Considering that the existence of relativistic particles in the protostellar jet has been confirmed by the detection of linearly polarized radio emission from the HH 80–81 jet,we search for gamma-rays from the HH 80...Considering that the existence of relativistic particles in the protostellar jet has been confirmed by the detection of linearly polarized radio emission from the HH 80–81 jet,we search for gamma-rays from the HH 80–81 system using ten-year Fermi-LAT observations.A significant point-likeγ-ray excess is found in the direction of the HH80–81 system with the Test-Statistic value>100,which is likely produced in the HH 80–81 jet.Theγ-ray spectrum extends only to 1 Ge V with a photon index of 3.5.No significant variability is found in the gamma-ray emission.It is discussed that the properties of HH 80–81 jet suffice for producing the observedγ-rays.展开更多
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financial supports from the National Natural Science Foundation of China(NSFC-11803081,NSFC-U1931114,NSFC-U2031205 and NSFC-12163006)the joint foundation of Department of Science and Technology of Yunnan Province and Yunnan University(2018FY001(-003))supported by the CAS Youth Innovation Promotion Association and Basic research Program of Yunnan Province(202001AW070013)。
文摘Considering that the existence of relativistic particles in the protostellar jet has been confirmed by the detection of linearly polarized radio emission from the HH 80–81 jet,we search for gamma-rays from the HH 80–81 system using ten-year Fermi-LAT observations.A significant point-likeγ-ray excess is found in the direction of the HH80–81 system with the Test-Statistic value>100,which is likely produced in the HH 80–81 jet.Theγ-ray spectrum extends only to 1 Ge V with a photon index of 3.5.No significant variability is found in the gamma-ray emission.It is discussed that the properties of HH 80–81 jet suffice for producing the observedγ-rays.
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.
