Fluctuations in modelswith sterile-WDM

Silvio BonomettoPhysics Dep., Trieste Univ. &INAF, Trieste Observatory

Conca Specchiulla, sep 10, 2014

Paper in collaboration with 3M’s

R.Mainini, A. Macciò, I.Musco

LWDM cosmologies, “spiced” with a pinch of strongly coupled CDM, meet all data LCDM fits, as well as data LCDM fails to fit

sterile mass predicted?

LCDM cosmologies meet cosmological data down to galactic scale

Problems below galactic scale:

•Milky Way satellite abundance LCDM N-body simulations yield 20 times more satellites than observed, for a galaxy of the MW size Klypin et al ApJ 522 (1999) 82, Moore et al. ApJ 524 (1999) L19

•Dwarf galaxies exhibit a core radial density not NFW in the central region Moore, Nature 370 (1994) 629, Flores & Primack, ApJ 427 (1994) L1, Diemand et al MNRAS 364 (2005) 665, Macciò et al MNRAS 378 (2007) 55, Springel et al., MNRAS 391 (2008) 1685, de Block et al., ApJ 552(2001) L23, Oh et al., AJ 141 (2011) 193

•Dwarf galaxy abundance in large voids ….

hydro sim.including baryonphysics reduce

discrepancyto factor 2-3

biggergalaxies also

found to have coreM-ind’nt size500-1000 pc

more controversial

LWDM cosmologies halos with coree.g. Macciò et al., MNRAS 428 (2013)

Core radius related toDM particle mass:To have a core around 500-1000 pcneed m = 80-110 eV

STERILE NEUTRINO with m \sim 90eV ?

a catch-22 problem:to have a dwarf galaxies with a 500-1000 pc corewe cannot have dwarf galaxies

however… cores & dwarfs do exist !!!

New class of models :LWDM spiced with a grain of DARK pepper

s-LWDM modelsnot ad-hoc

deriving from finding a newtracker solutionin coupled-DEmodels

gala

xie

s

clu

ste

rs

As previous plotin terms ofpower spectrumP(k)

Spiced LWDM cosmologies Summary

Background• A dual component in a stationary primeval Universe • Connecting DE with inflation

• Stationarity break and rise of present cosmic environment

Inhomogenities• Linear theory• Simulations: satellites and profiles

Problems• Early non linearity , DE-CDM decoupling

Bonometto S.A., La Vacca G., Sassi G., JCAP08 (2012) 015 Bonometto S.A. & Mainini R., JCAP03 (2013) 038 Macciò A.V., Bonometto S.A., Mainini R., Musco I. (in preparation)

Strong CDM-DE coupling allows fluctuations to persist also on dwarf galaxy and MW substructure scales

preliminary

Background metric

Quintessential DE

covariant form

Cou.DE :J.Ellis et al., PL 228B (1989) 264C.Wetterich, A&A 301 (1995) 321L.Amendola, PRD 69 (1999) 043501L.A. & Tocchi-Valentini D., PRD 66 (2002)043528…. and many many others

In FRW space

data (hopefully) to yield w(a) [sooner than V(F)]

couplingallows DE

to keep signif.density also

at high z

We shall forget the potential shape, just assumingw+1 at large z, w-1 at small z, transition at zd

resultsmildly dependent

on ad &

resultsmildly dep. on zd

scarse dep.on

classical approachesassume cou.CDM to beonly DM, then << 1

here CDM is a tiny componentmain DM is uncoupled

this allows quite large

w=+1 at large z is a generic featurefor any choice of self-inter. potential

Kinetic field would dilute as aCDM would dilute as aEnergy flow from CDM to DE makes both component to dilute as a--4

--3-6

= (mp/b) ln()

f=exp[-ln()]=1/L = ()

“…. mass redshifting”

density parametersduring radiative expansion

The solution found is an

ATTRACTOR

ConformalInvariance

At high z all components sharesimilar densities (remindingsimilar decoupling redshifts)in a fully stationary expansion

Eve of the present epoch: T approaches mw

apologiesfor different color

choice

Coupling persists down to z=0 Coupling fades after invariance break

=10

slow

tenta

tive

…

fluctuation evolution equations

dispersion relation

WDM fluc.’ns restarted &baryon fluc.’ns enhanced bylarge ampl. cou-CDM fluc.’ns

” Cou.CDM : NO meszaros’ effect

fluc’ns in CDM continue to grow afterentering the horizon, over any scale

Creating deep “potential wells”

