On the dependence between UV luminosity and Lyman-alpha equivalent width in high redshift galaxies

TL;DR

This study demonstrates that the observed distributions of high-redshift galaxies' UV luminosity and Lyman-alpha equivalent width can be explained without assuming any intrinsic correlation, highlighting observational effects and independence between these properties.

Contribution

The paper shows that the apparent lack of correlation between UV luminosity and Lyman-alpha equivalent width can be explained by simple assumptions and observational biases, challenging previous claims of dependence.

Findings

No correlation between Ly-alpha equivalent width and UV luminosity in high-redshift galaxies.

No dependence between Ly-alpha equivalent width and Ly-alpha luminosity in Ly-alpha emitters.

Observational biases can explain the absence of large equivalent width, UV bright galaxies.

Abstract

We show that with the simple assumption of no correlation between the Ly-alpha equivalent width and the UV luminosity of a galaxy, the observed distribution of high redshift galaxies in an equivalent width - absolute UV magnitude plane can be reproduced. We further show that there is no dependence between Ly-alpha equivalent width and Ly-alpha luminosity in a sample of Ly-alpha emitters. The test was expanded to Lyman-break galaxies and again no dependence was found. Simultaneously, we show that a recently proposed lack of large equivalent width, UV bright galaxies (Ando et al. 2006) can be explained by a simple observational effect, based on too small survey volumes.