@article{11526,
  abstract     = {We present the results from a MUSE survey of twelve z ≃ 3.15 quasars, which were selected to be much fainter (20 < iSDSS < 23) than in previous studies of giant Ly α nebulae around the brightest quasars (16.6 < iAB < 18.7). We detect H I Ly α nebulae around 100 per cent of our target quasars, with emission extending to scales of at least 60 physical kpc, and up to 190 pkpc. We explore correlations between properties of the nebulae and their host quasars, with the goal of connecting variations in the properties of the illuminating QSO to the response in nebular emission. We show that the surface brightness profiles of the nebulae are similar to those of nebulae around bright quasars, but with a lower normalization. Our targeted quasars are on average 3.7 mag (≃30 times) fainter in UV continuum than our bright reference sample, and yet the nebulae around them are only 4.3 times fainter in mean Ly α surface brightness, measured between 20 and 50 pkpc. We find significant correlations between the surface brightness of the nebula and the luminosity of the quasar in both UV continuum and Ly α. The latter can be interpreted as evidence for a substantial contribution from unresolved inner parts of the nebulae to the narrow components seen in the Ly α lines of some of our faint quasars, possibly from the inner circumgalactic medium or from the host galaxy’s interstellar medium.},
  author       = {Mackenzie, Ruari and Pezzulli, Gabriele and Cantalupo, Sebastiano and Marino, Raffaella A and Lilly, Simon and Muzahid, Sowgat and Matthee, Jorryt J and Schaye, Joop and Wisotzki, Lutz},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, techniques: imaging spectroscopy, intergalactic medium, quasars: emission lines, quasars: general},
  number       = {1},
  pages        = {494--509},
  publisher    = {Oxford University Press},
  title        = {{Revealing the impact of quasar luminosity on giant Lyα nebulae}},
  doi          = {10.1093/mnras/staa3277},
  volume       = {502},
  year         = {2021},
}

@article{11530,
  abstract     = {A prediction of the classic active galactic nucleus (AGN) unification model is the presence of ionization cones with different orientations depending on the AGN type. Confirmations of this model exist for present times, but it is less clear in the early Universe. Here, we use the morphology of giant Ly α nebulae around AGNs at redshift z ∼ 3 to probe AGN emission and therefore the validity of the AGN unification model at this redshift. We compare the spatial morphology of 19 nebulae previously found around type I AGNs with a new sample of four Ly α nebulae detected around type II AGNs. Using two independent techniques, we find that nebulae around type II AGNs are more asymmetric than around type I, at least at radial distances r > 30 physical kpc (pkpc) from the ionizing source. We conclude that the type I and type II AGNs in our sample show evidence of different surrounding ionizing geometries. This suggests that the classical AGN unification model is also valid for high-redshift sources. Finally, we discuss how the lack of asymmetry in the inner parts (r ≲ 30 pkpc) and the associated high values of the He II to Ly α ratios in these regions could indicate additional sources of (hard) ionizing radiation originating within or in proximity of the AGN host galaxies. This work demonstrates that the morphologies of giant Ly α nebulae can be used to understand and study the geometry of high-redshift AGNs on circumnuclear scales and it lays the foundation for future studies using much larger statistical samples.},
  author       = {den Brok, J S and Cantalupo, S and Mackenzie, R and Marino, R A and Pezzulli, G and Matthee, Jorryt J and Johnson, S D and Krumpe, M and Urrutia, T and Kollatschny, W},
  issn         = {1365-2966},
  journal      = {Monthly Notices of the Royal Astronomical Society},
  keywords     = {Space and Planetary Science, Astronomy and Astrophysics, galaxies: active, galaxies: high-redshift, intergalactic medium, quasars: emission lines, quasars: general},
  number       = {2},
  pages        = {1874--1887},
  publisher    = {Oxford University Press},
  title        = {{Probing the AGN unification model at redshift z ∼ 3 with MUSE observations of giant Lyα nebulae}},
  doi          = {10.1093/mnras/staa1269},
  volume       = {495},
  year         = {2020},
}