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

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 {\it Letter}, we demonstrate 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.

5 pages, 3 figures. Version accepted by ApJL

References in corpus (5)

• The Hubble Ultra Deep Field
• The observed ionization rate of the intergalactic medium and the ionizing emissivity at z >5: Evidence for a photon starved and extended epoch of reionization
• Mass and magnification maps for the Hubble Space Telescope Frontier Fields clusters: implications for high redshift studies
• A Geometrically Supported $z\sim 10$ Candidate Multiply-Imaged by the Hubble Frontier Fields Cluster Abell 2744
• Ultra-faint high-redshift galaxies in the Frontier Fields

Cited by in corpus (17)

• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Hubble Frontier Fields First Complete Cluster Data: Faint Galaxies at $z\sim 5-10$ for UV Luminosity Functions and Cosmic Reionization
• New redshift z ~ 9 galaxies in the Hubble Frontier Fields: Implications for early evolution of the UV luminosity density
• New Constraints on the Faint-end of the UV Luminosity Function at z~7-8 using the Gravitational Lensing of the Hubble Frontier Fields Cluster A2744
• z~2-9 Galaxies Magnified by the Hubble Frontier Field Clusters II: Luminosity Functions and Constraints on a Faint-End Turnover
• The sizes of $z\sim 6-8$ lensed galaxies from the Hubble Frontier Fields Abell 2744 data
• How robustly can we constrain the low-mass end of the $z\sim 6-7$ stellar mass function? -- The limits of lensing models and stellar population assumptions in the Hubble Frontier Fields
• Simulating JWST deep extragalactic imaging surveys and physical parameter recovery
• A Flexible Analytic Model of Cosmic Variance in the First Billion Years
• The clustering of $z>7$ galaxies: Predictions from the BLUETIDES simulation
• On the Significance of Rare Objects at High Redshift: The Impact of Cosmic Variance
• The UV luminosity functions of Bright z>8 Galaxies: Determination from ~0.41 deg2 of HST Observations along ~sim 300 independent sightlines
• SXDF-ALMA 2 Arcmin^2 Deep Survey: Resolving and Characterizing the Infrared Extragalactic Background Light Down to 0.5 mJy
• Geometric Corroboration of the Earliest Lensed Galaxy at z~10.8 from Robust Free-Form Modelling
• ALMA 26 arcmin${}^2$ survey of GOODS-S at one-millimeter (ASAGAO): millimeter properties of stellar mass selected galaxies
• Joint Strong and Weak Lensing Analysis of the Massive Cluster Field J0850+3604
• Cosmic Variance and the Inhomogeneous UV Luminosity Function of Galaxies During Reionization