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Home , Ergosphere, Quasar

Overview Analogy / Population in our Jets disk Rotating Black Holes Conclusion

Microquasars

Mierk Schwabe

TU M¨unchen MPE Garching

17 Dec 2004

Mierk Schwabe TU M¨unchen,MPE Garching 1 of 46 Overview Analogy Quasar/Microquasar Discovery Population in our galaxy Definition Jets Constituents Spectrum Rotating Black Holes The Jets Conclusion A ’microquasar’ in the galaxy

GRS1915+105: strongly variable X-ray source (1992) then: superluminal radio jets!

[Mirabel, Rodriguez, Nature 1992]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 2 of 46 Overview Analogy Quasar/Microquasar Discovery Population in our galaxy Definition Jets Constituents Accretion disk Spectrum Rotating Black Holes The Jets Conclusion What is a ”microquasar”?

X-ray binary with relativistic jets ... in our galaxy

Artist’s impression [Ribo 2004]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 3 of 46 Overview Analogy Quasar/Microquasar Discovery Population in our galaxy Definition Jets Constituents Accretion disk Spectrum Rotating Black Holes The Jets Conclusion Constituents

compact object: (BH) or neutron (NS) companion: heavy (HMXB) or low- (LMXB)

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 4 of 46 Overview Analogy Quasar/Microquasar Discovery Population in our galaxy Definition Jets Constituents Accretion disk Spectrum Rotating Black Holes The Jets Conclusion

Emission from Microquasars [Fender, R.]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 5 of 46 Overview Analogy Quasar/Microquasar Discovery Population in our galaxy Definition Jets Constituents Accretion disk Spectrum Rotating Black Holes The Jets Conclusion Emission from Jets

non-thermal, synchrotron SS433: emission lines → barionic nature [Marshall et al. 2002] direct follow-up of jet motion sometimes possible:

VLBA observation of SS433 at 1.5 GHz over 42 days [Rupen 2004]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 6 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Jets Orders of magnitude Accretion disk An analogy over eight orders of magnitude Rotating Black Holes Conclusion Quasars

galaxy with extreme optical and radio characteristic activity: AGN M ∼ 107 − 109MJ bipolar jets of relativistic particles: synchrotron Jet from Galaxy M87 [http://hubblesite.org]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 7 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Quasars Jets Orders of magnitude Accretion disk An analogy over eight orders of magnitude Rotating Black Holes Conclusion and Accretion rates

fraction of Ekin will be radiated away [Parades et al. 2003] accretion of efficient source of : 1 L =∼ Mc˙ 2 2

quasars microquasars luminosity ∼ 1047erg s−1 ∼ 1037erg s−1 accretion rates ∼ 10MJ yr −1 ∼ 10−9MJ yr −1

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 8 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Quasars Jets Orders of magnitude Accretion disk An analogy over eight orders of magnitude Rotating Black Holes Conclusion Temperatures

heating of accretion disk due to loss of black body temperature in last stable orbit:

1/4 M˙ T ≈ 1.4 · 107 M with T in K, M in MJ and M˙ in Eddington rates [Greiner 2000]. quasars microquasars temperature ∼ 105K ∼ 107K emission domain optical, UV X-ray

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 9 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Quasars Jets Orders of magnitude Accretion disk An analogy over eight orders of magnitude Rotating Black Holes Conclusion Time scales

Schwarzschild radius as characteristic dimension time scale: R τ ∼ S ∝ M c black hole mass 6 - 8 magnitudes smaller in microquasars → much faster few minutes observation of microquasar ≡ decades or millennia for quasar

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 10 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Quasars Jets Orders of magnitude Accretion disk An analogy over eight orders of magnitude Rotating Black Holes Conclusion An analogy over eight orders of magnitude

Similarities: same ingredients: compact object, accretion disk, jets same physics on different scales?

[Mirabel 2004]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 11 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Total number in

now known: 130 HMXB, 150 LMXB of those: 50 X-ray which are no radio emitters, 43 radio-emitting sources estimation of total number of X-ray binaries in galaxy brighter than 2 · 1034 erg s−1: about 700 thus upper limit on population of microquasars in our galaxy: ∼ 100 systems

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 12 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - HMXB

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 13 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - HMXB

first microquasar discovered

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 14 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - HMXB

during strong outburst, radio emission rises up by three orders of magnitudes

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 15 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - LMXB Part 1

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 16 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - LMXB Part 1

”runaway microquasar”: high velocity in eccentric orbit extraordinary kick, e.g. SN explosion

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 17 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - LMXB Part 1

first extrasolar point source of X-rays detected bipolar jets moving at 0.45c

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 18 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - LMXB Part 2

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 19 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Currently known microquasars - LMXB Part 2

the most extensively studied system

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 20 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Introduction to GRS1915+105

position: in , distance ∼ 12 kpc → very high in optical band (20-30 mag) [Greiner et al. 2001] donor star: K-M III late type giant most massive known: (14 ± 4) MJ [Greiner et al. 2001] most energetic object known in our galaxy: luminosity L ∼ 1038 erg/s in low state

