Synergistic cosmology across the spectrum

Transcription

1 Synergistic cosmology across the spectrum Stefano Camera Dipartimento di Fisica, Università degli Studi di Torino, Italy

2 Fundamental Cosmology Lion Panther She-wolf

3 Fundamental Cosmology Dark matter Dark energy Inflation

4 Synergies

5 UNIVERSITÀ Stefano Camera Synergies Synergistic cosmology across the spectrum 24 v 2017

6 Outline Synergies: Why and how? Synergies vs Noise: Synergies vs Cosmic Variance:

7 Correlations Cosmological perturbation [temperature anisotropies, density fluctuations ] f(t,x) Correlation function Power spectrum ξ f (t, x y )=hf(t,x)f(t,y)i hˆf k (t)ˆf? k 0 (t)i = δ D (k k 0 )P f (k,t)

8 Correlations Cosmological perturbation [temperature anisotropies, density fluctuations ] f(t,x) Correlation function Power spectrum ξ f (t, x y )=hf(t,x)f(t,y)i hˆf k (t)ˆf? k 0 (t)i = δ D (k k 0 )P f (k,t) Example #1: Cosmic microwave background temperature anisotropies f(t,x) T(t rec, ~ ) T CMB

9 Correlations Cosmological perturbation [temperature anisotropies, density fluctuations ] f(t,x) Correlation function Power spectrum ξ f (t, x y )=hf(t,x)f(t,y)i hˆf k (t)ˆf? k 0 (t)i = δ D (k k 0 )P f (k,t) Example #1: Cosmic microwave background temperature anisotropies ˆf k (t) a`m

10 Correlations Cosmological perturbation [temperature anisotropies, density fluctuations ] f(t,x) Correlation function Power spectrum ξ f (t, x y )=hf(t,x)f(t,y)i hˆf k (t)ˆf? k 0 (t)i = δ D (k k 0 )P f (k,t) Example #1: Cosmic microwave background temperature anisotropies ha`m a?`0m 0 i = δ``0,mm 0 K C T`

11 Correlations `(`+1)C T` /(2 )[(TCMB/µK) 2 ] θ[deg] [Planck Collaboration, 2015] `

12 Correlations Cosmological perturbation [temperature anisotropies, density fluctuations ] f(t,x) Correlation function Power spectrum ξ f (t, x y )=hf(t,x)f(t,y)i hˆf k (t)ˆf? k 0 (t)i = δ D (k k 0 )P f (k,t) Example #2: Matter power spectrum f(t,x) δ g (t,x)=b g (t)δ(t,x)

13 Correlations [SDSS-III BOSS Collaboration, 2012] ξ g (s = x y ) s[mpc/h]

14 Correlations [Klypin et al., 2016]

15 Cross-Correlations Cosmological perturbation Correlation function f(t,x) ξ fg (t, x y )=hf(t,x)g(t,y)i Power spectrum hˆf k (t)ĝ? k 0 (t)i = δ D (k k 0 )P fg (k,t)

16 Cross-Correlations Cosmological perturbation Correlation function f(t,x) ξ fg (t, x y )=hf(t,x)g(t,y)i Power spectrum hˆf k (t)ĝ? k 0 (t)i = δ D (k k 0 )P fg (k,t) WHY!?

17 Cross-Correlations Cosmological perturbation Correlation function f(t,x) ξ fg (t, x y )=hf(t,x)g(t,y)i Power spectrum hˆf k (t)ĝ? k 0 (t)i = δ D (k k 0 )P fg (k,t) Measurement [noise, systematic effects, cosmic variance ] C f,obs ` = s 2 f` C +Cf,sys (2`+1)f ` sky +N f`

18 Outline Synergies: Why and how? Synergies vs Noise: Indirect search of particle dark matter signatures Synergies vs Cosmic Variance: Multi-tracing galaxy number counts

19 Particle Dark Matter Particle dark matter established ingredient of concordance cosmology Weakly interacting massive particles (WIMPs) Indirect detection experimentrs: WIMP-sourced cosmic & gamma rays Decay Annihilation

20 DM-Sourced Gamma Rays

21 DM-Sourced Gamma Rays Hunting down signals of annihilations/decays of dark matter particles Gamma-ray energy spectrum [Fornasa & Sánchez-Conde, 2015] DGRB energy spectrum (Ackermann et al. 2014) Foreground system. error (Ackermann et al. (2014) Blazars (Ajello et al. (2015) 10 s -1 sr -1 ] Misaligned AGNs (Di Mauro et al. 2014) Star-forming galaxies (Tamborra et al. 2014) Dark matter Millisecond pulsars (Calore et al. 2014) 10 dφ/dedω [MeV cm E Energy [MeV] m DM

22 DM-Sourced Gamma Rays Hunting down signals of annihilations/decays of dark matter particles Gamma-ray anisotropies angular spectrum [SC, Fornasa, Fornengo & Regis, ApJL 2013] Auto-correlation γ-rays E > 1 GeV l (l+1) C l /(2π) blazars annihilating DM Fermi-LAT star-forming galaxies decaying DM Multipole l

23 Direct Gravitational Probes [Lukic et al.; Image: Casey Stark] Potential wells of the cosmic large-scale structure Gamma rays from astrophysical sources hosted within the dark matter halo Gamma rays from annihilations/decays of dark matter particles forming the halo

