PHIBSS: molecular gas, extinction, star formation and kinematics in the z=1.5 star forming galaxy EGS13011166

TL;DR

This study provides detailed spatially resolved observations of molecular gas, star formation, and kinematics in a z=1.53 star-forming galaxy, revealing a turbulent rotating disk with a near-linear gas-star formation relation.

Contribution

It presents the first matched resolution imaging spectroscopy of CO and H-alpha lines in a high-redshift galaxy, combining multi-wavelength data to analyze gas, stars, and extinction.

Findings

Gas and ionized gas kinematics are similar and consistent with a turbulent, rotating disk.

Stellar distribution is smoother than UV/optical light, with a central obscured bulge.

The molecular gas to star formation rate relation is near linear under a mixed extinction model.

Abstract

We report matched resolution, imaging spectroscopy of the CO J=3-2 line (with the IRAM Plateau de Bure millimeter interferometer) and of the H-alpha line (with LUCI at the Large Binocular Telescope)in the massive z=1.53 main-sequence galaxy EGS 13011166, as part of the "Plateau de Bure high-z, blue sequence survey (PHIBSS). We combine these data with HST V-J-J-H-band maps to derive spatially resolved distributions of stellar surface density, star formation rate, molecular gas surface density, optical extinction and gas kinematics. The spatial distribution and kinematics of the ionized and molecular gas are remarkably similar and are well modeled by a turbulent, globally Toomre unstable rotating disk. The stellar surface density distribution is smoother than the clumpy rest-frame UV/optical light distribution, and peaks in an obscured, star forming massive bulge near the dynamical center. The molecular gas surface density and the effective optical screen extinction track each other and are well modeled by a 'mixed' extinction model. The inferred slope of the spatially resolved molecular gas to star formation rate relation depends strongly on the adopted extinction model and can vary from 0.8 to 1.7. For the preferred mixed dust-gas model we find a near linear slope.