supervisors: maria cunningham (unsw), james urquhart (csiro) michael burton (unsw) collaborators:...
TRANSCRIPT
Chemical conditions within the G333 Giant Molecular Cloud
Supervisors: Maria Cunningham (UNSW), James Urquhart (CSIRO)
Michael Burton (UNSW)
Collaborators: Nadia Lo (UNSW/CSIRO), Bhaswati Mookerjea (Tata Institute)
Great Barriers in High Mass Star Formation, 14th September 2010
Vicki Lowe
University of New South WalesCSIRO Astronomy and Space Science
Motivation
“Low mass stars are like weeds in the Galaxy” – Tom Megeath
Characterising turbulence in molecular clouds (power spectrum analysis, D-variance analysis)
Following molecular abundances through an entire cloud complex (e.g. principal component analysis, Lo et al., 2009; 13CO & masers, Breen et al., 2007)Vicki Lowe UNSW/CSIRO
Great Barriers in High Mass Star Formation, 14th September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
Spitzer GLIMPSE: 3.6 µm (blue, starlight), 4.5 µm (green, shocked gas), 8.0 µm (red, ionised HII regions)
Within the Galactic Molecular Ring, 3.6 kpc away
13CO Bains et al. (2006)
C18O Wong et al. (2008)
The G333 Giant Molecular Cloud
b
l
Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
1.2 mm dust continuum Mookerjea et al. (2004)
HII region (RCW 106)Green Fuzzy
Motivation G333 GMC CLUMPFIND Abundances EGOs
The G333 Giant Molecular Cloud
Dust continuum
SIMBA on SEST 1.2 mm dust continuum
Cool, dense gas tracer
Molecules are complex depletion,
excitation Use millimetre
continuum to create a mask for molecules
Mookerjea et al. (2004)
Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
Clump analysis
1.2 mm continuum dust clumps was used as a mask to compare all molecular data
STARLINK (http://starlink.jach.hawaii.edu)
Clump identification algorithms CLUMPFIND, GAUSSCLUMP, FELLWALKER, REINHOLD
63 dust clumps were identified (3σ cut-off)
CLUMPFIND
Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
Chemical comparisons (i)/C18O 13CO HCN CS HNC HCO+ N2H+
Mean 6.2 0.8 0.7 0.6 0.6 0.5
Median 5.7 0.8 0.7 0.6 0.6 0.5
Stdev 1.5 0.2 0.7 0.4 0.2 0.5
Min 4.5 0.7 0.2 0.3 0.5 0.2
Max 13.1 1.0 1.3 0.9 0.7 0.9
% detect 100% 100% 100% 100% 100% 100%
Optically thinUbiquitous gas tracer
High density tracer
n ~ 104 cm-3
Dense cold (< 20 K)
gas tracern ~ 105 cm-3
Outflow & inflow tracer
Cold dense quiescent gas
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Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
Chemical comparisons (ii)
/C18OHC3N(10-
9)HC3N(11-
10)C2H SiO SO
Mean 0.2 0.1 0.2 0.1 0.2
Median 0.2 0.1 0.2 0.1 0.2
Stdev 0.1 0.3 0.1 0.2 0.0
Min 0.1 -0.1 0.1 0.0 0.2
Max 0.2 0.3 0.2 0.2 0.2
% detect 70% 40% 40% 30% 30%
High density (n ~ 106 cm-3)
tracer &Hot core molecule
Photodissociation regions
Shocked gas
High density (n ~ 106 cm-3)
tracer &Chemical
clock
Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
EGOs / Green FuzziesMotivation G333 GMC CLUMPFIND Abundances EGOs
C2H – PDRs
N2H+ – Cold, dense quiescent gas
tracer
SummaryThe Mopra G333 Survey mapped
approx. 20 different molecular transitions
Used 1.2 mm continuum dust clumps as a mask to compare all molecular data
CLUMPFIND with 3σ cut-off produced 63 millimetre continuum clumps
Variety of chemical conditions e.g. green fuzzies
Thank you Poster #37 Vicki Lowe UNSW/CSIROGreat Barriers in High Mass Star Formation, 14th
September 2010
Motivation G333 GMC CLUMPFIND Abundances EGOs
Website: www.phys.unsw.edu.au/~mariac/dqs/dqs.html