Title: The Trials and Transport of Cosmic Metals
1The Trials and Transport of Cosmic Metals
- Rob Wiersma Leiden Observatory
Joop Schaye, Claudio Dalla Vecchia, Craig Booth,
Marcel Haas, Freeke van de Voort, Luca
Tornatore, Volker Springel, Tom Theuns
2Metal distribution
- The cosmic metal distribution is still unknown
- density-temperature-metallicity space
- IGM-ICM-ISM-stars
- Large/medium/small halos?
- Missing metals problem
- Excess metals problem
3Observed metal distribution at z 2
Missing 3 - 63
IGM (DLAs Lya forest) lt 37
Galaxies (Gas Stars) 30 - 60
Bouché et al. (2007)?
4OWLS OverWhelmingly Large Simulations
- Cosmological simulations (N-body/SPH)?
- Default runs use 2 x 5123 (gas, dark matter)
particles over a 25 Mpc/h box (to z 2) and a
100 Mpc/h box (to z 0)?
5OWLS The Philosophy
- Vary physics (feedback strength, cooling, etc.)
as well as numerical parameters (box size and
resolution)? - Keep simple prescriptions for things we cant
resolve
6OWLS The Code (GADGET 2 and then some)?
- New star formation recipe
- Fully chemodynamical
- Following 11 elements
- Enrichment from
- Type Ia Supernovae
- Type II Supernovae
- AGB Stars
- Stellar winds
- Major cooling improvements
- Element by element treatment
- Considers the effect of photoionization on metals
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8Mass and Metal Mass Distribution
5123 particles 100 Mpc/h box z 0
9Where are the metals?
5123 particles 100 Mpc/h box
nH gt 10-1 cm-3
nH lt 10-1 cm-3
Stars
10Phases where the metals lie
11Box Size Test
100 Mpc, 5123 particles
25 Mpc, 1283 particles
12Box Size Test
13Resolution Test
25 Mpc, 5123 particles
25 Mpc, 1283 particles
14Resolution Test
15OWLS Cooling
- Using CLOUDY, we construct cooling tables that
- Element by element treatment
- Considers the effect of photoionization on metals
- Thus cooling is tabulated as a function of
temperature, density, redshift, and abundance of
element X - Freely available at http//www.strw.leidneuniv.nl/
WSS08
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17Cooling and Feedback Dependence
5123 particles 100 Mpc/h box
No metal-line cooling
Fiducial model
No metal-line cooling or feedback
18Cooling and Feedback Dependence
5123 particles 100 Mpc/h box z 0
19OWLS winds
- Use Type II Supernovae to drive galactic winds
- In simulations this can be done by kicking gas
particles - Default model has
- mass loading 2 x star forming mass
- velocity 600 km/s
- (see Dalla Vecchia and Schaye 2008)?
20Wind dependence Constant Energy
5123 particles 25 Mpc/h box
Mass Loading 8, Velocity 300 km/s
Mass Loading 1, Velocity 848 km/s
21Wind dependence Constant Energy
5123 particles 25 Mpc/h box z 2
22Alternative Wind Models
- Can scale parameters (mass loading and wind
velocity) with environment, time, etc. - Energy driven
- Winds use a constant fraction supernova energy
- Momentum driven
- Wind energy can vary (i.e., contribution of
radiation pressure on dust grains)? - (cf. Oppenheimer and Davé 2006, Oppenheimer and
Davé 2008)?
23Wind dependence Constant Energy
5123 particles 100 Mpc/h box
Sound speed scaled winds
Fiducial model
24Wind dependence Constant Energy
5123 particles 100 Mpc/h box z 0
25Wind dependence Momentum driven
5123 particles 25 Mpc/h box
Halo mass scaled winds
Fiducial model
26Wind dependence Momentum driven
5123 particles 25 Mpc/h box z 2
27OWLS star formation
- Abandon subgrid model
- Above nH 0.1 cm-3 enforce an equation of state
such that the Jeans length is independent of mass - Randomly sample the Kennicutt Schmidt law (n
1.4) from equation of state gas - (see Schaye and Dalla Vecchia 2007)?
28Star formation law dependence
5123 particles 25 Mpc/h box
Steep KS law
Fiducial model
29Star formation law dependence
5123 particles 25 Mpc/h box z 2
30Summary
Also star formation law, cosmology, IMF
(Extreme)?
No influence Type Ia supernova rate,
reionization history, IMF (Salpeter vs.
Chabrier), ISM equation of state
31O/Fe as a function of redshift
5123 particles 100 Mpc/h box
32Conclusion
- Under most models
- At z 2, metals are distributed evenly among the
stars, ISM and ICM/IGM - At z 0,
- 40 - 60 of metals are locked in stars
- 30 - 50 of metals are in the IGM
- Material dragged along in winds can result in
abundance ratios that differ from Type II SN
yields (particularly around low mass halos)?
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35a-Enhancement in Stars
36Metallicity Evolution