Cosmology with Ly forests from BOSS · James Rich (IRFU) Cosmology with Ly forests from BOSS...

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Cosmology with Lyα forests from BOSS

James Rich

DPhP-IRFUCEA-Saclay

91191 Gif-sur-Yvette

james.rich@cea.fr

CosmoBack, May , 2018

Outline

The Lyα forest

BOSS“Baryon Oscillation Spectroscopy Survey”

Baryon Acoustic Oscillations in the forestCosmological parameters from BAO

Reconstructing the linear power spectrumConstraints on neutrino massesWarm dark matterFuzzy dark matter

Future projects

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 2 / 33

Quasar = Black hole accreting hot gas

Spectrum: power-law + emission lines

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 3 / 33

Quasar = Black hole accreting hot gas

Absorption by atomic hydrogen (HI) blueward of Lyα emission

Absorption at λobserved depends on nHI at z + 1 = λobs/1215.

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 4 / 33

Need to model the smoothed forest spectrum

1 + δ(λ, ~θ) =

observed flux

expected flux

Fluctuations of nHI and of radial-velocity gradiant

⇒ Fluctuations of δ(λ, ~θ)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 5 / 33

Correlate forests to find ξ(r⊥, r‖)

ξ(r⊥, r‖) =

∑wiwjδiδj∑wiwj

.

Sums over pixel pairs (i , j)

separated by (r⊥, r‖)

Weight, wi , is chosen to minimize

variance of ξ.

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 6 / 33

BOSS results: Bautista et al. (2017)

BAO peak at r = rd (sound horizon)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 7 / 33

Measured quantities (∆θ,∆z)

∆θ =r⊥

DM(z)∆z =

r‖DH(z)

⇒ BAO peak position determines

rd/DM(z) (transverse)

rd/(c/H(z)) (radial)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 8 / 33

BOSS: Baryon-Oscillation Spectroscopy Survey

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 9 / 33

BOSS Spectrograph

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 10 / 33

BOSS Spectrograph,CCD

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 11 / 33

2 BOSS surveys (104deg 2 5 years)

6× 105 Large Red Galaxies (LRG)∼ 500 fibers per plate

(candidates from SDSS-I photometry)〈z〉 ∼ 0.6, n ∼ 10−4Mpc−3

BAO results: arXiv:1607.03155

1.6× 105 quasars with Lyα absorption∼ 280 fibers per plate

(candidates from SDSS-I photometry)〈z〉 ∼ 2.4BAO results: arXiv:1702.00176; 1708.02225

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 12 / 33

Outline

The Lyα forest

BOSS“Baryon Oscillation Spectroscopy Survey”

Baryon Acoustic Oscillations in the forestCosmological parameters from BAO

Reconstructing the linear power spectrumConstraints on neutrino massesWarm dark matterFuzzy dark matter

Future projects

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 13 / 33

Correlate forests

Bautista et al. (2017)Nearly radial direction:

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 14 / 33

Correlate quasars and forestsdu Mas des Bourboux et al. (2017)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 15 / 33

Constraints on (DM/rd ,DH/rd ) at z = 2.4

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 16 / 33

Summary of BAO measurements of D/rd

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 17 / 33

BAO H(z) ⇒ deceleration→acceleration

ΛCDM prediction

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 18 / 33

BAO (DM(z)/rd ,DH(z)/rd ) ⇒ (ΩΛ,ΩM , rdH0)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 19 / 33

Top-down: the BAO and SNIa Hubble diagram

Aubourg et al. arXiv:1411.1074

Calibrate SNIa luminosityby requiringDM(z = 0.57) from SNIaagree withDM(z = 0.57) from BAO

⇒ H0 = 67.3± 1.1

Distance ladder:H0 = 73.24± 1.74,arXiv:1604.01424

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 20 / 33

Outline

The Lyα forest

BOSS“Baryon Oscillation Spectroscopy Survey”

Baryon Acoustic Oscillations in the forestCosmological parameters from BAO

Reconstructing the linear power spectrumConstraints on neutrino massesWarm dark matterFuzzy dark matter

Future projects

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 21 / 33

Lyα flux transmission power spectrum

PF (~k) = Plin(k)b2F (1 + βµ2

~k)FNL(~k)

Bias parameters (bf , β).

