Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N

Details Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N

2009-10-12

arxiv.org/abs/0910.2270v2

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

The Astrophysical Journal, 706, 1036 (2009 December 1). Minor changes to match journal version, emulateapj

Scientific paper

Spectral line and continuum observations of the ionized and molecular gas in G20.08-0.14 N explore the dynamics of accretion over a range of spatial scales in this massive star-forming region. Very Large Array observations of NH_3 at 4'' angular resolution show a large-scale (0.5 pc) molecular accretion flow around and into a star cluster with three small, bright HII regions. Higher resolution (0.4'') observations with the Submillimeter Array in hot core molecules (CH_3CN, OCS, and SO_2) and the VLA in NH_3, show that the two brightest and smallest HII regions are themselves surrounded by smaller scale (0.05 pc) accretion flows. The axes of rotation of the large- and small-scale flows are aligned, and the timescale for the contraction of the cloud is short enough, 0.1 Myr, for the large-scale accretion flow to deliver significant mass to the smaller scales within the star formation timescale. The flow structure appears to be continuous and hierarchical from larger to smaller scales. Millimeter radio recombination line (RRL) observations at 0.4" angular resolution indicate rotation and outflow of the ionized gas within the brightest HII region (A). The broad recombination lines and a continuum spectral energy distribution (SED) that rises continuously from cm to mm wavelengths, are both characteristic of the class of HII regions known as "broad recombination line objects". The SED indicates a density gradient inside this HII region, and the RRLs suggest supersonic flows. These observations are consistent with photoevaporation of the inner part of the rotationally flattened molecular accretion flow. We also report the serendipitous detection of a new NH_3 (3,3) maser.

Affiliated with

Also associated with

No associations

Rating

Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N 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 Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Formation of an O-Star Cluster by Hierarchical Accretion in G20.08-0.14 N will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-639824