Lunch talk on Aug. 28, 2023

Investigating the nature of the X-ray emission of radio-loud quasars

Speaker: Shifu Zhu (USTC)

Venue: SWIFAR Building 2111

Time: 12:30 PM, Monday, Aug. 28, 2023

Abstract: 

A significant fraction ( ≈ 10%) of active galactic nuclei (AGNs) harbor powerful relativistic jets; these AGNs are called radio-loud AGNs (RL-AGNs), among which the most luminous population are radio-loud quasars (RLQs). RL-AGNs are more X-ray luminous than their radio-quiet counterparts, radio-quiet AGNs (and radio-quiet quasars; RQ-AGNs and RQQs), with matched disk luminosity by a typical factor of 2–3. Since the 1980s, it has been thought that the base of the jets is responsible for the excess X-ray emission of RLQs relative to that of RQQs. We select and analyze a large, high-quality RLQ sample and find that the X-ray emission of most RLQs is dominated by their disks/coronae instead of the jets. This result is supported by statistical model selection, X-ray spectral and variability properties of RLQs, and the correlation between the high-ionization emission line strength and X-ray continuum.

Report PPT:  SWIRAR_Shifu Zhu.pptx