The SCUBA HAlf Degree Extragalactic Survey (SHADES) - V. Submillimetre properties of near-infrared-selected galaxies in the Subaru/XMM-Newton deep field

Abstract

We have studied the submillimetre (submm) properties of the following classes of near‐infrared‐selected (NIR‐selected) massive galaxies at high redshifts: BzK‐selected star‐forming galaxies (BzKs); distant red galaxies (DRGs); and extremely red objects (EROs). We used the SCUBA HAlf Degree Extragalactic Survey (SHADES), the largest uniform submm survey to date. Partial overlap of SIRIUS/NIR images and SHADES in Subaru/XMM–Newton deep field has allowed us to identify four submm‐bright NIR‐selected galaxies, which are detected in the mid‐IR, 24μ m, and the radio, 1.4GHz. We find that all of our submm‐bright NIR‐selected galaxies satisfy the BzK selection criteria, i.e. BzK≡ (z−K)AB− (B−z)AB≥−0.2, except for one galaxy whose B−z and z−K colours are however close to the BzK colour boundary. Two of the submm‐bright NIR‐selected galaxies satisfy all of the selection criteria we considered, i.e. they belong to the BzK–DRG–ERO overlapping population, or ‘extremely red’BzKs. Although these extremely red BzKs are rare (0.25 arcmin−2), up to 20 per cent of this population could be submm galaxies. This fraction is significantly higher than that found for other galaxy populations studied here. Via a stacking analysis, we have detected the 850‐μ m flux of submm‐faint BzKs and EROs in our SCUBA maps. While the contribution of z∼ 2 BzKs to the submm background is about 10–15 per cent and similar to that from EROs typically at z∼ 1, BzKs have a higher fraction (∼30 per cent) of submm flux in resolved sources compared with EROs and submm sources as a whole. From the spectral energy distribution (SED) fitting analysis for both submm‐bright and submm‐faint BzKs, we found no clear signature that submm‐bright BzKs are experiencing a specifically luminous evolutionary phase, compared with submm‐faint BzKs. An alternative explanation might be that submm‐bright BzKs are more massive than submm‐faint ones.