We present an updated and revised analysis of the relationship between the Hβ broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of 9 new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create "AGN-free" images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the Hβ time lag, which is assumed to yield the average Hβ BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R BLR -L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of α = 0.533 +0.035 −0.033 , consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 ± 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R BLR -L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the Universe to be probed by a separate population of objects, and over a larger range of redshifts.

The standard cosmological model successfully describes many observations from widely different epochs of the Universe, from primordial nucleosynthesis to the accelerating expansion of the present day. However, as the basic cosmological parameters of the model are being determined with increasing and unprecedented precision, it is not guaranteed that the same model will fit more precise observations from widely different cosmic epochs. Discrepancies developing between observations at early and late cosmological time may require an expansion of the standard model, and may lead to the discovery of new physics. The workshop "Tensions between the Early and the Late Universe" was held at the Kavli Institute for Theoretical Physics on July 15-17 2019 † to evaluate increasing evidence for these discrepancies, primarily in the value of the Hubble constant as well as ideas recently proposed to explain this tension. Multiple new observational results for the Hubble constant were presented in the time frame of the workshop using different probes: Cepheids, strong lensing time delays, tip of the red giant branch (TRGB), megamasers, Oxygen-rich Miras and surface brightness fluctuations (SBF) resulting in a set of six new ones in the last several months. Here we present the summary plot of the meeting that shows combining any three independent approaches to measure H0 in the late universe yields tension with the early Universe values between 4.0σ and 5.8σ. This shows that the discrepancy does not appear to be dependent on the use of any one method, team, or source. Theoretical ideas to explain the discrepancy focused on new physics in the decade of expansion preceding recombination as the most plausible. This is a brief summary of the workshop.

We present a joint gravitational lensing and stellar dynamical analysis of fifteen massive field earlytype galaxies -selected from the Sloan Lens ACS (SLACS) Survey -using Hubble Space Telescope ACS images and luminosity weighted stellar velocity dispersions obtained from the Sloan Digital Sky Survey database. The sample of lens galaxies is well-defined (see Paper I), with a redshift range of z=0.06-0.33 and an average stellar velocity dispersion of σ ap = 263 km s −1 (rms of 44 km s −1 ) inside a 3-arcsec fiber diameter. The following numerical results are found: (i) A joint-likelihood gives an average logarithmic density slope for the total mass density of γ ′ = 2.01 +0.02 −0.03 (68% C.L.; ρ tot ∝ r −γ ′ ) inside R Einst = 4.2 ± 0.4 kpc (rms of 1.6 kpc). The inferred intrinsic rms spread in logarithmic density slopes is σ γ ′ = 0.12, which might still include some minor systematic uncertainties. A range for the stellar anisotropy parameterChanging from a Hernquist to a Jaffe luminosity density profile increases γ ′ by 0.05. (ii) The average position-angle difference between the light distribution and the total mass distribution is found to be ∆θ = 0 ± 3 degrees (rms of 10 degrees), setting an upper limit of γ ext 0.035 on the average external shear. The total mass has an average ellipticity q SIE =0.78±0.03 (rms of 0.12), which correlates extremely well with the stellar ellipticity, q * , resulting in q SIE /q * = 0.99±0.03 (rms of 0.11) for σ 225 km s −1 . At lower velocity dispersions, inclined S0 galaxies dominate, leading to a higher ratio (up to 1.6). This suggests that the dark-matter halo surrounding these galaxies is less flattened than their stellar component. Assuming an oblate mass distribution and random orientations, the distribution of ellipticities implies q 3 ≡ (c/a) ρ = 0.66 with an error of ∼0.2. (iii) The average projected dark-matter mass fraction is inferred to be f DM = 0.25 ± 0.06 (rms of 0.22) inside R E , using the stellar mass-to-light ratios derived from the Fundamental Plane as priors. (iv) Combined with results from the Lenses Structure & Dynamics (LSD) Survey at z 0.3, we find no significant evolution of the total density slope inside one effective radius for galaxies with σ ap ≥ 200 km s −1 : a linear fit gives α γ ′ ≡ d γ ′ /dz = 0.23 ± 0.16 (1 σ) for the range z=0.08-1.01. We conclude that massive early-type galaxies at z=0.06-0.33 on average have an isothermal logarithmic density slope inside half an effective radius, with an intrinsic spread of at most 6 % (1 σ). The small scatter and absence of significant evolution in the inner density slopes suggest a collisional scenario where gas and dark matter strongly couple during galaxy formation, leading to a total mass distribution that rapidly converge to dynamical isothermality.

