Download presentation
Presentation is loading. Please wait.
Published byPhoebe Farmer Modified over 9 years ago
1
(Massive) Black Hole X-Ray Binaries Roger Blandford KIPAC, Stanford +Jane Dai, Steven Fuerst, Peter Eggleton
2
Massive Black Holes in AGN Ubiquitous in normal galaxies (not dwarfs) Hole mass related to mass of bulge and velocity dispersion Most local black holes are dormant When fueled through an accretion disk L~10 44 (M/10 24 gs -1 ) erg s -1 for L< L Edd ~ 10 44 M 6 erg s -1 M~1.5x10 11 M 6 cm~5M 6 s Innermost Stable Circular Orbit KIAA2 xi 2010 Lauer et al 2007 2
3
AGN Stars Stellar dynamical mass Sgr A* (Ghez, Genzel) 10 6.6 M o ; ~100 OB stars (6Myr) S2: 15 yr, e~0.87, r min ~10 15.3 cm~ 3000m~70 r tid Disk distributions?? Invisible stars? Tidal disruption (Komossa) X-ray flares Fall back emission Fe line reverberation 2 xi 2010KIAA3
4
Tests of Relativity Orbital dynamics Apsidal motion LT precession Disk crossings 2 xi 2010KIAA [Dai, Fuerst, RB] 4
5
RE J1034+396 z=0.042 Seyfert galaxy L bol ~ 10 44.7 erg s -1 FUV-SX XMM-Newton observations 1 hr QPO in ~1 d observing Best example to date in AGN of a phenomenon quite common in stellar XRB ~ 16 overall but much higher for section of data ~7% sinusoidal profile Interpreted as diskoseismic mode Could it be an EMRI mass transfer binary? Planetars??? 2 xi 2010KIAA5
6
Close Binary Stars 2 xi 2010KIAA Cataclysmic variables WD + “red” star ~2000 P>80min Low Mass X-ray Binaries BH/NS + lower mass companion ~200 P>11min, L X ~10 36-38 erg s -1 Ultra Compact X-ray Binaries WD+Ns P>5min Evolve to overflow Roche Lobe through L1 Accretion disk + hot spot Orbits evolve by gravitational, magnetic braking Outbursts due to unstable supply, transfer and burning 6
7
Conservative Mass transfer Transfer m -> M at constant m+M, J J ~ mMP 1/3 If M>>m and gravitational radiation wins, dJ/dt~-m 2 M 4/3 P -7/3 If m fills Roche lobe, P~ -1/2 ~m 0.8 =>J~m 1.3 J decreases Orbit expands Period lengthens 2 xi 2010KIAA Stable Mass Transfer 7 cf Hameury et al
8
Relativistic Effects 2 xi 2010KIAA8
9
Relativistic Roche Problem Riemann -> local tidal tensor. Evaluate volume within critical equipotential and evaluate r(L1)=0.3m 1/3 P 2/3 R o (Roche)=90P -2 g cm -3 Good for N, ISCO (all a) Accurate interpolation Lose mass through L1, L2 2 xi 2010KIAA Roche Potential L1L2 9
10
Pre-Roche evolution Gravitational radiation dominates Need PPN corrections to torque Low mass star fills Roche lobe when P=P R =8m 0.8 hr [ => m < 0.1 M o ] Outside ISCO P > P ISCO ~ M [=>M<3x10 7 Mo] Time to overflow t R -t=2x10 5 M 6 -2/3 m 1.3 [(P/P R ) 8/3 -1] yr 2 xi 2010KIAA10
11
Stellar Evolution Differs from close binary case t dynamical << t transfer << t Kelvin S[m] will be frozen Solve: dP/dm=-Gm/4 r 4 dr/dm=1/4 r 2 [S(m),P] => d log < /d log m = =2 for convective low mass star 2 xi 2010KIAA dS/dm >=0 11
12
Evolution of solar star 2 xi 2010KIAA12
13
Radius-mass relation for adiabatic stars 2 xi 2010KIAA 0.3 M o ~ 2 1M o 8M o ~ M R~M (1- )/3 P~M - /2 R M 13
14
Orbital and stellar evolution 2 xi 2010KIAA Mass transfer rates are quite low, making adiabatic, conservative assumptions 14
15
Period vs mass 2 xi 2010KIAA15
16
Post-Roche Evolution After mass transfer orbit expands P ~ m - /2 ~ m -1 for low mass star t-t R =1400M 6 -2/3 m -1 P 8/3 [(P/P R ) 11/3 -1] yr; [~ 5000yr] Conservative Mass loss dm/dt = (dm/dt) R = -1.3x10 20 M 0.7 P -0.3 g s -1 [~ 10 21 g s -1 ] ~ -m 8.3 eventually till t transfer > t Kelvin Dynamical complications Holding pattern? Interactions, drag KIAA2 xi 201016
17
Mass transfer Mass flows from L1 onto relativistic disk forming hotspot Gas spirals in to r ms before plunging into hole Inclined orbits are more complex as streams may not self-intersect Disk flow may have complex gaps and resonances Hot spot Doppler beams emission Also spiral shocks, eccentricity 2 xi 2010KIAA17
18
X-ray observations Maximum efficiency for a ~ m P R ~ P ISCO Liberal mass loss Angular momentum ->Spin Wind Equatorial viewing L ~ D 4 D~2? 2 xi 2010KIAA L E a=0.99m 18
19
Observed X-ray emission 2 xi 2010KIAA a=0 a=0.998 i=5 i=30i=45 a=0 a=0.998 i=30 19
20
AGN QPOs: other mechanisms Passage of star through an accretion disk orbiting a spinning black hole (Zentsova; Nyakshin; Dai, Fuerst & RB) Inclined stellar orbit, apsidal motion, precession Inelastic collisions -> beamed X-ray emission Ray tracing Star moving through sub-Keplerian disk Diskoseismic modes Trapped g-modes 2 xi 2010KIAA20
21
Other observations 17 min IR QPO frm SgrA* (Genzel) 12yr period in OJ287?? Binary black holes??? (Lehto & Valtonen) LISA harbingers Discover incipient EMRI, coalescence Predictable evolution with degree position! Seek electromagnetic signal in phase with ~10 -9 power - eg LSST. 2 xi 2010KIAA21
22
Summary Observations of quasi-periodic X-ray emission from stars orbiting black holes in AGN is a potential probe of general relativity RE J1034+396 may not be an example Reasonable to search AGN X-ray database for QPO’s with P~5-20hr AGN black holes could have many “planetars” 2 xi 2010KIAA22
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.