Deep point spread function photometric catalog of the VVV survey data

Artikel i vetenskaplig tidskrift, 2019

Context. 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.
Aims. We aim at producing a deep, point spread function (PSF) photometric catalog for the VVV survey J-,H-, and K-s-band data. Specifically, we aim to take advantage of multiple epochs of the survey to reach high limiting magnitudes.
Methods. We developed an automatic PSF-fitting pipeline based on the DaoPHOT algorithm and performed photometry on the stacked VVV images in J,H, and K-s bands.
Results. We present a PSF photometric catalog in the Vega system that contains about 926 million sources in the J,H, and K-s 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 K-s bands, 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 and 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 used; it is not straightforward to assess which catalog is more accurate in different situations. Our new catalog is beneficial especially for science goals that require high limiting magnitudes; our catalog reaches such high magnitudes in fields that have a relatively uniform source number density. Overall, the limiting magnitudes and completeness are different in fields with different crowding conditions.