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XMM-Newton View of TeV Blazars

XMM-Newton View of TeV Blazars. 张有宏 清华大学天体物理中心. Outline. Introduction to Blazars X-ray variability properties of TeV blazars Blazars vs GRBs vs micro-quasars/blazars

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XMM-Newton View of TeV Blazars

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  1. XMM-Newton View of TeV Blazars 张有宏 清华大学天体物理中心 5th micro-quasar workshop

  2. Outline • Introduction to Blazars • X-ray variability properties of TeV blazars • Blazars vs GRBs vs micro-quasars/blazars • Multi-wavelength observations of PKS2155-304 with XMM-Newton (our work); comparisons with other coordinated multi-wavelength observations • XMM-Newton timing mode observations of Mrk 421 (other work) • Physical implications inferred from the observations 黑洞天体物理前沿问题年度研讨会（2006）

  3. Blazar SED Sequence optical X-ray • Nonthermal emission • Low energy: Synchrotron • High energy: Inverse Compton • Luminosity-related SED? • Peak energy (synchrotron) • HBLs, LBLs, FSRQs • Cooling-dependent • Variability comparison • Same mechanism •  GRBs and micro-quasars (micro-blazars) (Fossati et al . 1998) 黑洞天体物理前沿问题年度研讨会（2006）

  4. Jet/Synchrotron Emission (Mirabel, Sky and Telescope, May 2002, 32) 黑洞天体物理前沿问题年度研讨会（2006）

  5. TeV Blazars • 6 TeV blazars (confirmed): • Mrk 421, PKS 2155-304, Mrk 501 • HBLs: synchrotron component peaks at UV-X-rays • X-ray emission are the high energy tail of synchrotron emission  • X-rays are expected to be violently variable  • To probe particle acceleration and cooling of relativistic particles 黑洞天体物理前沿问题年度研讨会（2006）

  6. 由李-马公式的引用看甚高能伽玛射线天文学的兴衰由李-马公式的引用看甚高能伽玛射线天文学的兴衰 黑洞天体物理前沿问题年度研讨会（2006）

  7. X-ray Variability of TeV blazars: ASCA/SAX/RXTE • Flux variations: • Timescales: ~ days with rapid flicker superimposed • Variability amplitude: energy dependent • PSD: not useful, slpoe ~ 2.5 • Cross-correlation function (CCF)  time lags • Spectral evolution: • The higher flux, the harder spectrum • Peak energy shifts to higher energy with higher flux • Mrk 501: ~100 keV by SAX (Pian et al. 1998) • Similar optical variability in LBLs (e.g., BL Lac observed with Tsinghua 80cm telescopes) 黑洞天体物理前沿问题年度研讨会（2006）

  8. X-ray time lags of TeV blazars • Time lags are different from flare to flare: • Soft lags: soft photons lag hard ones • Hard lags: hard photons lag soft ones • Amplitude of lags: 0 - ~3 hours? • Time lags appear to correlate with • Photon energy • Flare’s duration • Spectral slope • Timescale (Fourier frequency) ? 黑洞天体物理前沿问题年度研讨会（2006）

  9. Lags: TeV blazars vs microquasars and GRBs • TeV blazars: X-ray soft/hard lags • GRBs: gamma-ray soft lags (hard lags?): cooling/accelerating time scales of relativistical electrons  jet/synchrotron mechanism for X-ray (optical-UV) in TeV blazars, and gamma-ray (X-ray-Optical) in GRBs • Microblazars, microquasars, X-ray binaries • Hard lags: Comptonization of soft photons by reletivistic electrons • From hot corona or from the jets • Hard (Soft?) lags  jet/synchrotron X-ray (lower energy) emission? • More complicated: e.g. soft X-rays may be dominated by the accretion disk 黑洞天体物理前沿问题年度研讨会（2006）

  10. Multi-wavelength variability of TeV blazars • Strongest constraints on emission models • Multi-wavelength variability: • Peak fluxes correlated: Mrk 421 • Different correlations over different timescales • Whether X-ray variability properties can be extrapolated to UV-Optical bands? • Coordinated multi-wavelength observations • Optical-UV and X-ray instruments onboard XMM 黑洞天体物理前沿问题年度研讨会（2006）

  11. XMM-Newton observations of TeV blazars • Calibration sources, observed about twice per year (and Guest Observers)  • Mrk 421 (31obs. > 9 orbits) and PKS 2155-304 (9 orbits) over about 6 years • Optical-UV-X-ray observations of PKS 2155-304 • X-ray timing mode observations of Mrk 421 黑洞天体物理前沿问题年度研讨会（2006）

