• No results found

Nonlinear Evolution in Cold Dark Matter + Neutrino Cosmologies

N/A
N/A
Protected

Academic year: 2023

Share "Nonlinear Evolution in Cold Dark Matter + Neutrino Cosmologies"

Copied!
32
0
0

Loading.... (view fulltext now)

Full text

(1)

Nonlinear Evolution in Cold Dark Matter + Neutrino Cosmologies

Marilena LoVerde

C. N. Yang Institute for Theoretical Physics Stony Brook University

ML 1405.4855, 1602.08108 Hu, Chiang, Li, ML 1605.01412

Chiang, Li, Hu, ML 1609.01701 + in prep.

(2)

Nonlinear Evolution in Cold Dark Matter + Neutrino Cosmologies

Marilena LoVerde

C. N. Yang Institute for Theoretical Physics Stony Brook University

ML 1405.4855, 1602.08108 Hu, Chiang, Li, ML 1605.01412

Chiang, Li, Hu, ML 1609.01701 + in prep. Chi-Ting Chiang (YITP, Stony Brook) Wayne Hu (KICP, Chicago)

Yin Li (Berkeley & IPMU, U Tokyo)

(3)

What we know about the neutrino mass scale

𝜈i ≳ 0.05eV

neutrino mass

lower bounds on mass from oscillation data

𝜈j ≳ 0.01eV

(4)

What we know about the neutrino mass scale

𝜈i ≳ 0.05eV

(Troitsk experiment 2011)

neutrino mass

upper bound on mass m𝞶e ≲ 2eV

lower bounds on mass from oscillation data

𝜈j ≳ 0.01eV

(5)

What we know about the neutrino mass scale

𝜈i ≳ 0.05eV

(Troitsk experiment 2011)

neutrino mass

upper bound on mass m𝞶e ≲ 2eV

Cosmology

lower bounds on mass from oscillation data

Σ mν ≾ 0.49eV

upper bound on sum of masses

(CMB alone, Planck 2015)

Σ mν ≾ 0.17eV

(CMB + BAO, Planck 2015)

𝜈j ≳ 0.01eV

(6)

What we know about the neutrino mass scale

𝜈i ≳ 0.05eV

(Troitsk experiment 2011)

neutrino mass

upper bound on mass m𝞶e ≲ 2eV

future cosmology?!

Cosmology

lower bounds on mass from oscillation data

Σ mν ≾ 0.49eV

upper bound on sum of masses

(CMB alone, Planck 2015)

Σ mν ≾ 0.17eV

(CMB + BAO, Planck 2015)

𝜈j ≳ 0.01eV

(CMB S4, SO, DESI, Euclid, LSST, WFIRST. . .)

(7)

What neutrinos masses do to observables

The gravitational evolution of large-scale structure is different for fast and slow moving particles

(clump easily) (don’t clump easily) baryons and cold dark

matter

neutrinos (or other exotic light dark

matter)

(8)

time

small-scale density perturbations don’t retain

neutrinos

𝝳𝞀c 𝞀c

cold dark matter and baryons density

perturbation growing

𝝳𝞀𝞶 𝞀𝞶

neutrino density perturbation

decaying

What neutrinos masses do to observables

(9)

large-scale density perturbations do

retain neutrinos

𝝳𝞀c 𝞀c cold dark

matter,

baryons and neutrinos

growing together

𝝳𝞀𝞶 𝞀𝞶

time

small-scale density perturbations don’t retain

neutrinos

What neutrinos masses do to observables

(10)

This scale-dependent growth is the effect that gives main cosmological constraints on neutrino mass

P(k) = ⟨δm(k)δm(k)⟩ where δm(k) = δρ—————ρmattermatter

Hu, Eisenstein, Tegmark 1998 Bond, Efstathiou, Silk 1980

Fourier mode k (h/Mpc)

small scales damped large-scales the same

Suppression in P(k) - variance of density fluctuations δneutrino

What neutrinos masses do to observables

(11)

This scale-dependent growth is the effect that gives main cosmological constraints on neutrino mass

Hu, Eisenstein, Tegmark 1998 Bond, Efstathiou, Silk 1980

What neutrinos masses do to observables

—> less gravitational lensing than a universe where all matter is

gravitationally clustered

—> lower amplitude galaxy clustering than a universe where all matter is

gravitationally clustered

(12)

Claim:

Small scale structure in regions (i) and (ii) will evolve differently. This gives new scale-

dependent signatures of massive neutrinos.

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

(13)

Claim:

Small scale structure in regions (i) and (ii) will evolve differently. This gives new scale-

dependent signatures of massive neutrinos.

δC

δν δC, δν

x.

. .. . x.

. .. .

δC(k >> kfs) δC(k << kfs)

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

(14)

Claim:

Small scale structure in regions (i) and (ii) will evolve differently. This gives new scale-

dependent signatures of massive neutrinos.

δC

δν δC, δν

x.

. .. . x.

. .. .

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

(e.g. eventual number of galaxies, amplitude of the small-scale power spectrum, etc will differ slightly in regions (i) and (ii))

(15)

δC

δν δC, δν

x.

. .. . x.

... .

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

Why?

evolution of 𝛅c(t)

t

δC(k >> kfs)

δC(k << kfs)

(16)

δC

δν δC, δν

x.

. .. . x.

