Abstract
We present ammonia observations of 193 dense cores and core candidates in the Perseus molecular cloud made using the Robert F. Byrd Green Bank Telescope. We simultaneously observed the NH3(1,1), NH3(2,2), C2S (21→ 10), and C342S(21→ 10) transitions near ν = 23 GHz for each of the targets with a spectral resolution of δ v ≈ 0.024 km s−1. We find ammonia emission associated with nearly all of the (sub)millimeter sources, as well as at several positions with no associated continuum emission. For each detection, we have measured physical properties by fitting a simple model to every spectral line simultaneously. Where appropriate, we have refined the model by accounting for low optical depths, multiple components along the line of sight, and imperfect coupling to the GBT beam. For the cores in Perseus, we find a typical kinetic temperature of Tk = 11 K, a typical column density of NNH3 ≈ 1014.5 cm −2, and velocity dispersions ranging from σv = 0.07 to 0.7 km s−1. However, many cores with σv > 0.2 km s−1 show evidence for multiple velocity components along the line of sight.
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