  12. UV and X-ray observations of PKS 2155-304 • Orbit 087: 2000 May 30-31 (Zhang et al. 2006) • ~ 0.3 days lag of UV to soft X-rays??? 黑洞天体物理前沿问题年度研讨会（2006）

  13. UV and X-ray observations of PKS 2155-304 • Orbit 171: 2000 Nov 19-20 (Zhang et al. 2006) • ~ no detectable lag of UV to X-ray (if, hard lag?) 黑洞天体物理前沿问题年度研讨会（2006）

  14. UV and X-ray observations of PKS 2155-304 • Variability amplitude vs energy 黑洞天体物理前沿问题年度研讨会（2006）

  15. UV and X-ray observations of PKS 2155-304 • Soft X-ray/UV hardness ratio vs count-rate 黑洞天体物理前沿问题年度研讨会（2006）

  16. Optical and X-ray observations of PKS 2155-304 • Orbit 362: 2001 November 30 黑洞天体物理前沿问题年度研讨会（2006）

  17. Comparison with previous multi-wavelength observations • 1991 November, achromatic quasi-periodic variability, soft X-rays (25A) led UV (1400A) by ~ 1 hour (Edelson et al. 1995) 黑洞天体物理前沿问题年度研讨会（2006）

  18. Comparison with previous multi-wavelength observations • 1994 May: well-defined flare; variability amplitude decreased, and temporal profile broadened with increasing wavelengths; X-rays led EUV and UV by ~ 1 and 2 days (Urry et al. 1997) 黑洞天体物理前沿问题年度研讨会（2006）

  19. XMM-Newton multi-wavelength observations: intra-day variability • Previous coordinated multi-wavelength observations: inter-day variability •  Complex multi-wavelength observations can occur over different timescales • XMM-Newton multi-wavelength observations are superior: • Resolution • Signal-to-noise ratio 黑洞天体物理前沿问题年度研讨会（2006）

  20. XMM timing mode observations of Mrk421 • Currently the highest Signal-to-noise ratio (Brinkmann et al. 2005) 黑洞天体物理前沿问题年度研讨会（2006）

  21. Time-resolved CCF analysis • Sliding window (2000s, 6000s, and 20000s) 黑洞天体物理前沿问题年度研讨会（2006）

  22. Characteristic timescales? • 5.2 ks, 7.2 ks, 10 ks for orbit 084, 546, 807 黑洞天体物理前沿问题年度研讨会（2006）

  23. Physical implications • Correlations at different time lags  a common “synchrotron” origin • Substantially different patterns of variability over different timescales  constraints on radiation models would be different from epoch to epoch, requiring, e.g., • changes in the parameters characterizing the emitting region or • different mechanisms operating 黑洞天体物理前沿问题年度研讨会（2006）

  24. Homogeneous Scenario the smaller the lag, the larger the combination of B andδ Zhang et al. (2002) 黑洞天体物理前沿问题年度研讨会（2006）

  25. UV vs X-ray lags • ~ 2 days in 1994 May • < 800 s in 2000 November •  theratio of B between 2000 November and 1994 May would be> 36 (δ ～ 10) •  the extreme values of B to be unacceptable in reality, but 黑洞天体物理前沿问题年度研讨会（2006）

  26. Interpretation of the observed lags may be very likely affected by, e.g., inhomogeneous emitting region(s): • stratified shock model or • an energy dependent volume 黑洞天体物理前沿问题年度研讨会（2006）

  27. Shoch-in-jet model • At tobs, emission from certain position R(t), and earlier emission from all positions; >~ 60% “background emission” • Two-colliding-shell model: shock structure developed; noticeable changes of the physical state of emission region and unexpected changes of emission properties (Brinkmann et al. 2005). 黑洞天体物理前沿问题年度研讨会（2006）

  28. Conclusions • The complex variability behaviour of TeV blazars; • It appears hard to uniquely constrain the underlying physical properties for the emission process from the observations; • Better observations and extended relativistic MHD numerical simulations • Well-defined major fares (possibly a single episode) might still provide the most likely situation to probe any detailed insight, e.g., • any connection between the sign of the lags and the rise and decay of the flux, and • any relation between the lags (sign) and the peak energy of the synchrotron emission. 黑洞天体物理前沿问题年度研讨会（2006）

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