{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/disc-cloaking-establishing-a-lower-limit-to","title":"Disc cloaking: Establishing a lower limit to the number density of local compact massive spheroids/bulges and the potential fate of some high-z red nuggets","arxiv_id":"2204.13408","date":"2022-04-28","proceeding":null,"authors":["Dexter S. -H. Hon","Alister W. Graham","Benjamin L. Davis","Alessandro Marconi"],"abstract":"The near-absence of compact massive quiescent galaxies in the local Universe implies a size evolution since $z\\sim2.5$. It is often theorised that such `red nuggets' have evolved into today's elliptical (E) galaxies via an E-to-E transformation. We examine an alternative scenario in which a red nugget develops a rotational disc through mergers and accretion, say, at $1\\lesssim z\\lesssim2$, thereby cloaking the nugget as the extant bulge/spheroid component of a larger, now old, galaxy. We have performed detailed, physically-motivated, multi-component decompositions of a volume-limited sample of 103 massive ($M_*/\\rm M_{\\odot} \\gtrsim 1\\times 10^{11}$) galaxies within 110\\,Mpc. Among our 28 galaxies with existing elliptical classifications, we found that 18 have large-scale discs, and two have intermediate-scale discs, and are reclassified here as lenticulars (S0) and elliculars (ES). The local spheroid stellar mass function, size-mass diagram and bulge-to-total ($B/T$) flux ratio are presented. We report lower-limits for the volume number density of compact massive spheroids, $n_\\mathrm{c,Sph}\\sim (0.17$-$1.2) \\times 10^{-4}\\,\\rm Mpc^{-3}$, based on different definitions of `red nuggets' in the literature. Similar number densities of local compact massive bulges were reported by de la Rosa et al. using automated two-component decompositions and their existence is now abundantly clear with our multi-component decompositions. We find disc-cloaking to be a salient alternative for galaxy evolution. In particular, instead of an E-to-E process, disc growth is the dominant evolutionary pathway for at least low-mass ($1\\times10^{10}