Adam Ginsburg's blog

Mordecai Mac-Low: Stellar Feedback

SNe explode away from their birthplaces

ionizing radiation contains 10x more energy than SNe
outer disk SF inadequate to explain kinetic energy observed
"almost constant velocity dispersion in HI in local universe"
ionization escape determined within 1pc (Peters) + fragmentation starvation
At high mass, high escape velocity, there is less unbound material
stellar winds relatively unimportant because of their rarity + B-stars give SNe, but not wind

Radiation Pressure

more effective if more scattering + Krumholz & Matzner, Fall: Momentum Driven (0-1 scatterings) + Thomson, Murray, Hopkins: Energy Driven (many-scattering)
Multi-scattering fails: RT instability + scattered radiation never dominant
Lopez 2013: HII-region pressure always dominant; hot gas slightly lower
Q Fan of CR driven winds. Galactic winds are multi-phase. Thoughts?
A:
Q Thomas Henning: What about positive feedback?
A: Will be addressed in next talk. But, positive feedback is a 10% effect

HI GASS + 12CO

effect of supershells on molecular gas fraction + shells are more molecular than surroundings
LMC: supergiant shells have comparable molecular gas fraction to the rest of the gas + Large scale: No effect + small scale: drive up local molecular gas fraction
OB cluster feedback: Not a major driver, but an important secondary role
Q Zinnecker: How did 30 Dor form?

The time between first O-stars and first SNe

mass loss is a strong effect of escape speed
Leakage? Approximate winds as momentum fluxes + leakage rate constant across M/R space
Effect of 1st SN? + no effect/small effect for high-mass clouds

Do you have predictions for velocity of knots as a function of distance or time? Rocket effect? Can "Rocket Effect" drive out gas?

Pipe Nebula affected by feedback O vs B star

B-star does not generate structure + heats shell + stays very smooth

O-star compresses

Cannot reproduce HI velocity dispersion

HII region morphologies

no relation between age of star and size of HII region
probabilistic flux decrements
SgrB2: 1 shrinking, 2-3 growing + predictions & observations match exactly
ALMA outflow predictions
K 3-50A VLA + CARMA observations + Pamela Klaasen 14.7 GHz obs of K3-50a + ionized gas entraining molecular gas
models do not include dust absorption

ALMA proposal for Sgr B2? Prediction for 3mm observability?

Observations that aren't explained by expanding shell

supersonic velocities in HII region
SED indicates density gradients
Modified Hollenbach photoevaporating disk model + velocity gradient of RRL not tied to disk or outflow + "Ballistic Infall" model
Q: Look similar to simulations of champagne flows.

Carina:

HAWK-I NIR stellar population study
CCCP Chandra 10,000 stars
60,000 msun in gas
10^6 msun total... half cold
300,000 msun of CO
1% of total SF in galaxy
G0 ~100-1000
hot wind gas (X-ray) flows out: anticorrelated with 70um Herschel
Q How do you know SFE is increasing (currently 3%)?
A: We see it going on now. Stellar mass is increasing. Efficiency must increase further.
Q Nicola Schneider: What if the pillars are eroded filaments? Revealed, not triggered?
A: Same mechanism? (unclear)
Q Hennebelle: Where is most of the mass? only 1/3 in CO?
A: 1/2 - 2/3 still in atomic gas

Bow shocks from runaway RSGs

25% of O-stars ejected