Beasts in the Bubbles: Remarkably UV-bright Galaxies at z=9-10

Subaru/SWIMS | 1.5N | PI - S. Fujimoto

(Awarded back-up instrument time on SWIMS)

We propose Keck MOSFIRE J-band spectroscopy for five UV-bright (H =24.5–25.4 mag) novel photometric candidates at z = 9 − 10 from the brand new COSMOS2020 catalogs, now benefitting from homogeneous near-IR and ultra-deep optical coverage that allowed for such identification. All candidates have clear Lyman-break features from Y to H bands, IRAC detection, tight distributions in PDF(z) at z = 9 − 10, the inconsistency with the templates of the stellar and dusty galaxy at lower redshift, and are confirmed at z > 9 with four independent redshift estimates. The volume density of these five candidates is also consistent with the bright-end of the latest UV luminosity function (UVLF) studies at z = 9 − 10. With the proposed observations, we will achieve the following two major goals: 1) confirming the redshift and the power-law nature of the UVLF at z = 9 − 10, and 2) testing if UV-bright galaxies at z = 9 − 10 host AGN via the Nv1243 line. Importantly, our targets are > ×10–20 brighter than the only other source confirmed at z = 9.11. Our targets will provide essential constraints on the bright/massive-end of luminosity/mass function at z > 9 and the CDM scenario for the formation of early galaxies, once at least one of their redshifts are confirmed.

John R. Weaver
John R. Weaver
PhD Fellow in Astrophysics

My research interests lie almost exclusively within the realm of extragalactic astrophysics and cosmology. I use state-of-the-art optical and infrared observatories and surveys to study the lives of galaxies, and how their properties change over cosmic time. This includes detailed case studies of individual galaxies, as well as statistical analyses of large survey catalogs.