Talk at the 29th Midwest Relativity Meeting, Grand Valley State University, Grand Rapids, MI, USA, October 4, 2019, https://doi.org/10.6084/m9.figshare.13699240

1. 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
danehkar@umich.edu
The 29th
Midwest Relativity Meeting, Grand Rapids, Michigan, USA, October 4th
, 2019

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Gravity Timeline
1687: Newtonian gravity
1915: General Relativity
1960-1975: golden age of GR (Kip Throne 1995)
– Cambridge (Sciama’s group)
– Hamburg GR group (Jordan)
– Potsdam AEI (Ehlers’ group)
– Syracuse (Bergmann’s grp)
– UT Austin (Schild’s group)
– ...
local interaction (Einstein field equations)
non-local long-range interaction (Binanchi identities)
Trumper 1964, Hawking 1966, Ellis 1971

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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)

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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

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Active Galactic Nuclei (AGN)
X-ray Observations of AGN (1999-present)
Chandra X-ray Observatory (1999-present)
XMM-Newton, X-ray Multi-Mirror Mission (2000-present)
NuSTAR, Nuclear Spectroscopic Telescope Array (2012-present)
Gierlinski + 1999
Lonanov 2007
Credit: Roen Kelly @ Astronomy

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Active Galactic Nuclei (AGN)
AGN Unified Model (radio-loud & -quiet AGN, Seyfert I & II Galaxies)
Beckmann & Shrader 2012,
Active Galactic Nuclei
Unified Models for AFNs
Antonucci, ARA&A, 1993, 31, 473
Unified Schemes for AGNs
Megan Urry & Padovani, 1995, PASP, 107,
803
(Bernie Fanaroff &
Julia Riley 1974)
AGN Unified Model
• Radio-Quiet AGN
 Seyfert I (BLR+NLR,
compact outflows)
 Seyfert II (NLR)
• Radio-Loud AGN
 FR I (compact radio jets)
 FR II (extended radio jets)
 Blazar (relativistic beams)
(Carl Seyfert 1942)

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Active Galactic Nuclei (AGN)
Dermer & Giebles 2016
AGN Classification (radio-loud & -quiet AGN, Seyfert I & II Galaxies)
Blandford, Netzer, Woltjer 1990, Active Galactic Nuclei

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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

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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

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Ultra-fast Outflow in AGN
Detection of relativistic outflows in X-ray
Cappi 2006

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Ultra-fast Outflow in AGN
Correlation between outflow kinematics and physical conditions
Tombesi + 2013
(Ultra-fast outflows)
(Warm Absorbers)

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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

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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)

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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)

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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

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Supermassive Black Hole Spin
BH Spin from Reflection Modeling
●
kerrconv (Brenneman & Reynold 2006)
●
relline (Dauser + 2010)
●
xillver (Garcia + 2010,11,13)
●
relxill (Garcia + 2014)
Dauser & Garcia + 2014

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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

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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)

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SMBH Spin Implication
Black Hole Spin Implication for a Unified AGN Model?
Danehkar +

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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

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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

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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

23. Image
Credit:
NASA/JPL-Caltech
Image
Credit:
NASA/JPL-Caltech
Thank you for your attention
Thank you for your attention