Astrophysical ConstraintsAstrophysical Constraints on Dark Matter: on Dark Matter: Warm or Cold ?Warm or Cold ?

Charling TAO

CPPM, IN2P3, France

Tsinghua Center for Astrophysics, Tsinghua University, China

Cooks’ Branch workshop on SN, april 2012

Euclid, an ESA M-class missionA geometrical probe of the universe proposed for Cosmic Vision

= +

All-sky optical imaging for gravitational lensing

All-sky near-IR spectra to H=22 for BAO

The Euclid Concept• Named in honour of the pioneer of geometry• Euclid will survey the extra-galactic sky (15 000 deg2) to

simultaneously measure its two principal dark energy probes:– Weak lensing:

• Diffraction limited galaxy shape measurements in one broad visible R/I/Z band.

• Redshift determination by photo-z measurements in 3 YJH NIR bands to H(AB)=24 mag, 5σ point source

– Baryonic Acoustic Oscillations:• Spectroscopic redshifts for 33% of all galaxies brighter

than H(AB)=22 mag, σz<0.006• With constraints:

– Aperture: max 1.2 m diameter– Mission duration: ~ 6 years,…

In october 2011, we have been chosen over PLATO for launch in 2019Official (financial) approval expected June 2012

Euclid and SN?About 20 people in SN WG

Leads: I. Hook, E. Capellaro, CT

Use opportunity of NIR YJH filters in space(no atmospheric transmission)!

Challenge : propose best possible SN survey within existing constraints

Dedicated Deep Survey for 6 months at end of mission (2024-?) or other options under study (survey strategy, choice of fields, calibrations,…)

Synergy with Pan-Starrs, LSST,JWST, Antarctica, …?

to develop if we can have an independent DS field

Graph source: Wikipedia

What we know is only 4%

of the energy density of the

Universe

We measure with precision the extent of our ignorance!

Concordance Model CDM

A mysterious Dark Universe with DE and DM !

An exciting lesson in humility !

Before 2000: Nature of DMHot or Cold?

CDM is non-relativistic

at decoupling, forms

structures in a hierarchical,

bottom-up scenario.

HDM is tightly bound byobservations and LSS formation

LSS structures

N-Body Simulations LSS favour CDM

VIRGO Consortium 1996http://www.mpa-garching.mpg.de/~virgo/virgo/

OMEGA = 0.3 LAMBDA = 0.7

H0 = 70 km/(Mpc sec) Sigma8 = 0.9

OMEGA = 1 LAMBDA =0

H0 = 50 km/(Mpc sec) Sigma8 = 0.51

OMEGA = 1 LAMBDA =0

H0 = 50 km/(Mpc sec) Sigma8 = 0.51

OMEGA = 0.3 LAMBDA = 0

H0 = 70 km/(Mpc sec) Sigma8 = 0.85

Boxsize 239.5 Mpc/h, 2563 particles

~2000 :Problems with CDM at small scales

Comparing more data with more precise N-body hydrodynamical simulations•Number of galactic satellites•cusp/core at GC

Predicted number

Observed number of luminous

satellite galaxies

Satellite galaxies are seen in Milky Way, e.g. Saggittarius, MCs

20km/s 100km/s10km/s

Too low number of visible satellite galaxies?

Universal Density ProfileNFW

Navarro, Frenk, White 1996

Cusp

Dark matter distribution—Density profiles

Salucci &

Frigerio Martins 2009

DM Cores in Dwarf galaxies

Oh et al. 2011

Data prefer Burkert Core Profile

Galaxy core vs cusp

Salucci & Frigerio Martins, 2009

Alternatives to CDM

• Self-Interacting Dark Matter (Spergel & Steinhardt 2000)

• Strongly Interacting Massive Particle

• Annihilating DM

• Decaying DM

• Fuzzy DM

• WDM: reduce the small scale power

WDM vs CDM

From Jing 2000

Density profileVelocity function

Nature of DMHot or Cold, or Warm?

