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arXiv · 1704.05101

Deep submillimeter and radio observations in the SSA22 field. I. Powering sources and Ly{\alpha} escape fraction of Ly{\alpha} 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. Ouchi·T. Saito·Y. Tamura·Y. Taniguchi·H. Umehata·A. Weiss
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Abstract

We study the heating mechanisms and Ly{\alpha} escape fractions of 35 Ly{\alpha} 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 Msun/yr. Likely radio counterparts are detected in 9 out of 29 investigated LABs. The detection of submm dust emission is more linked to the physical size of the Ly{\alpha} emission than to the Ly{\alpha} luminosities of the LABs. A radio excess in the submm/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 Ly{\alpha} escape fraction is about 3\% among the submm-detected LABs, which is lower than a lower limit of 11\% for the submm-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.

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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. Ouchi, T. Saito, Y. Tamura, Y. Taniguchi, H. Umehata, A. Weiss. 2017-04-17. Deep submillimeter and radio observations in the SSA22 field. I. Powering sources and Ly{\alpha} escape fraction of Ly{\alpha} blobs. https://doi.org/10.3847/1538-4357/aa960f

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