Galaxy Formation& Dark Matter
Ken Nagamine(Osaka / K-IPMU / UNLV)

Dark Matter
Dark Energyothers have not been corrected for the red-tilting eﬀectof luminosity-dependent bias. The Percival et al. (2001)
2dFGRS analysis unfortunately cannot be directly plottedin the figure because of its complicated window functions.
Figure 36 is the same as Figure 35, but restricted to acomparison of decorrelated power spectra, those for SDSS,
2dFGRS and PSCz. Because the power spectra are decorrelated, it is fair to do “chi-by-eye” when examining thisFigure. The similarity in the bumps and wiggles between`Precision Cosmology’

Summary ofObservations•Various obs suggest
the existence of DM.

<latexit sha1_base64="KTDo5AEuv16mG5RgsQBCpTiJuNw=">AAACEXicbZDLSgMxFIYz9VbrbdSlm2ApdFVmRNGVFHThRqxgL9AZSibNtKFJZkgyQhnmFdz4Km5cKOLWnTvfxrQdQVt/CHz8J4dzzh/EjCrtOF9WYWl5ZXWtuF7a2Nza3rF391oqSiQmTRyxSHYCpAijgjQ11Yx0YkkQDxhpB6OLSb19T6SikbjT45j4HA0EDSlG2lg9u+qFEuHUu+FkgHqpJzm8vM5g9uMEGfQU5fCkZ5edmjMVXAQ3hzLI1ejZn14/wgknQmOGlOq6Tqz9FElNMSNZyUsUiREeoQHpGhSIE+Wn04syWDFOH4aRNE9oOHV/d6SIKzXmZrsKR3qo5msT879aN9HhmZ9SESeaCDwbFCYM6ghO4oF9KgnWbGwAYUnNrhAPkYlImxBLJgR3/uRFaB3VXMO3x+X6eR5HERyAQ1AFLjgFdXAFGqAJMHgAT+AFvFqP1rP1Zr3PvhasvGcf/JH18Q27dJzn</latexit>⌦DM⇠5⌦bFig. 36.— Same as Figure 35, but restricted to a comparisonof decorrelated power spectra, those for SDSS, 2dFGRS and PSCz.
The similarity in the bumps and wiggles between the three power
spectra is intriguing.

ESA 2013⌦m ⇠ 0.3<latexit sha1_base64="(null)">(null)</latexit>`737’ ConcordanceΛCDM modelFig. 35.— Comparison with other galaxy power spectrum measurements. Numerous caveats must be borne in mind when interpreting
this figure. Our SDSS power spectrum measurements are those fromFigure 22, corrected for the red-tilting eﬀect of luminosity dependentbias. The purely angular analyses of the APM survey (Efstathiou& Moody 2001) and the SDSS (the points are from Tegmark et al.

Tegmark 2004

Fig. 37.— Comparison of our results with other P (k) constraints.

yet)
d.
a,sngmtu.
oConcordance ΛCDM model
WMAP, Planck
SN Ia(⌦M , ⌦⇤ , ⌦b , h,8 , ns ) ⇡ (0.3, 0.7, 0.04, 0.7, 0.8, 0.96)⌦DM ⇡ 0.26

• Successful on large-scales(>1Mpc)• Can we understand galaxy

Fig. 36.— Same as Figure 35, but restricted to a comparisonof decorrelated power spectra, those for SDSS, 2dFGRS and PSCz.
The similarity in the bumps and wiggles between the three power
spectra is intriguing.

formation in this context?

FFTsimulate

Tegmark+(2004) of our results with other P (k) constraints.
Fig. 37.— Comparison
The location of CMB, cluster, lensing and Lyα forest points in this“Back-bone of structure”

History of Cosmic Structure Formationin ΛCDM Universe
Cosmic time

1 Gyr

6 Gyr

13.8 GyrFirst Galaxies

Galaxy Evolution

z~6z~15

JWST
HST
SKA

z~1PFSHSCDESMOONSEUCLID…

SDSS, 2dFImage: NAOJ

1st-order Galaxy Formation
DM halo forms.

“spherical cow”
Gas inflow

Gas infall& shock heating

Gas dissipates,cools,& forms a disk.
Star, Galaxy Formation

Virial shockTvir

Rees & Ostriker ’77
White & Rees ’78
Fall & Efstathiou ’80
White & Frenk ‘91
Mo, Mao & White ‘98

Computational Cosmology
Self-consistent galaxy formation scenario
from first principles (as much as possible)
Baryonic physics

z~1100

Radiative
heating/cooling,
Star formation,& Feedback

z=100

Initial conditions

z=10Cosmological params,
Dark energy, Dark matter,
Baryons(+expanding universe)

Gravity + Hydrodynamics

z=3z=0Three Revolutions in Cosmological Hydro
Simulations

1990’: 1stRevolution

2001-2011
2nd Rev.

2012~
3rd Rev.

First cosmological, butcoarse calculation

Larger scale, medium
resolution w.
subgrid models

Zoom-in method allows
much higher res.

