Star-Massive Black Holes Encounters

Click here to load reader

  • date post

    31-Dec-2015
  • Category

    Documents

  • view

    28
  • download

    0

Embed Size (px)

description

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 ). - PowerPoint PPT Presentation

Transcript of Star-Massive Black Holes Encounters

  • Star-Massive Black Holes EncountersJ.-P.LuminetObservatoire de Paris (LUTH)Tidal Disruption Events Esa, Madrid 2012

  • Supermassive black holes (M > 106 MS) in active galactic nuclei Seyfert

  • Massive black holes (M > 106 MS) in quiescent galactic nuclei Sagittarius A*

  • M154000 MSG1/M3120 000 MSIntermediate mass black holes (103 < M < 106 MS) in globular clusters

  • The octopus model for AGNLuminet (1986)

  • Characteristic distances

  • Newtonian tidal fieldTidal field = relative acceleration between elements of mattertidal potentialtidal tensordeviation tensor

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

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

  • compressible bodies Luminet et al. 1982-1986 : affine modelin dynamical field (star-black hole encounter in parabolic orbit)Non-disruptive regime

  • From equilibrium to stellar disruptionCompare : timescale of varying tidal field / internal timescale of the starFar from the tidal radius :Close to and inside the tidal radius :Star adjusts its equilibium configurationStrongly dynamical tidal field => Star cannot respond

  • Parabolic orbitTidal radiusBlack holeRTRPCrucial parameter : the penetration factorCarter & Luminet (Nature, 1982)

  • Slight penetration (b ~ 1) in the tidal radiuscigar-like configuration after leaving the tidal radiusDisruption process in the ellipsoidal model (Luminet & Carter, 1986)

  • Slight penetration in the tidal radius Disruption process reproduced by hydrodynamical simulationscigar-like configuration after leaving the tidal radiusS-like configuration at the periastronEjected matter

  • Massive black holeAccretion of stellar debris (50%) Tidal FlaresLidskii & Ozernoy (1979), Rees (1988)

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

  • Giant X-UV luminous flaresDetection (ROSAT, Chandra, Galex) of X-UV flares from (non active) galactic nuclei

  • X-UV-optical luminous flaresDetection (Chandra, Galex, Pan-starrs) of flares from (non active) galactic nuclei(Komossa et al., Saxton et al. , Esquej et al., Gezari et al., etc.)

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

  • The Rolling Mill Effectfixed compressive point after periastron

  • Deep penetration (b > 3) in the tidal radiusDisruption process in the ellipsoidal model (Luminet & Carter, 1986)

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

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

  • Tidally induced supernovae? Luminet, 1986 Rosswog et al., 2008

  • log(M/M*)log (The pancake triangle (solar type stars)No disruption

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

  • ProblematicsStellar 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)

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

  • New Hydrodynamical Model Euler eqs. + Godunov methodsPrincipal axes of the tidal tensor1D approximation valid from the tidal radius to periastron

  • = 7velocityTidal radiusperiastronmax.compressionPhase1:collapse

  • = 7velocitymax.compression

  • = 7densitycollapseTidal radiusperiastronmax.compressionand bounce

  • = 7temperatureshock

  • = 15velocityshock 1(before bounce)shock 2(after bounce)

  • = 15densityshock 1(before bounce)

  • maximum central densitymaximum central temperature

  • = 10Shock-driven maximum temperature

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

  • Modelisation of Gamma-Ray Bursts

  • g-ray transients Swift J1644+57 and Swift J2058+05 (Zauderer 2011, Cenko 2012)interpreted as a relativistic outflow from transient accretion onto a 106 Ms black hole GRB 060614 (long ~100 s) without SN remnant : disruption of a WD by an intermediate mass BH ? (Lu et al. 2008)

    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

  • Relativistic tidal fieldE = specific total energyL = specific angular momentumfor parabolic orbits : E = 1Luminet & Marck, 1985

  • Precession effect : self-crossing orbit

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

  • Double point inside the tidal radiusSeveral compressionsBrassart & Luminet, 2011

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

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

  • Analogy with stellar collisionsAround a 109 MS black hole, the typical collisional velocities are > 5000 km/s within a distance 0.1 pc from the black hole

  • High velocity head-on collisions, polytropes 5/3 Barnes, 2003Makino, 1999 : disruption / : pancake effect

  • The End

    *********Pionneer work : Hills, 1975 ; Frank & Rees, 1976********But relativistc velocity at periastron => almost instantenous flattening**************************