Revisit LSI +61 303 with VLBA Yuanwei Wu (NTSC) G. Torricelli-Ciamponi (INAF); M. Massi(MPIfR); M.J. Reid (CfA); B. Zhang (SHAO); L. Shao (MPIfR); X. W. Zheng (NJU) YongPyong/EAVW 2018-09-07
Outline ● Background of LSI +61 303 ● VLBA Observations ● Results ➢ proper motion & 3D motions ➢ Precession period ➢ Jet geometry ● Future Plan
Background of LSI +61 303 ● Binary: Be star (B0) + compact object Microquasar or Pulsar wind D ~ 2 kpc ● X-ray, γ-ray (>400 GeV) 1 of 3 known star systems produce Very High Energy gamma rays ● Periodic light curve at optical, radio, X-ray, γ-ray ● 722 papers, 542 from 1998 to 2018
Background of LSI+61303
Background of LSI +61 303
Background of LSI +61 303 V. Dhawan; A. Mioduszewski & M. Rupen 2006
Background of LSI +61 303 Casares J. et al. 2005
Background of LSI +61 303 Albert J. et al. 2006
Background of LSI +61 303 Light cureve data ~ 6 yr M. Massi & Torricelli-Ciamponi G. 2014 P1 = 26.49 +- 0.07 day P2 = 26.92 +- 0.07 day P3 = 1628 +- 48 day
Background of LSI +61 303 P1 = 26.49 +- 0.07 day M. Massi & Torricelli-Ciamponi G. 2016 P2 = 26.92 +- 0.07 day P3 = 1628 +- 48 day
Background of LSI +61 303 M. Masssi et al. 2012 M. Massi & G. Torricelli-Ciamponi 2014
VLBA Observations ● 10-epoch phase reference observations 2015Jul15 --- 2015 Aug23 ● frequency setup same as 2006 observations 8.4 GHz, 4IFs,16 MHz per IF, dual polarization ● combine with 2006 observations There are 20 epoch data with time span of 9 year
Results: jet images
Results: precession ellipse
Results: proper motions and 3D motion ● Proper motion Our results GAIA results ● Distance 2.0 ± 0.3 kpc (Aragona et al. 2009) V LSR = 41.4 ± 10 km s ● 3D motion The very low peculiar motion is a strong evidence that the compact object is a black hole.
Results: precession period
Results: precession period
Results: geometry of the jet x', y' is the orbit plane B is the jet base x'', y' is the plane ┴ l.o.s BC is the jet axis
Results: geometry of the jet x', y' is the orbit plane B is the jet base x'', y' is the plane ┴ l.o.s BC is the jet axis Normal of the Orbit is same to the precession axis AG = 25 deg (Nagae et al. 2006) MAW = MOW = DAW=DBW = w = 230 deg Jet open angle = 6 deg, CG = 21 deg Jet open angle = 5 deg, CG = 20 deg for SS 433
Results: geometry of the jet Modeling the jet projection versus observations
Results: geometry of the jet Model of jet angle various with time
Future Plan ● LSI + 61 303 a good lab for study jet physics ● the core shift at high frequency will be much smaller, multi-epoch monitoring of the jet at higher frequency, its possible to separate precession and orbit motion ● High resolution multi-band jet data will yield properties of jet plasma (density & temperature), that can improve the model of radiation transfer, and the geometry of the radio jet
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