Ionized Gas Kinematics at High Resolution V: [NeII], Multiple Clusters, High Efficiency Star Formation and Blue Flows in He 2-10

TL;DR

This study uses high-resolution [NeII] spectroscopy to analyze ionized gas kinematics in He 2-10, revealing multiple star clusters, high star formation efficiency, and complex gas flows, providing insights into starburst dynamics and cluster longevity.

Contribution

It presents the first high-resolution 3D kinematic analysis of ionized gas in He 2-10, linking gas flows to star formation and cluster stability.

Findings

Multiple dense star clusters confirmed by kinematics

Star formation efficiencies of 30-40% suggest bound clusters

Detection of gas flows and interface features in HII regions

Abstract

We measured the $12.8\mu$m [NeII] line in the dwarf starburst galaxy He 2-10 with the high-resolution spectrometer TeXeS on the NASA IRTF. The data cube has diffraction-limited spatial resolution $\sim1^{\prime\prime}$ and total velocity resolution including thermal broadening of $\sim5$km/s. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the $M/R$ of the clusters and the $\simeq30-40$% star formation efficiencies the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature which we identify with the interface of the HII region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded HII regions with their environment.