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A SHARP view of H0LiCOW: $H_{0}$ from three time-delay gravitational lens systems with adaptive optics imaging

Geoff C. -F. Chen, Christopher D. Fassnacht, Sherry. H. Suyu, Cristian E. Rusu, James H. H. Chan, Kenneth C. Wong, Matthew W. Auger, Stefan Hilbert, Vivien Bonvin, Simon Birrer, Martin Millon, Leon V. E. Koopmans, David J. Lagattuta, John P. McKean, Simona Vegetti, Frederic Courbin, Xuheng Ding, Aleksi Halkola, Inh Jee, Anowar J. Shajib, Dominique Sluse, Alessandro Sonnenfeld, Tommaso Treu

TL;DR

This work advances time-delay cosmography as an independent probe of the Hubble constant by exploiting high-resolution adaptive optics imaging to model the mass distribution in three strong-lensing systems. The authors perform blind analyses for two lenses and extend prior RXJ 1131−1231 results, combining AO imaging with HST data, velocity dispersions, and line-of-sight information to infer $D_{ m  dt}$ and $H_{0}$ under a flat $\Lambda$CDM framework. They report AO-only joint $H_{0} = 75.6^{+3.2}_{-3.3}$ km s$^{-1}$Mpc$^{-1}$ and AO+HST joint $H_{0} = 76.8^{+2.6}_{-2.6}$ km s$^{-1}$Mpc$^{-1}$ for the three lenses, with PG 1115+080, HE 0435−1223, and RXJ 1131−1231 contributing lens-specific constraints. The results validate AO PSF reconstruction for precision lensing work and show that combining AO with HST reduces systematic uncertainties in the mass-modeling step, thereby tightening the cosmological inferences and reinforcing the role of strong lensing as a complementary, cross-checkable path to resolving the $H_{0}$ tension.

Abstract

We present the measurement of the Hubble Constant, $H_0$, with three strong gravitational lens systems. We describe a blind analysis of both PG1115+080 and HE0435-1223 as well as an extension of our previous analysis of RXJ1131-1231. For each lens, we combine new adaptive optics (AO) imaging from the Keck Telescope, obtained as part of the SHARP AO effort, with Hubble Space Telescope (HST) imaging, velocity dispersion measurements, and a description of the line-of-sight mass distribution to build an accurate and precise lens mass model. This mass model is then combined with the COSMOGRAIL measured time delays in these systems to determine $H_{0}$. We do both an AO-only and an AO+HST analysis of the systems and find that AO and HST results are consistent. After unblinding, the AO-only analysis gives $H_{0}=82.8^{+9.4}_{-8.3}~\rm km\,s^{-1}\,Mpc^{-1}$ for PG1115+080, $H_{0}=70.1^{+5.3}_{-4.5}~\rm km\,s^{-1}\,Mpc^{-1}$ for HE0435-1223, and $H_{0}=77.0^{+4.0}_{-4.6}~\rm km\,s^{-1}\,Mpc^{-1}$ for RXJ1131-1231. The joint AO-only result for the three lenses is $H_{0}=75.6^{+3.2}_{-3.3}~\rm km\,s^{-1}\,Mpc^{-1}$. The joint result of the AO+HST analysis for the three lenses is $H_{0}=76.8^{+2.6}_{-2.6}~\rm km\,s^{-1}\,Mpc^{-1}$. All of the above results assume a flat $Λ$ cold dark matter cosmology with a uniform prior on $Ω_{\textrm{m}}$ in [0.05, 0.5] and $H_{0}$ in [0, 150] $\rm km\,s^{-1}\,Mpc^{-1}$. This work is a collaboration of the SHARP and H0LiCOW teams, and shows that AO data can be used as the high-resolution imaging component in lens-based measurements of $H_0$. The full time-delay cosmography results from a total of six strongly lensed systems are presented in a companion paper.

A SHARP view of H0LiCOW: $H_{0}$ from three time-delay gravitational lens systems with adaptive optics imaging

TL;DR

This work advances time-delay cosmography as an independent probe of the Hubble constant by exploiting high-resolution adaptive optics imaging to model the mass distribution in three strong-lensing systems. The authors perform blind analyses for two lenses and extend prior RXJ 1131−1231 results, combining AO imaging with HST data, velocity dispersions, and line-of-sight information to infer and under a flat CDM framework. They report AO-only joint km sMpc and AO+HST joint km sMpc for the three lenses, with PG 1115+080, HE 0435−1223, and RXJ 1131−1231 contributing lens-specific constraints. The results validate AO PSF reconstruction for precision lensing work and show that combining AO with HST reduces systematic uncertainties in the mass-modeling step, thereby tightening the cosmological inferences and reinforcing the role of strong lensing as a complementary, cross-checkable path to resolving the tension.

