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Our Galactic Supermassive Black Hole Sgr A*: the Ideal Testbed for Theories of Accretion/Gravity and Black Hole Life Cycles

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Our Galactic Supermassive Black Hole Sgr A*: the Ideal Testbed for Theories of Accretion/Gravity and Black Hole Life Cycles Our Galactic supermassive black hole Sgr A*: the ideal testbed for theories of accretion/gravity and black hole life cycles Sera Markoff (API, University of Amsterdam) [F. Baganoff, P. Biermann, G. Bower, J. Dexter, S. Dibi, S. Drappeau, E. Gallo, H. Falcke, C. Fragile, C. Froning, E. Körding, R. Hynes, D. Maitra, J. Nip, M. Nowak, R. Plotkin, F. Yuan] (Image credit: Farhad Yusef-Zadeh) Black holes are central engines in the universe ➠ Conversion of rest mass to other forms of energy via gravity (accretion) is extremely efficient ➠ The energy liberated from matter as it infalls (due to losing angular momentum) from rout to rin is just the difference in the total energy: GM GM L = − − − M˙ !" 2rout # " 2rin #$ 2 GM GMM˙ rin ~ ξrg=ξGM/c = 0 − − M˙ = L=Ṁc2/(2ξ) ! " 2rin #$ 2rin For a black hole, depending on its spin, total conversion efficiency is ~10-40% (much higher than nuclear fusion!!) Black holes + accreting matter = enormous feedback! ~ 600k light years across! (McNamara et al. 2005) Black holes + accreting matter = enormous feedback! Single BH, via its jets, injects 1062 ergs, providing enough energy to raise every particle inside the cluster by 1/3 keV!! (McNamara et al. 2005) Black holes are central players in the universe (this talk!) Astrophysics Cosmology/ Particle Physics Theoretical physics (Volker Springel) (Francis Halzen) Black holes are central players in the universe (this talk!) Astrophysics Cosmology/ Particle Physics Theoretical physics (Volker Springel) (Francis Halzen) Some “big” questions involving black holes How do they grow over cosmological timescales? How does their growth relate to their host galaxy Cosmology growth? How fast are they spinning, and what determines this spin? Does GR give the correct description of their affect on spacetime? Theor. Physics Theor. How are relativistic jets launched, and what determines eventual particle acceleration? How much power is in the jets? How does the entire accretion process (leading to Astrophysics/ various feedback effects) depend on black hole particle physics mass, spin, and the surrounding environment? Some “big” questions involving black holes How do they grow over cosmological timescales? How does their growth relate to their host galaxy Cosmology growth? How fast are they spinning, and what determines We needthis spin? access to near-event horizon physics inDoes a source GR give that the correctcan be description well-understood of their affect on spacetime? Theor. Physics Theor. Introducing: Sagittarius (Sgr) A*!! How are relativistic jets launched, and what determines eventual particle acceleration? How much power is in the jets? How does the entire accretion process (leading to Astrophysics/ various feedback effects) depend on black hole particle physics mass, spin, and the surrounding environment? Outline An “exposed” black hole: brief intro to Sgr