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Deep Submillimeter and Radio Observations in the SSA22 Field. I. Powering Sources and the Lyα Escape Fraction of Lyα Blobs

Ao, Y.; Matsuda, Y.; Henkel, C.; Iono, D.; Alexander, D.M.; Chapman, S.C.; Geach, J.; Hatsukade, B.; Hayes, M.; Hine, N.K.; Kato, Y.; Kawabe, R.; Kohno, K.; Kubo, M.; Lehnert, M.; Malkan, M.; Menten, K.M.; Nagao, T.; Norris, R.P.; Ouchi, M.; Saito, T.; Tamura, Y.; Taniguchi, Y.; Umehata, H.; Weiss, A.

Deep Submillimeter and Radio Observations in the SSA22 Field. I. Powering Sources and the Lyα Escape Fraction of Lyα Blobs Thumbnail


Y. Ao

Y. Matsuda

C. Henkel

D. Iono

S.C. Chapman

J. Geach

B. Hatsukade

M. Hayes

N.K. Hine

Y. Kato

R. Kawabe

K. Kohno

M. Kubo

M. Lehnert

M. Malkan

K.M. Menten

T. Nagao

R.P. Norris

M. Ouchi

T. Saito

Y. Tamura

Y. Taniguchi

H. Umehata

A. Weiss


We study the heating mechanisms and Lyα escape fractions of 35 Lyα blobs (LABs) at z ≈ 3.1 in the SSA22 field. Dust continuum sources have been identified in 11 of the 35 LABs, all with star formation rates (SFRs) above 100 M ⊙ yr−1. Likely radio counterparts are detected in 9 out of 29 investigated LABs. The detection of submillimeter dust emission is more linked to the physical size of the Lyα emission than to the Lyα luminosities of the LABs. A radio excess in the submillimeter/radio-detected LABs is common, hinting at the presence of active galactic nuclei. Most radio sources without X-ray counterparts are located at the centers of the LABs. However, all X-ray counterparts avoid the central regions. This may be explained by absorption due to exceptionally large column densities along the line-of-sight or by LAB morphologies, which are highly orientation dependent. The median Lyα escape fraction is about 3% among the submillimeter-detected LABs, which is lower than a lower limit of 11% for the submillimeter-undetected LABs. We suspect that the large difference is due to the high dust attenuation supported by the large SFRs, the dense large-scale environment as well as large uncertainties in the extinction corrections required to apply when interpreting optical data.

Journal Article Type Article
Acceptance Date Oct 23, 2017
Online Publication Date Nov 30, 2017
Publication Date Nov 30, 2017
Deposit Date Jan 5, 2018
Publicly Available Date Jan 5, 2018
Journal Astrophysical Journal
Print ISSN 0004-637X
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 850
Issue 2
Article Number 178
Public URL


Published Journal Article (4.6 Mb)

Copyright Statement
© 2017. The American Astronomical Society. All rights reserved.

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