A massive disk galaxy at z>3 along the sightline of QSO 1508+5714

TL;DR

This paper reports the discovery of a massive disk galaxy at redshift greater than 3, potentially one of the most distant such galaxies known, based on deep multi-band imaging and photometric analysis.

Contribution

It presents the identification and analysis of a high-redshift massive disk galaxy, combining photometric redshift estimation with morphological analysis from HST imaging.

Findings

Detected a B-dropout galaxy near QSO 1508+5714

Photometric analysis suggests z~3.5 and L~3 L*

Morphology consistent with a massive disk galaxy

Abstract

We have obtained deep images in the BVRIJHKs bands of the field centered on QSO 1508+5714 (z_{em} =4.28) with the Suprime camera, FOCAS and MOIRCS cameras on Subaru telescope. We report here the detection of a B-dropout galaxy, which is $3\secpoint 5$ north-west of the QSO sightline. A photometric redshift analysis is presented to complement the color selection. Given the photometric properties of this object ($M = -22.2$, making $ L\approx 3 L^{\ast}$, if placed at its photometric redshift $z\sim 3.5$), as well as the S$\acute{e}$rsic index ($ n \sim 1$) derived from a 2-D imaging decomposition of the HST WFPC2 image taken in the $I_{F814}$ filter, the identified system is consistent with a massive disk galaxy at z>3. If confirmed, it would be one of the most distant massive disk galaxies known so far.