Resolution ~ kpc

Resolution~ 10-100pc

e.g. KN+ ’01, 04, 06

IC code: GRAFIC (Bertschinger)
MUSIC (Hahn & Abel ’11)

Resolution~100 kpc
e.g. Cen, Ostriker ’92-’93
Katz+ ’96

Springel & Hernquist ’03

ineWorld Scientific Series in As tr

phy si csThe

EncyclopediaofCosmology
Volume 2
Numerical Simulations in Cosmology

Kentaro Nagamine editor

Giovanni G Fazio editor

World ScientificAmazon, or

https://www.worldscientific.com/worldscibooks/10.1142/9496#t=toc

How do galaxies acquire gas?

Cold Flow & Virial ShockDekel+ʼ09

Cold FlowEﬃcient inﬂow of cold gas
Promotes SFRv

Gas Accretion & Virial ShockHeating to Tvir
300 kpc

Birnboim & Dekel ʼ03：
Keres+ʼ05

Prohibit SF

t_compression vs. t_cool
controls the thermal state of gas.

Transition from Cold to Hot mode

ガス降着率

M13 at Rv

coldhotHot mode

星形成率（SFR）

Coldmodez⇠2
Nakamura M-thesis

TΣgasΣgRv

600 ckpc/hmetalDM!12

Nakamura M-thesis

Cold flow: generic feature of ΛCDM
EnzoARTRAMSESAREPOGIZMO-PSPH(details of SF & feedback are different in each code)
Stewart+’17

“Cold Flow Disk”
z~3

Extended, flattened rotating structures of high–J material.
Stewart+’17

Cold gas in halos have 4x J
than dark matterspin param.
λx ≡ jx/ 2V R

λcold ≃ 0.15

λDM ≃ 0.04
Stewart+’17

Historical Flow Chart of SN Feedback Treatment
1st phase‘90s

Simple thermal feedback
Overcooling problem

2nd phase Phenomenological subgrid model (thermal + kinetic)
based on galactic properties (SFR, Mstar, Mhalo)’00-‘10Multi-phase ISM
model

3rd phase’10~(w/ zoom sim)

More direct, local,
thermal+kinetic+radiative feedback

Stellar-to-Halo Mass Ratio (SHMR)~1012M⦿SN Feedback

AGN Feedback?

Abundance Matching
resultBehroozi+’10, ’13, ‘18(cf. Ilbert+’10; George+’11; Leauthaud+’12)

Galaxy Stellar Mass Function (z=0)

Still much variations
among sims remain.
Some FB paramtuning is necessaryfor each resolution.

Schaye+ ’15
Crain+ ‘15

AREPOsimulation`Impact of SN feedback on Gas
zoom-in sim: from z=20 to 6, resol. ~ 30 pc @ z~6

No SN feedback

500 kpc (com)w. SN feedback

Yajima, KN+ ‘17

Different morphologies @ z~7 w/ diff. SF & FB models(zoom-in sim)

Yajima, KN+ ‘17

Intermittent SFR

Size—L relation

SFR

中心密度

脱出確率obs dataIR luminosity
SFR

Arata, Yajima, KN+ ‘18
Yajima, KN+ ‘17

m12q FIRE simulation

mdm~2e5 M⦿/hmb=5e3 M⦿/hϵdm=100 pc/h
ϵb=7 pc/h

II. Small-scale crisis
for CDM?

Small-scale problems of ΛCDM?
•Cusp-Core problem: simulations predicting too steep
inner halo profile
Flores & Primack ’94; Moore '94•

Missing satellites problem: too much substructure?
Klypin+’99; Moore+’99•

Too-big-to-fail problem: over-abundance of massive &dense substructures (in CDM sim) that could host gals afterreionization (but unobserved in MW-satellites)
Boylan-Kolchin+’11•

Void phenomenon: gals in voids are too normal?

•Satellites plane problem: satellites aligned in a plane forboth MW and Andromeda•….

Cuspy profile not universal
even with DM-only sims.
Fukushige+’14

Jing & Suto ‘00

Boylan-Kolchin & MaSN-driven gas outflow erases
DM cusp and create cores(zoom-in hydro sim)

Inner density profile
oscillates rapidly.

Pontzen & Governato ’12
Madau+’14

Yajima, KN+ ‘17`Gastrophysics’ can remove cusp prob.

Impact of baryonic feedback on
inner density profile(Tollet+’16)
Fitts+’16; Hopkins+’17

Bullock & Boylan-Kolchin ‘17

Original Substructure ProblemKlypin+’99; Moore+’99

Substructure problem?

Illustris
2015

Cumulative # count

Substructure Problem Solved?

Stellar mass

Garrison-Kimmel+’17
Bullock & Boylan-Kolchin ‘17

No Missing Satellite Problem??

