Co-evolution of Black Holes and Galaxies: Small Scales

Issues

Andrés Escala AstorquizaDAS, U. de Chile

Observational Evidence for Coevolution

MBH-σ (Ferrarese & Merrit/Gebhardt et al. 2000), MBH-Mbulge (Marconi & Hunt 2003) relations.

Co-evolution of cosmic SFR (Madau plot) and AGN activity.

AGN Heating needed for Galaxy Luminosity Function (Croton et al. 06’).

MBHs must be included in Standard Hierarchical Galaxy Formation within ΛCDM

Cosmology

Small Scale Issues:

Two basic unsolved issues that needs to be understood for a comprehensive scenario for MBH-Galaxy co-evolution are:

MBHs Mergers vs Last Parsec Stalling (->GW Recoil vs Three body problem).

MBH growth and its feedback on the environment (SF shutoff?).

Massive Black Hole Mergers

Mergers of Galaxies & MBHs (Begelman, Blandford & Rees 1980’)

Stellar loss-cone depletion by 3-body kicks implies stalling of MBH binary coalescence at sub-parsec separations.

MBHs-Disk Interactions• Gaseous disks are main candidates for

extracting angular momentum from MBH binaries and drive the final coalescence.

• Simulations in the literature of binary-disk interactions can be divided in 2 groups:

tmerge ~ 1000 torb(Type II)

tmerge ~ torb(Type I)

Escala et al. 04,05Dotti et al. 09

Artymowicz & Lubow 94Shi, Krolig et al. 12

Binary Proto-stars. Different

stages in the process of formation of binary stars shows different interactions with the gaseous envelopes.

This will not only affect their final separation but also in their final masses since accretion also varies dramatically in both cases.

Relevant to investigate when starts the type II stage.

Boss (1984) & more …

Artymowicz & Lubow (1994) & more…

Analytic Estimates Analytical estimates for a Gap Opening

Condition can be computed by comparing the timescales for closing (~∆R2/νturb) and opening (~∆L/T) a Gap.

Computed for torques from a Global Non-axisymmetric Density Enhancement instead from the Resonances that appears in the linear theory (not applicable for q≈1, only for q<<1).

Gives a criteria that can be expressed on 2 dimensionless quantities of the binary-disk system: h/rbin Mgas(<rbin)/Mbin

Time gap opening/ Time gap closing

If

SPH Simulations for Testing the Criteria (del Valle & Escala

12’)

del Valle & Escala (2012)

Can’t be explained by Lin & Papaloizou 86’:

Comparison of the Literature with del Valle & Escala 12’.

Are both types present in the real Universe? Probably YES

Type IIType I

Type I interaction should be more frequent in wet mergers and Type II in dry ones:

MBH accretion, its feedback and possible SF shutoff.

AGN Feedback: SF Shutoff?

• Proposed by several authors, based on simple analytical estimates of BH growth/feedback (e.g. Silk and Rees 98, King 03, Wyithe & Loeb 03, Begelman & Nath 05).

• DiMatteo et al (2005); Hopkins et al ++++++:

However …..• Resolution ≈ 100 RBH

inf (all BH-physics totally unresolved).

• These simulations have almost the same assumptions that simple analytical estimates (-> do not test them).

• A better approach is to perform smaller scale simulations that test these hypothesis.

• An example: hypothesis of Eddington Limited growth can be exceed thru Photon Trapping (Begelman 78), Super-Eddington Atmospheres due to unstable photon-bubbles (Begelman 02; Krumholz et al 05, 09).

Measuring AGN Feedback:

• Several ongoing attempts to quantify AGN feedback in both wind & jet modes (Krongold et al. 07,10; Rupke & Veilleux 11’; Harrison et al. 12’) .

• However, total momentum and energy observed in the outflow is still lower than required (~1/10) .

• Energy & momentum comes in the form of ionized gas Can this component transfer its momentum into heating the molecular ISM and stopping SF.

Mrk 573

If it is not feedback, what can set MBH-σ/MBH-MBulge relations?

Two Possibilties:

•No physical link between BH and Galaxies (Jahnke & Macciò 11’), relations are just a N vs N plot.