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 21 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Introduction to GRS1915+105

GRS1915+105 [Rau, A.]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 22 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Spectrum of GRS1915+105

strongly variable X-ray source long-term variation in X-rays [Greiner 2000]:

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 23 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Total number Jets Currently known microquasars Accretion disk Example: GRS1915+105 Rotating Black Holes Conclusion Spectrum of GRS1915+105

extremely variable in soft X-rays [Greiner et al. 1996] radio emission: jet composed of nodes which seem to move faster than [Mirabel et al. 1994]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 24 of 46 Overview Analogy Quasar/Microquasar Relativistic effects Population in our galaxy Propagation Jets Emission from Jets Accretion disk Formation Rotating Black Holes Conclusion

observed in four galactic sources, common in quasars angle between axis and observer small, velocity near approaching jet node reduces distance to observer by vt cos θ → light travel time progressively shorter v sin θ Figure: [Ribo 2004] vr,a = (1±β cos θ)

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 25 of 46 Overview Analogy Quasar/Microquasar Relativistic effects Population in our galaxy Propagation Jets Emission from Jets Accretion disk Formation Rotating Black Holes Conclusion Doppler boosting

for small angles (θ ≤ 10◦) and β ' 1: brightness of approaching jet considerably boosted ≡ Doppler favoritism, relativistic aberration radiation flux density of each cloud in its reference α frame: S0 ∝ ν , with α: spectral index S S = 0 r,a [γ(1 ± β cos θ)]k−α

constant k: 3 for discrete clouds, 2 for continuous jets

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 26 of 46 Overview Analogy Quasar/Microquasar Relativistic effects Population in our galaxy Propagation Jets Emission from Jets Accretion disk Formation Rotating Black Holes Conclusion Propagation of the jets

jet approaching observer on left difference between approaching and receding jet clearly visible: apparently brighter and faster on the left

jet motion of GRS1915+105 [Mirabel]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 27 of 46 Overview Analogy Quasar/Microquasar Relativistic effects Population in our galaxy Propagation Jets Emission from Jets Accretion disk Formation Rotating Black Holes Conclusion Emission from Jets

simplest interpretation: synchrotron radiation adiabatic expansion of plasma clouds causes electrons to loose energy → shift from IR to radio domain

GRS1915+105 [Mirabel et al. 1998]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 28 of 46 Overview Analogy Quasar/Microquasar Relativistic effects Population in our galaxy Propagation Jets Emission from Jets Accretion disk Formation Rotating Black Holes Conclusion Jet Formation

processes for collimation and acceleration of jets not fully understood jet but links to accretion disk found

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 29 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Low/Hard and High/Soft states

Figure: [Ribo 2004]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 30 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Low/Hard and High/Soft states

soft X-rays → disk (thermal)

hard X-rays → corona (inverse of photons, non-thermal)

transitions between states occasionally connected with transient ejection [Parades et al. 2003]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 31 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion X-ray light curve

quasi periodic 30 s flux reduction dominant 300 s flux suppresion energy spectrum softens during dips

X-ray flux and hardness GRS1915+105

[Greiner et al. 1996] Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 32 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Instabilities in disk

X-ray emission related to inner part of accretion disk → disk has to be altered dramatically accretion disk composed of rings of matter, transmission with certain flux rate dips might correspond to refilling of inner ring state transitions thought to be driven by changes in mass flux/mass accretion rate

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 33 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Correlation between Radio and X-ray flux

no correlation of radio emission with inner disk radius (soft X-ray flux) observed power law slope (hard X-rays) correlates with radio flux high radio emission: softer X-ray spectrum (steeper power law) Γ(FR ) correlation [Rau et al. 2003]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 34 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Accretion / ejection coupling

rebound after lull in light curve does not account for all the energy → channeled into different form (kinetic energy?) emergence of jet plasma clouds accompanied by sharp decay and softening of systems X-ray emission → disappearance of inner regions of [Mirabel et al. 1998] accretion disk

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 35 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion

Figure: [RXTE Discoveries http://heasarc.gsfc.nasa.gov/]

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 36 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion QPOs in microquasars - under 10 Hz

observation: arrival rate of photons quasiperiodic: certain frequencies with many photons hard X-ray photons arrive later than soft ones for LMXB popular model: beat frequency of rotational period of inner accretion disk and surface - black hole? other model: production of hard photons by scattering of soft ones in corona - explains observation well, but problem: waves of hard photons no more washed-out than soft ones

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 37 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion X-ray observations

when there are QPOs (under 10 Hz): correlation between QPO frequency and temperature of accretion disk; all changes of X-ray intensity in hard part of spectrum no QPOs: dominant changes of intensity in soft part this means: the intensity of the QPO depends on the producer the QPO frequency is determined by the accretion disk (disk temperature) thus link between the accretion disk and producer of the hard power law

