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1. The evolution of the size–mass relation at z = 1–3 derived from the complete Hubble Frontier Fields data set

   https://doi.org/10.1093/mnras/staa3713  

   Yang, Lilan; Roberts-Borsani, Guido; Treu, Tommaso; Birrer, Simon; Morishita, Takahiro; Bradač, Maruša (December 2020, Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT We measure the size–mass relation and its evolution between redshifts 1 < z < 3, using galaxies lensed by six foreground Hubble Frontier Fields clusters. The power afforded by strong gravitation lensing allows us to observe galaxies with higher angular resolution beyond current facilities. We select a stellar mass limited sample and divide them into star-forming or quiescent classes based on their rest-frame UVJ colours from the ASTRODEEP catalogues. Source reconstruction is carried out with the recently released lenstruction software, which is built on the multipurpose gravitational lensing software lenstronomy. We derive the empirical relation between size and mass for the late-type galaxies with $$M_{*}\gt 3\times 10^{9}\, \mathrm{M}_{\odot }$$ at 1 < z < 2.5 and $$M_{*}\gt 5\times 10^{9}\, \mathrm{M}_{\odot }$$ at 2.5 < z < 3, and at a fixed stellar mass, we find galaxy sizes evolve as $$R \rm _{eff} \propto (1+z)^{-1.05\pm 0.37}$$. The intrinsic scatter is <0.1 dex at z < 1.5 but increases to ∼0.3 dex at higher redshift. The results are in good agreement with those obtained in blank fields. We evaluate the uncertainties associated with the choice of lens model by comparing size measurements using five different and publicly available models, finding the choice of lens model leads to a 3.7 per cent uncertainty of the median value, and ∼25  per cent scatter for individual galaxies. Our work demonstrates the use of strong lensing magnification to boost resolution does not introduce significant uncertainties in this kind of work, and paves the way for wholesale applications of the sophisticated lens reconstruction technique to higher redshifts and larger samples. 

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2. Probing sub-galactic mass structure with the power spectrum of surface-brightness anomalies in high-resolution observations of galaxy–galaxy strong gravitational lenses. II. Observational constraints on the subgalactic matter power spectrum

   https://doi.org/10.1093/mnras/stad1402  

   Bayer, D.; Chatterjee, S.; Koopmans, L. V. E.; Vegetti, S.; McKean, J. P.; Treu, T.; Fassnacht, C. D.; Glazebrook, K. (May 2023, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT Stringent observational constraints on the subgalactic matter power spectrum would allow one to distinguish between the concordance ΛCDM and the various alternative dark-matter models that predict significantly different properties of mass structure in galactic haloes. Galaxy–galaxy strong gravitational lensing provides a unique opportunity to probe the subgalactic mass structure in lens galaxies beyond the Local Group. Here, we demonstrate the first application of a novel methodology to observationally constrain the subgalactic matter power spectrum in the inner regions of massive elliptical lens galaxies on 1–10 kpc scales from the power spectrum of surface-brightness anomalies in highly magnified galaxy-scale Einstein rings and gravitational arcs. The pilot application of our approach to Hubble Space Telescope (HST/WFC3/F390W) observations of the SLACS lens system SDSS J0252+0039 allows us to place the following observational constraints (at the 99 per cent confidence level) on the dimensionless convergence power spectrum $$\Delta ^{2}_{\delta \kappa }$$ and the standard deviation in the aperture mass σAM: $$\Delta ^{2}_{\delta \kappa }\lt 1$$ (σAM < 0.8 × 108 M⊙) on 0.5-kpc scale, $$\Delta ^{2}_{\delta \kappa }\lt 0.1$$ (σAM < 1 × 108 M⊙) on 1-kpc scale and $$\Delta ^{2}_{\delta \kappa }\lt 0.01$$ (σAM < 3 × 108 M⊙) on 3-kpc scale. These first upper-limit constraints still considerably exceed the estimated effect of CDM subhaloes. However, future analysis of a larger sample of galaxy–galaxy strong lens systems can substantially narrow down these limits and possibly rule out dark-matter models that predict a significantly higher level of density fluctuations on the critical subgalactic scales. 

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3. GRRMHD simulations of MAD accretion discs declining from super-Eddington to sub-Eddington accretion rates

