Thomas Collett Institute of Astronomy, Cambridge Probing Cosmological Parameters with Strong Lenses Thomas Collett Institute of Astronomy, Cambridge With: Matt Auger, Sherry Suyu, Phil Marshall and others

Today's model: ΛCDM Probing Cosmological Parameters with Strong Lenses Thomas Collett Today's model: ΛCDM

Why Dark Energy? Probing Cosmological Parameters with Strong Lenses Thomas Collett Why Dark Energy? Supernovae Cosmic Microwave Background Baryonic Acoustic Oscillations Weak Lensing

Lots of powerful probes... Probing Cosmological Parameters with Strong Lenses Thomas Collett Lots of powerful probes... Lots of powerful probes... inconsistent picture? Planck XVI, 2013

z=1000 Low redshift Lots of powerful probes... Probing Cosmological Parameters with Strong Lenses Thomas Collett Lots of powerful probes... Lots of powerful probes... inconsistent picture? z=1000 Low redshift Planck XVI, 2013

New physics? systematic errors? Probing Cosmological Parameters with Strong Lenses Thomas Collett New physics? systematic errors? Xia, Li & Zhang 2013

New physics? or systematic errors? Probing Cosmological Parameters with Strong Lenses Thomas Collett New physics? or systematic errors? Xia, Li & Zhang 2013

New physics? or systematic errors? Probing Cosmological Parameters with Strong Lenses Thomas Collett New physics? or systematic errors? All 3 probes are consistent

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source Image configurations depend on the distances

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source

Strong lensing is an optical bench Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Strong lensing is an optical bench Lens Source Image configurations depend on the lensing mass.

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

Strong lensing time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source

Strong lensing time delays Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source Longer Path

Strong lensing time delays Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source Longer Path More Shapiro delay

Strong lensing time delays Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source Longer Path More Shapiro delay Arrives later

Strong lensing time delays Probing Cosmological Parameters with Strong Lenses Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source Longer Path More Shapiro delay Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls Arrives later

Strong lensing time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Strong lensing time delays HE 1104-1805 Lens Source Longer Path More Shapiro delay Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls Arrives later Most sensitive to the Hubble constant.

w Σmν Nrel H0 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett w H0 Nrel Σmν

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

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

Advantages But, there are obstacles to overcome... Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Advantages One step measurement of H0 Don't need to rely on 'standardness' Insensitive to local environment (local void or peculiar velocities) Independent systematics Cheap experiment (dedicated 1m telescope and ~10s of HST orbits) But, there are obstacles to overcome...

Oscoz+ 2001: time delay is 422.6+/-0.6 Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Measuring time delays Historically very difficult. (1994) An intensive program of daily brightness monitoring suggests a further refinement of the time delay to 404 days (Schildt+ 1990) “delays less than about 475 days are strongly excluded” (Press+ 1992) Oscoz+ 2001: time delay is 422.6+/-0.6 (15 years of monitoring)

Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Measuring time delays Tewes+ 2012

Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Coverage gaps Microlensing Tewes+ 2012

Flux Time Measuring time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux Time Fassnacht+ 2002

Flux Time Measuring time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux Time Fassnacht+ 2002

Flux Time Measuring time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux Time Fassnacht+ 2002

Flux Time Measuring time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux Time Fassnacht+ 2002

Flux Time Measuring time delays Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux Time Fassnacht+ 2002

Flux Time B:0 C:31 A:36 D:77 Measuring time delays Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Measuring time delays Flux B:0 C:31 A:36 D:77 Time Fassnacht+ 2002

Cosmograil Monitoring lenses since 2004 Sampling every 2 – 5 days Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Cosmograil Monitoring lenses since 2004 Sampling every 2 – 5 days Seven 1-2m telescopes. Swiss Euler Telescope

Accurate time delays at +/- 3 day precision Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Cosmograil Blind, independent team and different method get the same result Accurate time delays at +/- 3 day precision Swiss Euler Telescope Rathna Kumar+ 2013

Time Delay 2-3% Error budget for a time delay lens: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3%

So many time delays, that we can't keep up! Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% So many time delays, that we can't keep up!

