TY - JOUR
T1 - Systematic survey of extended Lyα sources over z ∼ 3-5
AU - Saito, Tomoki
AU - Shimasaku, Kazuhiro
AU - Okamura, Sadanori
AU - Ouchi, Masami
AU - Akiyama, Masayuki
AU - Yoshida, Michitoshi
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2006/9/1
Y1 - 2006/9/1
N2 - Spatially extended Lyα sources that are faint and compact in continuum are candidates for extremely young (≲107 yr) galaxies at high redshifts. We carried out a systematic survey for extended Lyα sources, using deep intermediate-band imaging data taken with the Suprime-Cam on the Subaru Telescope. Our survey covers a field of view of 33′ × 25× and a redshift range of 3.24 ≲ z ≲ 4.95, down to a Lyα flux of ∼1 × 10-17 ergs cm-2 s-1. We identified 41 extended Lyα sources. The redshift distribution of these sources shows that this kind of object is common in the early universe over the surveyed redshift range. The identified objects have typical sizes of ∼10-15 kpc and luminosities of ∼1042 ergs s-1. Follow-up spectroscopy made for 7 of the 41 objects showed that our sample suffers from little contamination. All 7 objects have large equivalent widths of Lyα emission line, all but one exceeding 240 Å in the rest frame. The large equivalent widths suggest that their extended Lyα emissions are unlikely to be due to normal starbursts, but possibly originate from very young galaxies. All 41 objects in our sample have much smaller Lyα luminosities than the two Lyα blobs (LABs) found at a z ≃ 3.1 protocluster, in spite of our much larger survey volume. This suggests that large and luminous extended Lyα objects like the two LABs are very rare and are clustered in overdense regions.
AB - Spatially extended Lyα sources that are faint and compact in continuum are candidates for extremely young (≲107 yr) galaxies at high redshifts. We carried out a systematic survey for extended Lyα sources, using deep intermediate-band imaging data taken with the Suprime-Cam on the Subaru Telescope. Our survey covers a field of view of 33′ × 25× and a redshift range of 3.24 ≲ z ≲ 4.95, down to a Lyα flux of ∼1 × 10-17 ergs cm-2 s-1. We identified 41 extended Lyα sources. The redshift distribution of these sources shows that this kind of object is common in the early universe over the surveyed redshift range. The identified objects have typical sizes of ∼10-15 kpc and luminosities of ∼1042 ergs s-1. Follow-up spectroscopy made for 7 of the 41 objects showed that our sample suffers from little contamination. All 7 objects have large equivalent widths of Lyα emission line, all but one exceeding 240 Å in the rest frame. The large equivalent widths suggest that their extended Lyα emissions are unlikely to be due to normal starbursts, but possibly originate from very young galaxies. All 41 objects in our sample have much smaller Lyα luminosities than the two Lyα blobs (LABs) found at a z ≃ 3.1 protocluster, in spite of our much larger survey volume. This suggests that large and luminous extended Lyα objects like the two LABs are very rare and are clustered in overdense regions.
KW - Galaxies: formation
KW - Galaxies: high-redshift
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U2 - 10.1086/505678
DO - 10.1086/505678
M3 - Review article
AN - SCOPUS:33748770612
VL - 648
SP - 54
EP - 66
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1 I
ER -