   https://doi.org/10.1093/mnras/stac3330  

   Curd, Brandon; Narayan, Ramesh (November 2022, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT We present two general relativistic radiation magnetohydrodynamics (GRRMHD) simulations of magnetically arrested discs (MADs) around non-spinning (a* = 0) and spinning (a* = 0.9) supermassive black holes (BHs). In each simulation, the mass accretion rate is decreased with time such that we sample Eddington-scaled rates over the range $$3 \gtrsim \dot{M}/\dot{M}_{\rm {Edd}}\gtrsim 0.3$$. For the non-spinning BH model, the total and radiative efficiencies increase as the accretion rate decreases, varying over the range $$\eta _{\rm {tot}}\sim 9\!-\!16{{\ \rm per\ cent}}$$ and $$\eta _{\rm {rad}}\sim 6{-}12{{\ \rm per\ cent}}$$, respectively. This model shows very little jet activity. In contrast, the spinning BH model has a strong relativistic jet powered by spin energy extracted from the BH. The jet power declines with accretion rate such that $$\eta _{\rm {jet}}\sim 18{-}39{{\ \rm per\ cent}}$$ while the total and radiative efficiencies are $$\eta _{\rm {tot}}\sim 64{-}100{{\ \rm per\ cent}}$$ and $$\eta _{\rm {rad}}\sim 45{-}79{{\ \rm per\ cent}}$$, respectively. We confirm that mildly sub-Eddington discs can extract substantial power from a spinning BH, provided they are in the MAD state. The jet profile out to $$100\, GM/c^2$$ is roughly parabolic with a power-law index of k ≈ 0.43−0.53 during the sub-Eddington evolution. Both models show significant variability in the outgoing radiation which is likely associated with episodes of magnetic flux eruptions. The a* = 0.9 model shows semiregular variations with a period of $$\sim 2000\, GM/c^3$$ over the final $$\sim 10\, 000\, GM/c^3$$ of the simulation, which suggests that magnetic flux eruptions may be an important source of quasi-periodic variability. For the simulated accretion rates, the a* = 0 model is spinning up while the a* = 0.9 model is spinning down. Spinup–spindown equilibrium of the BH will likely be achieved at 0.5 < a*, eq < 0.6, assuming continuous accretion in the MAD state. 

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4. JWST’s PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191

   https://doi.org/10.3847/1538-3881/acbdff  

   Keel, William C.; Windhorst, Rogier A.; Jansen, Rolf A.; Cohen, Seth H.; Summers, Jake; Holwerda, Benne; Bradford, Sarah T.; Robertson, Clayton D.; Ferrami, Giovanni; Wyithe, Stuart; et al (March 2023, The Astronomical Journal)

   Abstract We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.3–4.5μm with high angular resolution, tracing the dust in detail from 0.6–1.5μm. Distinct dust lanes continue well beyond the bright spiral arms, and trace a complex web, with a very sharp radial cutoff near 1.7 Petrosian radii. We present attenuation profiles and coverage statistics in each band at radii 14–21 kpc. We derive the attenuation law with wavelength; the data both within and between the dust lanes clearly favor a stronger reddening behavior (R=A_V/E_B−V≈ 2.0 between 0.6 and 0.9μm, approaching unity by 1.5μm) than found for starbursts and star-forming regions of galaxies. Power-law extinction behavior ∝λ^−βgivesβ= 2.1 from 0.6–0.9μm.Rdecreases at increasing wavelengths (R≈ 1.1 between 0.9 and 1.5μm), whileβsteepens to 2.5. Mixing regions of different column density flattens the wavelength behavior, so these results suggest a different grain population than in our vicinity. The NIRCam images reveal a lens arc and counterimage from a background galaxy atz≈ 1, spanning 90° azimuthally at 2.″8 from the foreground elliptical-galaxy nucleus, and an additional weakly lensed galaxy. The lens model and imaging data give a mass/light ratioM/L_B= 7.6 in solar units within the Einstein radius 2.0 kpc. 

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5. TDCOSMO: IV. Hierarchical time-delay cosmography – joint inference of the Hubble constant and galaxy density profiles

   https://doi.org/10.1051/0004-6361/202038861  

   Birrer, S.; Shajib, A. J.; Galan, A.; Millon, M.; Treu, T.; Agnello, A.; Auger, M.; Chen, G. C.-F.; Christensen, L.; Collett, T.; et al (November 2020, Astronomy & Astrophysics)

   null (Ed.)

   The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H 0 = 73.3 −1.8 +1.7 km s −1 Mpc −1 , describing deflector mass density profiles by either a power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. The mass-sheet transform (MST) that leaves the lensing observables unchanged is considered the dominant source of residual uncertainty in H 0 . We quantify any potential effect of the MST with a flexible family of mass models, which directly encodes it, and they are hence maximally degenerate with H 0 . Our calculation is based on a new hierarchical Bayesian approach in which the MST is only constrained by stellar kinematics. The approach is validated on mock lenses, which are generated from hydrodynamic simulations. We first applied the inference to the TDCOSMO sample of seven lenses, six of which are from H0LiCOW, and measured H 0 = 74.5 −6.1 +5.6 km s −1 Mpc −1 . Secondly, in order to further constrain the deflector mass density profiles, we added imaging and spectroscopy for a set of 33 strong gravitational lenses from the Sloan Lens ACS (SLACS) sample. For nine of the 33 SLAC lenses, we used resolved kinematics to constrain the stellar anisotropy. From the joint hierarchical analysis of the TDCOSMO+SLACS sample, we measured H 0 = 67.4 −3.2 +4.1 km s −1 Mpc −1 . This measurement assumes that the TDCOSMO and SLACS galaxies are drawn from the same parent population. The blind H0LiCOW, TDCOSMO-only and TDCOSMO+SLACS analyses are in mutual statistical agreement. The TDCOSMO+SLACS analysis prefers marginally shallower mass profiles than H0LiCOW or TDCOSMO-only. Without relying on the form of the mass density profile used by H0LiCOW, we achieve a ∼5% measurement of H 0 . While our new hierarchical analysis does not statistically invalidate the mass profile assumptions by H0LiCOW – and thus the H 0 measurement relying on them – it demonstrates the importance of understanding the mass density profile of elliptical galaxies. The uncertainties on H 0 derived in this paper can be reduced by physical or observational priors on the form of the mass profile, or by additional data. 

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