... .

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

Why?

evolution of 𝛅c(t)

t

δC(k >> kfs)

δC(k << kfs)

local expansion aW = a(1 -𝛅c(t)/3)

t

δC(k >> kfs) δC(k << kfs)

(17)

δC

δν δC, δν

x.

. .. . x.

... .

(i) super-Jeans scale over-density (ii) sub-Jeans scale overdensity

Why?

evolution of 𝛅c(t)

t

δC(k >> kfs)

δC(k << kfs)

local expansion aW = a(1 -𝛅c(t)/3)

t

local growth of small-scale density perturbations

t

(18)

Ratio of fractional changes to (log of )

local expansion history for super/

sub Jeans regions

fν = 0.005

fν = 0.11

scale factor

Precisely:

(19)

Ratio of fractional changes to (log of )

local Hubble rate for super/sub Jeans

regions

Precisely:

scale factor

fν = 0.11

fν = 0.005

(20)

Predictions:

fractional neutrino energy density

~ squeezed-limit bispectrum

<𝝳(k___________s)𝝳(-ks -kL )𝝳(kL)>

P(kL)

The change in the growth rate in over/underdense regions is scale-dependent

(21)

wavenumber of long-wavelength mode kL

~ squeezed-limit bispectrum

<𝝳(k___________s)𝝳(-ks -kL )𝝳(kL)>

P(kL)

The change in the growth rate in over/underdense regions is scale-dependent

Predictions:

(22)

Predictions:

wavenumber k (Mpc-1)

scale-dependence of halo bias

b(k) = Phh(k)/Pmm(k)

(Spherical Collapse in Separate Universe) The halo bias is scale-dependent

ML 2014

(23)

Test this with N-body simulations in regions with different background densities δc(k,a) with different k

(24)

Test this with N-body simulations in regions with different background densities δc(k,a) with different k

Account for δc(k,a) by feeding GADGET the a, H(a) that an observer in regions with δc(k,a) would see

(25)

Test this with N-body simulations in regions with different background densities δc(k,a) with different k

Account for δc(k,a) by feeding GADGET the a, H(a) that an observer in regions with δc(k,a) would see

McDonald 2001 Sirko 2005;

Gnedin & Kravtsov 2011

Baldauf, Seljak, Senatore, Zaldarriaga 2011, 2015 Li, Hu, Takada 2014, 2016

Chiang, Wagner, Schmidt, Komatsu 2014a, (+perm) 2014b

So-called “Separate Universe” approach, now extended to cosmologies beyond LCDM

Hu, Chiang, Li, ML 1605.01412 Chiang, Li, Hu, ML 1609.01701

(26)

wavenumber k

Results

(27)

wavenumber k

The change in small-scale growth of structure depends the on wavelength of the background over/under density

“Response” of growth to background over density

ks

Chiang, Li, Hu, ML in prep

(28)

wavenumber k

The change in small-scale growth of structure depends the on wavelength of the background over/under density

~ squeezed-limit bispectrum

<𝝳(k___________s)𝝳(-ks -kL )𝝳(kL)>

P(kL)

ks

Chiang, Li, Hu, ML in prep

(29)

wavenumber k

The change in the abundance of halos depends the on wavelength of the background over/under density

Chiang, Li, Hu, ML in prep

(30)

wavenumber k

The change in the abundance of halos depends the on wavelength of the background over/under density

Chiang, Li, Hu, ML in prep

this gives rise to a step feature in the halo bias

“step” in the bias

(31)

wavenumber k

The change in the abundance of halos depends the on wavelength of the background over/under density

Chiang, Li, Hu, ML in prep

this gives rise to a step feature in the halo bias

“step” in the bias

(32)

Summary

Nonlinear structure formation is complicated! But, can lead to new phenomena that may provide new insights into neutrinos and beyond

We have a new way to simply study a limited set of

observables in cosmologies with multiple fluids and non- gravitational forces, while still only doing CDM simulations (i.e. no new code to model additional fluid behavior)

The presence of a Jeans scale can lead to new

observables (scale dependent bias, scale-dependent squeezed bispectrum)

References

Related documents

The literature suggests that immigrants boost Sweden’s performance in international trade but that Sweden may lose out on some of the positive effects of immigration on

För att uppskatta den totala effekten av reformerna måste dock hänsyn tas till såväl samt- liga priseffekter som sammansättningseffekter, till följd av ökad försäljningsandel

Coad (2007) presenterar resultat som indikerar att små företag inom tillverkningsindustrin i Frankrike generellt kännetecknas av att tillväxten är negativt korrelerad över

The increasing availability of data and attention to services has increased the understanding of the contribution of services to innovation and productivity in

Generella styrmedel kan ha varit mindre verksamma än man har trott De generella styrmedlen, till skillnad från de specifika styrmedlen, har kommit att användas i större

a) Inom den regionala utvecklingen betonas allt oftare betydelsen av de kvalitativa faktorerna och kunnandet. En kvalitativ faktor är samarbetet mellan de olika

Närmare 90 procent av de statliga medlen (intäkter och utgifter) för näringslivets klimatomställning går till generella styrmedel, det vill säga styrmedel som påverkar

Den förbättrade tillgängligheten berör framför allt boende i områden med en mycket hög eller hög tillgänglighet till tätorter, men även antalet personer med längre än