The Cosmic Infrared Background Experiment (CIBER): The Wide-Field Imagers

TL;DR

CIBER's wide-field imagers are designed to measure near-infrared background fluctuations from high-redshift galaxies, employing specialized cameras and spectral filters during sounding rocket flights to study the epoch of reionization.

Contribution

This paper introduces a novel imaging instrument with wide-field, spectral discrimination, and high sensitivity, optimized for detecting the spatial fluctuations of the extragalactic background light from reionization-era galaxies.

Findings

Instrument performed to specifications in multiple flights.

Characterized sensitivity, flat-field response, and noise properties.

Data analysis is ongoing for scientific results.

Abstract

We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The instrument is part of the Cosmic Infrared Background Experiment (CIBER), designed to observe the extragalactic background light above the Earth's atmosphere during a suborbital sounding rocket flight. The imaging instrument incorporates a 2x2 degree field of view, to measure fluctuations over the predicted peak of the spatial power spectrum at 10 arcminutes, and 7"x7" pixels, to remove lower redshift galaxies to a depth sufficient to reduce the low-redshift galaxy clustering foreground below instrumental sensitivity. The imaging instrument employs two cameras with \Delta \lambda / \lambda ~0.5 bandpasses centered at 1.1 and 1.6 microns to spectrally discriminate reionization extragalactic background fluctuations from local foreground fluctuations. CIBER operates at wavelengths where the electromagnetic spectrum of the reionization extragalactic background is thought to peak, and complements fluctuations measurements by AKARI and Spitzer at longer wavelengths. We have characterized the instrument in the laboratory, including measurements of the sensitivity, flat-field response, stray light performance, and noise properties. Several modifications were made to the instrument following a first flight in 2009 February. The instrument performed to specifications in subsequent flights in 2010 July and 2012 March, and the scientific data are now being analyzed.