We use stellar masses, surface photometry, strong lensing masses, and stellar velocity dispersions (σ e/2 ) to investigate empirical correlations for the definitive sample of 73 early-type galaxies (ETGs) that are strong gravitational lenses from the SLACS survey. The traditional correlations (Fundamental Plane [FP] and its projections) are consistent with those found for non-lens galaxies, supporting the thesis that SLACS lens galaxies are representative of massive ETGs (dimensional mass M dim = 10 11 − 10 12 M ⊙ ). The addition of high-precision strong lensing estimates of the total mass allows us to gain further insights into their internal structure: i) the average slope of the total mass density profile (ρ tot ∝ r −γ ′ ) is γ ′ = 2.078 ± 0.027 with an intrinsic scatter of 0.16 ± 0.02; ii) γ ′ correlates with effective radius (r e ) and central mass density, in the sense that denser galaxies have steeper profiles; iii) the dark matter fraction within r e /2 is a monotonically increasing function of galaxy mass and size (due to a mass-dependent central cold dark matter distribution or to baryonic dark matter -stellar remnants or low mass stars -if the IMF is non-universal and its normalization increases with mass); iv) the dimensional mass M dim ≡ 5r e σ 2 e/2 /G is proportional to the total (lensing) mass M re/2 , and both increase more rapidly than stellar mass M * (M * ∝ M 0.8 re/2 ); v) the Mass Plane (MP), obtained by replacing surface brightness with surface mass density in the FP, is found to be tighter and closer to the virial relation than the FP and the M * P, indicating that the scatter of those relations is dominated by stellar populations effects; vi) we construct the Fundamental Hyper-Plane by adding stellar masses to the MP and find the M * coefficient to be consistent with zero and no residual intrinsic scatter. Our results demonstrate that the dynamical structure of ETGs is not scale invariant and that it is fully specified by M re/2 , r e , and σ e/2 . Although the basic trends can be explained qualitatively in terms of varying star formation efficiency as a function of halo mass and as the result of dry and wet mergers, reproducing quantitatively the observed correlations and their tightness may be a significant challenge for galaxy formation models.

We present the definitive data for the full sample of 131 strong gravitational lens candidates observed with the Advanced Camera for Surveys (ACS) aboard the Hubble Space Telescope by the Sloan Lens ACS (SLACS) Survey. All targets were selected for higher redshift emission lines and lower redshift continuum in a single Sloan Digital Sky Survey (SDSS) spectrum. The foreground galaxies are primarily of early-type morphology, with redshifts from z ' 0:05 to 0.5 and velocity dispersions from ' 160 to 400 km s À1 ; the faint background emission-line galaxies have redshifts ranging from z ' 0:2 to 1.2. We confirm 70 systems showing clear evidence of multiple imaging of the background galaxy by the foreground galaxy, as well as an additional 19 systems with probable multiple imaging. For 63 clear lensing systems, we present singular isothermal ellipsoid and light-traces-mass gravitational lens models fitted to the ACS imaging data. These strong-lensing mass measurements are supplemented by magnitudes and effective radii measured from ACS surface brightness photometry and redshifts and velocity dispersions measured from SDSS spectroscopy. These data constitute a unique resource for the quantitative study of the interrelations between mass, light, and kinematics in massive early-type galaxies. We show that the SLACS lens sample is statistically consistent with being drawn at random from a parent sample of SDSS galaxies with comparable spectroscopic parameters and effective radii, suggesting that the results of SLACS analyses can be generalized to the massive early-type population.