Highlights of multi-wavelengths surveys in the Zone of Avoidance

TL;DR

This paper reviews recent multi-wavelength surveys in the Zone of Avoidance, highlighting discoveries of massive galaxies and galaxy transformations, and discusses future HI survey strategies with MeerKAT to better understand local universe dynamics.

Contribution

It presents recent discoveries in the ZOA and proposes future HI survey strategies with MeerKAT to address key questions about large-scale structure and local universe dynamics.

Findings

Discovery of the most massive disk galaxy to date (HIZOA 0836-43).

Observation of galaxy transformation during infall into the Norma cluster.

Future HI surveys with MeerKAT could resolve the Great Attractor/Shapley controversy.

Abstract

Rather than giving a complete overview on extragalactic Zone of Avoidance research, this paper will highlight some recent discoveries in the ZOA, such as new NIR to FIR observations (IRSF, Spitzer) of the most massive disk galaxy found to-date (HIZOA 0836-43), and deep multi-wavelength observations of a spiral galaxy WKK 6167 undergoing transformation while infalling along the Great Attractor Wall into the Norma cluster - reminiscent of similar incidences observed in two galaxies at higher redshifts (z ~ 0.2). While the recent systematic multi-wavelengths approaches to uncover the large-scale structure of galaxies across the ZOA have proven quite successful, in particular in the Great Attractor region, they lack the required depth to answer open questions with regard to our understanding of the dynamics in the Local Universe. The actual mass distribution is poorly understood and does not satisfactorily explain the observed peculiar velocity fields and the CMB dipole. We will present future HI survey strategies to be pursued with the South African SKA Pathfinder MeerKAT in the ZOA, that can - amongst others - resolve the long-standing Great Attractor/Shapley controversy, and determine at which distance range the cumulative peculiar motion of the Local Group flattens off and the Universe becomes homogeneous.