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Star-Massive Black Holes Encounters

Star-Massive Black Holes Encounters. J.-P.Luminet Observatoire de Paris (LUTH ). Tidal Disruption Events Esa, Madrid 2012. radiogalaxies. quasars. Supermassive black holes (M > 10 6 M S ) in active galactic nuclei. Seyfert. 2,7  10 6 M S < M < 3,5  10 6 M S ).

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Star-Massive Black Holes Encounters

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  1. Star-Massive Black Holes Encounters J.-P.Luminet Observatoire de Paris (LUTH) Tidal Disruption Events Esa, Madrid 2012

  2. radiogalaxies quasars Supermassive black holes (M > 106 MS) in active galactic nuclei Seyfert

  3. 2,7 106 MS < M < 3,5  106 MS) Massive black holes (M > 106 MS) in quiescent galactic nuclei Sagittarius A*

  4. Intermediate mass black holes (103 < M < 106 MS) in globular clusters M15 4000 MS G1/M31 20 000 MS

  5. The « octopus » model for AGN Luminet (1986)

  6. Accretion radius Collision radius Hills limit 108 MO Ablation radius Tidal radius BH’s gravitational radius Characteristic distances

  7. Newtonian tidal field Tidal field = relative acceleration between elements of matter tidal potential tidal tensor deviation tensor

  8. • For incompressible homogeneous bodies • static field (planet-satellite couple in circular orbit) Edouard Roche Roche limit (1847)

  9. • incompressible bodies in dynamical field (asteroid-black hole encounter in parabolic orbit) Luminet & Carter (1986) Kostic et al. (2009) Cigar-like regime Disk-like regime 0.16 RT ≤ Rp ≤ RT Rp ≤ 0.16 RT

  10. • compressible bodies in dynamical field (star-black hole encounter in parabolic orbit) Luminet et al. 1982-1986 : « affine » model Non-disruptive regime Oscillating Riemann ellipsoid => variable star ?

  11. From equilibrium to stellar disruption Compare : timescale of varying tidal field / internal timescale of the star Far from the tidal radius : Star adjusts its equilibium configuration Close to and inside the tidal radius : Strongly dynamical tidal field => Star cannot respond

  12. Parabolic orbit Crucial parameter : the penetration factor Carter & Luminet (Nature, 1982) Tidal radius Black hole RP RT

  13. Slight penetration (b ~ 1) in the tidal radius Disruption process in the ellipsoidal model (Luminet & Carter, 1986) « cigar-like » configuration after leaving the tidal radius

  14. Slight penetration in the tidal radius Disruption process reproduced by hydrodynamical simulations Ejected matter « cigar-like » configuration after leaving the tidal radius « S-like » configuration at the periastron

  15. Tidal radius Accretion of stellar debris (50%)  Tidal Flares Lidskii & Ozernoy (1979), Rees (1988) Massive black hole

  16. X-ray flare in RXJ 1242-11 (Komossa & Greiner, 1999) UV flare in NGC 4252 (Renzini et al. 1995)

  17. Giant X-UV luminous flares Detection (ROSAT, Chandra, Galex…) of X-UV flares from (non active) galactic nuclei

  18. « Relativistic » Tidal Flares Detection (Swift) of hard-X flares (Lx ~1047 ergs) (Zauderer et al. 2011, Cenko et al. 2012) Relativistic jets from tidal ejecta ? X-UV-optical luminous flares Detection (Chandra, Galex, Pan-starrs…) of flares from (non active) galactic nuclei (Komossa et al., Saxton et al. , Esquej et al., Gezari et al., etc.)

