CARMA Large Area Star- formation SurveY Completing observations of 5 regions of 120-200 square arcminutes with 7” angular resolution in the J=1-0 transitions of HCO+, HCN, and N2H+ Regions are in the Perseus and Serpens molecular clouds – covered by the c2d Spitzer Legacy project which characterized the young stellar population Using CARMA to get interferometric and single-dish data to make maps of the full emission Completed last week: 600 hours total array time
Transcript
CARMA Large Area Star-formation SurveY
Completing observations of 5 regions of 120-200 square arcminutes with 7” angular resolution in the J=1-0 transitions of HCO+, HCN, and N2H+
Regions are in the Perseus and Serpens molecular clouds – covered by the c2d Spitzer Legacy project which characterized the young stellar population
Using CARMA to get interferometric and single-dish data to make maps of the full emission
Completed last week: 600 hours total array time
NGC 1333High-Activity
~100 sq. arcmin.
Barnard 1Moderate-Activity
~150 sq. arcmin. (focus of this paper)
L1451Low-Activity
~150 sq. arcmin
~3.5 pc
~5.5 pc
Composite Herschel250, 350, 500 μm view
Approximate CARMA mapping areas
N2H+ Emission Velocity Field HCN Emission
NGC 1333 SVS -13 Region HCO+ Emission
NGC 1333 SVS-13 Herschel 350 microns versus N2H+
N2H+ emission tracks the structure in the long wavelength continuum….
The bright region to the northeast is a heated area associated with a reflection nebula.
N2H+ traces gas >105 per cc and give velocity information.
Provides resolution to study individual objects in the context of the large scale cloud.
Beam size in above three maps
Perseus B1 Region
main core
central filaments
southern clumps
N2H+
HCN HCO+
Herschel 250 μm
Cloudprops(best for sparse fields)
Object Identification Methods
Molecular Cloud structure is mostly hierarchical … dendrograms avoid small-scale segmentation and
naturally capture large-scales in addition to the small-scales
vs. Dendrograms
(best for dense/blended fields)
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Capturing Large and Small Scales with Dendrogram Approach
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Moment Zero Maps of Leaves and Branches
How do larger-scale gas structures compare to smaller-scale structures?
Facilitates an investigation of the turbulent properties of dense gas at different scales in a way that clumpfind-like segmentation would not allow
LeafBranch
IRAS 2 region of NGC 1333
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Integrated Intensity Maps
0.04 pc
Results: Non-Binary Dendrogramof NGC 1333 N2H+ (1-0)
How do larger-scale gas structures compare to smaller-scale structures?
We evaluated the size and kinematics of each identified gas structure
Turbulence … across different spatial scales within a single cloud… across different clouds at different stages of evolution?
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Fitted Line Dispersion Maps
How do larger-scale gas structures compare to smaller-scale structures?
Results: Non-Binary Dendrogramof NGC 1333 N2H+ (1-0)
We evaluated the size and kinematics of each identified gas structure
Turbulence … across different spatial scales within a single cloud… across different clouds at different stages of evolution?
Results: Line Dispersion vs. Sizein NGC 1333 Gas Structures
Capturing mean internal turbulence
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 11 K and 25 K
Results: Non-Binary Dendrogram Structure
of Barnard 1 N2H+ (1-0)
Spitzer IRAC+ N2H+ outline
black = nearby protostellar outflowsred = further from outflow activity
Results: Cross-Cloud ComparisonBarnard 1
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 9 K and 12 K
vs.
NGC 1333
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 11 K and 25 K
Results: Cross-Cloud ComparisonBarnard 1
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 9 K and 12 K
vs.
NGC 1333
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 11 K and 25 K
Observe supersonic turbulence at ~0.01 – 0.5 pc scales near active
young stars
Indication that outflows are an important turbulent driver of the dense
gas at these scales
not an outflow
N2H+ moment 0HCO+ outflows
Results: Cross-Cloud ComparisonBarnard 1
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 9 K and 12 K
vs.
NGC 1333
- - - - H2 thermal dispersion N2H+ thermal dispersion … at 11 K and 25 K
Observe subsonic turbulence in filamentary regions yet to form young, active stars
… expected if these dense gas filaments formed from supersonic turbulence
Next step to probe even larger scales and make connection to lower density gas
not an outflow
• Wealth of kinematics on ~1000s of AU size scale– fully sampled spatial scales •Dendrograms used to decompose dense gas emission and explore kinematics of structures in CLASSy clouds
• Compared turbulent linewidths of NGC 1333 and B1 gas structures:• Star formation feedback correlates with supersonic turbulence at the ~0.01 – 0.5 pc scale
• B1 filament is a great region to probe turbulence driven star formation theories
Summary
Smaller Scale Magnetic Field
Simultaneously observed CO outflow
Hull et al. 2013
Smaller Scale Magnetic FieldInferred magnetic fields are more consistent with random or anti-aligned with the outflow axis.
Maybe good news for young disks (Vorobyov 2010, Joos et al. 2012, Li et al. 2013)
Hull et al. 2013
Disks? What about magnetic braking?TADPOL results for L1527 and VLA 1623– coupled with no disk
