Deep PSF photometric catalog of the VVV survey data

TL;DR

This paper presents a deep, high-precision PSF photometric catalog for the VVV survey, utilizing all survey epochs to improve depth and reduce spurious detections in near-infrared imaging of the Galactic plane.

Contribution

The authors developed an automatic PSF-fitting pipeline and produced a catalog with about 926 million sources, reaching deeper magnitudes than previous catalogs with improved accuracy.

Findings

Catalog contains ~926 million sources in J, H, Ks bands.

Achieves 5 sigma limiting magnitudes of ~20.8, 19.5, 18.7 mag respectively.

Reaches about one magnitude deeper than previous PSF catalogs.

Abstract

The Vista Variables in the Via Lactea (VVV) survey has performed a multi-epoch near-infrared imaging of the inner Galactic plane. High-fidelity photometric catalogs are needed to utilize the data. We aim at producing a deep, point-spread-function (PSF) photometric catalog for the VVV survey J, H, and Ks band data. Specifically, we aim at taking advantage of all the epochs of the survey to reach high limiting magnitudes. We develop an automatic PSF-fitting pipeline based on the DaoPHOT algorithm and perform photometry on the stacked VVV images in J, H, and Ks bands. We present a PSF photometric catalog in the Vega system that contains about 926 million sources in the J, H, and Ks filters. About 10% of the sources are flagged as possible spurious detections. The 5 sigma limiting magnitudes of the sources with high reliability are about 20.8, 19.5, and 18.7 mag in the J, H, and Ks band, respectively, depending on the local crowding condition. Our photometric catalog reaches on average about one magnitude deeper than the previously released PSF DoPHOT photometric catalog. It also includes less spurious detections. There are significant differences in the brightnesses of faint sources between our catalog and the previously released one. The likely origin of these differences is in the different photometric algorithms that are utilized; it is not straightforward to assess which catalog is more accurate in which situations. Our new catalog is beneficial especially for science goals that require high limiting magnitudes; our catalog reaches such in fields that have a relatively uniform source number density. Overall, the limiting magnitudes and completeness are different in the fields with different crowding conditions.