The stellar remnants of high redshift nuclear starburst discs: a potential origin for nuclear star clusters?

Abstract

Nuclear starburst discs (NSDs) are very compact star-forming regions in the centers of galaxies that have been studied as a possible origin for the absorbing gas around a central active galactic nucleus. NSDs may be most relevant at $z\sim 1$ when obscured accretion onto supermassive black holes (SMBHs) is common. This paper describes the characteristics of the stellar remnants of NSDs at $z=0.01$, taking into account the evolution from $z=1$. Using a stellar synthesis model, the colours, masses, and luminosities of the stellar remnants are computed for a suite of 192 two-dimensional NSD models. These properties are compared to observations of local nuclear star clusters (NSCs), and a good match is found between the predicted and observed properties. Dynamical effects will likely cause the final remnant to be a rotating, nearly spherical distribution. In addition, $\approx 20$% of the NSD remnants have half-light radii <~ 10 pc, consistent with NSCs hosted in both late-type and early-type galaxies, and all the remnants follow similar size-luminosity relationships as observed in nearby NSCs. NSDs require the presence of a central SMBH and the most massive and compact stellar remnants are associated with the most massive SMBHs, although stellar clusters with a variety of sizes can be produced by all considered SMBH masses. Overall, NSDs at $z\sim 1$ appear to be a promising origin for the $\gg 1$ Gyr NSC population in early- and late-type galaxies with large SMBHs.

7 pages, 6 figures, accepted by MNRAS

References in corpus (12)

• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• The Coincidence of Nuclear Star Clusters and Active Galactic Nuclei
• Nuclear star clusters in 228 spiral galaxies in the HST/WFPC2 archive: catalogue and comparison to other stellar systems
• Clues to Nuclear Star Cluster Formation from Edge-on Spirals
• The Globular Cluster Migratory Origin of Nuclear Star Clusters
• The Structure of Nuclear Star Clusters in Nearby Late-type Spiral Galaxies from Hubble Space Telescope Wide Field Camera 3 Imaging
• New insights on the formation of nuclear star clusters
• Obscuring Active Galactic Nuclei with Nuclear Starburst Disks
• Caught in formation: the nuclear-cluster-to-be in NGC 2139
• Two-body relaxation driven evolution of the young stellar disc in the Galactic Centre
• Modeling the Vertical Structure of Nuclear Starburst Discs: A Possible Source of AGN Obscuration at $z\sim 1$