Science with an ngVLA: [CII] 158$\hat{I}¼$m Emission from $z\ge 10$ Galaxies

Abstract

We consider the capabilities of ALMA and the ngVLA to detect and image the[CII] 158\,$\hat{I}¼$m line from galaxies into the cosmic `dark ages' ($z\sim 10$ to 20). The [CII] line may prove to be a powerful tool in determining spectroscopic redshifts, and galaxy dynamics, for the first galaxies. In 40\,hr, ALMA has the sensitivity to detect the integrated [CII] line emission from a moderate metallicity, active star-forming galaxy [$Z_A=0.2Z_{\odot }$; star formation rate (SFR)= 5\,$M_{\odot }$\,yr${}^{-1}$], at $z=10$ at a significance of 6$\ddot{I}ƒ$. The ngVLA will detect the integrated [CII] line emission from a Milky-Way like star formation rate galaxy ($Z_A=0.2Z_{\odot }$, SFR = 1\,$M_{\odot }$\,yr${}^{-1}$), at $z=15$ at a significance of 6$\ddot{I}ƒ$. Imaging simulations show that the ngVLA can determine rotation dynamics for active star-forming galaxies at $z\sim 15$, if they exist. The [CII] detection rate in blind surveys will be slow (of order unity per 40\,hr pointing.

8 pages, 3 figures; to be published in the ASP Monograph Series, "Science with a Next-Generation VLA", ed. E. J. Murphy (ASP, San Francisco, CA). arXiv admin note: substantial text overlap with arXiv:1709.02001