Kinematics of parsec-scale radio jet in 3C48 Tao An 1, In collaboration with X.Y.Hong 1, M.J.Hardcastle 2, T.Venturi 3, D.Worrall 2,T.J.Pearson 4, Z.-Q.Shen 1, W.Zhao 1, W.X.Feng 5 1: Shanghai Astronomical Observatory, China 2: Department of Physics, University of Bristol, UK 3: INAF-Istituto di Radioastronomia, Italy 4: California Institute of Technology, USA 5: Liaocheng University, China

An et 2009 EAVN 2 OUTLINE 1.Motivation 2.Observations and data reduction 3.Images (total intensity and polarization) 4.Kinematics of pc-scale radio jet 5.Helical jet

An et 2009 EAVN 3 1. Motivations CSSs are good candidates for studying dynamics and evolution of host galaxies, AGN feedback to host galaxies. 3C48, first found QSO, a typical CSS, ample gas in host galaxy, violent jet-ISM, (Wilkinson et al. 1991, Worrall et al. 2004, Feng etal. 2005, Gupta etal.2005,Stockton et al. 2007; et al.) We propose to study the dynamics of the radio jet and physical environment in the host galaxy

An et 2009 EAVN OBSERVATIONS ArrayVLBA+VLA(1)EVNMERLIN R.A Dec Date2004 June June 7 Time (UT)08:00—20:0002:00—14:00 Freq (GHz)1.5/4.8/ Int.time(hour)2.6/2.6/2.688 Baseline(km)20— — —220 CalibratorsDA193,3C138,3C345DA193,3C138,3C286 BW(MHz)32 15 CorrelatorSocorro (VLBA)JIVE(MkIV)Jodrell Bank

An et 2009 EAVN Calibration of the data Standard data reduction procedure in AIPS Hybrid selfcalibration and imaging in AIPS/DIFMAP Polarization calibration (ionospheric Faraday rotation, D-term, absolute EVPA) Final image multi-frequency synthesis (bandwidth smearing) Combination of EVN and MERLIN data (alignment of flux scale and phase center)

An et 2009 EAVN Total intensity images

An et 2009 EAVN 7 Total intenstiy images

An et 2009 EAVN 8 Figure parameters Label Freq (GHz) Restoring Beam (mas,mas,degree) Rms (mJy/b) Contours (mJy/b) EVN x EVN+ MERLIN

An et 2009 EAVN 9 MODEL FITTING of radio components 1996 January 20, 1.5GHz (Worrall et al. 2004) 2004 June 25, 1.65GHz 2005 June 7, 1.5 GHz 1996 January 20, 5GHz (Worrall et al. 2004) 2004 June 25, 5 GHz 1996 January 20, 8.3 GHz (Worrall et al. 2004) 2004 Juen 25, 8.3 GHz 1996 January 20, 15GHz (Worrall et al. 2004)

An et 2009 EAVN Polarized emission Rotation of EVPA -- Faraday Rotation structure ? m%~5%, uniform magnetic field direction in extended radio structure

An et 2009 EAVN Kinematics of pc-scale jet – images

An et 2009 EAVN 12 Constraints to the viewing angle and jet speed Jet sideness parameter – jet-to-counterjet intensity ratio 2600>R>100 Jet apparent velocity Jet velocity>0.82c Viewing angle<30 O

An et 2009 EAVN Helical jet model fit – sketch map Assumptions of conservative quantities –E kin =const –V a =const –Opening angle=const Assumed parameters : –opening angle –viewing angle –Initial origin of K-H wave Measured parameters: –jet velocity, –position angle Fitted parameters –Wavelength –Initial amplitude and phase of K-H wave –Changing rate of position angle (Steffen et al Case 2; Hardee 1987,1990s,2000s)

An et 2009 EAVN Helical jet model fit – fitted curves

An et 2009 EAVN Helical jet model fit -- fitted parameters

An et 2009 EAVN conclusions MERLIN maps show two components – compact jet accounts for half of the total flux, surrounding by an envelope component Firstly distinct detection of inner 280pc jet Proper motions in 3C48: inner jet component 3.7c to the north; outer jet ~1.4c to the northeast Kinematics analysis suggests the kpc-scale jet is as fast as 0.8c, with viewing angle less than 30deg; the inner 280pc is even faster and/or closer to the line of sight. polarization images suggest an ordered magnetic field in extended component; while at some hot spots Faraday rotation structure is shown The general wavelike bending jet is fitted by a helical model; the model fitting suggest different K-H waves inside and outside 280pc (different physical condition)

An et 2009 EAVN Prospect EAVN observations of Compact Steep Spectrum sources EAVN monitoring of proper motions of CSO/GPS

An et 2009 EAVN 18

An et 2009 EAVN 19 We’ll see bright future in East Asia VLBI Network