The formation of galaxies

[L. Cortese; SDSS.]

[Dubois+16]

AGN         no AGN

How to explain morphological diversity at fixed mass?

The formation of galaxies

[L. Cortese; SDSS.]

[Dubois+16]

AGN         no AGN

How to explain morphological diversity at fixed mass?

[Kraljic+ in prep]

\(z=0\)

\( z = 100\)

\(z=0\)

\( z = 100\)

\[\mathbf{L}_\mathrm{lin.} \propto \int\mathrm{d}^3q(\mathbf{q}-\bar{\mathbf{q}})\times \nabla\phi\]

[White 84]

\(z=0\)

\( z = 100\)

[Genetic modifications: Roth+16, see also Rey&Pontzen 18, Stopyra+20]

Predicting angular momentum

Time

Predicting angular momentum

Accuracy of predicted AM

• better than linear prediction* at \(z = 0\)
• rises much later

*Tidal torque theory, see e.g. White 84

Predicting angular momentum

• Angular momentum of individual regions can be predicted accurately.
• AM of halos ⇒ requires boundaries of patch

[On patch boundaries: see Lucie-Smith+18]

Can we control baryonic
angular momentum?

Can we control baryonic
angular momentum?

Wechsler & Tinker 18

\({\color{red}M_\star} / M_\mathrm{h} \ll \Omega_b / \Omega_m \)
⇒ baryons & DM
originate from different regions

Baryon angular momentum

Simulations (9Mh @ DiRAC):

• Resolve disk height
  \(\Delta x = 35\ \mathrm{kpc}\)
• \(z \geq 2\), \(M_\mathrm{200c} = 10^{12}\ \mathrm{M}_\odot\)
• SF + AGN & SN feedback (à la Horizon-AGN)
• Modify \(l(z=2)\)
• Tracer particles
  Cadiou+19

\( l_0 \times 0.66\)

\( l_0 \times 0.8\)

\( l_0 \times 1.2\)

\( l_0 \times 1.5\)

\( l_0 \times 1.2\)

\( l_0 \times 1.5\)

\( l_0 \times 0.66\)

\( l_0 \times 0.8\)

\( l_0 \times 0.66\)

\( l_0 \times 0.8\)

\( l_0 \times 1.2\)

\( l_0 \times 1.5\)

+

Angular momentum of the baryons / stars within \(R_\mathrm{vir}\)

• AM of baryons can be controlled!
• ≠ effect on stars / baryons
• Little AGN/SN global self-regulation
• Observables are impacted (significantly!)

\( R_{1/2} \)

\( l_0 \times 1.2\)

\( l_0 \times 1.5\)

\( l_0 \times 0.66\)

\( l_0 \times 0.8\)

\( l_0 \times 0.66\)

\( l_0 \times 0.8\)

\( l_0 \times 1.2\)

\( l_0 \times 1.5\)

Dynamics of AM of accreted gas: torques

$$ \frac{\mathrm{d} j}{\mathrm{d} t} = \tau_\mathrm{grav} + \tau_\mathrm{pressure} $$

,          and

\( {\color{gray}\tau_\mathrm{grav} }= -r\times\nabla \phi \)

From                  gradients

\( {\color{red}\tau_\mathrm{pressure}} = -r\times\nabla P/\rho \)

DM

stars

gas

pressure

Mean of norm \(\langle |\tau|\rangle\)

Dynamics of AM of accreted gas: torques

Tillson+15

Mean of norm \(\langle |\tau|\rangle\)

Norm of mean \(|\langle\tau\rangle|\)

Pressure torques dominate

esp. in hot phase

Tillson+15

Norm of mean \(|\langle\tau\rangle|\)

Gravitational torques dominate!

esp. in cold phase

Ratio of torques \(\dfrac{|\langle\tau_\mathrm{g}\rangle|}{|\langle\tau_\mathrm{g}\rangle|+|\langle\tau_\mathrm{p}\rangle|}\)

Conclusion & outlook

Conclusion & outlook

• angular momentum is predictable
   

• boundary of halos in the ICs is a hard problem
  ⇒ limits practicality of predictions (for now)
   

• baryons can be controlled!
  ⇒ good news for weak lensing predictions
      stay tuned!
   