Abstract

We present the measurement of the Hubble Constant, , with three strong gravitational lens systems. We describe a blind analysis of both PG1115+080 and HE0435-1223 as well as an extension of our previous analysis of RXJ1131-1231. For each lens, we combine new adaptive optics (AO) imaging from the Keck Telescope, obtained as part of the SHARP AO effort, with Hubble Space Telescope (HST) imaging, velocity dispersion measurements, and a description of the line-of-sight mass distribution to build an accurate and precise lens mass model. This mass model is then combined with the COSMOGRAIL measured time delays in these systems to determine . We do both an AO-only and an AO+HST analysis of the systems and find that AO and HST results are consistent. After unblinding, the AO-only analysis gives for PG1115+080, for HE0435-1223, and for RXJ1131-1231. The joint AO-only result for the three lenses is . The joint result of the AO+HST analysis for the three lenses is . All of the above results assume a flat cold dark matter cosmology with a uniform prior on in [0.05, 0.5] and in [0, 150] . This work is a collaboration of the SHARP and H0LiCOW teams, and shows that AO data can be used as the high-resolution imaging component in lens-based measurements of . The full time-delay cosmography results from a total of six strongly lensed systems are presented in a companion paper.

Paper Structure

This paper contains 48 sections, 25 equations, 23 figures, 10 tables.

Table of Contents

  1. Introduction
  2. Distance Measurement Discrepancy: A 4.4$\sigma$ Tension on the Value of $H_{0}$
  3. Distance Measurement from Time-Delay Cosmography
  4. Lens Modeling with Adaptive Optics Data
  5. Basic theory
  6. Time-Delay Cosmography
  7. Joint Inference
  8. Data
  9. The Sample
  10. Keck Adaptive Optics Imaging
  11. Hubble Space Telescope Imaging
  12. MPIA 2.2 m Imaging
  13. Lens models
  14. Mass models
  15. Lens light models
  16. ...and 33 more sections

Figures (23)

  • Figure 1: Adaptive optics (top row) and HST (bottom row) images of the three gravitational lens systems. The solid horizontal line represents 1 scale. The foreground main lenses are located in the center of the lens systems. The multiple lensed images and the extended arc around the lensing galaxy are from the background AGN and its host galaxy.
  • Figure 2: 2.2m MPIA telescope image of the FOV around PG 1115$+$080 . We show the galaxies/group which we explicitly model here. As PG 1115$+$080 is embedded in a nearby group that consists of 13 galaxies labeled with solid circles, we model not only the main lens but also the group explicitly. The dotted circle represents $1-\sigma$ uncertainty of the priors of the group position ($\Delta \textrm{RA}=23.4\arcsec$ and $\Delta \textrm{DEC}=15.84\arcsec$) measured in WilsonEtal16. Since G1 and G2 have the first two largest value of $\Delta_3x$, we model either G1 or both G1 and G2 explicitly in addition to the main lens. We label G1 and G2 with the dashed circles.
  • Figure 3: $Rc$-band $240\arcsec\times240\arcsec$ image around PG 1115$+$080 . This is the same data shown in Figure \ref{['fig:PG1115_envir']}, but with contrast chosen to better show the detected objects. The large circles mark the $45\arcsec$ and $120\arcsec$ radii apertures centered on the lens. The inner $5\arcsec$ and outer $>120\arcsec$ masked regions are shown in color. For all objects $R\leq23$, small circles mark galaxies and star symbols mark stars.
  • Figure 4: Distributions of $\kappa_\mathrm{ext}$ for PG1115+080, for various lens models and their associated shear values. The constraints used to produce the distributions from the Millennium Simulation are the external shear $\gamma$, plus the combination of weighted counts corresponding to galaxy number counts inside the $45\arcsec$ and $120\arcsec$ apertures, as well as number counts weighted by the inverse of the distance of each galaxy to the lens. The numerical constraints are reported in Table \ref{['tab:weights']}. The distributions with G1 or G2 marked are calculated by removing those galaxies from the weighted count constraints, since these galaxies are explicitly included in the lens models. The size of the histogram bin is $\Delta\kappa_\mathrm{ext}=0.00055$. As the original distributions are noisy, we plot their convolution with a large smoothing window of size $30\times\Delta\kappa_\mathrm{ext}$. In the legend, "pow" refers to the power law model, "com" to the composite model, $\overline{\kappa}$ to the median of the distribution, and $\sigma_\kappa$ to the semi-difference of the 84 and 16 percentiles of the distribution.
  • Figure 5: PG 1115$+$080 AO image reconstruction of the most probable model with a source grid of $43 \times 43$ pixels and $59 \times 59$ pixels PSF for convolution of spatially extended images. Top left: The PG 1115$+$080 AO image. Top middle: the predicted image of all components including lens light, arc light, and AGN light. Top right: image residuals, normalized by the estimated 1-$\sigma$ uncertainty of each pixel. Bottom left: the arc-only image which removes the lens light and AGN light from the observed image. Bottom middle: predicted lensed image of the background AGN host galaxy. Bottom right: the reconstructed host galaxy of the AGN in the source plane.
  • ...and 18 more figures