Thomas Collett Institute of Astronomy, Cambridge Probing Dark Energy with Double Source-plane Strong Lenses Thomas Collett Institute of Astronomy, Cambridge With: Matt Auger and others

Probing Cosmological Parameters with Strong Lenses Thomas Collett

RARE Double source plane strong lensing Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Double source plane strong lensing A gravitational lens system with two background sources, each at a different redshift. RARE

Few Probes Precise measurements Systematics important Probing Cosmological Parameters with Strong Lenses Thomas Collett Few Probes Precise measurements Systematics important Mantz et al. 2014

Uncertainty in the mass model makes cosmography hard Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Uncertainty in the mass model makes cosmography hard Hubble constant + can add a term for spatial curvature Dark Energy Equation of State Matter Density

Approximately the ratio of Einstein radii Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The observable: Lens Strength Ratio Approximately the ratio of Einstein radii

The observable: Lens Strength Ratio Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: Lens Strength Ratio

No dependence on the Hubble constant! Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The observable: Lens Strength Ratio No dependence on the Hubble constant!

The observable: Lens Strength Ratio Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: Lens Strength Ratio

The observable: Lens Strength Ratio Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: Lens Strength Ratio

The observable: Lens Strength Ratio Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses The observable: Lens Strength Ratio Makes no assumptions about the lens mass distribution or source positions

Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett What do we need to do? ?

ρ∝ r ρ∝ r MASS LIGHT -η-1 -2 Lens modelling shear Sersic Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling shear -η-1 -2 ρ∝ r ρ∝ r ~ MASS LIGHT Sersic Regularized, Pixellated Sources

Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Lens modelling ( ) S1 M =

Modelling J0946 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Modelling J0946

Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Modelling J0946 σ=97±7 km/s 1.402 1.392 0.2 -1 -1 0.1 1.44 1.4 -1 1.36 -1 0.95 1 1.05 1.394 1.4 0.1 0.2 Powerlaw slope,

Second Source Redshift Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Second Source Redshift

Constraining Cosmology. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology.

Constraining Cosmology. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology.

Constraining Cosmology. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology.

Constraining Cosmology. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology.

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology.

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. J0946 + WMAP prior:

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. J0946 + WMAP prior (2013, 68% CLs)

Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The Future The Future

Expect at least hundreds! (maybe several hundreds) Euclid Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Euclid Expect at least hundreds! (maybe several hundreds) ~105 galaxy scale strong lenses (based on COSMOS ) 1 in 40-80 galaxy scale lenses will be doubles (Gavazzi+ 2008)

Euclid Black: 6 lenses, Ωk = 0 FoM = 14.2 Red: 100 lenses, Ωk ≠ 0 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Euclid Black: 6 lenses, Ωk = 0 FoM = 14.2 Red: 100 lenses, Ωk ≠ 0 FoM = 38 σ(Ωk) = 0.005 Collett+ in prep. (includes Planck prior)

Euclid Black: 6 lenses, Ωk = 0 FoM = 14.2 Red: 100 lenses, Ωk ≠ 0 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Euclid Black: 6 lenses, Ωk = 0 FoM = 14.2 Red: 100 lenses, Ωk ≠ 0 FoM = 38 σ(Ωk) = 0.005 Collett+ in prep. (includes Planck prior)

Summary Independent systematic errors Independent of Hubble constant Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Summary Independent systematic errors Independent of Hubble constant DSPLs will be competitive and complementary cosmological probes in the Euclid/LSST/SKA era

Source flux only in masked region Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Idealizations Pre-subtract galaxy Source flux only in masked region Deterministic location of first source mass Curvature regularized sources Simple Mass models No line of sight lensing

Finding more systems Piggy-back on deep, large area surveys Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Finding more systems Piggy-back on deep, large area surveys Target known lenses Target the most massive galaxies

Exotic lenses with Euclid/LSST Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Exotic lenses with Euclid/LSST ~ 40 lensed type Ia Sne ~ 30 DSPLs where one is an AGN ~ Triple source plane lenses? ~ Double time-delay systems? *These numbers have big error-bars!

Einstein Dartboards Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Einstein Dartboards

Systematics Mass between the two rings Mass of the intermediate source Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Systematics Mass between the two rings Mass of the intermediate source Mass along the line of sight

Perturbations by the intermediate source Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Perturbations by the intermediate source If completely neglected: LMC: ~1% systematic error on η MW: ~10% systematic error on η Effect is detectable: include in the lens model. (Sonnenfeld+ 2012, Fixed cosmology, photometric zs2)

Strong constraints on the mass profile γTOT = 1.98 ± 0.02 ± 0.01 OR Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Profile of the Lens Strong constraints on the mass profile γTOT = 1.98 ± 0.02 ± 0.01 OR γDM = 1.7 ± 0.2 Using dynamics and both Einstein radii (Sonnenfeld+ 2012)

Lens modelling Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling

Lens modelling Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling

Lens modelling Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling

Lens modelling Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling

Lens modelling Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Lens modelling

Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Lens modelling ( ) S1 M =

Intermediate source: θE=0.16”±0.05 σv≈100 kms-1 Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Intermediate source: θE=0.16”±0.05 σv≈100 kms-1 NB// Parametric source light

Intermediate source: θE=0.16”±0.05 σv≈100 kms-1 Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Intermediate source: θE=0.16”±0.05 σv≈100 kms-1 NB// Parametric source light

What about the assumption of flatness? Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Thomas Collett 45 45 45 What about the assumption of flatness? Ωk ≠ 0 Ωk ≡ 0

What if we can't measure the ratio of Einstein radii to 1%? Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett What if we can't measure the ratio of Einstein radii to 1%? 1. Compound lensing – the intermediate source has mass 2. The lens is an astrophysical object 3. Line of sight lensing may be significant

Cosmology with a population of systems. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Cosmology with a population of systems. SLACS: 1.1mm, S > 1 mJy → ~1.5 double source plane systems (1.5 in 78) 1.1mm, S > 0.3 mJy → ~3 double source plane systems (3 in 78) But can be more efficient if you focus only on the most massive lenses.

Constraints with 6 systems. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Thomas Collett Thomas Collett Constraints with 6 systems. Pick the set of systems that provided the median constraints on w. WMAP+6 systems is ~2.5 times better than WMAP+1. WMAP+ 1 system wDE = −0.99 ± 0.27 6 systems wDE = −1.01 ± 0.11 WMAP+BAO+Time Delay+ 6 systems wDE = −1.04 ± 0.09

Planck+6 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett 49 49 49 Planck+6

ρ=ρ0r-γ' Probing the mass profile of galaxies Probing Cosmological Parameters with Strong Lenses Cosmology with Strong Lensing. Thomas Collett 50 Probing the mass profile of galaxies Combine Einstein Radius with stellar dynamics Fit a power-law: ρ=ρ0r-γ' Lenses are approximately isothermal (γ'=2). (Koopmans+ 2006) (Auger+ 2010) γ' = 2.078 ± 0.027 with an intrinsic scatter of 0.16 ± 0.02