Exploring the early dust-obscured phase of galaxy formation with blind mid-/far-IR spectroscopic surveys

摘要

While continuum imaging data at far-infrared to sub-millimeter wavelengthshave provided tight constraints on the population properties of dusty starforming galaxies up to high redshifts, future space missions like the SpaceInfra-Red Telescope for Cosmology and Astrophysics (SPICA) and ground basedfacilities like the Cerro Chajnantor Atacama Telescope (CCAT) will allowdetailed investigations of their physical properties via theirmid-/far-infrared line emission. We present updated predictions for the numbercounts and the redshift distributions of star forming galaxiesspectroscopically detectable by these future missions. These predictionsexploit a recent upgrade of evolutionary models, that include the effect ofstrong gravitational lensing, in the light of the most recent Herschel andSouth Pole Telescope data. Moreover the relations between line and continuuminfrared luminosity are re-assessed, considering also differences among sourcepopulations, with the support of extensive simulations that take into accountdust obscuration. The derived line luminosity functions are found to be highlysensitive to the spread of the line to continuum luminosity ratios. Estimatesof the expected numbers of detections per spectral line by SPICA/SAFARI and byCCAT surveys for different integration times per field of view at fixed totalobserving time are presented. Comparing with the earlier estimates by Spinoglioet al. (2012) we find, in the case of SPICA/SAFARI, differences within a factorof two in most cases, but occasionally much larger. More substantialdifferences are found for CCAT.