Open Collections

Burgoyne, James

University of British Columbia

Quasi-stellar objects (QSOs) are a rare class of extremely luminous and distant active galactic nuclei (AGN) that emit intense radiation across a broad range of the electromagnetic spectrum. They are thought to be powered by the accretion of large amounts of gas onto supermassive black holes residing at the centres of their host galaxies. The prodigious amount of energy released by QSOs during their accretion phase can shape the evolution of the host galaxy by heating and ionizing the surrounding gas, triggering the formation of stars, and expelling gas from the galaxy’s disk, among other processes. The interplay between QSOs and their host galaxies is complex and not well understood, with evidence of both positive and negative feedback mechanisms. Here we report IRAM-NOEMA spectroscopy and JCMT SCUBA-2 continuum photometry of the distant hyper-luminous QSO Q2343+125 at z = 2.577. In total 10 lines are detected, including CO J = 3–2 through J = 8–7, an H₂O rotational line, both [CI] fine-structure lines, and OH+ 1₀ − 0₁. The CO-to-continuum luminosity ratio is 5 times larger than the mean submillimetre galaxies, and 3 times higher even than in the local example of such an excess, NGC 6240. Similar to NGC 6240, Q2343+125 has an elevated line-to-continuum ratio, indicative of shocks; however it also shows evidence of increased ionization paths more similar to Mrk 231, suggestive of an X-ray dominated region (XDR) as is typically found near active galactic nuclei. Confoundingly, Q2343+125 does not show elevated high-J CO rotational transitions, which is expected in both XDR and shock dominated systems. Q2343+125 may be providing us a snapshot into an extremely brief (∼ 1 Myr) post-merger period of massive galaxy evolution.

Text

2023-08-29

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85660

Astronomy

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/