Abstract. We identified new pre-main sequence stars in the region of high-latitude molecular clouds associated with the reflection nebula IC 2118, around l ∼ 208• and b ∼ −27• . The stars were selected as T Tauri candidates in objective prism plates obtained with the Schmidt telescope of Konkoly Observatory. Results of spectroscopic follow-up observations, carried out with the FLAIR spectrograph installed on the UK Schmidt and with ALFOSC on Nordic Optical Telescope, are presented in this paper. Based on spectral types, presence of emission lines and lithium absorption line, we identified five classical T Tauri stars and a candidate weak-line T Tauri star projected on the molecular clouds, as well as two candidate pre-main sequence stars outside the nebulous region. Using the near infrared magnitudes obtained from the 2MASS All Sky Catalog (IPAC 2003) we determined the masses and ages of these stars. We found that the five classical T Tauri stars projected on the clouds are physically related to them, whereas the other stars are probably background objects. Adopting a distance of 210 pc for IC 2118 (Kun et al. 2001) and using Palla & Stahler's (1999) evolutionary tracks we derived an average age of 2.5 × 10 6 yrs and a mass interval of 0.4-1.0 M for the members of the IC 2118 association.

Aims. We investigate the structure and velocity of cold molecular pillars, "elephant trunks", in expanding H ii regions.Methods. The trunks are seen in silhouette against the bright background in our Hα images. All trunks are filamentary, and show signs of being twisted. Four such trunks in NGC 7822, IC 1805, the Rosette Nebula, and DWB 44 were selected, and then mapped mainly in 12 CO and 13 CO. We determine the mass and density of the trunks. Most of the mass is concentrated in a head facing the central cluster, and in sub-filaments forming the body of the trunk that is connected to V-shaped filaments to the outer expanding shell. Results. We discovered that all four trunks rotate as rigid bodies (to a first approximation) about their major axes, and that at least two trunks are stretching along their major axes, meaning that the massive heads are lagging behind in the general expansion of the H ii regions. The rotational periods are of the order of a few million years -similar to the age of the clusters. Rotation, then, is responsible for the twisted appearance of many elephant trunks, since they are rooted in the outer shells. The trunks carry surprisingly large amounts of angular momentum, 3 × 10 48 −2 × 10 50 kg m 2 s −1 , with corresponding rotational energies of up to ∼10 37 J. However, we estimate the total magnetic energies to be even larger. The trunks continuously reshape, and the formation of twined, and in many cases helical, sub-filaments can be understood as a consequence of electromagnetic and inertia forces inside the trunks. A theory based on the concept of magnetically twisted trunks is developed further, where the initial angular momentum is a consequence of the twisting of parent filaments containing mass condensations. Our results also suggest a new process of removing angular momentum from parent molecular clouds.

We have carried out submillimeter 12 CO(J ¼ 3Y2) observations of six giant molecular clouds (GMCs) in the Large Magellanic Cloud (LMC) with the ASTE 10 m submillimeter telescope at a spatial resolution of 5 pc and very high sensitivity. We have identified 32 molecular clumps in the GMCs and revealed significant details of the warm and dense molecular gas with n(H 2 ) $ 10 3 Y10 5 cm À3 and T kin $ 60 K. These data are combined with 12 CO(J ¼ 1Y0) and 13 CO(J ¼ 1Y0) results and compared with LVG calculations. The results indicate that clumps that we detected are distributed continuously from cool ($10Y30 K) to warm (k30Y200 K), and warm clumps are distributed from less dense ($10 3 cm À3 ) to dense ($10 3.5 Y10 5 cm À3 ). We found that the ratio of 12 CO(J ¼ 3Y2) to 12 CO(J ¼ 1Y0) emission is sensitive to and is well correlated with the local H flux. We infer that differences of clump properties represent an evolutionary sequence of GMCs in terms of density increase leading to star formation. Type I and II GMCs (starless GMCs and GMCs with H ii regions only, respectively) are at the young phase of star formation where density does not yet become high enough to show active star formation, and Type III GMCs (GMCs with H ii regions and young star clusters) represent the later phase where the average density is increased and the GMCs are forming massive stars. The high kinetic temperature correlated with H flux suggests that FUV heating is dominant in the molecular gas of the LMC.