Radio Variability and Relativistic Beaming Effect for Blazars

摘要

Inthispaper,usingadatabaseoftheUniversityofMichiganRadioAstronomyObservatoryattheradiofrequencies(8GHzand14.5GHz),wedeterminedthevariabilitytimescales,andcalculatedthebrightnesstemperaturefor86radiosources(29BLLacertaeobjectsa€”BLsand57flatspectrumradioquasarsa€”FSRQs).Thetimescaleswerefoundintherangeoffrom3monthsto16.27yearswithanaveragedvaluescaleof2.34years.Weobtainedthefollowingresults:(1)Thebrightnesstemperatureisintherangeoflog$$T_{ mb,var}$$$$=$$10.98to$$T_{ mb,var}$$$$=$$15.35,whichsuggeststhattheDopplerfactorsareintherangeof$$delta$$$$=$$0.73to$$delta$$$$=$$20.74.Theaveragedvaluesare$$langledelta angle$$$$=$$5.95$$pm$$2.93for57FSRQsand$$langledelta angle$$$$=$$5.08$$pm$$2.63for29BLs.(2)Theradioluminosity,$$L_{ mob}$$,isfoundtobecorrelatedwiththeradioDopplerfactor,$$delta$$,log$$L_{ mob}$$$$=$$(0.58$$pm$$0.10)log$$delta^{3}$$$$+$$43.49$$pm$$0.21.(3)TheviewinganglesandtheLorentzfactorsweredeterminedfor53sources(15BLsand38FSRQS)withavailablesuperluminalvelocity(Zhangamp;Fan2008,Chin.J.Astron.Astrophys,8,385).Theaveragedvaluesare$$Gamma$$$$=$$24.1$$pm$$17.35and$$ heta$$$$=$$8$$.^circ$$7$$pm$$3$$.^{circ}$$5fortheFSRQs,and$$Gamma$$$$=$$13.5$$pm$$11.16and$$ heta$$$$=$$12$$^{circ}pm$$7$$^{circ}$$fortheBLs.