Making Black Holes - Early black hole formation scenarios - - - PowerPoint PPT Presentation

Making Black Holes

Tom Abel
 Kavli Institute for Particle Astrophysics and Cosmology
 SLAC National Accelerator Laboratory & Physics Department, Stanford University


Simulation: John Wise & Tom Abel 2011 Visualization: Ralf Kähler & Abel (KIPAC)

• Early black hole

formation scenarios

• Connect with Star

Formation? With: Matthew Turk, John Wise, Jeff Oishi, Ji-hoon Kim, Peng Wang, Marcelo Alvarez. Vis: Ralf Kaehler

?

Martin Rees 1980

Accessible to direct simulations in hydrodynamic and MHD limits Dynamic range > 1e10 + subgrid modeling Accessible to direct simulations in 
 N-body limit > 1e6 particles Numerical Relativity


First Black Holes

An old subject which modern simulations are poised to make substantial progress on.

Insignificant BH accretion - no mini quasars because of internal photo- evaporation, nor pre-cursors of Quasars, large local feedback.

Alvarez, Wise & Abel ApJL, 2008

solid: with radiation feedback
 dotted without feedback

Do the first black holes grow rapidly?

Yes! But how about the small seeds falling into rapidly growing galaxies. Surely they must grow then, isn’t it?

• Same initial conditions as

“Simulation B” of Wise et al (2008abcd…)

– 1.5 Mpc periodic box – 10243 effective resoltution – 0.3 pc resolution – H2 chemistry, pop III and pop II star formation, full radiative transfer, – First star forms at z~30 – Ionizing radiation from 100 M¤ stars coupled to hydro – Remnant black hole accretion and radiative feedback treated including secondary ionization Alvarez, Wise & Abel (2009)

~6 kpc proper

0.5 1 1.5 2 z (kpc) 0.5 1 1.5 2 z (kpc) 0.5 1 1.5 2 z (kpc) 0.5 1 1.5 2 x (kpc) 0.5 1 1.5 2 x (kpc) 0.5 1 1.5 2 z (kpc) 5 · 10−7 1 · 10−6 2 · 10−6 5 · 10−6 1 · 10−5 2 · 10−5 5 · 10−5 1 · 10−4 H2IFraction 0.01 0.02 0.05 0.1 0.2 0.5 ElectronFraction 10−26 10−25 10−24 10−23 10−22 Density(g/cm3) 5 · 103 1 · 104 2 · 104 Temperature(K)

z=8.2 still no further growth. Halo: 2⨉108 solar mass 3 solar masses total on 25 black holes

500 pc age of universe

Black holes spend almost all their time in the wrong places

Most Pop III stellar seed black holes do not grow.

• Only need to make one

bright high-z quasar per comoving Gpc. So only

• ne of hundreds of

thousands potential pop III remnant black holes has to experience runaway growth.

• Why that one?
• How does kpc scale

gas know to keep being available for accretion

• nto it?

500 pc

Wise, Alvarez, Abel in prep.

SMBH from direct gaseous collapse?

• Perhaps some halos with 104K can have central cores that collapse directly? (e.g.

Koushiappas et al. 2004; Volonteri & Rees 2005; Begelman et al 2006; Spaans & Silk 2006; Lodato & Natarajan 2006; Wise & Abel 2007; Regan & Haehnelt 2008)

• Numerical experiment
• Assume no molecules can be formed (actually very bad assumption ...)
• Only H, He cooling leads to the first cooling objects to be ~ 1e8 solar masses

which have a central 1e5 solar mass cloud contract fast.

• See it as a numerical experiment to study the collapse of a turbulent

isothermal cloud formed form cosmological initial conditions

• Interesting also as a model to start studying the role of turbulence in galaxy

formation

• Dynamic range of 1015 which is by far the highest resolution simulation carried
• ut. Beat our own record by 5 orders of magnitude ...
• Wise, Turk & Abel (2008), ApJ, 682, 745

Wise, Turk & Abel 2008, ApJ

Bars within Bars (and disks) are misaligned

• Turbulent viscosity sufficient.
• Angular momentum may be transported

quickly.

• Is this scenario realized when halo forms

next to a bright source? (Shang, Bryan & Haiman 2010)

• Lyman Werner band H2 dissociation so

strong that during collapse no molecules can form

• Need to have such a high flux for the

entire time the progenitors grow from 105 to 108 solar mass.

NGC1333 in Perseus

Numerical experiments: Model Setup

• Spherical cloud with total mass = 1200 Msun with total of


1641 Msun in the box and density profile: Turbulence Magnetic 
 field Wind Base

No

HD

virial No

MHD

virial 1e-4 G No

Wind

virial 1e-4 G Yes

Wind/Hydro virial

Yes

• cs = 0.265 km/s (T=20 K);
• Initial turbulence has k-2 Burger’s


power spectrum with M=9 


• Uniform magnetic field in z direction.


Mass-to-flux ratio: overall: 1.4; 
 central: 3.3.

• Sink particles to model star formation 


designed to give more or less the known 
 answer
 


• Protostellar outflow feedback.
• Top grid 128^3, 4 levels of refinement by 2, 


maximum resolution 100 AU 
 2048 dynamic range . Box size: 2 pc

Wang, Li, Abel, Nakamura 2010 ApJ

Formation of a Star Cluster in the Milky Way

Sim: Wang, Abel, Li, Nakamura 2009 Viz: Kähler, Wang & Abel 2009

Log of column density: blue-white yellow: kinetic energy - jets from young stars

Relevant physics in star formation

• Hydro/MHD models form stars much

to quickly and very accelerated ...

• With proto-stellar outflows and MHD
• ne gets const. star formation rate
• Winds keep turbulence allow cloud to

form stars for many dynamical times

• First Model with sustained star

formation over many dynamical times without large scale driving

• “primordial” turbulence decays fast,

most of the mass 


• f a star cluster is built during
• utflow-driven turbulence phase.
• Our models still are missing
• ambipolar diffusion
• IR radiation

Wang, Li, Abel, Nakamura 2010 ApJ turbulence + winds (no MHD)

Hydro +Turbulence +MHD +winds

Time in Myr Total Stellar Mass

|⇤ ⇥ B|

Summary

• B-fields are amplified from the start.

Relevant on small scales quickly. Viscous scale, Reynolds number and small scale dissipation are affected first.

• Radiation and supernovae feedback severe

for early small galaxies.

• Early black holes barely grow.
• Key in evaluating whether the direct

collapse scenario is viable will be to simultaneously and believably model star formation.

• The absence of Star Formation that allows/

enables super massive black hole formation remains poorly understood.

• At the same we have amazing codes now.

How can we use them to make progress?