Search

Far-infrared polarimetric observations reveal a transition parallel to the gas flow in the orientation of magnetic field lines in the Serpens South molecular cloud, allowing gravitational collapse to occur even in the presence of strong magnetic fields. Observations indicate that molecular clouds are strongly magnetized, and that magnetic fields influence the formation of stars. A key observation supporting the conclusion that molecular clouds are significantly magnetized is that the orientation of their internal structure is closely related to that of the magnetic field. At low column densities, the structure aligns parallel with the field, whereas at higher column densities, the gas structure is typically oriented perpendicular to magnetic fields, with a transition at visual extinctionsA(V) greater than or similar to 3 mag. Here we use far-infrared polarimetric observations from the HAWC+ polarimeter on SOFIA to report the discovery of a further transition in relative orientation, that is, a return to parallel alignment atA(V) greater than or similar to 21 mag in parts of the Serpens South cloud. This transition appears to be caused by gas flow and indicates that magnetic supercriticality sets in nearA(V) greater than or similar to 21 mag, allowing gravitational collapse and star cluster formation to occur even in the presence of relatively strong magnetic fields.

Far-infrared polarimetric observations reveal a transition parallel to the gas flow in the orientation of magnetic field lines in the Serpens South molecular cloud, allowing gravitational collapse to occur even in the presence of strong magnetic fields. Observations indicate that molecular clouds are strongly magnetized, and that magnetic fields influence the formation of stars. A key observation supporting the conclusion that molecular clouds are significantly magnetized is that the orientation of their internal structure is closely related to that of the magnetic field. At low column densities, the structure aligns parallel with the field, whereas at higher column densities, the gas structure is typically oriented perpendicular to magnetic fields, with a transition at visual extinctionsA(V) greater than or similar to 3 mag. Here we use far-infrared polarimetric observations from the HAWC+ polarimeter on SOFIA to report the discovery of a further transition in relative orientation, that is, a return to parallel alignment atA(V) greater than or similar to 21 mag in parts of the Serpens South cloud. This transition appears to be caused by gas flow and indicates that magnetic supercriticality sets in nearA(V) greater than or similar to 21 mag, allowing gravitational collapse and star cluster formation to occur even in the presence of relatively strong magnetic fields.