A zone of avoidance catalogue of 2MASS bright galaxies – I. Sample description and analysis

Abstract

We present a homogeneous 2MASS bright galaxy catalogue at low Galactic latitudes (|b| ≤ 10◦.0, called zone of avoidance, ZoA) which is complete to a Galactic extinction-corrected magnitude of Kso ≤ 11m. 25. It also includes galaxies in regions of high foreground extinctions [E(B − V) > 0m. 95] situated at higher latitudes. This catalogue forms the basis of studies of large-scale structures, flow fields, and extinction across the ZoA and complements the ongoing 2MASS Redshift and Tully–Fisher surveys. It comprises 3763 galaxies, 70 per cent of which have at least one radial velocity measurement in the literature. The catalogue is complete up to star density levels of log N∗/deg2 < 4.5 and at least for AK < 0m. 6 and likely as high as AK = 2m. 0. Thus, the ZoA in terms of bright NIR galaxies covers only 2.5–4 per cent of the whole sky. We use a diameter-dependent extinction correction to compare our sample with an unobscured, high-latitude sample. While the correction to the Ks-band magnitude is sufficient, the corrected diameters are too small by about 4 arcsec on average. The omission of applying such a diameter-dependent extinction correction may lead to a biased flow field even at intermediate extinction values as found in the 2MRS survey. A slight dependence of galaxy colour with stellar density indicates that unsubtracted foreground stars make galaxies appear bluer. Furthermore, far-infrared sources in the DIRBE/IRAS extinction maps that were not removed at low latitudes affect the foreground extinction corrections of three galaxies and may weakly affect a further estimated 20 per cent of our galaxies.