CMB spectra almost identicalto standard LCDMeven for very high

Plots obtained with modified CMBFAST

Transfer functions (CMBFAST)

A typical spectrum

(mw=220 eV = 20)

A possiblemodel pathology:coup’d CDM fluc.nsmay become >>1

Simplest solution:coupling shouldfade at low z

necessarily afterconformal inv. break by wdm derelativization

this preserves wdm fluc’n restoration

delay=Log[a(dec’g)/a(der’l’n)]

delay = 4decoup’gapproximativelywhen w shiftsfrom +1 to -1

delay = 2shown in the plot

after dec’gsufficient thatCDM+bar fluc’nsare linear

however : c<<b

models with non-linearCDM fluc’s could stillbe physicaljust hard to computestructure formation

early non-linearityto modify pop III predictions

2

mw/eV 96.80 48.51

g*/mw= 0.980

Simulated model

delay=4decouplingat +/- transition

very little changes for delay=2

Original simul.: Lbox=20 Mpc/h, Npa=300^3zoom grid: Npa=7200^3=3.73x10^11 Npa,halo=13.1x10^6,mpa=1500 Ms/h

Same halo: 2.07x10^10 Ms/h (within R200)CDM particles (v=0) WDM particles (thermal vel)

CDM pa. mw=95eV (thermal velocities)

Same halo: 2.07x10^10 Ms/h

CDM particles (v=0) 5 WDM part :1 part v=0

Original simul.: Lbox= 90 Mpc/h, Npa=300^3zoom grid: Npa=4800^3, Npa,halo=2.4x10^6, mpa=4.57x10^5 Ms/hM_halo = 1.1x10^12 Ms/h (not a lucky halo choice)

CDM particles WDM particles only NO small halos

M = 10^10 Ms/h

Density profiles

1kpc/h

MW size halo :almost overlapping profiles (but resolution is different)

1 kpc/h

LCDM “MW”

sLWDM “MW”

Satellites in 10^12 Ms halos-LWDM : reduction factor 2 / 3

PRELIMINARY CONCLUSIONS FROM SIMULATIONS

s-LWDM LCDM 1:6 cold

10^10 profile forming core NFW intermediate Dwarf closer to NFWGalaxy satellites almost 0 in excess intermediate just a few

10^12 profile NFW in all casesMilky fattening blobsWay satellites massive satellites remain small ones vanish

BUT:small halocomponentproportions

?

reso-lution

....

Conclusions

• Sub-galactic scale features hard to explain by LCDM• LWDM can help: critical feature warm particle mass• LWDM with particle 80-110 eV meets rotation curves, satellites, etc.• LWDM spectrum for such mass unsuitable

• New tracker solution for cou-DE models (background)• Primeval conformal invariance• 2 DM component already widely considered in literature• here CDM coupled + WDM uncoupled, similar primeval densities• LWDM models spiced with a pinch of cold dark pepper ….• tracker solution holding since inflation• possible connection with inflationary dynamics

• linear fluctuation evolution solved • Cou-CDM does not feel Meszaros effect• CMB spectra identical to LCDM• CDM fluc’ns re-create WDM fluc’ns

• excessive amplitude of CDM fluctuations: a computational problem• however: once conformal invariance brocken, decoupling harmless

• Simulations based on s-LWDM cosmologies confirm : rotation curves, satellite problems solved• Pop III physics to be revisited: early seeds

mostly

Thanks for

your attention

when coupling switched on w+1 at high z for any potential

Small values of to be coherent with observational dataDE decreases when w close -1, then almost parallel to CDM

11 eq(cold uncoupled…)

densities in the presenceof coupling

Spectral distorsionsdue toenergyflowfromDM toDEcompensatedbyspectral distorsionsdue toneutrino mass O(1ev)

La Vacca G. et al. J CAP 0904 (2009) 007 Amendola L. et al arXiv: 1111.1404 (0.180.16)

up to 0.18 consistent withdata if neutrino mass O(0.2eV)

CDM-DE coupling: a MUST if

“large” massdetected in particle

experiments (e.g.: )

C<0.4/mp

early universe:DE purely kinetic :constantlyd \sim 0.01c

at z \sim 10potential termtakes over

obtained with 11 eqad-hoc program

(uncoupled DM is cold)