Modelling the lenses B1608 RXJ1131 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Modelling the lenses Swiss Euler Telescope B1608 RXJ1131

zd=0.630, zs=1.394 zd=0.295, zs=0.658 Modelling the lenses B1608 Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Modelling the lenses zd=0.630, zs=1.394 zd=0.295, zs=0.658 Swiss Euler Telescope B1608 RXJ1131

36 31 91 77 Modelling the lenses B1608 RXJ1131 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Modelling the lenses 36 31 91 77 ±1.5 d ±1.5 d Swiss Euler Telescope B1608 RXJ1131

Modelling the lenses Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Modelling the lenses Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls What's the constant of proportionality? Location of the images Gravitational potential Swiss Euler Telescope

cΔt =DΔt ( ½(θ1− β)2 − ½(θ2 − β)2 − ψ(θ1) + ψ(θ2) ) Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Modelling the lenses Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls What's the constant of proportionality? Location of the images Gravitational potential cΔt =DΔt ( ½(θ1− β)2 − ½(θ2 − β)2 − ψ(θ1) + ψ(θ2) ) Swiss Euler Telescope

cΔt =DΔt ( ½(θ1− β)2 − ½(θ2 − β)2 − ψ(θ1) + ψ(θ2) ) Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Modelling the lenses Δt ∝ DΔt = (1+ zl) (Dl Ds) / Dls What's the constant of proportionality? Location of the images Gravitational potential How much mass is in the annulus? cΔt =DΔt ( ½(θ1− β)2 − ½(θ2 − β)2 − ψ(θ1) + ψ(θ2) ) Swiss Euler Telescope

Not enough information Constraining the steepness of the potential Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining the steepness of the potential Not enough information

(For precision cosmology) Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining the steepness of the potential Not enough information (For precision cosmology)

Lots of information Constraining the steepness of the potential Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining the steepness of the potential Lots of information

Constraining the steepness of the potential Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining the steepness of the potential (Most probable) Model Data (F814W)

Constraining the steepness of the potential Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining the steepness of the potential (Most probable) Model Source

2-3% ~5% Time Delay Lens Profile Error budget for a time delay lens: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% Lens Profile ~5%

2-3% ~5% ? Time Delay Lens Profile Line of Sight Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% Lens Profile ~5% Line of Sight ?

This is NOT the correct context of a strong lens: Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett This is NOT the correct context of a strong lens: Swiss Euler Telescope B1608 RXJ1131

This is the correct context of a strong lens: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett This is the correct context of a strong lens: r<23 100” Swiss Euler Telescope B1608 RXJ1131

? ? ? ? H0 ~ H0homogeneous × (1-κext) The Mass Sheet Degeneracy Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy H0 ~ H0homogeneous × (1-κext) ? Underestimate Overestimate ? ? ? Hilbert+ 2010 Ray tracing through the Millennium Simulation

? ? ? ? H0 ~ H0homogeneous × (1-κext) The Mass Sheet Degeneracy Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy H0 ~ H0homogeneous × (1-κext) ? Underestimate Overestimate ? ? ? Hilbert+ 2010 Ray tracing through the Millennium Simulation

This is the correct context of a strong lens: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett This is the correct context of a strong lens: r<23 100” Swiss Euler Telescope B1608 RXJ1131

The Mass Sheet Degeneracy Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy 45 arcsec

The Mass Sheet Degeneracy Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy 45 arcsec Greene+ 2013

The Mass Sheet Degeneracy Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy 45 arcsec Greene+ 2013

The Mass Sheet Degeneracy Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy 45 arcsec Greene+ 2013

The Mass Sheet Degeneracy Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy

The Mass Sheet Degeneracy Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The Mass Sheet Degeneracy

