[Ne II] Observations of Gas Motions in Compact and Ultracompact H II Regions

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

79 pages, 48 figures, 2 tables, accepted for publication in The Astrophysical Journal Supplement. The orders of figure 47 and

Scientific paper

10.1086/588731

We present high spatial and spectral resolution observations of sixteen Galactic compact and ultracompact H II regions in the [Ne II] 12.8 microns fine structure line. The small thermal width of the neon line and the high dynamic range of the maps provide an unprecedented view of the kinematics of compact and ultracompact H II regions. These observations solidify an emerging picture of the structure of ultracompact H II regions suggested in our earlier studies of G29.96-0.02 and Mon R2 IRS1; systematic surface flows, rather than turbulence or bulk expansion, dominate the gas motions in the H II regions. The observations show that almost all of the sources have significant (5-20 km/s) velocity gradients and that most of the sources are limb-brightened. In many cases, the velocity pattern implies tangential flow along a dense shell of ionized gas. None of the observed sources clearly fits into the categories of filled expanding spheres, expanding shells, filled blister flows, or cometary H II regions formed by rapidly moving stars. Instead, the kinematics and morphologies of most of the sources lead to a picture of H II regions confined to the edges of cavities created by stellar wind ram pressure and flowing along the cavity surfaces. In sources where the radio continuum and [Ne II] morphologies agree, the majority of the ionic emission is blue-shifted relative to nearby molecular gas. This is consistent with sources lying on the near side of their natal clouds being less affected by extinction and with gas motions being predominantly outward, as is expected for pressure-driven flows.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

[Ne II] Observations of Gas Motions in Compact and Ultracompact H II Regions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with [Ne II] Observations of Gas Motions in Compact and Ultracompact H II Regions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and [Ne II] Observations of Gas Motions in Compact and Ultracompact H II Regions will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-351870

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.