Photometric properties of classical bulge and pseudo-bulge galaxies at $0.5\le z<1.0$

TL;DR

This study compares the photometric properties and star formation rates of classical and pseudo-bulge galaxies at intermediate redshifts, revealing evolutionary trends and differences in structure and activity between the two bulge types.

Contribution

It provides a detailed comparison of classical and pseudo-bulge galaxies at $0.5 extless z extless 1.0$, highlighting their structural and star formation differences and evolutionary trends.

Findings

Classical bulge galaxies have smaller radii and higher B/T ratios than pseudo-bulges.

Star formation activity is lower in classical bulges, especially at larger radii.

Differences between bulge types decrease at higher redshifts, indicating evolutionary convergence.

Abstract

We compare the photometric properties and specific star formation rate (sSFR) of classical and pseudo-bulge galaxies with $M_* \ge 10^{9.5} \rm M_{\odot}$ at $0.5\le z<1.0$, selected from all five CANDELS fields. We also compare these properties of bulge galaxies at lower redshift selected from MaNGA survey (Hu et al. 2024). This paper aims to study the properties of galaxies with classical and pseudo-bulges at intermediate redshift, to compare the differences between different bulge types, and to understand the evolution of bulges with redshift. Galaxies are classified into classical bulge and pseudo-bulge samples according to the S$\mathrm{\acute{e}}$rsic index n of the bulge component based on results of two-component decomposition of galaxies, as well as the position of bulges on the Kormendy diagram. For the 105 classical bulge and 86 pseudo-bulge galaxies selected, we compare their size, luminosity, and sSFR of various components. At given stellar mass, most classical bulge galaxies have smaller effective radii, larger $B/T$, brighter and relatively larger bulges, and less active star formation than pseudo-bulge galaxies. Besides, the two types of galaxies have larger differences in sSFR at large radii than at the central region at both low and mid-redshifts. The differences between properties of the two types of bulge galaxies are in general smaller at mid-redshift than at low redshift, indicating that they are evolving to more distinct populations towards the local universe. Bulge type is correlated with the properties of their outer disks, and the correlation is already present at redshift as high as $0.5<z<1$.