# Interstellar C 2 in the Perseus molecular complex: excitation temperature and density of a molecular cloud with anomalous microwave emission - Astrophysics > Cosmology and Nongalactic Astrophysics

Interstellar C 2 in the Perseus molecular complex: excitation temperature and density of a molecular cloud with anomalous microwave emission - Astrophysics > Cosmology and Nongalactic Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: Interstellar absorption lines up to J-=10 in the 2,0 band and up to J-=6 inthe 3,0 band of the C$2$ $A^1\Pi u$ - $X^1\Sigma^+ g$ system are detectedtoward star Cernis 52 BD+31$^o$ 640 in the Perseus molecular complex. Thestar lies in a redenned line of sight where various experiments have detectedanomalous microwave emission spatially correlated with dust thermal emission.The inferred total C$2$ column density of NC${2}$ = 10.5$\pm$ 0.2 x10$^{13}$ cm$^{-2}$ is well correlated with that of CH as expected fromtheoretical models and is among the highest reported on translucent clouds withsimilar extinction. The observed rotational C$2$ lines constrain thegas-kinetic temperature T and the density n=nH+nH$2$ of the interveningcloud to T = 40$\pm$10 K and n = 250 $\pm$ 50 cm$^{-3}$, respectively. This isthe first determination of gas-kinetic temperature and particle density of acloud with known anomalous microwave emission.

Author: Susana Iglesias-Groth

Source: https://arxiv.org/