The Chandra Deep Wide-Field Survey: A New Chandra Legacy Survey in the Bo\"otes Field I. X-ray Point Source Catalog, Number Counts and Multi-Wavelength Counterparts

TL;DR

This paper presents a comprehensive Chandra X-ray survey of the Boötes field, detecting thousands of sources, analyzing their properties, and providing valuable data for understanding high-redshift universe and cosmic X-ray background.

Contribution

It introduces a large, deep X-ray point source catalog with detailed multi-wavelength counterparts and robust analysis methods, expanding the resources for high-redshift universe studies.

Findings

Detected 6891 X-ray point sources down to faint flux limits.

Resolved approximately 65% of the cosmic X-ray background in 0.5-2 keV band.

Provided redshifts and luminosities for most sources, enabling detailed population studies.

Abstract

We present a new, ambitious survey performed with the Chandra X-ray Observatory of the 9.3 deg$^2$ Bo\"otes field of the NOAO Deep Wide-Field Survey. The wide field probes a statistically representative volume of the Universe at high redshift. The Chandra Deep Wide-Field Survey exploits the excellent sensitivity and angular resolution of Chandra over a wide area, combining 281 observations spanning 15 years, for a total exposure time of 3.4 Ms, and detects 6891 X-ray point sources down to limiting fluxes of $4.7\times10^{-16}$, $1.5\times10^{-16}$, and $9\times10^{-16}$ erg cm$^{-2}$ s$^{-1}$, in the $0.5-7$ keV, $0.5-2$ keV, and $2-7$ keV bands, respectively. The robustness and reliability of the detection strategy is validated through extensive, state-of-the-art simulations of the whole field. Accurate number counts, in good agreement with previous X-ray surveys, are derived thanks to the uniquely large number of point sources detected, which resolve $65.0 \pm 12.8\%$ of the cosmic X-ray background between $0.5-2$ keV and $81.0 \pm 11.5\%$ between $2-7$ keV. Exploiting the wealth of multi-wavelength data available on the field, we assign redshifts to $\sim 94\%$ of the X-ray sources, estimate their obscuration and derive absorption-corrected luminosities. We provide an electronic catalog containing all the relevant quantities needed for future investigations.