Lyman-Alpha Emitter Galaxies at z ~ 2.8 in the Extended Chandra Deep Field-South: I. Tracing the Large-Scale Structure via Lyman-Alpha Imaging
, , , , , , and .
(2016)cite arxiv:1606.07073Comment: 22 pages, 20 figures, 5 tables. Accepted to ApJ Supplement.

We present a narrowband survey with three adjacent filters for z=2.8--2.9 Lyman Alpha Emitter (LAE) galaxies in the Extended Chandra Deep Field South (ECDFS), along with spectroscopic followup. With a complete sample of 96 LAEs in the narrowband NB466, we confirm a large-scale structure at z~ 2.8. Compared to the blank field in NB470 and NB475, the LAE density excess in the NB466 field is ~6.0+/-0.8 times the standard deviation expected at z~2.8, assuming a linear bias of 2. The overdense large scale structure in NB466 can be decomposed into 4 protoclusters, whose overdensities are 4.6 - 6.6. These 4 protoclusters are expected to evolve into a Coma-like cluster at z~ 0. In the meanwhile, we investigate the average star-formation rates derived from Ly\alpha, rest-frame UV and X-ray, the Ly\alpha luminosity functions, the Ly\alpha photon densities and their dependence on the environment. We find that the Ly\alpha photon density in the overdense field (NB466) is ~50\% higher than that in the blank field (NB470+NB475). The 3 brightest LAEs, including a quasar at z=2.81, are all detected in X-ray and in NB466. These three LAE-AGNs contribute an extra 20--30\% Ly\alpha photon density. Furthermore, we find that LAEs in overdense regions are younger and less dusty. We conclude that the structure we found is a significant and rare density peak, and narrowband imaging is an efficient method to detect and study such structures in the high-z universe.
  • @miki
This publication has not been reviewed yet.

rating distribution
average user rating0.0 out of 5.0 based on 0 reviews
    Please log in to take part in the discussion (add own reviews or comments).