Penetrating the “zone of avoidance”. II. Optically detected galaxies in the region 180° ≤ l≲ 240°

Abstract

We have carried out a systematic search for galaxies in the galactic plane in a ten degree wide strip (-5° ≤ b ≤ +5°). In an area of 300 square degrees between ℓ = 180° and ℓ = 210°, 755 galaxies have been detected on Palomar red-sensitive prints. The smallest galaxies show diameters of 0.1 mm corresponding to 67. We extended our survey to δ = -27° i.e. ℓ ≋ 247° to check our catalogue for completeness by comparing it with the Saitō et al. (1990, 1991) catalogues of galaxies and present 334 new galaxy candidates at ℓ ≥ 210°. An asymmetry with respect to the galactic equator is obvious. By assuming the 60 μ and 100 μ sky flux density to be a rough measure of the total interstellar galactic extinction, and comparing them with the surface densities of the galaxies, we detected one possible galaxy cluster candidate at , a concentration of galaxies at (ℓ,b) ≈ (195°, +4.°5), and confirmed three other galaxy concentrations. Finally, we argue that the red-sensitive surveys (ESO R; POSS II-R, POSS II-IR) are the best suitable material for galaxy searches in the zone of avoidance.