Detecting z > 10 objects through carbon , nitrogen and oxygen emission lines

By redshift of 10, star formation in the first objects should have produced considerable amounts of Carbon, Nitrogen and Oxygen. The submillimeter lines of C, N and O redshift into the millimeter and centimeter bands (0.5mm–1.2 cm), where they may be detectable. High spectral resolution observations could potentially detect inhomogeneities in C, N and O emission, and see the first objects forming at high redshift. We calculate expected intensity fluctuations and discuss frequency and angular resolution required to detect them. For CII emission, we estimate the intensity using two independent methods: the line emission coefficient argument and the luminosity density argument. We find they are in good agreement. At 1 + z ∼ 10, the typical protogalaxy has a velocity dispersion of 30 km s and angular size of 1 arcsecond. If CII is the dominant coolant, then we estimate a characteristic line strength of ∼ 0.1Kkm s. We also discuss other atomic lines and estimate their signal. Observations with angular resolution of 10 can detect moderately nonlinear fluctuations of amplitude 2 · 10 times the microwave background. If the intensity fluctuations are detected, they will probe matter density inhomogeneity, chemical evolution and ionization history at high redshifts. Subject headings: cosmology: theory — early universe — galaxies: formation — intergalactic medium — radio lines: general submitted to The Astrophysical Journal Department of Physics, the University of Tokyo, Tokyo 113, Japan [email protected], JSPS Research Fellow RESCEU, School of Sciences, the University of Tokyo, Tokyo 113, Japan [email protected], JSPS Postdoctoral Fellow [email protected]