%0 Journal Article
%T Obscured star formation in Ly-alpha blobs at z = 3.1
%A Yoichi Tamura
%A Yuichi Matsuda
%A Soh Ikarashi
%A Kimberly S. Scott
%A Bunyo Hatsukade
%A Hideki Umehata
%A Tomoki Saito
%A Kouichiro Nakanishi
%A Min S. Yun
%A Hajime Ezawa
%A David H. Hughes
%A Daisuke Iono
%A Ryohei Kawabe
%A Kotaro Kohno
%A Grant W. Wilson
%J Physics
%D 2013
%I arXiv
%R 10.1093/mnras/stt077
%X We present results from the AzTEC/ASTE 1.1-mm imaging survey of 35 Ly-alpha blobs (LABs) found in the SSA22 protocluster at z = 3.1. These 1.1-mm data reach an r.m.s. noise level of 0.7-1 mJy/beam, making this the largest millimetre-wave survey of LABs to date. No significant (> 3.5-sigma) emission is found in any of individual 35 LABs, and from this, we estimate 3-sigma upper limits on the far-infrared luminosity of L_FIR < 2e+12 Lsun. Stacking analysis reveals that the 1.1-mm flux density averaged over the LABs is S(1.1mm) < 0.40 mJy (3-sigma), which places a constraint of L_FIR < 4.5e+11 Lsun. This indicates that earlier 850-um measurements of the LABs may have overestimated their flux densities. Our results suggest that LABs on average have little ultra-luminous obscured star-formation, in contrast to a long-believed picture that LABs undergo an intense episode of dusty star-formation activities with star-formation rates of ~ 10^3 Msun/yr. Observations with ALMA are needed to directly study the obscured part of star-formation activity in the LABs.
%U http://arxiv.org/abs/1301.2596v1