2-3% ~5% ~5% Time Delay Lens Profile Line of Sight Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% Lens Profile ~5% Line of Sight ~5%

B1608+656 and WMAP5: Cosmological results Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Cosmological results B1608+656 and WMAP5:

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

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

H0 = 79±5 Cosmological results Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Cosmological results H0 = 79±5

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

Comparison with other probes Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Comparison with other probes owCDM BAO: Percival+ 2010 (SDSS DR7) SN: Hicken+2009 (Constitution)

Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett And along came Planck

2σ outlier And along came Planck (1 in 20) Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett And along came Planck 2σ outlier (1 in 20)

What went wrong? Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett What went wrong?

What went wrong? High ΩM, low h Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett What went wrong? High ΩM, low h

WMAP ΩM What went wrong? High ΩM, low h Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What went wrong? High ΩM, low h WMAP ΩM

WMAP ΩM What went wrong? High ΩM, low h 1131 probably is high Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What went wrong? High ΩM, low h 1131 probably is high The lens profile is shallower than we inferred OR The line of sight is more dense than we inferred WMAP ΩM

Model choice could bias H0 by 20%! Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Revisiting the lens profile: Model choice could bias H0 by 20%! (A little bit alarmist) Schneider & Sluse, 2013

Revisiting the lens profile: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Revisiting the lens profile: Realistic Mock Lenses Blindly modelled with different methods Same answers for the slope with each code so far But is it the right answer?!? TBC... Working to make lenses even more realistic

H0 = 79.7 +/- 5 Revisiting the lens profile: Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Revisiting the lens profile: H0 = 79.7 +/- 5

Revisiting the external convergence: Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Revisiting the external convergence:

Revisiting the external convergence: Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Revisiting the external convergence: 3 arcmin

Revisiting the external convergence: Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Revisiting the external convergence: 3 arcmin

Revisiting the external convergence: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Revisiting the external convergence: 0.01 precision on κ. Unbiased* Width of ensemble P(κext) 3 arcmin

2-3% ~5% ~5% Time Delay Lens Profile Line of Sight Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% Lens Profile ~5% Line of Sight ~5%

2-3% ~5% 1% Time Delay Lens Profile Line of Sight Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Error budget for a time delay lens: Time Delay 2-3% Lens Profile ~5% Line of Sight 1%

Could be useful for SNe, and high-z galaxies Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Other advantages of reconstructing the Line of Sight: Mass isn't all in a sheet at the lens redshift H0 ~ H0homogeneous × (1-κext) Could be useful for SNe, and high-z galaxies

The future for time delays. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The future for time delays. Right now (HST cycle 20)

The future for time delays. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett The future for time delays. LSST: 3000 measured time delays. (Including 50 lensed SNe Ia)

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

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

What is double source plane strong lensing? Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What is double source plane strong lensing? A gravitational lens system with two background sources, each at a different redshift. SLACS J0946+1006

What is double source plane strong lensing? Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What is double source plane strong lensing? A gravitational lens system with two background sources, each at a different redshift. Lens Galaxy SLACS J0946+1006

What is double source plane strong lensing? Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What is double source plane strong lensing? A gravitational lens system with two background sources, each at a different redshift. Images of the intermediate source SLACS J0946+1006

What is double source plane strong lensing? Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett What is double source plane strong lensing? A gravitational lens system with two background sources, each at a different redshift. Images of the background source SLACS J0946+1006

The observable: The Ratio of Einstein Radii. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: The Ratio of Einstein Radii.

The observable: The Ratio of Einstein Radii. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: The Ratio of Einstein Radii.

The observable: The Ratio of Einstein Radii. Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett The observable: The Ratio of Einstein Radii.

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: The Ratio of Einstein Radii. No dependence on the Hubble constant!

