# HI observations of IC 10 with the DRAO synthesis telescope

## TL;DR

This study presents detailed HI observations of the galaxy IC 10 using the DRAO synthesis telescope, revealing its kinematic properties, a faint HI feature, and signs of ongoing accretion, with implications for dark matter distribution.

## Contribution

First detailed HI kinematic analysis of IC 10 with the DRAO telescope, showing rotation curve behavior and insights into dark matter presence and galaxy interactions.

## Key findings

- Confirmed faint NW HI emission feature with 4.7 x 10^5 M_sun
- Inner disk rotation curve rises steeply then flattens, max velocity 30 km/s
- Outer HI features suggest ongoing accretion, not interaction with M31

## Abstract

HI observations of the nearby blue compact dwarf galaxy IC 10 obtained with the Dominion Radio Astrophysical Observatory synthesis telescope (DRAO), for a total integration of $\sim$1000 hours, are presented. We confirm the NW faint 21 cm HI emission feature discovered in GBT observations. The HI feature has an HI mass of 4.7 $\times 10^{5}$ M$_{\odot}$, which is only $\sim$ 0.6$\%$ of the total HI mass of the galaxy (7.8 $\times 10^{7}$ M$_{\odot}$). In the inner disk, the rotation curve of IC 10 rises steeply, then flattens until the last point where it rises again, with a maximum velocity of 30 km s$^{-1}$. Based on our mass models, the kinematics of the inner disk of IC 10 can be described without the need of a dark matter halo. However, this does not exclude the possible presence of dark matter on a larger scale. It is unlikely that the disturbed features seen in the outer HI disk of IC 10 are caused by an interaction with M 31. Features seen from our simulations are larger and at lower surface density than can be reached by current observations. The higher velocity dispersions seen in regions where several distinct HI features meet with the main core of IC 10 suggests that there is ongoing accretion.