matteo viel- warm dark matter and structure formation

8/3/2019 Matteo Viel- Warm Dark Matter and Structure Formation

1/30

MATTEO VIEL

WARM DARK MATTER AND STRUCTURE FORMATION

INAF and

INFN Trieste

(Italy)

ENTApP, DESY, Hamburg (Germany) - 25th February 2008


2/30

Intergalactic Medium + first stars +

Dwarf galaxies + cluster

Credit: NASA


3/30

OUTLINE

Impact of warm dark matter particles on structure formation

- Dark matter haloes and galaxies

- IGM and the Lyman- forest

Natarajan: impact on first stars

Ruchayskiy: X-ray constraints

Pieri: Substructures and dark matter


4/30

WARM DARK MATTER

HALOES

Smoothing of halo coresLower characteristic density

Late (z


5/30

Dark Matter projected density

Bode, Ostriker & Turok 2001

z=3

z=2

z=1

CDM m = 350 eV m = 175 eV

5 keV

0.2 keV

~ 1

~


6/30

Number of dark matter haloes


7/30

Number of dark mattersatellites as a function of

parent halo mass


8/30

Halo-density profilessteeper than NFW with sterile of

0.5 keV?

Colin, Valenzuela, Avila-Reese (2008)

R (kpc/h)

Haloes A and B close to the filtering

Mass 3x10 12 Msun


9/30

Concentration (ratio of the halo radiusand radius which contains 1/5 of the mass)

of host haloes is smaller in WDM than CDM

Colin, Valenzuela, Avila-Reese (2008)

1. In WDM the accretion/formation rate of guest haloes is smaller than CDM

2. In WDM the destruction rate of guest haloes is more efficient than CDM

In WDM models the haloes tend to form later when the universe is denser: c is lower


10/30

Wang & White 2007

Numerical artifacts?


11/30

Anomalous flux ratios in strong

QUASAR gravitational lensing

(cusp configuration)

Miranda & Maccio 2007


12/30


13/30

Strigari et al. 2007

You cannot put dwarf galaxies in the most massive subhaloes..


14/30

Strigari et al 2008

Common mass scale 2x107 Msun this correspond to a thermal mass

of ~ 6 keV


15/30

Strigari et al 2006 Fitting of the Fornax dSph core 5 globular clusters

whose evolution could be explained (?) by a core of 1.5 kpc


16/30

Simon & Geha 2007

8 ultra-faint dwarf galaxies

If galaxy formation in low-mass dark matterhaloes is strongly suppressed after reionization

there are still a factor of ~4 too few dwarf

galaxies compared to CDM

m > 3.16 keV


17/30

GAS

Intergalactic Medium: afaithful tracer of dark matter at

high-z and small scales

Inanu

tshe

ll


18/30

80 % of the baryons at z=3are in the Lyman- forest

baryons as tracer of the dark

matter density field

IGM ~ DM at scales larger than the

Jeans length ~ 1 com Mpc

-

Bi & Davidsen (1997), Rauch (1998)

THEORY

DATA


19/30


20/30

Lyman- and Warm Dark Matter - I


21/30

Lyman- and Warm Dark Matter - I

CDM GAS WDM GAS 0.5 keV

30 comoving Mpc/h z=3

MV, Lesgourgues, Haehnelt, Matarrese, Riotto, PRD, 2005, 71, 063534

k FS ~ 5 Tv/Tx (m x/1keV) Mpc-1

In general

Set by relativistic degrees of freedom at decoupling

See Colombi, Dodelson, Widrow, 1996Colin, Avila-Reese, Valenzuela 2000Bode, Ostriker, Turok 2001

Abazajian, Fuller, Patel 2001Wang & White 2007Colin, Avila-Reese, Valenzuela 2008

Lyman- and Warm Dark Matter - II


22/30

Lyman and Warm Dark Matter II

CDM

MV, Lesgourgues, Haehnelt, Matarrese, Riotto, PRD, 2005, 71, 063534

[P (k) WDM/P (k) CDM ]1/2

P(k) = A kn T2 (k)

Tx 10.75

=

T g (TD)

1/3

1/3

Light gravitino contributingto a fraction of dark matter

Warm dark matter

10 eV

100eV


23/30

Lyman- and Warm Dark Matter - IV


24/30

mWDM

> 550 eV thermal

> 2keV sterile neutrino

WDM CWDM

(gravitinos)

neutrinos

Lyman and Warm Dark Matter IV

Viel et al. (2005)from high-res

z=2.1 sample

Seljak, Makarov, McDonald, Trac, PhysRevLett, 2006, 97, 191303

mWDM

> 1.5-2 keV thermal

> 10-14 keV sterile neutrino

MATTER FLUX

FLUX FLUX

MV, Lesgourgues, Haehnelt, Matarrese, Riotto, PhysRevLett, 2006, 97, 071301

Lyman- and Warm Dark Matter - V


25/30

MV et al., Phys.Rev.Lett. 100 (2008) 041304

Tightest constraints on mass ofWDM particles to date:

m WDM > 4 keV (early decoupled

thermal relics)

m sterile > 28 keV

SDSS + HIRES data

SDSS range Completely new small scale regime

Lyman and Warm Dark Matter V


26/30


27/30


28/30


29/30


30/30

matteo viel- warm dark matter and structure formation

Documents