English

Growth of bulges in disc galaxies since $z\sim1$

Astrophysics of Galaxies 2018-05-01 v1 Cosmology and Nongalactic Astrophysics

Abstract

We investigate the growth of bulges in bright (MB<20M_B<-20) disc galaxies since z1z\sim1, in rest-frame B and I-band, using images from HST ACS and WFC3 in GOODS-South for high redshifts (0.4<z<1.00.4<z<1.0) and SDSS for local (0.02<z<0.050.02<z<0.05). The growth history has been traced by performing two-component bulge-disc decomposition and further classifying the bulges into pseudos and classicals using Kormendy relation. We have about 27%27\% pseudo and 40%40\% classical bulges in our sample. Classical bulges are brighter than pseudo, in both rest-bands, at all redshifts probed here; in fact since z0.77z\sim0.77, classical are about 1\sim1 mag brighter than pseudo bulges. Both bulges have witnessed substantial growth, more than half of their present day stellar mass has been gained since z1z\sim1. Their host discs have grown concurrently, becoming progressively brighter in rest-frame I-band. The high redshift host discs of both pseudo and classical bulges are found to be equally clumpy in rest-frame B-band. In the same band, we found that the growth of classical bulges is accompanied by fading of their host discs - which might be an indication of secular processes in action. However, both host disc as well as the bulge have grown substantially in terms of stellar mass. Our analysis suggests that, clump migration and secular processes alone can not account for the bulge growth, since z1z\sim1, accretion and minor mergers would be required.

Keywords

Cite

@article{arxiv.1704.02449,
  title  = {Growth of bulges in disc galaxies since $z\sim1$},
  author = {Sonali Sachdeva and Kanak Saha and Harinder P. Singh},
  journal= {arXiv preprint arXiv:1704.02449},
  year   = {2018}
}

Comments

15 pages, 10 figures, accepted for publication in ApJ