gbt galactic hii region discovery survey dana s. balser
DESCRIPTION
GBT Galactic HII Region Discovery Survey Dana S. Balser. Collaborators. Tom Bania (Boston University). Loren Anderson ( Laboratoire d’Astrophysique de Marseille). Bob Rood (University of Virginia). HII Region Surveys. Eagle Nebula NGC 6611 M16. POSS. - PowerPoint PPT PresentationTRANSCRIPT
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GBT Galactic HII Region Discovery SurveyDana S. Balser
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Collaborators
Tom Bania (Boston University)
Bob Rood(University of Virginia)
Loren Anderson(Laboratoire d’Astrophysiquede Marseille)
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HII Region Surveys
Eagle Nebula NGC 6611 M16
POSS
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Radio Continuum Surveys
Westerhout (1958)
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Radio Recombination Lines (RRLs)
Hoglund & Mezger (1965)
Ant
enna
Tem
pera
ture
Frequency
H109
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Radio Recombination Line Surveys
Reifenstein et al. (1970)
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HII Region Emission
CO Integrated Emission (K km/s)
Simulated 30 GHz HII Region Emission (mK)Master Catalog of 1442 Objects Paladini et al. (2003)
Dame et al. (2001)
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HII Region Targets
RGB 8, 4.5, 3.6 microns RGB 24, 8, 3.6 microns
Spitzer IR MAGPIS 20cm (white contour) GRS 13CO (green contour)
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GBT HII Region Survey
)s km 0.4 v( kHz 12
arcsec 80 ~HPBW
GHz) 10-(8 H93 - H87
1 b 1- and 67 16-
cm 20 @mJy 100 Flux
cm 20 and m 24 Coincident
1-
oooo
All HII regions ionized by a single O-type star within the Solar orbit
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GBT Spectra
'5
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GBT Spectra
'5
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Longitude-Velocity Diagram
602 Detections448 Directions 95% Spiral ArmsBeyond Solar
Orbit
Nuclear Disk
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HII Region Radial Distribution
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Galactic Structure
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Summary
• Detected 602 RRLs (448 directions)• 95% of sample targets detected• Doubled number of know HII regions in
this part of the Milky Way• 25 HII regions detected beyond the Solar
orbit in the first Galactic quadrant
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Future
• Determine distances (HI E/A experiments)• Galactic structure• Galactic chemical evolution
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Additional Slides
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Spiral Arms
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3 kpc Arm (Carbon Monoxide)
0) (1 CO
Dame & Thaddeus (2008)
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3 kpc Arm (Carbon Monoxide)
Dame & Thaddeus (2008)0) (1 CO
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3 kpc Arm (Methanol Masers)
Green et al. (2009))A 6 (5 OHCH 013
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HII Region Electron Temperature Gradient
GBT 9 GHz RRL and Continuum
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HII Region Electron Temperature Gradient
oo 360 Az 330
oo 30 Az 0
oo 60 Az 30
GBT 9 GHz RRL and Continuum