Source plane reconstruction of the giant gravitational arc in Abell 2667: a candidate Wolf-Rayet galaxy at z~1

TL;DR

This study reconstructs the source plane of a giant gravitational arc in Abell 2667, revealing a high-redshift spiral galaxy with Wolf-Rayet features, providing insights into galaxy structure and stellar populations at z~1.

Contribution

We developed an updated lens model and performed a detailed morphological and spectroscopic analysis of a lensed galaxy at z~1, identifying Wolf-Rayet features and high-redshift galaxy properties.

Findings

Reconstructed the galaxy's morphology showing a typical spiral structure.

Detected Wolf-Rayet features indicating a starburst galaxy.

Identified negative radial color gradients and metal-rich central bulge.

Abstract

We present a new analysis of HST, Spitzer telescope imaging and VLT imaging and spectroscopic data of a bright lensed galaxy at $z$=1.0334 in the lensing cluster Abell~2667. Using this high-resolution imaging we present an updated lens model that allows us to fully understand the lensing geometry and reconstruct the lensed galaxy in the source plane. This giant arc gives a unique opportunity to peer into the structure of a high-redshift disk galaxy. We find that the lensed galaxy of Abell 2667 is a typical spiral galaxy with morphology similar to the structure of its counterparts at higher redshift $z\sim 2$. The surface brightness of the reconstructed source galaxy in the z$_{850}$ band reveals the central surface brightness $I(0)=20.28\pm0.22$ mag arcsec$^{-2}$ and the characteristic radius $r_s=2.01\pm0.16$ kpc at redshift $z \sim 1$. The morphological reconstruction in different bands shows obvious negative radial color gradients for this galaxy. Moreover, the redder central bulge tends to contain a metal-rich stellar population, rather than being heavily reddened by dust due to high and patchy obscuration. We analyze the VIMOS/IFU spectroscopic data and find that, in the given wavelength range ($\sim 1800-3200$ \AA), the combined arc spectrum of the source galaxy is characterized by a strong continuum emission with strong UV absorption lines (FeII and MgII) and shows the features of a typical starburst Wolf-Rayet galaxy NGC5253. More specifically, we have measured the EWs of FeII and MgII lines in the Abell 2667 spectrum, and obtained similar values for the same wavelength interval of the NGC5253 spectrum. Marginal evidence for CIII] 1909 emission at the edge of the grism range further confirms our expectation.