- VLA Survey
DnC at 24-36 GHz
Brick NH3 + very high temperatures in brick: 100's of K + optically thin 4-4,5-5,7-7 + brightest, densest clumps have lowest temperatures + 300K gas, but no SF
- CR heating?
- Shock heating?
36 GHz methanol maser + shock excited + dozens of point sources + 75 candidates, 29 T_B > 1000K (masing)
why so many masers? + large-scale shocks? + 80 km/s velocity gradient across cloud + methanol & ammonia emission dominated by convergence point of velocities
class I methanol masers usually show SF
- SF in the Brick?
- 7 VLA continuum sources + peaks in a more distributed set of continuum emission
- 25 GHz continuum + most continuum outside of the molecular gas + external ionization
- Rest of the CMZ
- Pistol & Quintuplet continuum with streaks from the nonthermal filaments + second LBV seen in radio
- NH3 near Sgr A* + NH3 traces edges of Sgr A East SNR + some SF in 50km/s cloud and 20km/s cloud
- CND not in HC3N, weakly in ammonia
- no NH3 or HC3N at brightest submm clump
- nonthermal 3-3 line
- Sgr B2
- CH3OH only non-self-absorbed against hot core + shell structure
- NH3 2-2 maser
Questions
- Q Walsh: NH3 3-3 maser. Expected more of those. Were there others?
- A: yes, there are at least 2 others
- Q: Temperatures of ammonia. Is ammonia the only tracer that gives high temperature towards the Brick?
- A: Yes, only one towards brick. 400-600K from H2 from Rodriguez-Fernandez. 400K in Sgr A from NH3 too.
- Q: Formation pumping?
- A: yes, possible. Need to form on short timescales.
- Q: Need hefty CR for that heating. Can you expand on what VLA is good for?
- A: CRs 10^-14, 10^-15. May happen. Hard to explain 100's K
- A: VLA gets NH3 transitions for temperatures. ALMA gives density. VLA gives free-free. No overlap in frequency
- Q: Is the brick a cloud? Is this really a transient colliding flow?
- A: I don't claim that it's bound.