The Physics of Galaxy Formation. Daniel Ceverino (NMSU/Hebrew U.) Anatoly Klypin, Chris Churchill, Glenn Kacprzak (NMSU) Socorro, 2008

A too massive and concentrated spheroid Abadi et al. 2003, 500 pc force resolution, 10 5 particles. Governato, Mayer, Brook 2008, 300 pc resolution, particles

Flat rotation curves are still the most sensitive test for feedback models Ceverino & Klypin 2007 Resolution 45 pc. Thermal stellar feedback + runaway stars Combination of resolution and feedback improves the rotation curves 85 % of stars at 3R d MW-progenitor at z=3. Scale-length: R d =1.4 Kpc R vir = 40 Kpc M vir = M  M * = M  Fraction of cold baryons (stars and cold gas) inside R vir is 0.5 universal = 0.5 bar / m Radius / Scale-length Total DM Baryons Stars Gas

Stellar Feedback Thermal energy from stellar winds and supernova explosions. Feedback heating vs radiative cooling

In the beginning… Rosette Nebula there was an Overheated, Overpressure, bubble expanding in a molecular cloud Overpressure Cavity 40 pc Expands !!

Feedback: two conditions 1) Create overpressured region: Heating > Cooling Difficult to satisfy this condition for T gas > 10 4 K; need very low gas density. Temperature regime K is crucial for initial stage of formation of superbubbles 2) Pressure gradient > gravity force: AntiJeans regime Limits on resolution: X < 70pc Need balance of force resolution X and threshold of star formation nH

Champagne flow Molecular clouds 40 pc 10 pc 10 7 degrees gas X-rays from Chandra (Townsley et al. 2003) M17, Horseshoe Nebula

Modeling ISM with 8 pc resolution: Kpc-scale outflows Wave accelerates on declining density Early stages of evolution: first star cluster dumps its energy 4 Kpc

Our implementation Ceverino & Klypin 2007 Kravtsov ART hydro code: Physical processes included: AMR shock capturing hydro metallicity-dependent cooling + UV heating (Haardt & Madau). CLOUDY. Compton cooling Temperature range for cooling: 10 2 K K Jeans length resolved with 4 cells Energy release from stellar winds+ SNII +SNI Thermal feedback: most * form at T 10cm -3 Runaway stars: massive stars move with exp(-v/17km/s)   =2-20 Myr  = Myr Effective Mass consumption rate per free-fall time averaged over gas “molecular” gas (n>30cm -3 ) is 0.03

A piece of a galactic disk 4 Kpc 8 pc resolution Projected density

Projection to the disk planeProjection along the disk plane 4 kpc Advanced stages: fully turbulent ISM Projected density

Super-bubbles and galactic chimneys The effect of the stellar feedback in the ISM (Ceverino & Klypin 2007): A multiphase medium: Cold (T 10 4 K) gas. 14 pc resolution 8 pc resolution 4x4 Kpc 2 Slices perpendicular to the disk plane

Ceverino & Klypin 2007 z=3.5 Major progenitor. 45 pc resolution Face-on view SFR =10Msun/year 400 kpc proper Slice of gas density Cold Flow regime Cosmology: formation of MW galaxy

14 Ceverino & Klypin 2007z=3.5 Major progenitor of MW. 45 pc resolution Face-on view 400 kpc proper Slice of temperature Cold Flow regime

Ceverino & Klypin 2007z=3.5 Major progenitor of MW. 45 pc resolution Face-on view 400 kpc proper Cold Flow regime V max =1000 km/s Slice of gas velocity: Log scale in km/s

Ceverino & Klypin 2007 z=3.5 Major progenitor of MW. 45 pc resolution Face-on view 100 kpc proper Gas velocity Log scale V max =1000 km/s

Ceverino & Klypin 2007 z=3.5 Major progenitor of MW. 45 pc resolution Face-on view 100 kpc proper Gas velocity In the horizontal direction. VxVx

Growth of a disk after a major merger After merger (z=3.5) Before merger (z=5) After merger (z=3.5) Before merger (z=5) R d =1.4 Kpc R d =0.7 Kpc Surface density of starsCircular velocity The disk grows in mass and size after a merger

19 60 kpc z=1.3 Dwarf galaxy: Vmax =50km/s outflow= 2000 km/s Edge-on view Log (V)Density SNII metallicity

Temperature Dwarf starburst galaxy (M82 analog): z=2 V c =70 km/s 500 km/s outflow (jet) 50 Kpc combined Hubble, Spitzer, Chandra image of M82 Density Log(Velocity)

Outflows extend to large distances

Conclusions Stellar feedback maintains a 3-phase ISM. It generates super-bubbles and galactic chimneys. Cosmological simulations with 30 pc resolution and more accurate models of stellar feedback produce naturally galactic outflows and more realistic rotation curves.

Ceverino & Klypin 2007z=3.5 Major progenitor of MW. 45 pc resolution Face-on view 100 kpc proper Stars

The problem: A strong spheroid Abadi et al. 2003, 500 pc force resolution, 10 5 particles. Governato, Mayer, Brook 2008, 300 pc resolution, particles 3.3 R d Still, too concentrated models