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
Murante, Monaco, Giovalli, Borgani, Diaferio, 2010, MNRAS, 405, 1491
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
(See Monaco, Murante, Borgani, Dolag, 2012, MNRAS, 421, 2485)




Gives ISM characteristics
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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MASS
FLOWS

Mc
M
c
= 


M
cool

 M sf  M
evap
MOLECULAR GAS

M
MH2 ->
SF

cool

M
sf

tcool
 f star  M H 2
t dyn
 f rest  M sf

M
h

M rest
M
M
evap
 f evap  M H 2
t dyn
On hot
phase!
Mh
RESTORATION
On cold
phase!

M

= 

M

sf
 M rest
Heidelberg, May 15th, 2012

M

h

=  M cool  M rest 
Disk Galaxy Formation in a cosmological(context)
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
M
evap
3
Energy exchanges
SPH
Multi-Phase particle
Δt, ΔS
Ėhydro = ΔS/(γ-1)ρ(γ-1)Δt
Ėhot = -Ėcool+Ėsn+Ėhydro
new ΔS
etc...
Heidelberg, May 15th, 2012
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ENERGY FLOW(S..)

Hot phase
energy
Eh
ENERGY RELEASED BY SNe
E
SN
 E 51  f fb ,in
M

 sf
E SN


 E cool  E hydro
ENERGY CONTRIBUTION
DUE TO HYDRODYNAMICS
ENERGY LOSS DUE TO COOLING





sf
E cool

Eh
tcool

E
1
fcoll 
 P0 
1  4

 Pext 
Heidelberg, May 15th, 2012
1 S SPH
dt (  1)   1
this is the ENTROPY variation
due to SPH hydrodynamics
PRESSURE-DRIVEN SF
M H 2  fcoll  Mc
hydro

Phenomenological
(Blitz & Rosolowsky 2006)
Pext Ptherm with P0 = 35000
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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
Heidelberg, May 15th, 2012
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Dynamical
SK
relation
Monaco, Murante,
Borgani,
Dolag, 2012, MNRAS,
421, 2485
Heidelberg, May 15th, 2012
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Cosmological disk galaxy simulations
(Stoehr+, 2002, MNRAS, 355, 84)
(See The Aquila comparison project, Scannapieco+, 2012, MNRAS, in press)
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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Our best
disk
galaxy
Heidelberg, May 15th, 2012
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How does the gas accrete?
We:
• 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.
Murante, Calabrese, De Lucia, Monaco Borgani, Dolag, 2012, ApJL, 749, 34
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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Heidelberg, May 15th, 2012
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Accretion channels
Warm gas
GADGET
Heidelberg, May 15th, 2012
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Galaxy
Heidelberg, May 15th, 2012
GA vs AQ
Disk Galaxy Formation in a cosmological(context)
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Halo
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Multiphase properties of gas in channels
Aq-C-5
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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Resolution
(results for accretion on galaxy)
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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Metal cooling
(results for GA1)
Heidelberg, May 15th, 2012
Disk Galaxy Formation in a cosmological(context)
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Clumpiness
Cold gas is
clumpy!
Our gas clumps
have DM… (107
Msol min)
Heidelberg, May 15th, 2012
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(results for GA2)
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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
Heidelberg, May 15th, 2012
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