A forming, dust enshrouded disk at z=0.43: the first example of a late type disk rebuilt after a major merger?

TL;DR

This study combines high-resolution imagery and kinematic data to model a distant galaxy, revealing a dust-enshrouded disk likely rebuilt after a major merger, illustrating galaxy evolution processes.

Contribution

It provides the first detailed physical model of a late-type galaxy at z=0.43 showing signs of being rebuilt post-merger using combined imaging and kinematic analysis.

Findings

Galaxy has a dust-enshrouded disk with half the Milky Way's radius.

The galaxy exhibits a high star formation rate of 20 solar masses per year.

Kinematic features suggest a recent merger of two gas-rich galaxies.

Abstract

Abreg: By combining HST/UDF imagery with kinematics from VLT/GIRAFFE we derive a physical model of distant galaxy J033245.11-274724.0 in a way similar to what can be done in the nearby Universe. Here we study the properties of a distant compact LIRGs galaxy. Given the photometric and spectro photometric accuracies, we can decompose the galaxy in sub components and correct them for reddening. The galaxy is dominated by a dust enshrouded disk revealed by UDF imagery. The disk radius is half that of the Milky Way and the galaxy have a SFR=20Mo/yr. Morphology and kinematics show that gas and stars together spiral inwards rapidly to feed the disk and the central regions. A combined system of a bar and two non rotating spiral arms regulates the material accretion, induces large sigma, with sigma larger than 100 km/s and redistributes the angular momentum (AM). The detailed physical properties resemble to the expectations from modeling a merger of two equal mass, gaseous rich galaxies, 0.5 Gyr after the merger. In its later evolution, this galaxy could become a late type galaxy which falls on the T-F relation, with an AM mostly induced by the orbital AM of the merger.