The Innermost Jet of 3C 84 The Innermost Jet of 3C 84 Sascha Trippe - PowerPoint PPT Presentation

The Innermost Jet of 3C 84 The Innermost Jet of 3C 84 Sascha Trippe 사샤 트리페 Sascha Trippe 사샤 트리페 서울대학교 서울대학교 SNU Seoul SNU Seoul

The Innermost Jet of 3C 84 The Innermost Jet of 3C 84 Junghwan Oh Jeff Hodgson Sascha Trippe Thomas Krichbaum Jae-Young Kim Bindu Rani

Marscher (2005)

Jet from B-field – black hole interaction? Jet from B-field – black hole interaction? (Blandford & Znajek 1977) (Blandford & Znajek 1977) Narayan & Quataert (2005)

Jet from B-field – accretion disk interaction? Jet from B-field – accretion disk interaction? (Blandford & Payne 1982) (Blandford & Payne 1982) Hujeirat+ (2003)

… or maybe both? or maybe both? … BH jet Disk jet Disk jet Hardee+ (2007)

3C 84 (NGC 1275) BU blazar monitoring group ➢ z = 0.0176 ➢ Radio galaxy / Seyfert 1.5 ➢ γ -ray bright C1 C2 C3 A. Edge

3C 84 Diagram: M.-L. Menzel (MPE)

1 mas = 0.36 pc = 12,000 R S ( M BH = 3.2  10 8 M sol , H 0 = 70 km/s/Mpc)

Distance C1a – C1b is ~800 R S (~1 light-month) If C1 were the jet base, we have Blandford–Payne mechanism at work (Blandford–Znajek requires <10 R S ). However , the required size is probably even too large for an accretion disk: Accretion disk size vs. black hole mass (Morgan+ 2010): Expected for 3C 84: ~54 R S (half-light radius) ↳ C1 is probably not the jet base

Doppler boosting in bent / helical jet? Doppler boosting in bent / helical jet? Scaling of brightness temperature … with Doppler factor … constrains bulk speed to Scaling of flux … constrains power-law index to … which gives a spectral index of SSA? But : Geometry? Why for C1a and C1b separately? Consistency with projected bulk flow speeds ≺ c ?

Variation of intrinsic flux? Variation of intrinsic flux? Assumption: we observe multiple, independent, emitters cooling down while traveling along the jet. Fluxes decay by factors ≽ 5 within ≼ 1 year  synchrotron cooling times ≼ 6 months. Because this is consistent with B ≈ 10 μ T, γ electron ≈ 10,000 (for δ ≈ 1) But : requires roughly constant “start” fluxes in 2008 – 2015?

≾ 2700 Black hole is ≾ 2700 R behind C1a/b R S Black hole is S behind C1a/b Projected: ≾ 2400 R S De-projection with θ = 65 ̊ (Fujita & Nagai 2017) conical jet profile parabolic jet profile

Summary Summary ➢ We monitored the structure of 3C 84 with GMVA in 2008–2015 ➢ There are two “cores” separated by ~800 R S  we do not see the jet base but rather a jet sheath above the central engine ➢ Brightness temperatures and fluxes of C1a/b correlate with relative position angle, varying by factors ~10 and ~5, respectively ➢ Doppler boosting is possible but seems to require improbable bulk flow speeds and/or geometries ➢ Intrinsic variability consistent with B ≈ 10 μ T, γ electron ≈ 10,000, but seems to require roughly constant initial fluxes over 7 years ➢ The central black hole is located ≾ 2700 R S behind C1a/b