Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters

Brant E. Robertson*, Richard S. Ellis, James S. Dunlop, Ross J. McLure, Dan P. Stark, Derek McLeod

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a reduced survey volume and, in this Letter, we demonstrate that there is an associated increase in the cosmic variance uncertainty. As an example, we show that the cosmic variance uncertainty of the high-redshift population viewed through the Hubble Space Telescope Frontier Field cluster Abell 2744 increases from ~35% at redshift z ~ 7 to >~ 65% at z ~ 10. Previous studies of high-redshift galaxies identified in the Frontier Fields have underestimated the cosmic variance uncertainty that will affect the ultimate constraints on both the faint-end slope of the high-redshift luminosity function and the cosmic star formation rate density, key goals of the Frontier Field program.
Original languageEnglish
Article number27
Number of pages5
JournalAstrophysical Journal Letters
Volume796
Issue number2
DOIs
Publication statusPublished - 1 Dec 2014

Keywords

  • galaxies: high-redshift
  • galaxies: statistics
  • gravitational lensing: strong
  • ULTRA-DEEP FIELD
  • STAR-FORMING GALAXIES
  • EXTRAGALACTIC LEGACY SURVEY
  • SIMILAR-TO 7
  • LUMINOSITY FUNCTION
  • YOUNG GALAXY
  • REIONIZATION
  • CAMPAIGN
  • CANDELS
  • A2744

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