Galaxy formation with warm dark matter
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Transcript of Galaxy formation with warm dark matter
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Galaxy formation with warm dark matter
Mark LovellAdrian Jenkins, Carlos Frenk, Vince Eke, Tom Theuns, Liang
Gao, Shi Shao, Simon White, Alexey Boyarsky, Oleg Ruchayskiy…
Ripples in the Cosmos 22/07/2013
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Outline
• WDM reminder (see Carlos’ talk)• How does subhalo structure change with WDM
particle mass?• Effect of WDM on reionisation?
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nMSMU
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• Neutrino Minimal Standard Model (nMSM) conceived to explain neutrino masses (Asaka & Shaposhnikov, 2005).
• Adds three sterile neutrinos to the SM. The lightest of these would be a dark matter candidate.
• Large velocities at early times => WDM / CWDM
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WDM• Phase space limit
(small cores ~pc)• Free-streaming
Lovell et al. 2012
• Low mass substructures suppressed.
• Later formation times
• Concentrations lower
• Reionisation delayed
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Subhalo structure
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Simulation Suite – Vital Statistics
• 5 resimulations of the Aquarius Aq-A halo: 4WDM models + CDM, WMAP7 cosmology
• Dark matter simulation particle mass 1.5x104Msun
• WDM particle masses mp=1.4keV, 1.6keV, 2.0keV, 2.3keV (thermal relics)
• PWDM/PCDM = (1+(ak)n)-10/n [n=1] • a=a[mp]
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m1.4
m1.6
m2.0
m2.3
CDM
PWDM/PCDM = (1+(ak)n)-10/n [n=1] (Bode et al. 2001)
Lovell et al. (in prep.)
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z=3
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Msub - Vmax
Lovell et al. (in prep.)
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Vmax – rmax [concentration]
Lovell et al. (in prep.)
WMAP7
WMAP1
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NFW vs Einasto
Lovell et al. (in prep.)
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Density Profiles (1)
Lovell et al. (in prep.)
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Density Profiles (2)
Lovell et al. (in prep.)
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Vcirc profiles
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Subhaloes
Central DensitiesField Haloes# Too Big to Fail:CDM: 6m2.3: 4m2.0: 3m1.6: 3m1.4: 1
No Problem for WDM
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Reionisation
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Simulations
CN CW
WN WW
CDM
WDM (1.4keV)
No feedback
Feedback enabled
• Aq-A4 halo• SPH – Gadget3 code• CDM/WDM vs.
Supernova feedback/no feedback
• Salpeter IMF• Multiphase ISM• Primordial cooling tables• Decoupled winds
(Springel&Hernquist 2003)
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No theory talk is complete without a
movie …
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Star formation rate
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Reionising the (Local) Universe…
Preliminary
Warning!!Uber-simple model!
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Just WDM?
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Conclusions• Exciting WDM / CWDM models motivated by
nMSM• Subhalo structure
o Vmaxes, central densities lower with progressively warmer models at a given mass – alleviates ‘too big too fail’ problem. Cosmology also plays a role.
• Reionisationo WDM models produce enough photons to reionise each hydrogen
atom, subgrid model important.
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Mass functions
Lovell et al. (in prep.)
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Since you asked…
Lovell et al. (in prep.)
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…
Lovell et al. (in prep)
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