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. zl = 0.35 zs1 = 0.6 zs2 = 1.5 Collett+ 2012

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. zl = 0.35 zs1 = 0.6 zs2 = 1.5 WMAP Collett+ 2012

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. zl = 0.35 zs1 = 0.6 zs2 = 1.5 WMAP Combination Collett+ 2012

Jullo et al. (2010) Results: ΩM= 0.25 ± 0.05, wDE = −0.97 ± 0.07 Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Jullo et al. (2010) Results: ΩM= 0.25 ± 0.05, wDE = −0.97 ± 0.07 (Abel 1689 + WMAP5 + X-ray cluster constraints) The mass is very complicated Hard to control systematics

Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Jullo et al. (2010) Results:

Constraining Cosmology. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraining Cosmology. Preliminary models of J0946 suggest statistical uncertainty of ~1% on the ratio of Einstein Radii. Uncertainty is dominated by the lens' mass density slope

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

Constraints with 6 systems. Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Constraints with 6 systems. Collett+ 2012 Forecast the distribution of lens and source redshifts 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

Beyond wCDM Evolving models of dark energy: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Beyond wCDM Collett+ 2012 Evolving models of dark energy: Olive: 6 double source plane lenses Grey: Planck (Forecast, including polarization and weak lensing constraints) Black: combination

Beyond wCDM Evolving models of dark energy: Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Beyond wCDM Collett+ 2012 Evolving models of dark energy: Olive: 6 double source plane lenses Grey: Planck (Forecast, including polarization and weak lensing constraints) Black: combination FoM = 6.17π/A95 = 14.2 WMAP plus Union SNe → 15 (Mortonson+2010)

Forecasting the rate of strong lensing Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Forecasting the rate of strong lensing Lenses are close to Isothermal Constant physical deflection angle

Forecasting the rate of strong lensing Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Forecasting the rate of strong lensing Lenses are close to Isothermal Constant physical deflection angle

Forecasting the rate of strong lensing Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Forecasting the rate of strong lensing Lenses are close to Isothermal Constant physical deflection angle Population of sources e.g. Ilbert+ 2009 Population of ellipticals e.g. Choi+ 2007

Forecasting the rate of strong lensing Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Forecasting the rate of strong lensing Lenses are close to Isothermal Constant physical deflection angle Population of sources e.g. Ilbert+ 2009 Population of ellipticals e.g. Choi+ 2007 Detectability is harder to forecast

Forecasting the rate of strong lensing Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Forecasting the rate of strong lensing Toy experiment: Observing known lenses with ALMA

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 even thousands) 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 even thousands) ~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)

Stage VI “optimistic” Euclid (and a stronger prior) Constraining Dark Energy with Double Source Plane Strong Lenses Probing Cosmological Parameters with Strong Lenses Thomas Collett Thomas Collett Stage VI “optimistic” (and a stronger prior) Euclid Ωk ≠ 0 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)

Super-cool lenses with Euclid/LSST Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Super-cool lenses with Euclid/LSST ~ 40 lensed type Ia Sne ~ 30 DSPLs where one is an AGN ~ 1 or 2 triple source plane lenses ~ 1 or 2 Double time-delay systems *These numbers have big error-bars!

We have to control systematics, to make a meaningful contribution Probing Cosmological Parameters with Strong Lenses Constraining Dark Energy with Double Source Plane Strong Lenses Thomas Collett Thomas Collett Summary Strong lensing provides powerful complementary constraints on cosmological parameters We have to control systematics, to make a meaningful contribution

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)

Intermediate source: θE=0.16”±0.02 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”±0.02 σv≈100 kms-1

Intermediate source: θE=0.16”±0.02 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”±0.02 σv≈100 kms-1

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)

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 128 128 128 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 – they aren't perfectly isothermal or perfectly spherical

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 132 132 132 Planck+6

ρ=ρ0r-γ' Probing the mass profile of galaxies Probing Cosmological Parameters with Strong Lenses Cosmology with Strong Lensing. Thomas Collett 133 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