1. Structure & Magnetic Fields of the Star-Forming Region NGC 6334A
T. H. Troland
Physics & Astronomy Department
University of Kentucky, USA
OSU, June 21, 2006

2. Collaborators Elizabeth Mayo (University of Kentucky)
Nick Abel (University of Kentucky)
Anuj Sarma (DePaul University)
Goren Sandell (NASA Ames / USRA)

3. Location of NGC 6334 in the Galaxy
SHASSA
l=351.0o, b=0.7o
distance 1.7 kpc
Southern H-Alpha Sky Survey Atlas (SHASSA)

4. Location of NGC 6334 in the Galaxy
SHASSA
l=351.0o, b=0.7o
distance 1.7 kpc ?
Cat’s Paw Nebula

5. Ionized gas - (H-alpha)
5 pc
Optical H-alpha image from Antilhue Observatory, Chile, image by Daniel Verschatse
Antilhue Observatory

6. Ionized gas – 18cm radio continuum contours
5 pc
Optical H-alpha image from Antilhue Observatory, Chile, image by Daniel Verschatse
Sarma et al. 2000

7. Molecular gas – C18O, J=2-1 5 pc
H.E. Matthews, W. H. McCutcheon, G. J. White

8. Molecular gas – C18O, J=2-1 with 18 cm radio continuum contours
5 pc

9. 2MASS

10. 2MASS
With C18O, J=2-1

11. 2MASS
With C18O, J=2-1
With 18cm radio continuum contours

12. 2MASS

13. 850 
With 18cm radio continuum contours
JMCT archival data

14. NGC 6334 A
850  dust continuum, contours at 0.9, 0.7, 0.5, 0.3, 0.1  Jy/beam
With 18cm radio continuum contours
850  continuum, contours at 0.9, 0.7, 0.5, 0.3, 0.1 x 15 Jy/beam
1667 MHz continuum, contours at 0.9, 0.7, 0.5, 0.3, 0.1, 0.05, x 0.98 Jy/beam
0.5 pc

15. Column densities and masses inferred from 850  Dust emission
dust/N(H) = C computed by Cloudy (Ferland 1998)
Also, dust  (Jy/beam)/Tdust
So N(H)  (Jy/beam) / (C  Tdust)
Results for peak of 15 Jy/beam (NGC 6334 A):
N(H)peak  1  1024  (100/Td) cm-2
Av,peak  500  (100/Td) mag
Used ISM grains, Si + graphite

16. SiO, J=7-6 v = 4.5 km/s With 850  contours
Integrated SiO line with 850  contours at 0.9, 0.7, 0.5, 0.3, 0.1, 0.05, x 15 Jy/beam
v = 4.5 km/s
JMCT archival data

17. 18 cm radio continuum Northern lobe gap
1667 MHz continuum, contours at 0.9, 0.7, 0.5, 0.3, 0.1, 0.18, 0.15, 0.1, 0.05,  0.98 Jy/beam
Central shell source (2  enlarged scale)
Southern lobe
Carral et al. (2002), 3.5 cm

18. 3.3  PAH With 18cm radio continuum contours
3.3  PAH image with 1667 MHz continuum contours at 0.9, 0.7, 0.5, 0.3, 0.1, 0.18, 0.15, 0.1, 0.05,  0.98 Jy/beam
Burton et al (PAH)

19. Zeeman effect in 1665 and 1667 MHz OH absorption lines
Quasi-thermally excited OH absorption lines observed against background H+ region.
Zeeman effect reveals line-of-sight magnetic field, Blos.

20. Blos toward central shell source (G)
/home63/aipsj/emayo/BCOMB/BFIELD.ps
Note that beam for 1667 MHz is 8.3  5.1 arc sec, beam for 1665 MHz is 9.1  5.5 arc sec.
Combined 1665 & 1667 Blos - Cell size 1”, beam  8.7”  5.3
This is the combined data, 1665 and 1667 MHz B values, averaged together with weights proportional to one over the errors squared.

21. Energetics of NGC 6334 A M  1000 Msolar (850 map)
R  0.3 pc (850 map)
v  4.5 km s-1 (SiO line width)
Btot  1.2 mG (OH Zeeman data)
Gravitational energy (2T)   1047 ergs
Internal kinetic energy (W)  2.3  1047 ergs
Magnetic energy (M)  1.2  1047 ergs

22. Some Conclusions for NGC 6334 A
Northern lobe is not part of a bipolar H+ region, it is detached and separately excited.
Magnetic fields are energetically important in the molecular cloud if OH absorption samples a representative volume.