SpIES: The Spitzer IRAC Equatorial Survey

TL;DR

The SpIES survey provides deep infrared data over 115 deg^2 in Stripe 82, enabling improved detection of high-redshift and obscured quasars, and offers valuable catalogs for studying quasar clustering and luminosity functions.

Contribution

This paper presents the first data release of the SpIES survey, including deep infrared imaging, source catalogs, and methods, significantly enhancing quasar detection capabilities compared to previous surveys.

Findings

SpIES recovers 98% of spectroscopically-confirmed quasars in Stripe 82.

At high redshift (z > 3.5), SpIES recovers 94% of quasars, outperforming WISE.

Deep infrared imaging enables detection of obscured and high-redshift quasars.

Abstract

We describe the first data release from the Spitzer-IRAC Equatorial Survey (SpIES); a large-area survey of 115 deg^2 in the Equatorial SDSS Stripe 82 field using Spitzer during its 'warm' mission phase. SpIES was designed to probe sufficient volume to perform measurements of quasar clustering and the luminosity function at z > 3 to test various models for "feedback" from active galactic nuclei (AGN). Additionally, the wide range of available multi-wavelength, multi-epoch ancillary data enables SpIES to identify both high-redshift (z > 5) quasars as well as obscured quasars missed by optical surveys. SpIES achieves 5{\sigma} depths of 6.13 {\mu}Jy (21.93 AB magnitude) and 5.75 {\mu}Jy (22.0 AB magnitude) at 3.6 and 4.5 microns, respectively - depths significantly fainter than WISE. We show that the SpIES survey recovers a much larger fraction of spectroscopically-confirmed quasars (98%) in Stripe 82 than are recovered by WISE (55%). This depth is especially powerful at high-redshift (z > 3.5), where SpIES recovers 94% of confirmed quasars, whereas WISE only recovers 25%. Here we define the SpIES survey parameters and describe the image processing, source extraction, and catalog production methods used to analyze the SpIES data. In addition to this survey paper, we release 234 images created by the SpIES team and three detection catalogs: a 3.6 {\mu}m-only detection catalog containing 6.1 million sources, a 4.5 {\mu}m-only detection catalog containing 6.5 million sources, and a dual-band detection catalog containing 5.4 million sources.