2009ApJ...699.1843W

We present the radio and X-ray properties of 1.2 mm MAMBO source candidates in a 1600 arcmin2 field centered on the Abell 2125 galaxy cluster at z = 0.247. The brightest, nonsynchrotron millimeter source candidate in the field has a photometric redshift z = 3.93^+1.11_–0.80 and is not detected in a 31 ks Chandra X-ray exposure. These findings are consistent with this object being an extremely dusty and luminous starburst galaxy at high redshift, possibly the most luminous yet identified in any blank-field millimeter survey. The deep 1.4 GHz Very Large Array imaging identifies counterparts for 83% of the 29 mm source candidates identified at ≥4σ (S_1.2 mm_= 2.7-52.1 mJy), implying that the majority of these objects are likely to lie at z ≲ 3.5. The median millimeter-to-radio wavelength photometric redshift of this radio-detected sample is z ∼ 2.2 (first and third quartiles of 1.7 and 3.0), consistent with the median redshift derived from optical spectroscopic surveys of the radio-detected subsample of bright submillimeter galaxies (S_850 µm_> 5 mJy). Three millimeter-selected quasars are confirmed to be X-ray luminous in the high-resolution Chandra imaging, while another millimeter source candidate with potential multiple radio counterparts is also detected in the X-ray regime. Both of these radio counterparts are positionally consistent with the millimeter source candidate. One counterpart is associated with an elliptical galaxy at z = 0.2425, but we believe that a second counterpart associated with a fainter optical source likely gives rise to the millimeter emission at z ∼ 1.