Jill Rathborne: ALMA’s view of the initial conditions within a massive protocluster

The Brick / Lima Bean
  • deep extinction feature
  • Tdust 20K
  • MALT90 gas gives different T than dust + HNCO usually traces 70K gas at n~10^6 + 0.3 pc resolution
ALMA 13pt mosaic
  • 1.7", dv=3.5 km/s, 20 microJy/bm
  • column pdf is fairly lognormal + tiny excess on the tail + tail is only location of active SF
  • lognormal is predicted...
  • will form stars (already forming some)
Gallery of data
  • rgb slice movies
  • cold absorption filaments + huge aspect ratio & line width + only seen in HCO+ + approximately perpendicular to polarization

Questions

  • Q Mitch: Any qualtitative feel for the bulk velocity field? Rotation, shear, compression?
  • A: Probably shear.
  • Q: Estimate mach number of shocks?
  • A: yes can but haven't yet.
  • A Steve: M~70
  • Q: Column to volume densities. What range?
  • A: 10^6 cm^-3 from the dust, up to 10^7
  • A: Only one transition of each molecule, haven't done local density estimates
  • Q Lang: Is the absorption filament a continuum feature?
  • A: Doesn't line up with anything in particular.
  • A Betsy: There's a parallel filament.
  • Q Farhad: What is happening at the one site of SF?
  • A: 80 blobs throughout the cloud, sizes ~0.3 pc, masses 10-100 msun. 1 water maser with 85 msun. No YSO correspondence

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