We investigate theγ-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 activ...We investigate theγ-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 inγ-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 theγ-ray activity.The broad-band X-ray spectrum obtained with Swift-XRT and Nu STAR is described well by a broken power law model,with an extremely flat spectrum（Γ_1~0.1）below the break energy,E_（break）~2.1 keV,and Γ_2~1.5 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 andγ-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.展开更多
基金supported by the National Program on Key Research and Development Project(Grant No.2016YFA0400804)the National Natural Science Foundation of China for Youth(11603059)+3 种基金the National Natural Science Foundation of China(11373055,11633007,11233006 and U1431123)the CAS grant(QYZDJ-SSW-SYS023)financial support from Chinese Academy of Sciences through the President’s International Fellowship Initiative(CAS PIFI,Grant No.2015PM059)support by the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘We investigate theγ-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 inγ-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 theγ-ray activity.The broad-band X-ray spectrum obtained with Swift-XRT and Nu STAR is described well by a broken power law model,with an extremely flat spectrum（Γ_1~0.1）below the break energy,E_（break）~2.1 keV,and Γ_2~1.5 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 andγ-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.
