# Angular Momentum Content in Gas Rich Dwarf Galaxies

## TL;DR

This study measures the angular momentum of gas-rich dwarf galaxies, revealing they have higher specific angular momentum than spiral galaxies, which suggests different evolutionary processes affecting their angular momentum acquisition and retention.

## Contribution

It provides the first detailed comparison of the j-M relation for gas-rich dwarf galaxies with that of spirals, highlighting significant deviations and implications for galaxy evolution models.

## Key findings

- Dwarf galaxies have higher specific angular momentum than expected from spiral galaxy relations.
- The probability that dwarfs follow the same j-M relation as spirals is less than 10^{-6}.
- Differences may be due to baryon fraction, outflows, or anisotropic accretion.

## Abstract

We derive the specific baryonic angular momentum of five gas rich dwarf galaxies from HI kinematics complemented by stellar mass profiles. Since the gas mass of these galaxies is much larger than the stellar mass, the angular momentum can be determined with relatively little uncertainty arising from the uncertainties in the stellar mass to light ratio. We compare the relation between the specific baryonic angular momentum (j) and the total baryonic mass (M) for these galaxies with that found for spiral galaxies. Our combined sample explores the j-M plane over 3 orders of magnitude in baryon mass. We find that our sample dwarf have significantly higher specific angular momentum than expected from the relation found for spiral galaxies. The probability that these gas rich dwarf galaxies follow the same relation as spirals is found to be $<10^{-6}$. This implies a difference in the evolution of angular momentum in these galaxies compared to larger ones. We suggest that this difference could arise due to one or more of the following: a lower baryon fraction in dwarf galaxies, particularly that arising from preferential outflows low angular momentum gas as found in high resolution simulations that include baryonic feedback; "cold mode" anisotropic accretion from cosmic filaments. Our work reinforces the importance of the j-M plane in understanding the evolution of galaxies.