2019A&A...632A.115G

In order to search for further observational evidence of cloud-cloud collisions in one of the promising candidates, L1188, we carried out observations of multiple molecular lines toward the intersection region of the two nearly orthogonal filamentary molecular clouds in L1188. Based on these observations, we find two parallel filamentary structures, both of which have at least two velocity components being connected with broad bridging features. We also found a spatially complementary distribution between the two molecular clouds, as well as enhanced ¹³CO emission and ¹²CO self-absorption toward their abutting regions. At the most blueshifted velocities, we unveil a 1pc-long arc ubiquitously showing ¹²CO line wings. We discover two 22GHz water masers, which are the first maser detections in L1188. An analysis of line ratios at a linear resolution of 0.2pc suggests that L1188 is characterised by kinetic temperatures of 13-23K and H₂ number densities of 10³-10^3.6cm^–3. On the basis of previous theoretical predictions and simulations, we suggest that these observational features can be naturally explained by the scenario of a cloud-cloud collision in L1188, although an additional contribution of stellar feedback from low-mass young stellar objects cannot be ruled out.