Whether high mass stars continue to accrete material beyond the formation of an HII region is still an open question. Ionized infall and outflow have been seen in some sources, but their ties to the surrounding molecular gas are not well constrained.
We aim to quantify the ionized and molecular gas dynamics in a high mass star forming region (K3-50A) and their interaction. We present CARMA observations of the 3mm continuum, H41alpha, and HCO+ emission, and VLA continuum observations at 23 GHz and 14.7 GHz to quantify the gas and its dynamics in K3-50A. We find large scale dynamics consistent with previous observations. On small scales, we find evidence for interaction between the ionized and molecular gas which suggests the ionized outflow is entraining the molecular one. This is the first time such an outflow entrained by photo ionized gas has been observed. Accretion may be ongoing in K3-50A because an ionized bipolar outflow is still being powered, which is in turn entraining part of the surrounding molecular gas. This outflow scenario is similar to that predicted by ionization feedback models.
Many of the proposed future applications of graphene require the controlled introduction of defects into its perfect lattice. Energetic ions provide one way of achieving this challenging goal. Single heavy ions with kinetic energies in the 100 MeV ra
nge will produce nanometer-sized defects on dielectric but generally not on crystalline metal surfaces. In a metal the ion-induced electronic excitations are efficiently dissipated by the conduction electrons before the transfer of energy to the lattice atoms sets in. Therefore, graphene is not expected to be irradiation sensitive beyond the creation of point defects. Here we show that graphene on a dielectric substrate sustains major modifications if irradiated under oblique angles. Due to a combination of defect creation in the graphene layer and hillock creation in the substrate, graphene is split and folded along the ion track yielding double layer nanoribbons. Our results indicate that the radiation hardness of graphene devices is questionable but also open up a new way of introducing extended low-dimensional defects in a controlled way.