Cumulative # countApproaching toreionization suppression
scale
40-50 ultra-faint dwarfs
have been newly
discovered

Distance from gal center

Garrison-Kimmel+’17; Graus+’18

Latest obs by: SDSS, Pan-STARRS, DES, MagLiteS,…

Too-big-to-fail problem
N-body simulation

Boylan-Kolchin+ ‘11hydro sims (Fitts+’16)`too big’ to have failed toform stars…

Various Dark Matter
Thermal relic

1.

e.g. WIMP (10GeV ~ 1TeV)
standard QCD-axion(1µeV ~ 1meV)

becomes non-relativistic earlier, suppress
perturbation at galactic or smaller scales.
(gravitino, sterile neutrino,…)2.

3.

remains relativistic until late time, anderase structures at super-galactic scales.

(𝝼,…)

4+

Fuzzy(axion-like), Self-interacting DM
ALP

WDM
Suppression of P(k) @ small scales

lower mass

higher mass

Maio & Viel ‘15
Colin+’00; Bode+’01; Viel+’05; Colin+’08; Colombi+’09; Viel+’12; Menci+’17

z=0

m=1 keV

z=2Viel+’12

Ly-𝛼 forest constraint

1D flux
power spec

marginalize overcosmo params& T0, γusing COSMOMC
against obs data

Viel+’13
Baur+’16

WDM conclusions• WDM models w/ ≲ 3keV have been explored —strong alternative candidate to CDM• mdm ≳ a few keV seems more likely than < 1keV.
• Viel+13, Ly-a forest: m>3.3 keV (2-σ), Mh,min~2e8 M⦿
Baur+16: m>2.96 eV (for thermal relic)• Further study is needed with high-resol. and realistic SF &feedback models — e.g. impact of AGN feedback on
small-scale power (van Daahlen+’11; Semboloni+’11)

Impact of Self-interaction`Heat’ transfer fromoutside to inside
cf. WIMP
Spergel & Steinhart ‘00
Rocha+’13<latexit sha1_base64="(null)">(null)</latexit>/m ⇠ 10 38 cm2 /g
Tulin & Yu ‘18

SIDM

Elbert+’15
Tulin & Yu ‘18

Impact of Baryons on Rotation Curves

回転曲線の比WDM

SIDM

SIWDM

DM-onlyw. Hydro

Hydro
vs.
DMO
Fitts+ ‘18

Fuzzy Dark Matter (FDM)
Ultra Light Bosons, Wave-like, Axion-like•

non-thermal boson field (particularly scalar), non-rela,low-momentum state as a cold BEC•

m~10-22 eV, λde Broglie~1kpc•

expect suppression of halos at 107-1010 M⦿•forms a central core as a “soliton” (Schrödinger-Poissoneq.)•on large-scales, ≈ CDM
Baldeschi+83; Kim ’87; Sin+94; Hu+00; Marsh+14; Schive+14;
Hui+17; Mocz+17; Robles+18; Zhang+18; .….

Solitonic Core of FDM simulation
Schive+14
gravitationally boundsolitonic coree.g.
for Fornax dSph gal.

for MW core

Vertmaat+ ‘18- zoom sim. w/ Enzo code
- outside: N-body- inside halo: Schrödinger-Poisson eq.

- solitonic core:● core-halo mass relation— consistent w. Schive+’14● quasi-periodic oscillation- difficulty of boundary conditions⇢ = | |2 : FDM density<latexit sha1_base64="crouaVtiaA6Cw81nZT/IBYg+xXY=">AAAB+HicbVBNS8NAEJ3Ur1o/GvXoZbEInkpSBL0oBS8eK9gPaGLZbDft0s0m7G6EmvaXePGgiFd/ijf/jds2B219MPB4b4aZeUHCmdKO820V1tY3NreK26Wd3b39sn1w2FJxKgltkpjHshNgRTkTtKmZ5rSTSIqjgNN2MLqZ+e1HKhWLxb0eJ9SP8ECwkBGsjdSzy54cxugKTbyGYpOHWs+uOFVnDrRK3JxUIEejZ395/ZikERWacKxU13US7WdYakY4nZa8VNEEkxEe0K6hAkdU+dn88Ck6NUofhbE0JTSaq78nMhwpNY4C0xlhPVTL3kz8z+umOrz0MyaSVFNBFovClCMdo1kKqM8kJZqPDcFEMnMrIkMsMdEmq5IJwV1+eZW0alXXqbp355X6dR5HEY7hBM7AhQuowy00oAkEUniGV3iznqwX6936WLQWrHzmCP7A+vwBsLuSbw==</latexit>

comoving S-P eq.

Robles+18

— Concluding remarks —• Feedback !! — thermal, kinetic, radiative• Cold flow — how gals acquire gas & J• Small-scale prob. might exist — but at the level that can be

resolved by `gastrophysics’•

Missing satellite prob. — quickly disappearing; opposite prob.?

• Better understanding ofWDM, SIDM, FDM, … w. hydro & feedback• How do we reflect the nature of elementary particles realisticallyto the sims?
• DM発見時のために準備が必要（〜 重力波天文学＋数値相対論）