Accretion Onto the Milky Way: The Smith Cloud

TL;DR

The paper discusses the Smith Cloud, a massive gas cloud accreting onto the Milky Way, highlighting its properties, potential dark matter halo, and implications for galactic gas accretion processes.

Contribution

It provides detailed observations and analysis of the Smith Cloud, proposing the possibility of a dark matter halo supporting its survival and accretion onto the galaxy.

Findings

Contains several million solar masses of gas

Lies two kpc below the Galactic plane

May be embedded in a dark matter halo of 10^8 solar masses

Abstract

Active gas accretion onto the Milky Way is observed in an object called the Smith Cloud, which contains several million solar masses of neutral and warm ionized gas and is currently losing material to the Milky Way, adding angular momentum to the disk. It is several kpc in size and its tip lies two kpc below the Galactic plane. It appears to have no stellar counterpart, but could contain a stellar population like that of the dwarf galaxy Leo P. There are suggestions that its existence and survival require that it be embedded in a dark matter halo of a few 10^8 solar masses.