Galaxies behind the Galactic plane: First results and perspectives from the VVV Survey

TL;DR

This paper reports the discovery of 204 new galaxy candidates behind the Galactic plane using near-infrared VVV survey data, significantly increasing the known galaxy density in this obscured region.

Contribution

It presents the first systematic search for background galaxies in the VVV survey data, identifying new candidates and providing a comprehensive catalog with their properties.

Findings

Increased galaxy density behind the Milky Way by over tenfold.

Validated galaxy candidates with color, size, and visual inspection.

Compared observed galaxy counts with models and simulations.

Abstract

Vista Variables in The Via Lactea (VVV) is an ESO variability survey that is performing observations in near infrared bands (ZYJHKs) towards the Galactic bulge and part of the disk with the completeness limits at least 3 mag deeper than 2MASS. In the present work, we searched in the VVV survey data for background galaxies near the Galactic plane using ZYJHKs photometry that covers 1.636 square degrees. We identified 204 new galaxy candidates by analyzing colors, sizes, and visual inspection of multi-band (ZYJHKs) images. The galaxy candidates colors were also compared with the predicted ones by star counts models considering a more realistic extinction model at the same completeness limits observed by VVV. A comparison of the galaxy candidates with the expected one by Milennium simulations is also presented. Our results increase the number density of known galaxies behind the Milky Way by more than one order of magnitude. A catalog with galaxy properties including ellipticity, Petrosian radii and ZYJHKs magnitudes is provided, as well as comparisons of the results with other surveys of galaxies towards Galactic plane.