High energy properties of the flat spectrum radio quasar 4C 50.11

• 来源期刊: 天文和天体物理学研究
• 年，卷（期）: 2018,（1）
• 页码范围: 69-82
• 页数: 14页
• 语种: 英文
• DOI: 10.1088/1674-4527/18/1/6

摘要

We investigate the γ-ray and X-ray properties of the flat spectrum radio quasar (FSRQ) 4C 50.11 at redshift z =1.517.The Fermi-LAT data indicate that this source was in an active state since July 2013.During this active period,the source's emission appeared harder in γ-rays,with the flux having increased by more than a factor of three.We analyze two distinct flares seen in the active state and find that the variability is as short as several hours.The Swift-XRT data show that the source was variable at X-ray energies,but no evidence is found for flux or spectral changes related to the γray activity.The broad-band X-ray spectrum obtained with Swift-XRT and NuSTAR is described well by a broken power law model,with an extremely fiat spectrum (Г1 ～ 0.1) below the break energy,Ebreak ～ 2.1 keV,and Г2 ～ 1.5 above the break energy.The spectral flattening below ～ 3 keV is likely due to the low energy cut-off in the energy distribution of the photon-emitting electron population.We fit the broad-band spectral energy distribution of the source during both the active and quiescent states.The X-ray and γ-ray emission from the jet is mainly due to the inverse-Compton scattering process,with seed photons provided from the broad line region,and the jet is estimated to be larger than the accretion power if the jet is mainly composed of electron-proton pairs.