A Search for Dense Molecular Gas in High Redshift Infrared-Luminous Galaxies
نویسندگان
چکیده
We present a search for HCN emission from four high redshift far infrared (IR) luminous galaxies. Current data and models suggest that these high z IR luminous galaxies represent a major starburst phase in the formation of spheroidal galaxies, although many of the sources also host luminous active galactic nuclei (AGN), such that a contribution to the dust heating by the AGN cannot be precluded. HCN emission is a star formation indicator, tracing dense molecular hydrogen gas within star-forming molecular clouds (n(H2) ∼ 10 cm). HCN luminosity is linearly correlated with IR luminosity for low redshift galaxies, unlike CO emission which can also trace gas at much lower density. We report a marginal detection of HCN (1-0) emission from the z = 2.5832 QSO J1409+5628, with a velocity integrated line luminosity of L′HCN = 6.7±2.2×10 K km s pc,
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