The Ratio of CO to Total Gas Mass in High Redshift Galaxies

Understand

Walter et al.

• (20012) have recently identified the J=6-5, 5-4, and 2-1 CO rotational emission lines, and [C_{II}] fine-structure emission line from the star-forming interstellar medium in the high-redshift submillimeter source HDF 850.1, at z = 5.183.
• We employ large velocity gradient (LVG) modeling to analyze the spectra of this source assuming the [C_{II}] and CO emissions originate from (i) separate unvirialized regions, (ii) separate virialized regions, (iii) uniformly mixed unvirialized region, and (iv) uniformly mixed virialized regions.
• We present the best fit set of parameters, including for each case the ratio $\alpha$ between the total hydrogen/helium gas mass and the CO(1-0) line luminosity.