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SUMMARY:The early stages of low-mass star formation: subsonic turbulence\,
  isothermal filaments and a First Hydrostatic Core Candidate - Jaime Pined
 a (Jodrell Bank Centre for Astrophysics\, University of Manchester)
DTSTART:20120313T163000Z
DTEND:20120313T170000Z
UID:TALK36512@talks.cam.ac.uk
CONTACT:David Titterington
DESCRIPTION: Low-mass stars are formed in Dense Cores\, via gravitational 
 collapse.  However\, the formation process of Dense Cores is not clear.  I
  will present single dish observations in a dense gas tracer (NH3 using th
 e GBT) of four regions in the nearby Perseus Molecular Cloud.  These data 
 show\, for the first time in a single tracer\, the transition between the 
 subsonic dense core and the dense but more turbulent gas surrounding it.  
 This transition is sharp and unresolved\, very similar to a shock.  It is 
 possible that these subsonic structures are needed stage for the star-form
 ation process to take place (at least in low-mass).\n   I will also presen
 t NH3 EVLA+GBT observations of the Barnard 5 region with a 6” beam.  The
  observations reveal\, for the first time\, the presence of striking filam
 entary structure (20” wide of 5\,000 AU at the distance of Perseus) in t
 his low-mass star-forming region.  The integrated intensity profile of thi
 s structure is consistent with models of an isothermal filament in hydrost
 atic equilibrium.  Also\, the observed separation between the B5-IRS1 youn
 g stellar object (YSO)\, in the central region of the core\, and the north
 ern starless condensation matches the Jeans length of the dense gas.  This
  suggests that the dense gas in the coherent region is fragmenting.  The r
 egion observed displays a narrow velocity dispersion\, where most of the g
 as shows evidence for subsonic turbulence\, and where little spatial varia
 tions are present.  It is only close to the YSO where an increase in the v
 elocity dispersion is found\, but still displaying subsonic non-thermal mo
 tions.\n   Finally\, if there is enough time\, I will briefly present inte
 rferometric follow-up results in one of the regions studied with the GBT. 
  I will present the evidence for a central source\, a slow-velocity outflo
 w\, and the modelling efforts that suggests the presence of a First Hydros
 tatic Core candidate.\n
LOCATION:Ryle Seminar Room\, Cavendish Laboratory
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