FNL(~k) describes “non-linear” effects.

Galaxy power spectrum depends on unknown astrophysics of galaxyand star formation.

Lyα power spectrum depends on complicated but mostly understoodhydrodynamics of the inter-galactic medium.

⇒Use simulations of IGM to find (bF , β,FNL(~k)) to derive Plin(k)

from measured PF (~k)

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 22 / 33

The Lyα forest: 1A ∼ 1Mpc

Low-resolution (BOSS)

High-resolution spectrum (Keck).Simulations must resolveJeans-length of IGM (∼ 100kpc).

Complications from non-HIabsorbers

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 23 / 33

Predicted PF 3d (~k)/PL(k) (Arinyo et al.,2016)

0.01

0.1

0.1 1 10

PF(k

)/P

L(k

)

k [h/Mpc]

color: D1black: D1, q2 = 0

z = 2.2Radial direction

At small kPradial Ptransverse

(because b 1)

Transverse direction

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 24 / 33

Predicted PF 3d (~k)/PL(k) (Arinyo et al.,2016)

0.01

0.1

0.1 1 10

PF(k

)/P

L(k

)

k [h/Mpc]

color: D1black: D1, q2 = 0

z = 2.2

Radial direction

At large kPradial suppressed(thermal broadening,chaotic velocityfield)

Transverse direction

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 25 / 33

Radial Power: BOSS, VLT, Keck

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 26 / 33

Deduced PL(k) (Palanque-Delabrouille et al

1410.7244)

Normalization of powerspectrum ∆2

Predicted by Planck ΛCDMin agreement withObserved in Lyαforest

⇒No room for extra freestreaming effects ofneutrinos

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 27 / 33

Suppression of power by massive neutrinos.

Villaescusa et al.arXiv:1708.01154

Lyα P1d(k‖)0.2 < k‖ < 4

Pgalaxy (k)0.01 < k < 1

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 28 / 33

Limits on∑

mν from Lyα -CMB comparison

Seljac, Slosar & McDonald (2006)∑

mν < 0.17 eVSDSSI + WMAP-3yr

Palanque-Delabrouille et al. (2015)∑

mν < 0.15 eVBOSS+Planck 1yr

Yeche et al. (2017)∑

mν < 0.14 eVBOSS+VLT+Planck 2015

All assume ns not running.DESI limit goal: σ(

∑mν) = 0.02eV∑

mν = 0.06 (0.11) for normal (inverted) mass ordering

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 29 / 33

Warm or Fuzzy DM cuts off the power spectrum

WDM: free-streaming

kc ∼ 6 Mpc−1(mwdm

keV

)1.1FDM: deBroglie wavelength

kc ∼ 5 Mpc−1( mfdm

10−22eV

)0.46Observed large-k power consistent with expected thermal effectsBOSS,VLT,Keck Lyαpower⇒ mwdm >∼ 5keV [arXiv:1706.03118, 1702.03314]⇒ mfdm >∼ 3× 10−21eV [arXiv:1703.09126]

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 30 / 33

Future: Dark Energy Spectroscopy Survey (DESI)

. BOSS H(z)

DESI H(z):arXiv:1611.000362.5M Sloan Telescope→4M Mayall1000fibers → 5000 fibers

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 31 / 33

WEAVE

DESI: H(z) precision

WEAVE: precision withimproved quasar selectionusing J-PAS narrow-bandphotometry

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 32 / 33

Lyα cosmology summary

Large CCD arrays and fiber-optic-fed

spectrometers have allowed (will allow)

BOSS→eBOSS→DESI to

Constrain parameters of homogeneous

cosmology with a well-understood standard

ruler from BAO

Study the small-scale power spectrum to place

constaints on massive neutrinos, warm dark

matter, and fuzzy dark matter.

James Rich (IRFU) Cosmology with Lyα forests from BOSS CosmoBack, May 2018 33 / 33