The environments of extreme star-forming galaxies across cosmic time – Dr Tom Cornish

This talk was part of the UH Centre for Astrophysics Research (CAR) 2023-2024 seminar series. For the ongoing programme, please see: https://www.herts.ac.uk/research/cent...

Date: 6 February 2024
Speaker: Dr Thomas Cornish – University of Oxford
Title: The environments of extreme star-forming galaxies across cosmic time

Abstract: Unravelling the histories of massive elliptical galaxies in the local Universe is a monumental task. Identifying the progenitors of these galaxies is a crucial step towards achieving this goal, but is made difficult by their complex evolution. Submillimetre galaxies (SMGs) are the sites of some of the most extreme star formation in the Universe, and represent one such population of candidate progenitors. Since massive elliptical galaxies typically reside in galaxy clusters, it is therefore expected that SMGs should typically reside in protoclusters at high redshift, which are typically identifiable as regions with galaxy densities in excess of the blank field. In this talk, I will present results from two studies in which we explore the link between SMGs and massive elliptical galaxies through searches for protoclusters. The first is a narrowband VLT/HAWK-I search for overdensities of H-alpha and [OIII] emitters around an unbiased sample of three spectroscopically-confirmed SMGs at z ~ 2–3, which we use to verify that SMGs are likely the progenitors of massive elliptical galaxies in clusters. The second is a JCMT/SCUBA-2 search for overdensities of SMGs in the environments of massive, radio-quiet galaxies at z ~ 1–3, conducted as part of the RAdio Galaxy Environment Reference Survey (RAGERS). The motivation behind RAGERS is that while HzRGs are seen to reside in SMG-rich, protocluster-like environments, it is not clear whether this is primarily driven by their high stellar masses or their AGN activity. Our study of similarly massive, radio-quiet counterparts thus enables us to disentangle these two effects.