A* Accretion around Sgr A*: current paradigm Using Sgr A* to “train” our GRMHD simulations Application of Fundamental Plane (mass scaling accretion physics at low ṁ) to Sgr A* Potential to image the event horizon of Sgr A* Outlook & Summary Context: zooming in on Sgr A* MIR: Spitzer IRAC (Ramirez, Stolovy, Arendt) Context: zooming in on Sgr A* Radio: VLA 6cm (Lang), 20cm (Yusef-Zadeh), 90cm (Lazio) Sgr B Sgr C 10 pc Context: zooming in on Sgr A* Context: zooming in on Sgr A* (Yusef-Zadeh ea. 00) Context: zooming in on Sgr A* (Yusef-Zadeh ea. 93,00; Genzel ea. 03) Context: zooming in on Sgr A* (Yusef-Zadeh ea. 93,00; Genzel ea. 03) Context: zooming in on Sgr A* (Yusef-Zadeh ea. 93,00; Genzel ea. 03) How to weigh a black hole: Sgr A* Orbits: 6 MBH=4x10 M⊙ Lowest luminosity black hole we know! -9 ⇒ L = 10 LEdd ! (Genzel et al., 92-04, Ghez et al., 95-04) Stellar orbits and types measured — Can estimate available “fuel” for SMBH ‣ Estimates based on stellar winds and simulations thereof: -5 -3 10 — 10 M☉ /yr ‣ At 10% efficiency would expect –4 –2 LBol∼ 10 – 10 LEdd (Coker & Melia 97, 00, Cuadra ea. 05) Sgr A* quiescent spectrum — Very weak! Typical LLAGN PL? Typical LLAGN X-ray flux? Diffuse gas from 33 Lx≈L☉ =2x10 erg/s outer accretion flow -6 -11 ➠ ☉ =10 LEdd !? Ṁ∼10 M /yr Yuan et al. 2003 Sgr A* quiescent spectrum — Very weak! The extremelyTypical low X-rayLLAGN PL? flux was already a shocker for theorists!Typical LLAGN Since then: Faraday rotation measuresX-ray flux? give -9 -7 10 – 10 M⊙ /yr, depending on magnetic field geometry and equipartion ➠ Sgr A* must have been moreDiffuse active gas from in past! 33 Lx≈L☉ =2x10 erg/s outer accretion flow -6 -11 ➠ ☉ =10 LEdd !? Ṁ∼10 M /yr Yuan et al. 2003 But wait, there’s more! — ∼Daily X-ray flares ✦ Sgr A* flares about once a day, typically few-10x quiescent flux, sometimes 100x ✦ Nonthermal dominates over thermal in X-rays, timescale ➠ origin w/in 10’s of Rg of black hole! (Baganoff ea. 2001, Nature; SM ea. 2001; Yuan ea. 2003; Dodds-Eden ea 2009,2011, etc.) Sgr A* in quiescence — physical models (very good constraints on <10rs conditions) Jet + “leaky” ADAF Synchrotron: — γe∼100 e s, B∼20-50 G w/in 10’s of Rg (Narayan ea. 98; Blandford & Begelman 99; Quataert & Gruzinov 00; SM ea. 01; Yuan, SM & Falcke ea. 02; Yuan ea. 03) Sgr A* flaring — hints about plasma processes near BH SSC Synchro (Porquet et al. 08) (SM et al. 01, 03) ➠ About 20 flares detected so far. Larger flares show “hiccups” (Porquet et al. 2008) like aftershocks! Most models focus on SSC/synchrotron processes (SM ea.; Liu & Melia; Yuan, Quatert & Narayan; Yusef-Zadeh ea.; Dodds-Eden ea., etc.; but see Zubovas, Nayakshin & SM (2012) for a fun alternative!) Sgr A* flaring — hints about plasma processes near BH SSC Synchro (Porquet et al. 08) (SM et al. 01, 03) ➠ About 20 flares detected so far. Larger flares show “hiccups” (Porquet et al. 2008) like aftershocks! Most models focus on SSC/synchrotron processes (SM ea.; Liu & Melia; Yuan, Quatert & Narayan; Yusef-Zadeh ea.; Dodds-Eden ea., etc.;(Maitra, but see SM Zubovas, & Falcke 2009) Nayakshin & SM (2012) for a fun alternative!) Can we “reproduce” Sgr A* numerically? Advancing the Astrophysical Model 3D Magnetohydrodynamics General