On the origin of the X-ray oxygen emission-lines in obscured AGN

REYNALDI, VICTORIA; GUAINAZZI, MATTEO; STEFANO BIANCHI; ILEANA ANDRUCHOW; FEDERICO GARCÍA; NICOLÁS SALERNO; IVÁN LÓPEZ

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2020 vol. 449 p. 5107 - 5120

0035-8711

We present the Catalog of High REsolution Spectra of Obscured Sources (CHRE-SOS) from the XMM-Newton Science Archive. It comprises the emission-line luminosi-ties of H- and He-like transitions from C to Si, and the Fe 3C and Fe 3G L-shell ones.Here, we concentrate on the soft X-ray OVII (f) and OVIII Lyα emission lines to shedlight onto the physical processes with which their formation can be related to: activegalactic nucleus vs. star forming regions. We compare their luminosity with that oftwo other important oxygen key lines [OIII]λ5007Å, in the optical, and [OIV]25.89μm,in the IR. We also test OVII (f) and OVIII Lyα luminosities against that of contin-uum bands in the IR and hard X-rays, which point to different ionization processes.We probe into those processes by analyzing photoionization and colisional ioniza-tion model predictions upon our lines. We show that both scenarios can explain theformation and observed intensities of OVII (f) and OVIII Lyα. By analyzing the rela-tionships between OVII (f) and OVIII Lyα, and all other observables: [OIII]λ5007Å,[OIV]25.89μm emission lines, and MIR 12μm, FIR 60μm, FIR 100μm, 2?10 keV and14?195 keV continuum bands, we conclude that the AGN radiation field is mainlyresponsible of the soft X-ray oxygen excitation.