We have conducted a sensitive search for the redshifted HCN(1-0) line (νrest = 88.6304 GHz) towards three luminous submillimeter galaxies at z ∼ 2.5-2.8 using the K-band receiver (17.6--27.1 GHz) on the 110 m Robert C. Byrd Telescope (also known as the Green Bank Telescope). Aided by gravitational lensing, we place strong upper limits on the intrinsic line luminosity of all three sources (L'HCN(1-0) ≲ 2× 1010 K km s-1 pc2). We conclude that all four submillimeter galaxies that have been observed in HCN to date are consistent with the tight relation between FIR and HCN luminosity observed in a variety of local star-forming systems, ranging from Galactic dense cores to (ultra)luminous infrared galaxies at z≲ 0.1.
From Z-Machines to ALMA: (Sub)Millimeter Spectroscopy of Galaxies
- Pub Date:
- October 2007