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Using the stokes Monte Carlo radiative transfer code, we revisit the predictions of the spectropolarimetric signal from a disc-like broad emission line region (BLR) in type I active galactic nuclei due to equatorial scattering. We reproduce the findings of previous works, but only for a scatterer that is much more optically and geometrically thick than previously proposed. We also find that when taking into account the polarized emission from all regions of the scatterer, the swing of the polarization position angle (PA) is in the opposite direction to that originally proposed. Furthermore, we find that the presence of outflows in the scattering media can significantly change the observed line profiles, with the PA of the scattering signal being enhanced in the presence of radially outflowing winds. Finally, a characteristically different PA profile, shaped like an 'M', is seen when the scatterer is co-spatial with the BLR and radially outflowing. [ABSTRACT FROM AUTHOR]

We present new calculations of the Clumpy AGN Tori in a 3D geometry (CAT3D) clumpy torus models, which now include a more physical dust sublimation model as well as active galactic nucleus (AGN) anisotropic emission. These new models allow graphite grains to persist at temperatures higher than the silicate dust sublimation temperature. This produces stronger near-infrared emission and bluer mid-infrared (MIR) spectral slopes. We make a statistical comparison of the CAT3D model MIR predictions with a compilation of subarcsecond resolution ground-based MIR spectroscopy of 52 nearby Seyfert galaxies (median distance of 36 Mpc) and 10 quasars. We focus on the AGN MIR spectral index αMIR and the strength of the 9.7 μm silicate feature SSil. As with other clumpy torus models, the new CAT3Dmodels do not reproduce the Seyfert galaxies with deep silicate absorption (SSil <−1). Excluding those, we conclude that the new CAT3D models are in better agreement with the observed αMIR and SSil of Seyfert galaxies and quasars. We find that Seyfert 2 are reproduced with models with low photon escape probabilities, while the quasars and the Seyfert 1-1.5 require generally models with higher photon escape probabilities. Quasars and Seyfert 1-1.5 tend to show steeper radial cloud distributions and fewer clouds along an equatorial line of sight than Seyfert 2. Introducing AGN anisotropic emission besides the more physical dust sublimation models alleviates the problem of requiring inverted radial cloud distributions (i.e. more clouds towards the outer parts of the torus) to explain the MIR spectral indices of type 2 Seyferts. [ABSTRACT FROM AUTHOR]

The time lag between optical and near-infrared continuum emission in active galactic nuclei (AGN) shows a tight correlation with luminosity and has been proposed as a standardizable candle for cosmology. In this paper, we explore the use of these AGN hot-dust time lags for cosmological model fitting under the constraints of the new VISTA Extragalactic Infrared Legacy Survey (VEILS). This new survey will target a 9 deg² field observed in J and Ks band with a 14-d cadence and will run for 3 yr. The same area will be covered simultaneously in the optical griz bands by the Dark Energy Survey, providing complementary time-domain optical data. We perform realistic simulations of the survey setup, showing that we expect to recover dust time lags for about 450 objects out of a total of 1350 optical type 1 AGN, spanning a redshift range of 0.1 < z < 1.2. We use the lags recovered from our simulations to calculate precise distance moduli, establish a Hubble diagram, and fit cosmological models. Assuming realistic scatter in the distribution of the dust around the AGN as well as in the normalization of the lag-luminosity relation, we are able to constrain ΩΛ in ΛCDM with similar accuracy as current supernova samples. We discuss the benefits of combining AGN and supernovae for cosmology and connect the present work to future attempts to reach out to redshifts of z > 4. [ABSTRACT FROM AUTHOR]