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SUMMARY PROBING STRONG GRAVITY IN AGN Kirpal Nandra Imperial College London
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PROBING STRONG GRAVITY The Promise The Probes The Progress The Problems The Prospects Probably… Paul Reviews Observations (and Theory)
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THE PROMISE What are the processes close to the event horizon? Are black holes in AGN spinning? How does BH spin evolve on the Cosmic Scale? How does matter behave in the strong field? Does it obey the predictions of GR?
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THE PROBES Broad emission lines Narrow emission lines Narrow absorption lines Variability/reverb. Broadband/disk/reflection spectra Polarimetry Binary Black Holes Microlensing (Zoghbi, de Marco, Ponti, Goosmann) (Iwasawa, Ballantyne, Guainazzi, de la Calle, Svoboda, Miniutti) (Cappi, Reeves,) (Dovciak) (Laor, Walton) (Cappi) (Komossa, Liu) NOBODY! + Nikolajuk: TBC
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PROBES: MICROLENSING RX J1131-123116 Chartas et al. 2009 Dai et al. 2009 MICROLENSING! Direct measurement of size of emission region: X-rays from 10 R g (Optical 70 R g )
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THE PROGRESS
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Risaliti et al. 2005 NGC1365 Mrk 509 (long-look, 200ks) MC et al., 2009 Dadina et al. ‘05 Obs1 Obs2 Obs3 Variability allows to place limits on location, mass, etc. (See also Krongold et al. 2007 on NGC4051) Cappi PROGRESS: INFLOWS/OUTFLOWS
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PROGRESS: HOTSPOTS Turner et al. 2005Iwasawa et al. 2004 Cappi, Iwasawa, Reeves, De Marco
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PROGRESS: THE INNER FLOW Iwasawa Nikolajuk
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PROGRESS: BROAD LINES 45% of XMM-Newton Seyfert sample with >30,000 counts Nandra et al. (2007) De La Calle, Guainazzi
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PROGRESS: BROAD LINES Zoghbi
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If η implies a * Fanidakis et al. arXiv:0911.1128 PROGRESS: SPIN MEASUREMENT Laor: disk continuum fitting
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PROGREES: SPIN MEASUREMENT Miniutti: broad emission lines SWIFT J1247 Fairall-9 Implications for black hole accretion/merger history through cosmic time (also Ballantyne)
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PROGRESS: STRONG GRAVITY Iwasawa Walton Svoboda
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THE PROBLEMS Broad lines Predicted to be universal, but not always observed Degenerate with complex absorption Lines are much weaker than we might have hoped Sometimes variable, sometimes now Narrow lines NOT predicted unless extreme anisotropic effects. Limited statistical significance (Vaughan & Uttley) “Spallation” of Fe Non-repeatable observations -> cannot test models Should be transient (Kepler timescale) – is this too convenient? QPOs Finally one decent AGN example (RE 1034; Middleton) Ooops it went away (Middleton) Which QPO to associate with GBHC? Interpretation in GBHC not clear despite vastly better data Overall, two major problems: 1)Repeatability of observations 2)Prediction and testing of models
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PROBLEMS: BROAD LINES Zoghbi Absorption highly unlikely to be sole explanation, but details (e.g. spin) very hard to disentangle
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K. Nandra: broad lines in AGN PROBLEMS: BROAD LINES Disk line upper limits typically 50-100 eV Criteria: <99% significance for blurred reflection 12 total: IC4329A (1) NGC 5506(1), NGC 5548(1) NGC 7469(1) 30% of Sample Why are broad lines absent? (Almost) unavoidable prediction of accreting systems… Ionization, Fe abundance, Extreme blurring?
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Ignacio de la Calle 16 February 2010 6.7 PROBLEMS: S/N RATIO De la Calle
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PROBLEMS: NARROW FEATURES Lines statistical significance? (transient features, number of trials in time and energy, etc…) Identifications of edges/lines energies? (Kallman et al. 2005, Kaspi et al. for PG1211) Local “contamination”? (PDS456 at risk? McKernan et al. ’04, ‘05 ) Publication bias? Only positive detection, low signif., Vaughan & Uttley ‘08 ) cz (km/s) Outflow v (km/s) Solutions: Large Samples, Systematic analysis: Cappi, de Marco, de la Calle, Ponti
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Strong narrow K line at 6.4 keV. Constant flux over 3 years. However redshifted but relatively narrow line emission is observed at 5.4 keV and 5.9 keV in 2005 low state. Obs 1 vs Obs2 PROBLEMS: NARROW LINES Reeves
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PROBLEMS: NARROW LINES SuzakuAll XMM co-add Mostly S. Vaughan 5.4 keV If 5.4 keV is real, it is variable (thus not spallation) Reeves
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PROBLEMS: LINE VARIABILITY Bhayani & Nandra (2010) Variability key to break degeneracies: Iwasawa, Zoghbi, Reeves, de Marco, Ponti, Goosmann BUT… source behaviour not predictable with current models
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PROSPECTS: REVERBERATION Zoghbi Reeves
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PROSPECTS: POLARIZATION Dovciak X-ray polarimetry: a new window to be opened by GEMS, NHXM, IXO
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PROSPECTS: BH SPIN ASTRO-H: First high resolution, high throughput spectroscopy at 6 keV IXO XMS NGC 3783 300ks MCG-6-30-15 100ks IXO IXO: ULTRA-HIGH THROUGHPUT IXO ASTRO-H
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PROSPECTS: TRACING HOTSPOTS IXO: high throughput Flux constraint ~20% 400s exposure: 1/10 t Keplerian at 6 r g C. Reynolds
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PROSPECTS: TESTING GR? GR correct =0.5 0.2 =0.0 (GR) Johanssen & Psaltis (2009) Testing the no-hair theorem =0 C. Reynolds
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PROGNOSIS Strong gravity effects in AGN can be probed For example, lensing shows X-rays arise within ~10 Rg Major issues: Model degeneracies Unrepeatable observations Lack of testable model framework Major progress Large samples, systematic analysis Variability studies, reverberation Huge future potential High resolution spectroscopy High throughput spectroscopy Polarimetry See you in Progue 2020! Promising Prospects for Proactive Promotion of Proposed Projects IXO
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