Andrea Cattaneo and Boris Häußler and Ulrike Kuchner and Francesco Shankar and Guillermo Barro and Fernando Buitrago and Sandra M. Faber and Dale D. Kocevski and Anton M. Koekemoer and David C. Koo and Simona Mei and Reynier Peletier and Joel Primack and Aldo Rodriguez-Puebla and Mara Salvato and Diego Tuccillo},
journal= {arXiv preprint arXiv:1902.04089},
year = {2019}
}