CDM is non-relativistic

at decoupling, forms

structures in a hierarchical,

bottom-up scenario.

HDM is tightly bound byobservations and LSS formation

WDM?

But doubts on Lyresultsby SDSS people!

A fashionable candidate Sterile neutrinos

Constraints on sterile neutrinos

Limits on mass of WDM particles

• Stellar dynamics in MW satellites (Boyanovsky, de Vega, Sanchez

2008; de Vega and Sanchez 2009)

• High-z QSO LF (e.g. Song and Lee 2009)

• Ly-alpha forest to constrain P(k) at small scales and different

z’s (Most popular method: Narayanan et al 2000; Viel et al 2005;2008)

• Ly-a + SDSS results (Boyarsky et al 2009)

• QSO lensing ( Miranda & Maccio 2007 )

• Abundance of dwarf satellites of MW (Maccio & Fontanot 2010;

Polysensky & Ricotti, 2010)

Mass WDM ~ 1- 5 keV

Cosmic shear power spectra Markovic et al. 2010 Euclid-like DE space survey+Planck:

Sensitive to m_WDM < 2.5 keV

Nonthermal production of dark matter

Non thermal production in the early universe,

Large annihilation cross section, Large velocity depresses the

small scale structure. Possible constraints from galactic

center gamma-ray

fTv

scmh

13272 103

Lin, Huang, Zhang, Brandenberger, PRL86,954 (2001)

Bi, Brandenberger, Gondolo, Li, Yuan, Zhang, 0905.1253

CDM scenario with WDM?

•''cusp-core problem'',

•"missing satellite problem'',

“Evidence” for WDM ?

Hot topic, eg

WARM DARK MATTER IN THE GALAXIES:

THEORETICAL AND OBSERVATIONAL PROGRESSES

CIAS Observatoire de Paris, Château de Meudon, Meudon campus

8, 9 and 10 June 2011

CLUES simulations, Yepes, 2010

Velocity widths in Galaxies

Velocity widths in galaxies from 21 cm HI surveysPapastergis et al, 2011; Zavala et al., 2009NB: The red curve is for 1 keV WDM

Or inability of HI to trace the maximum halo rotational velocity of low-mass systems?

CDM vs WDM: HI velocity functions

Virgo and Anti Virgo directions

« No simple feedback mechanism to explain the factor 10 depletion from CDM » ?

arXiv:1005.2687: Constrained Local UniversE Simulations (CLUES)

Gottloeber, Hoffman , Yepes

•"missing satellite problem'',

•''cusp-core problem'',

• mini-voids The sizes of mini-voids in the local universe: an argument in favor of a warm dark matter model? Tikhonov et al.

•HI determinations of velocity function profiles N-Body simulation Comparisons with Virgo results by Arecibo Legacy (ALFALFA)

“Evidence” for WDM ?

•"missing satellite problem'',

•''cusp-core problem'',

• mini-voids The sizes of mini-voids in the local universe: an argument in favor of a warm dark matter model? Tikhonov et al.

•HI determinations of velocity function profiles N-Body simulation Comparisons with Virgo results by Arecibo Legacy (ALFALFA)

• Detection of 2.5 keV X-ray from dark dwarf galaxy?

“Evidence” for WDM ?

Before we get too depressed or excited

…

Before we get too depressed or excited

…

• Do not trust fashion fads !

• How much can one trust N-Body simulations?

• Beware of data analysis bias ! Blind analysis?

Strong Reliance on N-body Strong Reliance on N-body simulationssimulations

eg Gao et al., Jing et al., Yepes et al.,

WDM and CDM simulations.

- Non-linear collapse of WDM structures

- A replacement for the NFW model (WDM)

- Effects of Baryons

CDM Dark matter halo profilefrom N-Body simulations

Cusps?Old CDM Simulations cusps(Navarro, Frenk, White 1996):

The latest cosmological N-body simulations find two intriguing properties for dark matter haloes: (1) their radial density profile, ρ, is better fit by a form that flattens to a constant at the halo center (the Einasto profile) than the widely-used NFW form;(2) the radial profile of the pseudo-phase-space density, continues to be well fit by a power law, as seen in earlier lower-resolution simulations.