  19. The Pancake Effect (Carter & Luminet, Nature, 1982) Fixed compressive principal direction of the tidal tensor in the « vertical » direction ==> For deep penetration ( > 3)

  20. Cartoon version The « Rolling Mill » Effect fixed compressive point after periastron

  21. Deep penetration (b > 3) in the tidal radius Disruption process in the ellipsoidal model (Luminet & Carter, 1986)

  22. Explosive stellar disruption ? Compression and heating strongly dependent from the penetration factor Maximum values for an ideal gas with polytropic index 5/3 : Conditions required for explosive thermonuclear reactions

  23. Detonation of metals (C, N, O, …) by radiative proton captures (Luminet & Pichon 1989) Helium detonation by triple alpha (Pichon 1985)

  24. Tidally induced supernovae? Luminet, 1986 Rosswog et al., 2008 A special type of GRB ? Carter, 1992 Lu et al. 2008; Gao et al. 2011

  25. Black hole enters the star 109 K Star enters the Black hole 108 K 107 K The pancake triangle (solar type stars) log ( No disruption log(M•/M*)

  26. Shock waves in stellar pancakes (Brassart & Luminet, 2008-2010)

  27. Problematics • Stellar pancakes calculated in the affine model(Luminet et al. 1983- 1989) ==> Elliptical deformations of the star • Stellar pancakes calculated by 3D hydro (Bicknell & Gingold 1983; Laguna et al. 1993; Fulbright 1996) ==> SPH method (uses artificial viscosity to simulate shock waves) N.B. : Generalized affine model(Ivanov et al. 2001-2003)

  28. Disagreement : compression of the stellar core less than in the affine model: max ~ 1.5 for  < 10 max ~ const for  > 10 • Due to shock waves occuring during the phase of vertical direction ?? • Or bad treatment (SPH) of shock waves ?

  29. New Hydrodynamical Model Euler eqs. + Godunov methods 1D approximation valid from the tidal radius to periastron Principal axes of the tidal tensor

  30.  = 7 Tidal radius velocity periastron max.compression Phase1: collapse

  31. Subsonic collapse Supersonic collapse  = 7 velocity max.compression Phase 2: bounce Subsonic expansion

  32. Shock (after bounce)  = 7 density collapse Tidal radius periastron max.compression and bounce

  33.  = 7 temperature shock

  34. = 15 shock 1 (before bounce) velocity shock 2 (after bounce)

  35. shock 2 (after bounce)  = 15 shock 1 (before bounce) density

  36. maximum central density maximum central temperature

  37.  = 10 Shock-driven maximum temperature

  38. Wang & Merritt (2004), Tal (2005) BH binaries : Chen et al (2009) Number of disruption events: UV/X/gamma-ray flares

  39. Long GRB jet jet Short GRB Modelisation of Gamma-Ray Bursts

  40. • g-ray transients Swift J1644+57 and Swift J2058+05(Zauderer 2011, Cenko 2012) • GRB 060614 (long ~100 s) without SN remnant : disruption of a WD by an intermediate mass BH ? (Lu et al. 2008) interpreted as a relativistic outflow from transient accretion onto a 106 Ms black hole • A new class of g-ray bursts from stellar disruptions by IMBH ? (Gao et al., 2010)  From a total of 328 Swift GRBs with accurate measured durations and without SN association, 25 GRBs satisfying the criteria for GRB060614-type bursts…

  41. Relativistic tidal field Luminet & Marck, 1985 E = specific total energy L = specific angular momentum for parabolic orbits : E = 1

  42. Precession effect : self-crossing orbit

  43. Double point inside the tidal radius: Luminet & Marck, 1985

  44. Brassart & Luminet, 2011 Double point inside the tidal radius Several compressions

  45. Multi-pancake effect and X/ bursts • Multi-peak structure and timescales compatible with GRB 970815 (and others ?)

  46. Recent hydro models … • 3D simulationscoupling hydrodynamics and nuclear network (Guillochon et al., 2011): Confirm the occurrence of tidally induced supernovae • Red giants / BH interactions (Mac Leod et al., 2012): Tidal stripping of atmosphere • White dwarfs / IM BH strong encounters (Rosswog et al. 2010, Hass et al. 2012): Confirm nuclear ignition (e.g. helium detonation)

  47. crushing factor b = RT/Rp b = vcoll/v* Supermassive BH > 108 MS Massive BH (104 - 108 MS) Glob. Clusters, GN, Seyfert Quasars, Giant elliptical … Analogy with stellar collisions Around a 109 MS black hole, the typical collisional velocities are > 5000 km/s within a distance 0.1 pc from the black hole

  48. : disruption / : pancake effect High velocity head-on collisions, polytropes 5/3 Barnes, 2003 Makino, 1999

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