An overdensity of Lyα emitters at redshift z ≈ 5.7 near the hubble ultra deep field

We have identified an obvious and strong large-scale structure at redshift z ≈ 5.75 in a wide (31′ × 33′) field, narrowband survey of the Chandra Deep Field-South region. This structure is traced by 17 candidate Lyα emitters, among which 12 are found in an 823 nm filter (corresponding to Lyα at z = 5.77 ± 0.03) and five in an 815 nm image (z = 5.70 ± 0.03). The Lyα emitters in both redshift bins are concentrated in one quadrant of the field. The Hubble Ultra Deep Field, the Chandra Deep Field-South, and the Great Observatories Origins Deep Survey-South fields all lie near the edge of this overdensity region. Our results are consistent with reports of an overdensity in the Ultra Deep Field region at z ≈ 5.9. This structure is the highest redshift overdensity found so far.