Characterizing the circumgalactic medium of quasars at z ~ 2.2 through Hα and Lyα emission
Hα emission detected around a quasar at z ≈ 2.2, next to its Lyα nebula, helps to constrain the density and motion of the gas in the circumgalactic medium.
What was found
- Lyα nebulae were first detected around three bright quasars at redshifts where infrared sky lines do not interfere with Hα, and the most extended one was followed up in Hα.
- Hα emission is detected out to about 20 physical kpc.
- The Lyα-to-Hα ratio agrees with the Slug Nebula and with pure recombination, which points to high gas densities or a very broad density distribution.
- The Hα profile suggests several overlapping, fairly quiescent components, which disfavours both quasar-driven outflows leaving the halo and disk-like rotation in a halo above 1012 solar masses.
This summary is written for a general audience. The paper has the full details.
Cite this paper
Langen, V., Cantalupo, S., Steidel, C. C., Chen, Y., Pezzulli, G., & Gallego, S. G. 2023, MNRAS, 519, 5099–5113, doi:10.1093/mnras/stac3205
@article{langen2023,
author = {Langen, Vivienne and Cantalupo, Sebastiano and Steidel, Charles C. and Chen, Yuguang and Pezzulli, Gabriele and Gallego, Sofia G.},
title = {{Characterizing the circumgalactic medium of quasars at z ~ 2.2 through Hα and Lyα emission}},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2023},
volume = {519},
pages = {5099--5113},
doi = {10.1093/mnras/stac3205},
eprint = {2303.05531},
archivePrefix = {arXiv}
}