An OSIRIS study of the gas kinematics in a sample of UV-selected galaxies: Evidence of "Hot and Bothered" starbursts in the local Universe

TL;DR

This study uses integral field spectroscopy to analyze the gas kinematics of nearby UV-bright galaxies, revealing disturbed, dispersion-dominated dynamics that serve as local analogs to high-redshift Lyman Break Galaxies, providing insights into starburst processes.

Contribution

It offers detailed kinematic analysis of supercompact UV-Luminous Galaxies, demonstrating their disturbed dynamics and their relevance as local analogs to high-redshift star-forming galaxies.

Findings

Most galaxies show disturbed, non-rotational kinematics.

Two of three galaxies are dispersion-dominated with v/sigma < 1.

Simulations at high redshift reveal observational biases and similarities.

Abstract

We present data from Integral Field Spectroscopy for 3 supercompact UV-Luminous Galaxies (ScUVLGs). As nearby (z~0.2), compact (R_50~1-2 kpc), bright Paschen-alpha sources, with unusually high star formation rates (SFR=3-100 M_sun/yr), ScUVLGs are an ideal population for studying detailed kinematics and dynamics in actively star-forming galaxies. In addition, ScUVLGs appear to be excellent analogs to high redshift Lyman Break Galaxies (LBGs) and our results may offer additional insight into the dynamics of LBGs. Previous work by our team has shown that the morphologies of these galaxies exhibit tidal features and companions, and in this study we find that the dynamics of ScUVLGs are dominated by disturbed kinematics of the emission line gas-- suggestive that these galaxies have undergone recent feedback, interactions or mergers. While 2 of the 3 galaxies do display rotation, v/sigma < 1 -- suggesting dispersion dominated kinematics rather than smooth rotation. We also simulate how these observations would appear at z~2. Lower resolution and loss of low surface brightness features causes some apparent discrepancies between the low-z (observed) and high-z (simulated) interpretations and quantitatively gives different values for v/sigma, yet simulations of these low-z analogs manage to detect the brightest regions well and resemble actual high-z observations of LBGs.