Environment of the submillimeter-bright massive starburst HFLS3 at $z\sim$6.34

TL;DR

This study investigates the environment around the massive starburst galaxy HFLS3 at redshift 6.34, searching for nearby Lyman-break galaxies to understand galaxy clustering and formation during reionization.

Contribution

It provides a detailed analysis of the galaxy environment around HFLS3 at z~6.34, including candidate identification and environmental density assessment, using combined HST and GTC data.

Findings

No strong evidence for an overdensity of bright LBGs near HFLS3.

Identified three faint potential z~6 galaxies close to HFLS3.

UV luminosity function at z~6 consistent with previous studies.

Abstract

We describe the search for Lyman-break galaxies (LBGs) near the sub-millimeter bright starburst galaxy HFLS3 at $z$$=$6.34 and a study on the environment of this massive galaxy during the end of reionization.We performed two independent selections of LBGs on images obtained with the \textit{Gran Telescopio Canarias} (GTC) and the \textit{Hubble Space Telescope} (HST) by combining non-detections in bands blueward of the Lyman-break and color selection. A total of 10 objects fulfilling the LBG selection criteria at $z$$>$5.5 were selected over the 4.54 and 55.5 arcmin$^2$ covered by our HST and GTC images, respectively. The photometric redshift, UV luminosity, and the star-formation rate of these sources were estimated with models of their spectral energy distribution. These $z$$\sim$6 candidates have physical properties and number densities in agreement with previous results. The UV luminosity function at $z$$\sim$6 and a Voronoi tessellation analysis of this field shows no strong evidence for an overdensity of relatively bright objects (m$_{F105W}$$<$25.9) associated with \textit{HFLS3}. However, the over-density parameter deduced from this field and the surface density of objects can not excluded definitively the LBG over-density hypothesis. Moreover we identified three faint objects at less than three arcseconds from \textit{HFLS3} with color consistent with those expected for $z$$\sim$6 galaxies. Deeper data are needed to confirm their redshifts and to study their association with \textit{HFLS3} and the galaxy merger that may be responsible for the massive starburst.