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 38 of 46 Overview Analogy Quasar/Microquasar States Population in our galaxy Instabilities Jets X-Ray - radio correlation Accretion disk Accretion / ejection coupling Rotating Black Holes Quasi-periodic oscillations Conclusion Stable QPOs in Microquasars

GRS1915+105: 67 Hz, GRO J 1655-40: 300 Hz, no strong changes, no correlation as before could be produced at inner border of disk - fits well with rotational frequency at last stable orbit; problem: energy dependency (maximum does not fit temperature of inner disk) other effect: Thirring-Lense-Effect

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 39 of 46 Overview Analogy Quasar/Microquasar Thirring-Lense-Effect Population in our galaxy Jets Last stable orbit Accretion disk Observation Rotating Black Holes Conclusion Thirring-Lense-Effect

purely relativistic effect: if central black hole rotates very fast, it pulls space time with it characteristic precession of accretion disk, which depends on angular momentum of black hole F. Embacher: up to 90 % of theoretically possible http://www.ap.univie.ac.at/users/fe/Rel/ angular momentum necessary to ω 1 R R 3 = S explain QPO frequencies Ω 3 R r

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 40 of 46 Overview Analogy Quasar/Microquasar Thirring-Lense-Effect Population in our galaxy Ergosphere Jets Last stable orbit Accretion disk Observation Rotating Black Holes Conclusion The shape of the ergosphere

within ”stationary limit” rsl , nothing can escape being dragged around the black hole ergosphere: region between stationary limit and rh the ergosphere touches the spherical event horizon at the rotational axis and is flattened at the equator

2 21/2 rh = M + M − a 2 2 2 1/2 rsl = M + m − a cos θ

with G = c = 1, a = J/M specific angular momentum

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 41 of 46 Overview Analogy Quasar/Microquasar Thirring-Lense-Effect Population in our galaxy Ergosphere Jets Last stable orbit Accretion disk Observation Rotating Black Holes Conclusion The last stable orbit

direction of rotation rlast none rlast (a = 0) = 3rs prograde rlast (a = M) = 0.5rs retrograde rlast (a = M) = 4.5rs

with rs = 2M

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 42 of 46 Overview Analogy Quasar/Microquasar Thirring-Lense-Effect Population in our galaxy Ergosphere Jets Last stable orbit Accretion disk Observation Rotating Black Holes Conclusion

Imagine the

http://imagine.gsfc.nasa.gov/docs/features/movies/ Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 43 of 46 Overview Analogy Quasar/Microquasar Thirring-Lense-Effect Population in our galaxy Ergosphere Jets Last stable orbit Accretion disk Observation Rotating Black Holes Conclusion Observation in some microquasars

temperature at last stable orbit calculated from radiation 6= standard model for non-rotating black hole with fitting for rotating black holes consistent solution: GRO J1655-40: a=0.93M, M = 7MJ, rotating at 93 % of maximal rate GRS1915+105: possible solution a = 0.998M

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 44 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Summary Jets References Accretion disk Rotating Black Holes Conclusion Summary

study of microquasars allows insights into physics of relativistic jets in quasars and microquasars connection between instabilities in accretion disk and formation of jets jet composition and its interaction with interstellar environment might make possible determination of spins of black holes better understanding of relativistic effects (both special and general) time scales of microquasars well adapted to average life span of

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 45 of 46 Overview Analogy Quasar/Microquasar Population in our galaxy Summary Jets References Accretion disk Rotating Black Holes Conclusion

Corbel, S. 2004. Similarities ... for AGN and XRB. Contr. Workshop ”Multiband Approach to AGN”

Greiner, J., Morgan E., Remillard, R., 1996. RXTE observations of GRS 1915+105. astro-ph/9610062

Greiner, J., 2000. Mikroquasare. SuW 8/2000: 640

Greiner, J., Cuby, J., McCaughrean, M., An unusually massive stellar black hole, Nat, 414, 522

Janiuk, A., Czerny, B., 2004. Time delays between the soft and hard X-ray... astro-ph/0409671 v1

Marshall, Herman L.; Canizares, Claude R.; Schulz, Norbert S. 2002, ApJ 564 941

Mirabel, I.F., Rodriguez, L.F., 1994. A superluminal source in the Galaxy. Nat, 371, 46.

Mirabel, I.F., Dhawan, V., Chatly, S., et al. 1998. Accretion instabilities .. in GRS1915+105. A&A, 330, L9.

Mirabel, I.F., 2004. Microquasars. Contribution to 5th Microquasar Workshop

Parades, J.M., Marti, J, 2003. Microquasars in the Galaxy. , 2(3): 303-314

Rau, A., Greiner, J., 2003. Comptonization and reflection of X-ray-radio... A&A 397, 711-722

Ribo, M., 2004: Microquasars n the INTEGRAL era. Contr. 5th Microquasar Workshop

Rupen, M., 2004. Radio Imaging of SS433. http://www.aoc.nrao.edu/ mrupen/XRT/SS433/ss433.shtml

Mierk Schwabe TU M¨unchen,MPE Garching Microquasars 46 of 46