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

Y. Ao, Y. Matsuda, C. Henkel, D. Iono, D.~M. Alexander, 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. OuchiT. Saito, Y. Tamura, Y. Taniguchi, H. Umehata, A. Weiss

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10 Citations (Scopus)


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.
Original languageEnglish
Pages (from-to)178
Number of pages1
JournalThe Astrophysical Journal
Issue number2
Early online date30 Nov 2017
Publication statusPublished - 30 Nov 2017


  • galaxies: active, galaxies: formation, galaxies: high-redshift, galaxies: ISM, infrared: galaxies


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