1 / 31

Radio quiet AGN

Radio quiet AGN. B. Czerny Copernicus Astronomical Center Warsaw. VHE: are radio quiet AGN of any interest?. bad news: only a small fraction of energy emitted above 100 KeV good news: AGN are the best probes of GR – X-ray spectroscopy. Outline. general introduction X-ray spectroscopy

aspen-cook
Download Presentation

Radio quiet AGN

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Radio quiet AGN B. Czerny Copernicus Astronomical Center Warsaw

  2. VHE: are radio quiet AGN of any interest? • bad news: only a small fraction of energy emitted above 100 KeV • good news: AGN are the best probes of GR – X-ray spectroscopy Moriond 2005

  3. Outline • general introduction • X-ray spectroscopy • current developments based on results obtained in collaboration with: S. Collin R. Goosman, M. Mouchet, A.-M. Dumont, M. Dovciak, V. Karas, A. Rozanska, G. Ponti Moriond 2005

  4. Radio quiet AGN: intro • Definition: • Properties: L from 1047 erg/s down broad band spectra Moriond 2005

  5. Radio-quiet AGN:intro What are they? Black holes John Michell (1724-1793) Roy Kerr (1934-) Karl Schwarzschild (1873-1916) Albert Einstein (1879-1955) Moriond 2005

  6. Radio quiet AGN: intro • What are they? Accreting black holes M ~ 106 – 1010 Ms M~ from tens of Ms/year down Moriond 2005

  7. Type 1 and type 2 objects • Type 1: viewed roughly face on not strongly obscured but warm absorber present • Type 2: viewed at high inclinations strongly obscured (so called „dusty/molecular torus” – most probably a type of wind) High energy processes better followed in type 1 objects Moriond 2005

  8. Components: • Cold optically thick accretion disk • Hot optically thin plasma: geometry under discussion Paticles roughly in Keplerian motion if pressure gradient unimportant General relativity effect: presence of the marginally stable orbit Moriond 2005

  9. Emission of accretion disks • Stationary cold Keplerian acccretion disk Moriond 2005

  10. Accretion disk spectra • Tmax~105 K • Disk emission peaks in far UV Composite spectrum of bright quasars from sample of Fransis et al. (1991) after Morris, disk black body fit and schematic representation of the composite of Zheng et al/Laor et al. Moriond 2005

  11. AGN flow geometry Plausible geometry: L/LEdd < 0.1 disk far from marginally stable orbit L/LEdd ~0.1 – 1 disk approaches marginally stable orbit L/LEdd > 1 disk puffs up Moriond 2005

  12. Hot plasma emission • Bremsstrahlung • Synchrotron • Compton scattering They form broad band spectra, difficult to assign to any particular distance from the gravity center; problems with definite determination of geometry Moriond 2005

  13. Cold plasma emission • Thermal emission T ~ 105 K • Reprocessing of incident hard X-rays - thermalization - Thomson/Compton scattering - emission of atomic lines In AGN elements like C,N,O, Si, S,… and Fe are not fully ionized in the disk even close to the marginally stable orbit The option of line emission gives the full advantage of X-ray spectroscopy Moriond 2005

  14. Broad Kα iron line • The shape of iron line tests the particle motion close to horizon Moriond 2005

  15. First detecion of Kαline Detection of broad line in MCG -6-15-30 in ASCA data (Tanaka et al.. 1995) Moriond 2005

  16. New observations of K Broad line in the same object (MCG-6-30-15) measured with XMM (Fabian et al. 2002) Moriond 2005

  17. Variability of the line profile Detection Line profile in of variosu luminosity states in ASCA data (Iwasawa et al.. 1996) broad line in MCG -6-15-30 in ASCA data (Tanaka et al.. 1995) Moriond 2005

  18. Variability of hard X-rays Lightcurve of MCG -6-15-30 form XMM (Ponti et al.. 2004) Moriond 2005

  19. Time-dependent process Moriond 2005

  20. Single spot • Computations of the reflection component require solution of radiative transfer - continuum - hundreds of atomic lines A few codes exists. Titan/Noar code of Collin, Dumont & Abrassart (2000) is the best for optically thick media. Moriond 2005

  21. Local spectrum • Result depends on the flare phase Local X-ray spectrum of irradiated accretion disk (Collin et al. 2003) State 2: unexpanded disk State 3: disk expanded due to the X-ray heating Moriond 2005

  22. Single spot R. Goosmann, in preparation Moriond 2005

  23. Spot motion, light propagation in curved space Moriond 2005

  24. Mean and rms spectra Model parameters: a = 0.95 , i =30 deg, M = 107 Ms Tfl = 2e5 (r/18)3/2 [s], Ffl ~ r-3 [s], uniform flare distribution Work in progress… Moriond 2005

  25. Single flare observations • Bright flare from MCG -6-15-30 Ponti et al.. 2004 Moriond 2005

  26. Iron line delay in a single flare Ponti et al. 2004 Moriond 2005

  27. In which sense AGN are better than GBH ? • Typical current count rate 10 cts/s 10 000 cts/s • Typical Keplerian timescale at inner disk orbit 103 s 10-3 s • so counts per single orbit 100 cts 10 cts • lower ionization level GBH better for evolutionary studies Moriond 2005

  28. Spatial resolution of observations Typowe osiągane zdolności rozdzielcze: Typ Masa Odległość 1”[cm] 1”[RSchw] GBH 10 10 kpc 1017 3x1011 Milky Way 2.6x106 10 kpc 1017 106 MBH 107 50 Mpc 5x1020 109 MBH 109 1 Gpc 1022 2x109 Specjalne techniki (VLBI, fotometria plamkowa) pozwalają osiągnąć wyniki lepsze o parę rzędów wielkości, ale to wciąż za mało. Obszar w bezpośredniej bliskości czarnej dziury można jednak badać pośrednio poprzez analizę widma promieniowania, także w zależności od czasu. Moriond 2005

  29. Are central objects indeed black holes? • So far everything is consistent with GR expectations although accuracy is not high Moriond 2005

  30. If something looks like a black hole … From www page of Peter King Moriond 2005

  31. Moriond 2005

More Related