24 Direct Gravitational Probes Find an optimal tracer of the cosmic dark matter distribution on large scale to filter out astrophysical non-thermal emission from the dark matter gamma-ray signal Main tracers of the cosmic large-scale structure: Weak gravitational lensing (cosmic shear, CMB lensing ) Clustering of structures (galaxies, galaxy clusters ) [SC, Fornasa, Fornengo & Regis, ApJL 2013; Fornengo, Perrotto, Regis & SC, ApJL 2015; Shirasaki et al. 2013; 2015] [Fornengo & Regis, 2014; Ando et al., 2014; Xia et al., ApJS 2015; Regis et al., PRL 2015; Shirasaki et al., 2015, Branchini, SC et al., ApJS 2017]

25 Gamma Rays & Weak Lensing [SC, Fornasa, Fornengo & Regis, ApJL 2013] 10-3 shear - blazar, b bla = b h (M(L bla )) shear - SFG, b sfg = b h (M(L sfg )) shear - dec. DM 10-3 shear - blazar, b bla = b h (M(L bla )) shear - SFG, b sfg = b h (M(L sfg )) shear - ann. DM l (l+1) C l /(2π) F lim = cm -2 s -1 (E > 100 MeV) E > 1 GeV x 100 l (l+1) C l /(2π) Cross-correlation Fermi LAT - Dark Energy Survey 10-4 Auto-correlation E > 1 GeV blazars annihilating DM Multipole l Multipole l Multipole l l (l+1) C l /(2π) Fermi-LAT star-forming galaxies γ-rays decaying DM 10-6 F lim = cm -2 s -1 (E > 100 MeV) E > 1 GeV x 100 Cross-correlation Fermi LAT - Euclid

26 Gamma Rays & Weak Lensing [SC, Fornasa, Fornengo & Regis, 2015] Uncertainty on dark matter properties Thermal cross-section Benchmark model Uncertainty on unresolved astrophysical emission

27 Gamma Rays & Weak Lensing σannv [cm 3 s 1 ] HIGH HIGH + astro MID LOW Thermal cross-section [Tröster, SC et al., 2017] b b, CFHTLenS + RCSLenS + KiDS m DM [GeV]

28 Gamma Rays & Clusters [(cm -2 s -1 sr -1 ) sr] Fermi-LAT x redmapper E γ > 1 GeV [Branchini, SC et al., 2017] blazars magn SFG ICM noise C l γc Multipole l

29 Outline Synergies: Why and how? Synergies vs Noise: Indirect search of particle dark matter signatures Synergies vs Cosmic Variance: Multi-tracing galaxy number counts

30 Galaxy Number Counts Proxy of the matter power spectrum f(t,x) δ g (t,x)=b g (t)δ(t,x) Primordial non-gaussianity One of inflation s 4 smoking guns Tightest available constraints from CMB: f NL < ~10 f NL > 0 P δ (k,z) P g (k,z)

31 Galaxy Number Counts Proxy of the matter power spectrum f(t,x) δ g (t,x)=b g (t)δ(t,x) Primordial non-gaussianity One of inflation s 4 smoking guns Tightest available constraints from CMB: f NL < ~10 f NL > 0 P δ (k,z) P g (k,z)

32 Galaxy Number Counts Proxy of the matter power spectrum f(t,x) δ g (t,x)=b g (t)δ(t,x) Primordial non-gaussianity One of inflation s 4 smoking guns Tightest available constraints from CMB: f NL < ~10 f NL > 0 P δ (k,z) P g (k,z)

33 Galaxy Number Counts Proxy of the matter power spectrum f(t,x) δ g (z,ˆn)= N g(z,ˆn) N g (z) N g (z)

34 Galaxy Number Counts Proxy of the matter power spectrum N g (z,ˆn) N g (z) N g (z) δρ(z,ˆn) ρ( z) d ρ d z δz(z,ˆn) ρ( z) + δv(z,ˆn) V(z) [Yoo, 2010; Bonvin & Durrer, 2011; Challinor & Lewis, 2011; Bertacca et al., 2012]

35 Galaxy Number Counts Proxy of the matter power spectrum N g (z,ˆn) N g (z) N g (z) δρ(z,ˆn) ρ( z) d ρ d z δz(z,ˆn) ρ( z) + δv(z,ˆn) V(z) Newtonian density fluctuations [Yoo, 2010; Bonvin & Durrer, 2011; Challinor & Lewis, 2011; Bertacca et al., 2012] Redshift-space distortions Lensing Gravitational redshift, time delay, Sachs-Wolfe and integrated Sachs-Wolfe

36 Accessing the Largest Scales Probe huge volumes [high sensitivity at high-z over large sky areas] [SDSS-III BOSS Collaboration, 2012] Beat cosmic variance [we have only one Universe to observe!]???????

37 Multi-Tracer Technique Comparing the relative clustering of different populations of tracers [Seljak, 2009; Seljak & McDonald, 2009]

38 Multi-Tracer Technique Comparing the relative clustering of different populations of tracers [Seljak, 2009; Seljak & McDonald, 2009] [Fonseca, SC, Santos & Maartens, ApJ Lett. 2015] Forecast error on fnl Noise level

39 Summary Great time for synergies among cosmological surveys at various wavelengths Cross-correlations valuable for: Cross-checking validity of cosmological results Accessing signal buried in noise or cosmic variance [e.g. particle dark matter signatures, multi-tracing for non-gaussianity] Removing/alleviating contamination from systematic effects [e.g. radio-optical cosmic shear]