Angular Momentum Transport in Lopsided Galaxies

About 30% of spiral galaxies in the local universe are lopsided (e.g., the well-known M101). In a typical lopsided galaxy, the spatial distribution of stars and gas are elongated in one direction than the other and the asymmetry is often prominent in the out-skirts of the disk. Such a lopsided asymmetry is also evident in the kinematics. However, despite being common and a large-scale asymmetry, its role in the angular momentum (AM) transfer remained unexplored. Recently, Saha & Jog (2014) showed that like bars and spirals, lopsidedness also takes part in the outward AM transport in a galaxy, provided it is leading in nature. It was shown that a combination of trailing spiral and leading lopsidedness is necessary for a galaxy to transport AM outward - facilitating smooth in-flow of cold gas along the galactic plane from cosmic filaments. Using N-body simulations of off-centered disk and dark matter halo, we first generate lopsidedness in the outer part of the disk and demonstrate that indeed lopsidedness is leading in nature.