CO Survey toward high redshift Galaxies

CO survey of high-z galaxies
In order to demonstrate the capabilities and test the feasibility of the newly upgraded 45m telescope (e.g. Nakajima et al. 2012), we have targeted five sources that are bright and have spectroscopic (or CO) redshifts. The sources we select in this pilot study are, SXDF 1100.001 (Orochi) (Ikarashi et al. 2011), SDP9, and SDP17 (Negrello et al. 2010; Lupu et al. 2010), SDSS160705 + 533558 (Clements et al. 2009), and COSMOS-AzTEC1 (Smolcic et al. 2011). These sources have apparent infrared luminosities of ~10^13 L_solar, and are promising sources for CO detection. Here we present initial results from our ongoing CO survey toward bright high redshift submm bright sources using the upgraded 45m telescope.
From our recent observations toward five submm bright high redshift sources using the the recently upgraded Nobeyama 45m telescope, we have successfully detected CO emission from at least three sources. All of the sources have significant amount of molecular gas mass (M_H2 ~10^10-11 M_solar) and relatively large line-widths. One source shows a double peak spectrum.
We plan to expand this project by tuning the two different polarizations to different frequencies, allowing us to instantaneously observe 16 GHz bandwidth in a singlebeam. This will lead to a large blind redshift survey of SMGs and will be executed from the following observing season. Further, a new 3-color camera, which is currently being installed and commissioned at ASTE, will detect and simultaneously provide constraints to the redshifts of the newly detected SMGs. Sources observable in the northern hemisphere will then be followed up at the 45m telescope for the final determination of their CO redshifts.

Reference
Iono, D. et al., "Initial Results and Project Description of the Nobeyama Molecular Gas Observations of Distant Bright Galaxies", Publ. Astron. Soc. Japan 64, L2, 2012
Nakajima, T. et al., "A New 100-GHz Band Two-Beam Sideband-Separating SIS Receiver for Z-Machine on the NRO 45-m Radio Telescope", Publ. Astron. Soc. Pacific, 125, 252, 2013