Ma Chung Pei, Chang, P., Zhang, 2009

Predict the two properties cannot hold at all scales

Einasto vs NFW

Nature of dark matter or astrophysics process?

eg, Maschenko et al. 2006, Nature, or 2008, science, etc…

SN feedback and Radiation pressure

answer the cuspy/cored issue for spiral galaxy Maccio et al. ApJ 2012

- High resolution cosmological hydro-dynamical simulations effects of dissipative processes on the inner distribution of dark matter in Milky-Way like objects (M ≈ 1012 M ⊙ ).

- supernova feedback + effects of radiation pressure of massive stars before explosion

increased stellar feedback expansion of the DM halo instead of contraction with respect to N-body simulations.

Baryons erase the DM cuspy distribution flat , cored DM density profile, well fit by a Burkert profile, with fitting parameters consistent with observations.

More faint or dark galaxies discovered

Eg, Belokurov et al, 2010

Missing satellites: CDM way out

• satellites do exist, but star formation suppressed (after reionization?)

• satellites orbit do not bring them to close interaction with disk, so they will not heat up the disk.

• Local Group dwarf velocity dispersion underestimated

• Galaxies may not follow dwarves

Halo substructures may be probed by -Lensing-local Milky Way structures

Future Measurements of DM properties with lensing

I. Cosmic shear power spectra: Mass constraints? II. Galaxy-scale DM density profiles:

• Galaxy-galaxy lensing

• Magnification

Sensitivity of detection scales by lensing

Strong lensing: 1-10 kpc

Flexion: 10-100 kpc

Weak lensing: <100 kpc

Cosmic shear power spectra Markovic et al. 2010 Euclid-like DE space survey +Planck:

Integral effects → better than matter power spectrum

Sensitive to m_WDM < 2.5 keV

Cosmic shear power spectra Markovic et al. 2010 Euclid-like DE space survey

+Planck:

Power spectra and sensitivity to WDM

Is that interesting ? Lyman constraints m > 2 or 4 keV or even higher – But doubts on Lyresults!

Baryon physics (AGN feedback) affects Matter Power Spectrum

Semboloni et al. (2011)

Van Daalen et al.(2011)

Shale et al :OWLS simulation

Consequences on WL

cosmological parameters fits

Baryon effects different from neutrino or WDM effects

Semboloni et al. 2011

Mandelbaum et al. (2006)

Stacked galaxy—galaxy weak lensing signal fit with various profiles.

CL0024

Tyson, Kochanski, & Dell’Antonio (1998)

Probing DM Particle properties

Galaxy-galaxy lensing

Measure the correlation of shear of the background galaxies with mass of the foreground galaxies

To obtain the galaxy-galaxy lensing signal, we need two important ingredients that we can extract from the data

1)the redshift distribution of the lensed background galaxies

2)the shape of the lensed background galaxies

Surface density profile measurements obtained from galaxy groups

in the COSMOS survey Leauthaud et al. 2010

Magnification (Van Waerbeke et al. 2010)

An alternative way to determine the galaxy profile, especially for the high redshift galaxies (z>=1).

- Need: precise photometry (but not shape)

- Measure: number density of galaxies

-Noise:

1. Poisson noise

2. galaxy clustering

Conclusions• Astrophysical observations existence of non baryonic

Dark Matter

• N-Body simulations of LSS existence of not-hot DM?

• Many problems with CDM simulations

can be solved with O(1keV) WDM

- Or Baryon feedback ?

More work on N-body simulations needed !

-What can WDM be? Sterile neutrinos? -How can O(1keV) WDM be observed? Lensing , X-ray,…-How can massive CDM be observed: Direct and Indirect detection experiments + accelerator production of new particles…

Thank You!