star-massive black holes encounters
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 PresentationTRANSCRIPT
Star-Massive Black Holes Star-Massive Black Holes EncountersEncounters
J.-P.Luminet
Observatoire de
Paris (LUTH)Tidal Disruption Events
Esa, Madrid 2012
2,7 106 MS < M < 3,5 106 MS)
Massive black holes (M > 106 MS) in quiescent galactic nuclei
Sagittarius A*Sagittarius A*
Accretion radius
BH’s gravitational radius
Characteristic distances
Collision radius
Ablation radius
Tidal radius
€
RT ≈ R∗
M•
M∗
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 3
Hills limit108 MO
Newtonian tidal field
Tidal field = relative acceleration between elements of matter
tidal potential
tidal tensor deviation tensor
• For incompressible homogeneous bodies • static field
(planet-satellite couple in circular orbit)Edouard Roche
Roche limit (1847)
€
RT = 2.45R*
M •
M*
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 3
• incompressible bodies
Luminet & Carter (1986)
in dynamical field
(asteroid-black hole encounter in parabolic orbit)
Kostic et al. (2009)
0.16 RT ≤ Rp ≤ RT Rp ≤ 0.16 RT
Cigar-like regime Disk-like regime
• compressible bodies
Luminet et al. 1982-1986 : « affine » model
in dynamical field
(star-black hole encounter in parabolic orbit)
Non-disruptive regime
€
RT ≈ 2.9R*
M •
M*
⎛
⎝ ⎜
⎞
⎠ ⎟
1/ 3
Oscillating Riemann ellipsoid => variable star ?
From equilibrium to stellar disruptionFrom equilibrium to stellar disruption
Compare : timescale of varying tidal field / internal timescale of the star
Far from the tidal radius :
Close to and inside the tidal radius :
Star adjusts its equilibium configuration
Strongly dynamical tidal field => Star cannot respond
Parabolic orbit
Tidal radius
Black hole
RTRP
Crucial parameter :
the penetration factor
Carter & Luminet (Nature, 1982)
Slight penetration ( 1) in the tidal radius
« cigar-like » configuration after leaving the tidal
radius
Disruption process in the ellipsoidal model (Luminet & Carter, 1986)
Slight penetration in the tidal radius Disruption process reproduced by
hydrodynamical simulations
« cigar-like » configuration after leaving the tidal radius
« S-like » configuration at the periastron
Ejected matter
Massive black hole
Tidal radius
Accretion of stellar debris (50%) Tidal FlaresLidskii & Ozernoy (1979), Rees (1988)
Giant X-UV luminous flaresGiant X-UV luminous flares
Detection (ROSAT, Chandra, Galex…) of Detection (ROSAT, Chandra, Galex…) of X-UV flaresX-UV flares from (non active) galactic nucleifrom (non active) galactic nuclei
X-UV-optical luminous flaresX-UV-optical luminous flares
Detection (Chandra, Galex, Pan-starrs…) of Detection (Chandra, Galex, Pan-starrs…) of flaresflares from from (non active) galactic nuclei(non active) galactic nuclei
« Relativistic » Tidal Flares« Relativistic » Tidal Flares
Detection (Swift) of Detection (Swift) of hard-X flareshard-X flares (L (Lxx ~10 ~104747 ergs) ergs)
(Zauderer et al. 2011, Cenko et al. 2012)(Zauderer et al. 2011, Cenko et al. 2012)
Relativistic jets from tidal ejecta ?
(Komossa (Komossa et alet al., Saxton ., Saxton et alet al. , Esquej . , Esquej et al.et al., Gezari , Gezari et alet al., etc.)., etc.)
The Pancake EffectThe Pancake Effect(Carter & Luminet, (Carter & Luminet, NatureNature, 1982), 1982)
For deep penetration ( > 3)
Fixed compressive principal direction of the tidal tensor in the « vertical » direction ==>
The « Rolling Mill » EffectThe « Rolling Mill » Effect
Cartoon version
fixed compressive point after periastron
Deep penetration ( 3) in the tidal radius
Disruption process in the ellipsoidal model (Luminet & Carter, 1986)
Explosive stellar disruption ? Explosive stellar disruption ?
Compression and heating strongly dependent from the Compression and heating strongly dependent from the penetration factorpenetration factor
Maximum values for an ideal gas with polytropic index 5/3 :Maximum values for an ideal gas with polytropic index 5/3 :
Conditions required for Conditions required for explosive thermonuclear explosive thermonuclear reactionsreactions
Detonation of Detonation of metalsmetals (C, N, O, …) by radiative (C, N, O, …) by radiative proton proton captures captures (Luminet & Pichon 1989(Luminet & Pichon 1989))
HeliumHelium detonation by detonation by triple alpha triple alpha (Pichon 1985(Pichon 1985))
Tidally induced supernovae? Tidally induced supernovae?
Luminet, 1986
Rosswog et al., 2008
A special type of GRB ? A special type of GRB ?
Carter, 1992
Lu et al. 2008; Gao et al. 2011
log(M•/M*)
log
(
The pancake triangle (solar type stars)
No disruption
Black hole enters the sta
r
Star enters the Black hole
107 K
108 K
109 K
Shock waves in stellar pancakesShock waves in stellar pancakes(Brassart & Luminet, 2008-2010)(Brassart & Luminet, 2008-2010)
ProblematicsProblematics
• 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)
• 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 ?
New Hydrodynamical Model Euler eqs. + Godunov methods
Principal axes of the tidal tensor
1D approximation
valid from the tidal radius to periastron
= 7
velocity
max.compression
Phase 2:
bounce Subsonic collapse
Supersonic collapse
Subsonic expansion
Number of disruption events:
UV/X/gamma-ray flares
€
N ≈10−5 β−1 / year /galaxy
€
N(z < 0.8) ≈104 β−1 / year
Wang & Merritt (2004), Tal (2005) BH binaries : Chen et al (2009)
• -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 060614GRB 060614 (long (long ~100 s) without SN remnant : ~100 s) without SN remnant : disruption of a WD by an intermediate mass BH ? disruption of a WD by an intermediate mass BH ?
(Lu et al. 2008)(Lu et al. 2008)
• A new class of -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 field
E = specific total energy
L = specific angular momentum
for parabolic orbits :
E = 1
Luminet & Marck, 1985
Double point Double point insideinside the tidal radius the tidal radius
Several compressionsSeveral compressions
Brassart & Luminet, 2011
Multi-pancake effect and X/ bursts
• • Multi-peak structure and timescales compatible with Multi-peak structure and timescales compatible with GRB 970815GRB 970815 ( (and and others ?)others ?)
• • White dwarfs / IM BH strong encounters White dwarfs / IM BH strong encounters ((Rosswog et al. 2010, Hass et al. 2012Rosswog et al. 2010, Hass et al. 2012):):
Confirm nuclear ignition (e.g. helium Confirm nuclear ignition (e.g. helium detonation)detonation)
• 3D simulations3D simulations coupling hydrodynamics and nuclear network (Guillochon et al., 2011):
Confirm the occurrence of tidally induced supernovae
Recent hydro models …
• Red giants / BH interactions (Mac Leod et al., 2012):
Tidal stripping of atmosphere
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
= vcoll/v* crushing factor
= RT/Rp
Massive BH (104 - 108 MS)
Supermassive BH > 108 MS
Glob. Clusters, GN, Seyfert Quasars, Giant elliptical …
High velocity head-on collisions, polytropes 5/3
Barnes, 2003Makino, 1999
: disruption / : pancake effect