G. Murante – INAF OATo P. Monaco – Univ. Ts M. Calabrese – SISSA Ts G. De Lucia - INAF OATs S....

Disk Galaxy Formation in a cosmological(context) content

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A WARM MODE OF ACCRETION IN SIMULATIONS

OF GALAXY FORMATION

G. Murante – INAF OATo

P. Monaco – Univ. Ts

M. Calabrese – SISSA Ts

G. De Lucia - INAF OATs

S. Borgani – Univ. Ts

K. Dolag – Obs..Munchen

Heidelberg, May 15th, 2012


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MUPPI: MUlti Phase Particle Integrator

Star formation & feedback algorithm Implemented in GADGET-3 Integrates ISM equations for each particle at each SPH

time step Effective thermal feedback Obtains SK relation without imposing it

Gives ISM characteristics


Murante, Monaco, Giovalli, Borgani, Diaferio, 2010, MNRAS, 405, 1491

(See Monaco, Murante, Borgani, Dolag, 2012, MNRAS, 421, 2485)

MOLECULAR GAS

cM cM

M

M

hM

hM

=

= =

MASS

FLOWS

sfM

sfM

STA

R

FO

RM

ATIO

Ndyn

Hstarsf tf MM 2

restM

RESTORATION

restM

sfrestrest MM f

coolM

coolM

CO

OLIN

G

cool

hcool tMM

EVAPO

RATIO

N

evapM

evapM

dyn

Hevapevap tf MM 2

MH2 ->SF

On hotphase!

On coldphase!

Heidelberg, May 15th, 2012 3Disk Galaxy Formation in a cosmological(context)

content


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Ėhot = -Ėcool+Ėsn+Ėhydro

Multi-Phase particle

Δt, ΔSĖhydro = ΔS/(γ-1)ρ(γ-1)Δt

SPH

new ΔS

etc...Heidelberg, May 15th, 2012

Energy exchanges

ENERGY FLOW(S..)

Hot phase energy hydrocoolSNh EEEE

ENERGY RELEASED BY SNe

sf

sfinfbSN

MEE f

,51

ENERGY LOSS DUE TO COOLING

cool

hcool t

EE

ENERGY CONTRIBUTION DUE TO HYDRODYNAMICS

1)1(

1

SPH

hydro

S

dtE

this is the ENTROPY variationdue to SPH hydrodynamics PRESSURE-DRIVEN SF

ext

coll

ccollH

PP

f

MfM

0

2

41

1

Phenomenological (Blitz & Rosolowsky 2006)Pext Ptherm with P0 = 35000

Heidelberg, May 15th, 2012 5Disk Galaxy Formation in a cosmological(context)

content


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More characteristics


• Thermal energy given to neighbouring particles in a directional way

• Chemical evolution (Tornatore et al 2007)

• Primordial AND metal dependent cooling

• Stocastic kinetic winds: a fraction of particles continously receive also kinetic energy from neighbouring particles. They decouple from the gas. Wind speed depends on local SF. In cosmological simulations, velocities up to 1000 km/s

7Disk Galaxy Formation in a cosmological(context) content

Dynamical SK

relation


Monaco, Murante, Borgani,Dolag, 2012, MNRAS, 421, 2485


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Cosmological disk galaxy simulations


(Stoehr+, 2002, MNRAS, 355, 84)

(See The Aquila comparison project, Scannapieco+, 2012, MNRAS, in press)


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Our best disk

galaxy



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How does the gas accrete?


• use simulations without chemical evolution/metal cooling • identify stars/gas particles at z=0 within R200, Rgal=0.1 R200

• follow back particles and recorded their maximum T• also construct SUBFIND merger trees of haloes• use three temperature ranges:

1. 0 < Tmax < 250,000 K (cold);2. 250,000 K < Tmax < 106 K (warm)3. Tmax > 106 K

• see to which accretion channel gas particles belong, if they ever were into clumps, both for particles within R200 and Rgal.

We:

Murante, Calabrese, De Lucia, Monaco Borgani, Dolag, 2012, ApJL, 749, 34


11Heidelberg, May 15th, 2012


Accretion channels


Warm gas

GADGET


GA vs AQ


Galaxy Halo


Multiphase properties of gas in channels


Aq-C-5


Resolution


(results for accretion on galaxy)


Metal cooling


(results for GA1)


Clumpiness

Heidelberg, May 15th, 2012 (results for GA2)

Cold gas isclumpy!

Our gas clumpshave DM… (107 Msol min)


Conclusions


• MUPPI can produce reasonable disk galaxies• Accretion on halo is mainly cold• With an efficient thermal feedback scheme, a new gas accretion channel on galaxy arises: warm accretion• Warm accretion is fuelled by gas heated by Sne feedback• Cold accretion on galaxies is at least 50% clumpy• Our result does not depend upon resolution, our chosen

halo, chemical evolution/metal cooling: only on the efficiency of thermal feedback

• MUPPI can produce reasonable disk galaxies• Accretion on halo is mainly cold• With an efficient thermal feedback scheme, a new gas accretion channel on galaxy arises: warm accretion• Warm accretion is fuelled by gas heated by Sne feedback• Cold accretion on galaxies is at least 50% clumpy • Our result does not depend upon resolution, our chosen

halo, chemical evolution/metal cooling: only on the efficiency of thermal feedback

G. Murante – INAF OATo P. Monaco – Univ. Ts M. Calabrese – SISSA Ts G. De Lucia - INAF OATs S....

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