AIM-CO: Cosmic Structure and Galaxy Evolution through Intensity Mapping of Molecular Gas
Geoffrey C. Bower1*, Tzu-Ching Chang2, Ming-Tang Chen1,2, You-Hua Chu2, Homin Jiang2, Patrick Koch2, Derek Kubo1, Chao-Te Li2, Kai-Yang Lin2, Ranjani Srinivasan1, Garrett Keating3, Dan Marrone4, Cheng-Yu Kuo5, Guo-Chin Liu6, Kin-Wang Ng7
1Institute of Astronomy and Astrophysics, Academia Sinica, Hilo, HI, USA
2Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, Taiwan
3Astronomy, UC Berkeley, Berkeley, CA, USA
4Astronomy, University of Arizona, Tucson, AZ, USA
5Physics, National Sun Yat-Sen University, Kaosiung City, Taiwan
6Physics, Tamkang University, Tamsui, Taiwan
7Institute of Physics, Academia Sinica, Taipei, Taiwan
* presenting author:Geoffrey Bower,
The origin and evolution of structure in the Universe is one of the major challenges of observational cosmology. How does baryonic structure trace the underlying dark matter? How have galaxies evolved to produce the present day Universe? A multi-wavelength, multi-tool approach is necessary to provide the complete story of the evolution of structure in the Universe. Intensity mapping, which relies on the ability to detect many objects at once through their integrated emission rather than direct detection of individual objects, is a critical part of this mosaic. In particular, our understanding of the molecular gas component of massive galaxies is being revolutionized by ALMA and EVLA but the population of smaller, star-forming galaxies, which provide the bulk of star formation cannot be individually probed by these instruments.

In this talk, I will summarize two intensity mapping experiments to detect molecular gas through the carbon monoxide (CO) rotational transition. We have completed sensitive observations with the Sunyaev-Zel'dovic Array (SZA) telescope at a wavelength of 1 cm that are sensitive to emission at redshifts 2.3 to 3.3. The SZA experiments sets strong limits on models for the CO emission and demonstrates the ability to reject foregrounds and telescope systematics in very deep integrations. I also describe the development of an intensity mapping capability for the Yuan-Tseh Lee Array, a 13-element interferometer located on Mauna Loa, Hawaii and operated by ASIAA. In its first phase, this project focuses on detection of CO at redshifts 1 to 3 with detection via power spectrum and cross-correlation with other surveys. The project includes a major technical upgrade, a new digital correlator and IF electronics component to be deployed in 2015/2016. The Y.T. Lee Array observations will be more sensitive and extend to larger angular scales than the SZA observations.

Keywords: cosmology, galaxy evolution, radio astronomy, instrumentation, molecular gas