Relativity Inflow: Accretion Outflow: Jets BH – MHD interface (ISCO) Microphysics: Heating & cooling of particles Radiation Transport Can we reproduce basic parameters, spectrum, size, and variability of Sgr A*? (Gammie et al.) Simulation startup (Cosmos++) (zoom) (Cosmos++: Anninos, Fragile & Salmonson 2005; Drappeau, Fragile, SM & Dexter 2012) Simulation startup (Cosmos++) (zoom) (Cosmos++: Anninos, Fragile & Salmonson 2005; Dibi, Drappeau, Fragile, SM & Dexter 2012) Targeting desired Ṁ -5 B4S9T3M7C B4S9T3M8C B4S9T3M9C -6 -7 -8 -9 -10 log( Accretion Rate [ solar mass / yr] ) -11 0 1 2 3 4 5 6 7 Time [orbit] (Dibi, Drappeau, Fragile, SM & Dexter 2012) Spectra: confirmation of low Ṁ 1039 sgra data -7 38 10 10 10-8 10-9 1037 1036 1035 [erg/s] ν 1034 L ν 1033 1032 1031 30 10 18 20 108 1010 1012 1014 1016 10 10 ν [Hz] (Drappeau, Dibi, Dexter, SM & Fragile, subm.) Effect of cooling on temperature and structure (Dibi, Drappeau, Fragile, SM & Dexter 2012) -9 Best fit to submm “bump” with 10 M⊙ /yr 1036 sgra data B4S9T3M9C 35 10 This is ok! 34 10 Also ok! 33 [erg/s] 10 ν L ν 1032 1031 1030 108 1010 1012 1014 1016 1018 1020 ν [Hz] (Drappeau, Dibi, Dexter, SM & Fragile, subm.) “Jets” are not realistic ➠ next frontier (Dibi, Drappeau, Fragile, SM & Dexter 2012) Effect of black hole spin on spectrum 1037 sgra data a*=0 36 10 a*=0.5 a*=0.7 a*=0.9 35 10 a*=0.98 a*=-0.9 1034 [erg/s] ν 33 L 10 ν 1032 1031 1030 108 1010 1012 1014 1016 1018 1020 ν [Hz] (Drappeau, Dibi, Dexter, SM & Fragile, subm.) Sgr A* in context: is what we’re learning here relevant for other, more luminous systems? Can we compare sources across the MBH scale? Jet X-ray Binary: Black hole/Neutron star compact corona Donor star Supermassive BH= Active Galactic Nucleus (AGN) (Jets optional) Accretion disk corona Accretion disk 7-9 MBH ~ 10 M☉ MBH ~ 10 M☉ 104-5 yrs! 1 day Fundamental plane of BH accretion: Mass & Power scales SM 2004; SM 2005; Merloni et al. 2006; Kording et al. 2006; Gültekin 2006; SM 2004;2005;etal.2006; etal. Gültekin SM Merloni Kording (SM et al. 2003; Merloni,Heinz &diMatteo 2003; & (SM etal. 2003;Merloni,Heinz Falcke,Körding Supermassive BHs (AGN) et al. 2009; Plotkin, SM et al. 2011) 2009; SM etal. et al. Plotkin, Stellar BHs (erg/s) R (XRBs) Log L Log 0.6 Lg LX + Log0.78 L LgX (erg/s) M (erg/s) (movie courtesy of S. Heinz) Fundamental plane of BH accretion: Mass & Power scales SM 2004; SM 2005; Merloni et al. 2006; Kording et al. 2006; Gültekin 2006; SM 2004;2005;etal.2006; etal. Gültekin SM Merloni Kording (SM et al. 2003; Merloni,Heinz &diMatteo 2003; & (SM etal. 2003;Merloni,Heinz Falcke,Körding Supermassive BHs (AGN) et al. 2009; Plotkin, SM et al. 2011) 2009; SM etal. et al. Plotkin, Stellar BHs (erg/s) R (XRBs) Log L Log 0.6 Lg LX + Log0.78 L LgX (erg/s) M (erg/s) (movie courtesy of S. Heinz) Fundamental plane of BH accretion: Mass & Power scales SM 2004; SM 2005; Merloni et al. 2006; Kording et al. 2006; Gültekin 2006; SM 2004;2005;etal.2006; etal. Gültekin SM Merloni Kording (SM et al. 2003; Merloni,Heinz &diMatteo 2003; & (SM etal. 2003;Merloni,Heinz Falcke,Körding Supermassive BHs (AGN) et al. 2009; Plotkin, SM et al. 2011) 2009; SM etal. et al.
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