Abstract
Aims. The physics of star formation is an important part of Galactic evolution. Most stars are formed in high-density environments (n > 10(4) cm(-3)) and emit lines of diverse molecular transitions. In the present part of our survey we search for ammonia emitters in the Aquila rift complex, which trace the densest regions of molecular clouds.
Methods. From a CO survey carried out with the Delingha 14-m telescope we selected similar to 150 targets for observations in other molecular lines. Here we describe the mapping observations in the NH3(1, 1) and (2, 2) inversion lines of the first 49 sources performed with the Effelsberg 100-m telescope.
Results. The NH3(1, 1) emission lines are detected in 12 and the (2, 2) in 7 sources. Among the newly discovered NH3 sources, our sample includes the following well-known clouds: the starless core L694-2, the Serpens cloud cluster B, the Serpens dark cloud L572, the filamentary dark cloud L673, the isolated protostellar source B335, and the complex star-forming region Serpens South. Angular sizes between 40 '' and 80 '' (similar to 0.04-0.08 pc) are observed for compact starless cores but can be as large as 9' (similar to 0.5 pc) for filamentary dark clouds. The measured kinetic temperatures of the clouds lie between 9 K and 18 K. From NH3 excitation temperatures of 3-8 K we determine H-2 densities with typical values of similar to(0.4-4) x 10(4) cm(-3). The masses of the mapped cores range between similar to 0.05 and similar to 0.5 M-circle dot. The relative ammonia abundance X = [NH3]/[H-2] varies from 1 x 10(-7) to 5 x 10(-7) with the mean < X > = (2.7 +/- 0.6) x 10(-7) (estimated from spatially resolved cores assuming a filling factor of eta = 1). In two clouds, we observe kinematically split NH3 profiles separated by similar to 1 km s(-1). The splitting is most likely due to bipolar molecular outflows, for one of which we determine an acceleration of (V) over dot less than or similar to 0.03 km s(-1) yr(-1). A starless core with significant rotational energy is found to have a higher kinetic temperature than the other ones, which is probably caused by magnetic energy dissipation.