text: 399,21,1299222634098376704,140287694,Anowar J Shajib,"Our new paper is on arXiv today: <LINK>. By analyzing 23 elliptical lens galaxies from SLACS, we find that the dark matter distribution is close to the NFW profile on average at z~0.2 without any contraction/expansion. A summary with some figures in the thread. We perform state-of-the-art lens modeling for these 23 lens galaxies. This figure shows 5 of them. <LINK> We combine the strong lensing constraints with the stellar kinematics and weak lensing measurements to individually constrain the stellar and dark matter distributions. Our model allows for adiabatic contraction in the dark matter and a M/L gradient in the stellar distribution. <LINK> We find that the NFW+stars profile deviate upwards by ~5% on average from the power-law model near the Einstein radius. <LINK> On average, there is no significant contraction/expansion in the dark matter halos with M_200 ~ 10^13.1 M_sun at z~0.2. Furthermore, almost no gradient in the stellar M/L is favored around the effective or half-light radius. <LINK> Comparing our inferred stellar masses with those from SPS-based measurements supports a heavy IMF like the Salpeter IMF in these elliptical galaxies. <LINK> All of our results are consistent with a scenario where halos of massive elliptical galaxies first contract up to z~2 due to baryonic cooling, but then the halos primarily grow through dissipationless mergers while AGN feedback counteracts the initial contraction.",https://arxiv.org/abs/2008.11724,"We investigate the internal structure of elliptical galaxies at $z\sim 0.2$ from a joint lensing-dynamics analysis. We model Hubble Space Telescope images of a sample of 23 galaxy-galaxy lenses selected from the Sloan Lens ACS (SLACS) survey. Whereas the original SLACS analysis estimated the logarithmic slopes by combining the kinematics with the imaging data, we estimate the logarithmic slopes only from the imaging data. We find that the distribution of the lensing-only logarithmic slopes has a median $2.08\pm0.03$ and intrinsic scatter $0.13 \pm 0.02$, consistent with the original SLACS analysis. We combine the lensing constraints with the stellar kinematics and weak lensing measurements, and constrain the amount of adiabatic contraction in the dark matter (DM) halos. We find that the DM halos are well described by a standard Navarro-Frenk-White halo with no contraction on average for both of a constant stellar mass-to-light ratio ($M/L$) model and a stellar $M/L$ gradient model. For the $M/L$ gradient model, we find that most galaxies are consistent with no $M/L$ gradient. Comparison of our inferred stellar masses with those obtained from the stellar population synthesis method supports a heavy initial mass function (IMF) such as the Salpeter IMF. We discuss our results in the context of previous observations and simulations, and argue that our result is consistent with a scenario in which active galactic nucleus feedback counteracts the baryonic-cooling-driven contraction in the DM halos. ","Dark matter halos of massive elliptical galaxies at $z \sim 0.2$ are