n wake of recoiled black holes Roya Mohayaee NRS, Institut d’Astrophysique de Paris Jacques Colin Observatoire de la Côte d’Azur, Nice Joe Silk University of Oxford astro-ph/07093321 P Lasota conference, Wroclaw 2007
Accretion wake of recoiled black holes Roya Mohayaee CNRS, Institut d’Astrophysique de Paris Jacques Colin Observatoire de la Côte d’Azur, Nice
Joe Silk University of Oxford
astro-ph/07093321 J-P Lasota conference, Wroclaw 2007
Galaxy (black hole) mergers
BHs at the centre of many galaxies
Galaxy mergers
BH mergers
Emission of gravitational waves
formation of a new
central BH
HST : colliding galaxies in Canis MajorNGC 2207 –IC 2163
Black hole & dark matter
Adiabatic accretion:
ffinal(Efinal,Lfinal) = finitial(Einitial,Linitial)
Initially : initial ~ r-
Black hole & dark matter
(Young 1980, Gondolo & Silk 1999)
Without BH : initial ~ r-
With BH : final ~ r-(9-2)/(4-)
Absolute luminosity (L) of BH in -rays +
L = luminosity factor x ∫2 dV /s luminosity factor = [N <v>/m
2] c4/cm 3/s/Gev2
For M31: Fornasa et al
2007
Galaxy (black hole) mergers
BHs at the centre of many galaxies
Galaxy mergers
BH mergers
Emission of gravitational waves
If isotropic
formation of a new
central BH
HST : colliding galaxies in Canis MajorNGC 2207 –IC 2163
Galaxy (black hole) mergers
BHs at the centre of many galaxies
Galaxy mergers
BH mergers
Emission of gravitational waves
Ejection of the
BH
From the galaxy
If isotropic If anisotropic
formation of a new
central BH
HST : colliding galaxies in Canis MajorNGC 2207 –IC 2163
Ejection of a black hole during galaxies mergers
Ejection of a black hole during galaxies mergers
€
η =m1m2
(m1 + m2)2
=X
(1+ X)2
Spin=zero
X=0.38
Ejection of a black hole during galaxies mergers
spin ≠ 0
recoil velocity 4000 km/s
Campanelli et al 2007
Orbit of an ejected BH
Virial radius
V~0
low high v
high
Density profile of the accretion wake
Cold medium >Bondi-Hoyle accretion (1944) Two-body problem +mass conservation
V
r
(q) dq
(x) dx=(q) dq
Density profile of the accretion wake
Analytic solution for stationary BHs : (r)~ 1/√r
hot medium (e.g. Maxwellian velocity distribution) > Danby & Camm (1957)
V
Jean’s theorem numerical solution for density
Wake density : radius of influence
Wake density : hot versus cold medium
Hot environment
Wake density : hot versus cold medium
Hot environment Cold environment
Constant density contours : large
Constant density contours : reducing
Wake density contoursWake density contours, small
Highest density at the apapsis passage
Virial radius
V~0
low high v
high
Time to reach the apapsis
Initial velocity of BH / escape velocity
Absolute luminosity of a recoiled BH in -rays
L(M,z) = [N <v>/m2] ∫2 dV /s
L= 1025 (1+z)4 (M/Mo) R2cutoff
/s
LBH /L host
galaxy
Diffused -ray background
BH Mass function
Press & Schechter (1974)Density peaks in initially random gaussian field collapse to form ‘‘galaxies’’
Number density of galaxies of mass M at redsift z N(M,z)
Diffused -ray background=H0 ∫∫ t(M,z) L(M,z) N(M,z) dM dr(z)
Time the BH spends at apapsis
1025 (1+z)4 (M/Mo) R2cutofff /s
Press-Schechter mass function
Time spent at apapsis
=H0 ∫∫ t(M,z) L(M,z) N(M,z) dM dr(z)
> 10 -8 cm-2 s-1 sr-1
Future Prospects: Confronting the observations
Future Prospects: Confronting the observations
HESS, VERITAS
MAGIC
GLAST
EGRET
10-
12
10-7
10-11
10-10
10-9
10-8
cm-2 s-1 sr-1
> 10 -8 cm-2 s-1 sr-1