•Such link exists and we need to look for alternatives. Any galactic problem relevant in controlling MBH growth will work.

Implicit assumption of huge number of MBH mergers!

A personal Candidate: Galactic-Scale Fueling

Unavoidable step in the growth of Massive Black Holes and it is indeed a galactic problem!

Fueling Flowchart (Wada 2004):

Transport Supersonically Turbulent Disk (Final Kpc)

Becerra, M.Sc. 12’ Levine et al (2008)

Mass transport in turbulent disk (assuming a power-law inertial range):

BH ~ vrot 3 (Escala 06’,07’)

G

KS Law BH α Bulge

E(k)~k-3

E(k)~k-5/3

THANKS!

Motivation: fate of MBHs after Galaxy Mergers

Galaxy mergers are common events in

the universe.

Each galaxy with a sizeable bulge is

expected to have a MBH.

What is the fate of the BHs? Will also

Coalesce?

NGC 6240

MBH inclusion in Standard Hierarchical ΛCDM Cosmology

Di matteo

Gap Opening Condition• The migration timescales predicts completely

different behaviours (in the two cases) in terms of an eventual coalescence.

• Crucial to predict whether a Gap will be opened or not and apply it for different scenarios for binary MBHs/Protostars growth.

• Since Type I disks are generally thicker and more massive than Type II ones, M and H will be parameters to explore.

Summary I• We have studied under which

conditions the interaction of a disk with a binary will open a gap.

• We successfully test our analytical expectations against full 3-D hydrodynamic simulations.

• We are now in the position to predict under which scenarios we expect an efficient MBH merging.

• Also in a position to study when starts the type II stage in binary proto-stars.

Star Formation Triggering in Disc Galaxies

Part of Fernando Becerra´s Masters Thesis (work currently in progress)

KS Law

SFR-Mrot relation (Escala 2011)

SFR-Σgas/tdyn (Silk)

Our work• Explore the possibility of second

parameters

• Example: Escala (2011)

Star Formation Triggering

Aim: Study galactic-scale triggering of star formation.

In particular the role of Mrot (maximum mass scale not stabilized by rotation)

Compare different star formation laws: Kennicutt Law vs SFR-Mrot relation (Escala 2011).

Summary

Differences with terrestrial fluids:

Nontrivial Flows: on the Earth generated by solid bodies. In space also by gravitational forces, radiation field and explosions.

Astrophysical fluids are frequently partially ionized. Thus, electromagnetic forces can play a role in the macroscopic dynamics.

Why Numerical Simulations are so important in

Astronomy Most problems requires a large dynamic

range (4, 5, 6 and more orders of magnitude).

A broad variety of physical processes involved (gravity, hydro, radiation, B, etc) in complex geometries (full 3-d).

HPC needed! (Software & Hardware solutions ).

Astrophysical Fluids Basic Ingredients:

Gravity: always.

Hydrodynamics: gas, stars only when collisions are not negligible.

Many More: Radiation Fields, G.R. corrections, Chemical/Nuclear Reactions, etc. -> generally included as sub-grid physics.

Hydro Methods Used

Eulerian: Adaptive Mesh Refinement (AMR).

Lagrangian: Smooth Particle Hydrodynamics (SPH).

Methods: SPH The fluid its sampled and represented by

particles smoothed by a kernel W. Allows any function to be expressed in

terms of its values at a set of disordered points, i.e.:

hj is the variable smoothing length, adjusted to keep the number of neighbors N constant.

ρ (r) = Σ mj W(r-rj;hj)j=1

N

adaptive spatial resolution

SPH Example: Large Scale Struc.

Methods: AMR Grid-based Technique.

Uses a criteria for automatic increase of the resolution.

Criterias can be chosen to guarantee resolve: density contrast, jeans length , shocks, etc.

AMR Example: detonations

SPH Simulations using Gadget-2 code.

Galaxy Mergers

Para ver esta pel cula, debeﾒdisponer de QuickTime y deﾪ

un descompresor YUV420 codec.

Para ver esta pel cula, debeﾒdisponer de QuickTime y deﾪ

un descompresor YUV420 codec.

AMR Simulations using ENZO code.