John Bally - Hi-Gal CMZ

Summary of Hi-Gal:
  • 900hrs,
  • inner ±60 deg, then outer ±60 deg, then full 360 deg.
  • Release scheduled late in 2013.
  • 0.5 million band-merged sources

The CMZ:

  • we live in a mildly barred galaxy
  • NGC 1097 as an analog
  • our CMZ less symmetric

Multiwave comparison:

  • asymmetry: 24, 70 right; gas left
  • snrs, evolved stars, nonthermal filaments, arched filaments...

The Gas:

  • 10^7 Msun

  • CMZ clouds more massive, more turbulent

  • Cold gas to the left of Sgr B2, warmer to the right

  • Column density somewhat flat from l=1.5 to l=0 + "Optically thick as a brick"

  • Molinari "ring" - column density, some evidence from velocities + vertical oscillation = 2x circular speed + offset... + predicts Sgr B2 at tangent of ring

    • velocity of Sgr B2 too slow
    • Sgr B2 has significant proper motion: 80 km/s
    • Molinari ring falsified: must extend to larger long

  • Few point sources in the Arched Filaments

Sofue-Handa ('84) lobe:
  • brightest super-bubble in galaxy
  • powered by AGN or starburst?
  • Warning: Lots of foreground towards CMZ. + Sco-Cen group + radio emission associated with wall of scocen
Sgr B2 spectroscopy:
  • Two temperature components in Sgr B2
  • PACS sees 300K CO

Sgr C mention

Bania's clump
  • 200 km/s linewidth
The Brick
  • most extreme IRDC
  • 24, 70 opaque
  • HCO+ cubes
Dust
  • Are dust grains different?
  • Temperature differs between gas and dust
Questions:
  • COMMENT: NGC 1068 has 100 pc molecular ring, will mention later in discussion
  • Lang: Sources in arched filaments - are they aligned with filament?
  • A: Yes, 50-60 in filament. SEDs look like protostars.
  • Jerry (?): Note - hard to avoid conical wind from Sgr A* dynamically.
  • Bally: Yes. High-latitude CO gas off-plane: entrained. Starburst likely, AGN unlikely to entrain it.
  • Jay Gallagher: M82 energy density ~100x higher than in MW, driving wind out of smaller potential. Galaxy requires huge pressure change.
  • Bally: Yes, wimpy nucleus
  • Michael: Evidence for bar from cobe & spitzer. Is it related to gas bar?
  • Bally: Related. Gas bar 20 ±3 from line of sight, but infrared stellar bar more like 45 degrees. Why offset? controversial. Generically related.

Comments