Active Galactic Nuclei Laboratory for Gravitational Physics Image Credit: NASA/JPL-Caltech Image Credit: NASA/JPL-Caltech Ashkbiz Danehkar Department of Astronomy, University of Michigan [email protected] The 29th Midwest Relativity Meeting, Grand Rapids, Michigan, USA, October 4th, 2019
10/04/2019 Midwest Relativity Meeting 3 Gravity Timeline 1992-present: golden age of cosmology (Alan Guth 2001) 2019: EHT imaging of SMBH in M87 2016: LIGO detection of gravitational waves ● (Weiss+Throne+Barich 2017) 1995: acceleration expansion of the universe (Perlmutter+Schmidt+Riess 2011) 1974: Test of GR in a binary pulsar (Hulse+Taylor 1993)
10/04/2019 Midwest Relativity Meeting 4 Active Galactic Nuclei (AGN) 2019: EHT imaging of SMBH in M87 First Image of a Supermassive Black Hole Credit: Science History Images / Alamy Stock Photo
10/04/2019 Midwest Relativity Meeting 8 Ultra-fast Outflow in AGN Detection of relativistic outflows in X-ray ● Seyfert I PG 1211+143 Ionized outflow at -0.06c and -0.11 c Danehkar + 2018 Pounds + 2003,2006,2009 Ionized outflow at -0.06c
10/04/2019 Midwest Relativity Meeting 9 Ultra-fast Outflow in AGN Detection of relativistic outflows in X-ray ● Seyfert I PDS 456 Ionized outflow at -0.24c and -0.48 c Biossay-Malaquin, Danehkar + 2019
10/04/2019 Midwest Relativity Meeting 12 Ultra-fast Outflow in AGN X-ray Ionized Outflows in AGN Ionization parameter Gas density Radius Column density Shell thickness Outflow velocity Luminosity (0.0136- 13.6 keV) King & Pounds 2015; XMM-Newton & Suzaku (42 radio-quiet, Tombesi et al 2011; 51 AGN, Gofford et al. 2013) BH mass
10/04/2019 Midwest Relativity Meeting 13 Ultra-fast Outflow in AGN Theories for Relativistic Outflows in AGN ● strong magnetic field in accretion flow/disk of rotating BH – Blandford-Znajek process (1977) for strong jets from flow – Blandford-Payne process (1982) for slow winds from disk ● frame dragging (gravitomagnetism indirectly) – Penrose process (1971) – Kerr spacetime of rotating BH – extracting black-hole rotational energy ● frame dragging + magnetic field (e.g. Narayan & Quataert 2005) ● gravitomagnetism (directly)? Frame dragging+magnetic (Narayan & Quataert 2005) Blandford-Znajek process (Thorne 1995)
10/04/2019 Midwest Relativity Meeting 14 Supermassive Black Hole Spin Black Hole Spin Measurement (see Brenneman 2013) ● Thermal Continuum Fitting (UV observation) – stellar-mass black hole – AGN (may problematic due to UV absorption lines!) ● Inner Disk Reflection Modeling – AGN (X-ray) ● High Frequency Quasi-Periodic Oscillations – AGN + stellar-mass black hole (fully not developed) ● X-ray Polarimetry – Need sensitive X-ray polarimter (not available now!) ● Imaging the Event Horizon Shadow – Need Very Long Baseline Interferometry (in development) – Suitable only for Sgr A* and M87 a = J c / G M2 (a: BH spin, J: angular momentum, M: BH mass, G: gravitational constant, c: speed of light)
10/04/2019 Midwest Relativity Meeting 15 Supermassive Black Hole Spin Relativistically broadened Kα iron line (6.4 keV) Compton hump (> 10keV) Black Hole Spin Measurement from X-ray a = - 1 a = 0 a = 1 Image credit: NASA/JPL-Caltech
10/04/2019 Midwest Relativity Meeting 17 Supermassive Black Hole Mass BH Mass from Reverberation Mapping Technique (Kaspi + 2000) ● Variation in light curves of broad emission line region (BLR) in Seyfert I AGN ● Time delay in variation of BLR luminosity (Hb 4861A) relative to variation of accretion disk luminosity (continuum 5100A) www.techfreaq.de Bentz + 2006
10/04/2019 Midwest Relativity Meeting 18 SMBH Spin Implication Black Hole Spin Implication for a Unified AGN Model? Garofalo + 2010 Beckmann & Shrader 2012, Active Galactic Nuclei AGN Unified Model - Radio-Quiet AGN: Seyfert I, Seyfert II - Radio-Loud AGN: FR I, FR II (extended radio jets)
10/04/2019 Midwest Relativity Meeting 20 Future Direction for X-ray Astronomy ● XRISM, X-Ray Imaging and Spectroscopy Mission (2022) – Japan Aerospace Exploration Agency (JAXA) – Replacement for Hitomi, ASTRO-H (2016, failed) ● ATHENA, Advanced Telescope for High Energy Astrophysics (2031) – European Space Agency (ESA) ● Lynx X-ray Observatory (proposed 2035) – National Aeronautics and Space Administration (NASA) ● Arcus X-ray observatory (proposed 2023) – NASA
10/04/2019 Midwest Relativity Meeting 21 Proposed Direction for Numerical GR ● Finite-difference Time-domain (FDTD; 1980) ● Discontinuous Time-domain Method (FETD; 2000) ● Finite Element Method (FEM; 1973) ● Finite Integration Technique (FIT, 1977) ● …. ? For Maxwell EM equations, there are several numerical methods: For Einstein field equations (local gravitational interaction), there are several numerical methods (see review by Font 2003 for numerical GR; Fornt 2008 for GR+MHD) For example, for Bianchi dynamical formulas of non-local (Weyl) gravitational fields: Newtonian Tidal force Non-Newtonian effect Gravitational waves shear induction? computational hydrodynamics simulation not fully developed angular momentum ● Finite Difference Method (FDM; 1988) ● Smoothed Particle Hydrodynamics (SPH; 1977) ● Spectral Methods (1988) ● Flow Field-dependent Variation Method (FDV; 2002) ● …. One of reference books for mathematics of Weyl fields
10/04/2019 Midwest Relativity Meeting 22 Summary Implication of Supermassive Black Hole Angular Momentum for AGN Outflows? Relativistic Outflows in AGN measured from – blue-shifted highly-ionized absorption lines in X-ray spectra AGN Outflow Physical conditions from – photo-ionization modeling of absorbers Black Hole Spin measured from – relativistic Fe Kα line (6.4 keV) – Compton hump (> 10keV) Black Hole Mass measured from – time delay in BLR vs. disk light curves in Seyfert I AGN (Reverberation-mapping) Physical Mechanism behind relativistic outflows in AGN? – Need for larger sample and future X-ray observations (XRISM 2022, ATHENA 2031, Lynx 2035) – Future developments in numerical methods & simulations of GR hydrodynamics Credit: Roen Kelly @ Astronomy
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