Interacting LAEs at z = 5.1. Episodic star formation in a group of LAEs at z= 5.07

We are undertaking a search for high-redshift low luminosity Lyman Alpha sources in the SHARDS survey. Among the pre-selected Lyman Alpha sources 2 candidates were spotted, located 3.19 arcsec apart, and tentatively at the same redshift. Here we report on the spectroscopic confirmation with GTC of the Lyman Alpha emission from this pair of galaxies at a confirmed spectroscopic redshifts of z=5.07. Furthermore, one of the sources is interacting/merging with another close companion that looks distorted. Based on the analysis of the spectroscopy and additional photometric data, we infer that most of the stellar mass of these objects was assembled in a burst of star formation 100 Myr ago. A more recent burst (2 Myr old) is necessary to account for the measured Lyman Alpha flux. We claim that these two galaxies are good examples of Lyman Alpha sources undergoing episodic star formation. Besides, these sources very likely constitute a group of interacting Lyman Alpha emitters (LAEs).

The dependence of the Lyman_a luminosity function on Redshift using SHARDS

We report in this work on a project aimed at determining Ly{alpha} luminosity functions from z=3 to z=6. The project is based on the use of very deep photometry from the SHARDS Survey, in a set of 24 medium band filters in the GOODS-N field. We present here some preliminary work carried out with four test images in four consecutive bands. We use the narrow band selection technique for searching emission line candidates. Eleven candidates have been detected so far, many of which are strong Ly{alpha} candidates. In particular, we have seen a firm candidate to an interacting pair of Ly{alpha} sources at z=5.4.