Massive molecular outflows at high spatial resolution

We present high-spatial resolution Plateau de Bure Interferometer CO(2-1) and SiO(2-1) observations of one intermediate-mass and one high-mass star-forming region. The intermediate-mass region IRAS20293+3952 exhibits four molecular outflows, one being as collimated as the highly collimated jet-like outflows observed in low-mass star formation sources. Furthermore, comparing the data with additional infrared H2 and cm observations we see indications that the nearby ultracompact HII region triggers a shock wave interacting with the outflow. The high-mass region IRAS19217+1651 exhibits a bipolar outflow as well and the region is dominated by the central driving source. Adding two more sources from the literature, we compare position-velocity diagrams of the intermediate- to high-mass sources with previous studies in the low-mass regime. We find similar kinematic signatures, some sources can be explained by jet-driven outflows whereas other are better constrained by wind-driven models. The data also allow to estimate accretion rates varying from a few times 10^{-5}Msun/yr for the intermediate-mass sources to a few times 10^{-4}Msun/yr for the high-mass source, consistent with models explaining star formation of all masses via accretion processes.Comment: 14 pages text, 4 tables, 8 figures, accepted for Ap

SB62-12/13: Amending House Rules

SB62-12/13: Amending House Rules. This resolution passed 21Y-4N on a roll call vote during the March 13, 2013 meeting of the Associated Students of the University of Montana (ASUM)

The chemistry of fluorine-bearing molecules in diffuse and dense interstellar gas clouds

We present a theoretical investigation of the chemistry of fluorine-bearing molecules in diffuse and dense interstellar gas clouds. The chemistry of interstellar fluorine is qualitatively different from that of any other element, because - unlike the neutral atoms of any other element found in diffuse or dense molecular clouds - atomic fluorine undergoes an exothermic reaction with molecular hydrogen. Over a wide range of conditions attained within interstellar gas clouds, the product of that reaction - hydrogen fluoride - is predicted to be the dominant gas-phase reservoir of interstellar fluorine nuclei. Our model predicts HF column densities ~ 1.E+13 cm-2 in dark clouds and column densities as large as 1.E-11 cm-2 in diffuse interstellar gas clouds with total visual extinctions as small as 0.1 mag. Such diffuse clouds will be detectable by means of absorption line spectroscopy of the J = 1 - 0 transition at 243.2 micron using the Stratospheric Observatory for Infrared Astronomy (SOFIA) and the Herschel Space Observatory (HSO). The CF+ ion is predicted to be the second most abundant fluorine-bearing molecule, with typical column densities a factor ~ 100 below those of HF; with its lowest two rotational transitions in the millimeter-wave spectral region, CF+ may be detectable from ground-based observatories. HF absorption in quasar spectra is a potential probe of molecular gas at high redshift, providing a possible bridge between the UV/optical observations capable of probing H2 in low column density systems and the radio/millimeter-wavelength observations that probe intervening molecular clouds of high extinction and large molecular fraction; at redshifts beyond ~ 0.3, HF is potentially detectable from ground-based submillimeter observatories in several atmospheric transmission windows.Comment: 34 pages, including 11 figures (10 color), accepted for publication in Ap

SB77-12/13: Amending the ASUM Constitution

SB77-12/13: Amending the ASUM Constitution. This resolution passed during the April 10, 2013 meeting of the Associated Students of the University of Montana (ASUM)

SB97-12/13: Amending Bylaws

SB97-12/13: Amending Bylaws. This resolution passed during the May 8, 2013 meeting of the Associated Students of the University of Montana (ASUM)

SB101-12/13: Amending House Rules

SB101-12/13: Amending House Rules. This resolution passed during the May 8, 2013 meeting of the Associated Students of the University of Montana (ASUM)

SB99-12/13: Amending Bylaws

SB99-12/13: Amending Bylaws. This resolution passed during the May 8, 2013 meeting of the Associated Students of the University of Montana (ASUM)

SB55-12/13: Amending Fiscal Policy

SB55-12/13: Amending Fiscal Policy. This resolution passed with unanimous consent during the February 13, 2013 meeting of the Associated Students of the University of Montana (ASUM)