Ipac logo
Beating Cosmic Variance: UV Luminosity Functions and Clustering at Cosmic Dawn with Roman
Program ID 19017
Science Category Galaxies
Program Type Analysis
Category Large
Principal Investigator Steven Finkelstein
PI Institution University of Texas, Austin
Co-Investigators
  • Julian Munoz (University of Texas, Austin)
  • Rachel Somerville (Center for Computational Astrophysics)
  • Aaron Yung (Space Telescope Science Institute / STScI)
  • Casey Papovich (Texas A & M University)
  • Katherine Chworowsky (University of Texas, Austin)
  • Ansh Gupta (University of Texas, Austin)
  • Natalia Villanueva (University of Texas, Austin)
  • Tiger Hsiao (University of Texas, Austin)
  • Vasily Kokorev (University of Texas, Austin)
  • Anthony Taylor (University of Texas, Austin)
  • Owen Chase (University of Texas, Austin)
  • Pierluigi Rinaldi (Space Telescope Science Institute / STScI)
  • John Chisholm (University of Texas, Austin)
  • Harry Ferguson (Space Telescope Science Institute / STScI)
  • Mic Bagley (University of Texas, Austin)
  • Mauro Giavalisco (University of Massachusetts, Amherst)
  • Seiji Fujimoto (University of Toronto)
  • Romeel Dave (University of Edinburgh)
  • Dale Kocevski (Colby College)
  • Anton Koekemoer (Space Telescope Science Institute / STScI)
  • Rebecca Larson (Space Telescope Science Institute / STScI)
  • Gene Leung (MIT Kavli Institute for Astrophysics and Space Research)
  • Fabio Pacucci (Smithsonian Astrophysical Observatory)
  • Nor Pirzkal (Space Telescope Science Institute / STScI)
  • Russell Ryan Jr (Space Telescope Science Institute / STScI)
  • Lukas Furtak (University of Texas, Austin)
  • Sebastian Gomez (University of Texas, Austin)
Abstract JWST has shown that the universe forms luminous galaxies and accreting black holes earlier and more abundantly than theoretical models predicted. However, these discoveries are based on data covering relatively small volumes, with systematic uncertainties dominated by cosmic variance. We propose to overcome this limitation by analyzing data from the Roman High Latitude Wide Area Survey (HLWAS) Deep tier, which spans 19 deg^2 (40× larger than JWST's combined legacy fields), reducing cosmic variance uncertainties to negligible levels, to achieve four important scientific goals: i) We will measure the bright end of the UV luminosity function (UVLF) using 100,000 galaxies at z~7–11, with ~1000 at z~10 alone, pinning down the UVLF shape and distinguishing between models with varying physical mechanisms invoked to explain the excess of UV-luminous galaxies. This sample will include ~500 GN-z11-like systems that will unlock the early universe for detailed IFU followup study. ii) We will measure the evolution of the little red dot (LRD) UVLF at z~2–4, where existing ground-based and Euclid studies disagree by over 1 dex. A shallow decline indicates super-Eddington accretion persists to surprisingly low redshifts, while a steeper decline marks the onset of "normal" black hole growth. iii) We will measure the angular clustering of galaxies and LRDs to infer host halo masses, distinguishing massive AGN halos from lower-mass star-forming halos for LRDs, and bursty versus high star-formation efficiency models for galaxies. iv) We will identify new strong lensing clusters among the 15 known SZ-detected systems in the footprint, extending our science goals to fainter luminosities via gravitational magnification. We will deliver robust source and photometric redshift catalogs, completeness matrices, and strong lensing mass maps, made available via MAST and the Roman Research Nexus.