High Resolution Observations of CO(3-2) in Haro 2: Cool Molecular Outflows of a Ly$\alpha$ Emitter

TL;DR

This study uses high-resolution CO(3-2) observations to reveal detailed structures of molecular outflows in Haro 2, a nearby Lyα emitter, highlighting the dynamics of starburst-driven gas ejections.

Contribution

It provides the first high-resolution imaging of CO(3-2) in Haro 2, uncovering new outflow components and their relation to ionized gas and star formation regions.

Findings

Detection of a confined molecular outflow opposite the ionized outflow

Identification of an additional outflow near a weak star-forming region

All outflow velocities are within ±50 km/s of the galaxy's systemic velocity

Abstract

Haro 2 is a blue compact dwarf galaxy and the closest (at 21Mpc) known $Ly\alpha$ emitter. UV and optical observations have found Haro 2 to be immersed in shells of partly ionized gas expanding at $\sim200$km/s. Observations of CO(2-1) (Becket et al 2020; Paper 1) with moderate ($2^{\prime\prime}$) resolution discovered a large-scale one-sided outflow associated with a soft X-ray bubble and apparently driven by the young star clusters created in the recent starburst. We present here SMA observations of CO(3-2) with $1.1^{\prime\prime}$ resolution in Haro 2. The opposite-side component of the large molecular outflow is detected lying in the direction of the fast ionized outflow; it is very confined in area. An additional outflow is apparent in the CO(3-2); it is south-east of the galaxy in a region holding weak star formation and a moderate-luminosity hard X-ray source. All the molecular outflow and filament velocities are within $\lesssim\pm50$km/s of the systemic velocity of the galaxy.