We report spectroscopic redshift measurements for three bright submillimeter galaxies (SMGs) near the GOODS-N field, each with SCUBA-2 850 micron fluxes > 10 mJy, using the Northern Extended Millimeter Array (NOEMA). Our molecular linescan observations of these sources, which occupy a ~7 arcmin$^2$ area outside of the HST coverage of the field, reveal that two lie at $z sim$ 3.14. In the remaining object, we detect line emission consistent with CO(7-6), [C I], and H2O at $z$ = 4.42. The far-infrared spectral energy distributions of these galaxies, constrained by SCUBA-2, NOEMA, and Herschel/SPIRE, indicate instantaneous SFRs $sim4000 ~{rm M_{odot}~yr^{-1}}$ in the $z$ = 4.42 galaxy and $sim 2500~{rm M_{odot}~yr^{-1}}$ in the two $z sim$ 3.14 galaxies. Based on our sources CO line luminosities, we estimate $M_{{rm gas}}sim10^{11} M_{odot}$ and find gas depletion timescales of $tau_{{rm depl}}sim 50$ Myr, consistent with findings in other high-redshift SMGs. Finally, we show that the two $z sim$ 3.14 sources, which alone occupy a volume $sim$10 Mpc$^3$, very likely mark the location of a protocluster of bright SMGs and less dusty optical sources.
تحميل البحث