paper

The size--mass and other structural parameter () relations for local bulges/spheroids from multicomponent decompositions

arXiv:2209.01550 · doi:10.1093/mnras/stac3704

Abstract

We analyse the bulge/spheroid size-(stellar mass), , relation and spheroid structural parameters for 202 local (predominantly ) galaxies spanning and from multicomponent decomposition. The correlations between the spheroid Sérsic index (), central surface brightness (), effective half-light radius (), absolute magnitude () and stellar mass () are explored. We also investigate the consequences of using different scale radii, , encapsulating a different fraction (, from 0 to 1) of the total luminosity. The correlation strengths for projected mass densities, and , vary significantly with the choice of . Spheroid size () and mass () are strongly correlated for all light fractions . We find: with a small scatter of . This result is discussed relative to the \textit{curved} size-mass relation for early-type galaxies due to their discs yielding larger galaxy radii at lower masses. Moreover, the slope of our spheroid size-mass relation is a factor of , steeper than reported bulge size-mass relations, and with bulge sizes at which are 2 to 3 times smaller. Finally, we show that the local spheroids align well with quiescent galaxies at --. In essence, local spheroids and high- quiescent galaxies appear structurally similar, likely dictated by the virial theorem.

19 pages, 15 figures, Accepted to MNRAS

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