• AM kinematics in accreted gas is dominated by gravitational torques, esp. in cold flows!
  ⇒ “connection” with cosmic web is retained!
  ⇒ interesting physics happen in CW \(\leftrightarrow\) disk interface (CGM!)

Conclusion & outlook

Questions?
 

More infos in Cadiou+21a,b,c (2012.02201, 2107.03407, 2110.05384)

📧 c.cadiou@ucl.ac.uk           @cphyc         🔗 cphyc.github.io

• angular momentum is predictable
   

• boundary of halos in the ICs is a hard problem
  ⇒ limits practicality of predictions (for now)
   

• baryons can be controlled!
  ⇒ good news for weak lensing predictions
      stay tuned!
   

• AM kinematics in accreted gas is dominated by gravitational torques, esp. in cold flows!
  ⇒ do not expect to “lose connection” with cosmic web

What if the galaxy had formed here instead?

What if the galaxy had formed here instead?

or here?

The causal origin of DM halo concentration

The causal origin of DM halo concentration

The causal origin of DM halo concentration

The causal origin of DM halo concentration

$$\rho_\mathrm{DM}(r) = \frac{\rho_0}{\frac{r}{R_\mathrm{vir}/c} \left(1 + \frac{r}{R_\mathrm{vir}/c}\right)^2}$$

Wechsler+02

Splicing in 1D

Splicing in 1D

Most likely* field \(f\) with

• same value in spliced region (\(a\)),
• as close as possible outside (\(b\))

Mathematically \(f\) is solution of:

\( f= a\) in \(\Gamma\)

minimizes \(\mathcal{Q} = (b-f)^\dagger\mathbf{C}^{-1}(b-f) \) outside \(\Gamma\)

Verify that

\[\xi_\mathrm{lin}(r) \sim \left\langle {\color{green}\underbrace{\delta(x=d)}_\mathrm{in}} {\color{purple} \underbrace{\delta(x=d+r)}_\mathrm{out}}\right\rangle \]

is the same in spliced / ref simulation.

Verify that

\[\xi_\mathrm{lin}(r) \sim \left\langle {\color{green}\underbrace{\delta(x=d)}_\mathrm{in}} {\color{purple} \underbrace{\delta(x=d+r)}_\mathrm{out}}\right\rangle \]

is the same in spliced / ref simulation.

Verify that

\[\xi_\mathrm{lin}(r) \sim \left\langle {\color{green}\underbrace{\delta(x=d)}_\mathrm{in}} {\color{purple} \underbrace{\delta(x=d+r)}_\mathrm{out}}\right\rangle \]

is the same in spliced / ref simulation.

[Danovich+15]

The origin of high \(z\) angular momentum

[Danovich+15]

I. Torque with cosmic web

The origin of high \(z\) angular momentum

[Danovich+15]

I. Torque with cosmic web

II. Transport at constant AM

The origin of high \(z\) angular momentum

[Danovich+15]

I. Torque with cosmic web

II. Transport at constant AM

III. Torque down in inner halo

The origin of high \(z\) angular momentum

[Danovich+15]

I. Torque with cosmic web

II. Transport at constant AM

III. Torque down in inner halo

IV. Mixing in inner disk & bulge

The origin of high \(z\) angular momentum

The origin of high \(z\) angular momentum

[Danovich+15]

IV. Mixing in inner disk & bulge

III. Torque down in inner halo

II. Transport at constant AM

I. Torque with cosmic web

Predict pre-accretion AM?

Alignment with environment?

The origin of high \(z\) angular momentum

[Danovich+15]

IV. Mixing in inner disk & bulge

III. Torque down in inner halo

II. Transport at constant AM

I. Torque with cosmic web

Predict pre-accretion AM?

Alignment with environment?

The origin of high \(z\) angular momentum

[Danovich+15]

IV. Mixing in inner disk & bulge

III. Torque down in inner halo

II. Transport at constant AM

I. Torque with cosmic web

Predict pre-accretion AM?

Alignment with environment?