Detalles de publicación

PP 010068

Interstellar C_2 in the Perseus molecular complex: excitation temperature and density of a molecular cloud with anomalous microwave emission.

Iglesias-Groth, Susana
Instituto de Astrofis\'{\i}ca de Canarias, 38200 La Laguna, Tenerife, Canary Islands, Spain Universidad de La Laguna, E-38205 La Laguna, Tenerife, Spain
Interstellar absorption lines up to J"=10 in the (2,0) band and up to J"=6 in the (3,0) band of the C_2 A^1 Pi_u - X^1 Sigma^+_g system are detected toward star Cernis 52 (BD+31^o 640) in the Perseus molecular complex. The star lies in a redenned line of sight where various experiments have detected anomalous microwave emission spatially correlated with dust thermal emission. The inferred total C$_2$ column density of N(C_2) = (10.5$ pm 0.2) x 1013 cm^-2 is well correlated with that of CH as expected from theoretical models and is among the highest reported on translucent clouds with similar extinction. The observed rotational C$_2$ lines constrain the gas-kinetic temperature T and the density n=n(H)+n(H_2) of the intervening cloud to T = 40pm 10 K and n = 250 pm 50 cm^-3, respectively. This is the first determination of gas-kinetic temperature and particle density of a cloud with known anomalous microwave emission.

Aceptado para publicación en MNRAS | Enviado el 2010-10-01 | Proyecto 3E4407