AGN, Microquasars and Jets
Brice-Olivier Demory EPFL – ESO - TUM [email protected] B.-O. Demory Introduction Acknowledgements & References Acknowledgements Perspectives Microquasars phenomena as sources of high-energy Case studies Jets Microquasars Active Galactic Nuclei GRS 1915+105 M87 Superluminal motion Relativistic beaming Jets Formation of the Physics of jets AGN Comparison with AGN Paradigm Doppler Boosting 2/32 B.-O. Demory Active Galactic Nuclei (AGN) Typical picture : Typical amount of gravitational potential energy : onto the black hole releases a large Gas accreting masses (cf. talk of S. Taubenberger). center. Masses ranges from ca. 10 Most galaxies have supermassive black-holes at their L = e M D c 2 6 to 10 9 Solar 3/32 B.-O. Demory Active Galactic Nuclei (AGN) phenomena : Accretion processes produce several observational central region Mechanical power in form of outflows and jets from the the black hole X-ray emission from high temperature plasma close to in the accretion disk Broad spectral lines due to Doppler shift of gas orbiting Very high luminosity from a point source in the nucleus 4/32 B.-O. Demory Classes of AGN AGN are classified into numerous types : AGN are classified into numerous Seyfert galaxies km/s) bright cores and found unusually lines (up to emission 8500 broad very Carl Seyfert obtained spectra of several nearby galaxies with First class to be observed 5/32 B.-O. Demory Classes of AGN Quasars high luminosity of the nucleus to detect the light from host galaxy due to the Difficult High redshift (record z=6.4 ?) Broad emission lines Broad UV flux spectral energy distribution, with large Point-like sources associated (originally with radio-sources) (z=0.158 for the brightest one, m=13.1) Distant and luminous objects with highly redshifted spectra Courtesy of STScI ofCourtesy 6/32 B.-O. Demory Classes of AGN Quasars spectral energy distribution Roughly characterized by a power law :
F ν =
C ν
− α 7/32 B.-O. Demory AGN Unification relativistic effect. Doppler boosting is an important factor too as a realizing that the orientation of AGN is important. It was the discovery of superluminal motion that made AGN are not spherically symmetric 8/32 B.-O. Demory motion. of the angle between line sight and direction radiation received by an observer is a very strong function the When an emitting body is moving relativistically, Doppler boosting of the radiation. Relativistic aberration changes the angular distribution of arrival of the photons. The Doppler effect changes the energy and frequency
α δ Is the spectral index Is the Doppler factor s obs = s
em δ ( 3
− α ) 9/32 B.-O. Demory of Boosting Consequences percentage of the total population. sources will only be a small The highly boosted of sight. line to the angles viewed with their axes at small cores will be those Sources with the strongest 100. by density of flux boosting to 10. Implies possible factors of 5 Lorentz motion implies Superluminal 10/32 B.-O. Demory Doppler boosting 11/32 B.-O. Demory The AGN Paradigm 12/32 B.-O. Demory Microquasars astrophysics : relativistic They combine two relevant aspects of seen in quasars. Mimic on a smaller scale many of the phenomena galaxy Stellar-mass black holes in our systems Binary Jets of particles Accreting black holes 13/32 B.-O. Demory Microquasars & AGN Particles ejected at Particles ejected temperature of temperature the Black hole’s mass relativistic speed relativistic speed accretion disk Mean thermal travel up to Several million degrees Several million A few solar masses Microquasar Microquasar Few light-years Several thousand degrees Several million light years Several million Several million solar Several million masses AGN AGN 14/32 B.-O. Demory Microquasars & AGN 15/32 B.-O. Demory The Jets of an accretion disk. it seems they are related to the presence In both cases, recent) Found in AGN and X-ray binaries (the latter is more engine Vehicles observational clues of the activity in core telescopes and by X-ray variability in MQ. Discovered in AGN during the first observations with radio degrees. Collimated ejecta with opening angles less than 15 16/32 B.-O. Demory Properties of Jets transport from the nucleus by narrow jets Rees & Blandford (1974) : lobes are fed by energy Single or twin jets observed 17/32 B.-O. Demory Are all jets double ? Some single jets are observed. hypotheses : directions. Jet is intrinsically single-sided and flips between opposite jet is Material in the moving relativistically Receding jet is more suppressed than the forward jet efficiently Equal energy is flowing into both but one is radiating more More fuel is pumped into one, so it is more visible. 18/32 B.-O. Demory Lifetimes and energy requirements AGN : Mechanical energy required has derived from the central engine. continuous is jet right-hand The the centre. In the case of NGC 6251, the outer lobes are 300 kpc away from 19/32 B.-O. Demory The physics of jets synchrotron radiation Emission is not anisotropic but highly beamed. exceeds the 10 Dramatically Core emissions are very compact suppress synchrotron radiation by some mechanism. should jet material of transport fluid A complex energy and magnetic field strength. lifetime proportional to the inverse of the electron A synchrotron radiating ensemble of electrons has a 12 K limit for 20/32 B.-O. Demory The physics of jets What causes this high degree of collimation ? the medium moving at a velocity exceeding the Jet material is sound speed in mechanism An extremely long beam jet must be collimated by some It should expand sideways as it moves forward 21/32 B.-O. Demory Courtesy of I. L. Tregillis, T. W. Jones , and D. Ryu , and magnetic T. W. Jones pressure. Tregillis, I. L. of Courtesy flow and log of speed, shocks, plasma compression to locate are: bulk to right left panel. Shown in each s the by shown jet radii from its origin, 100 it has propagated about after jet MHD 8 of a simulated light Mach renderings Volume The physics of jets transported by the jet itself. It seems that the emission comes from material being Two key parameters : surrounding medium Ratio of the density of the gas within jet to that How supersonic is the jet (Mach number) quare on the right right on the quare 22/32 B.-O. Demory Formation of the Jets Production of relativistic particles (synchrotronProduction of particles emission) relativistic condensations. disappeareance of accretion disk and sudden ejection of Steady-state MHD models don’t account for the connection between First simulations show that the ejected jet has a two-layer structure. Most models use elements of MHD acceleration and collimation. collimated jet is requiredAfter it to change the wide-angle a centrifugal outflow into plasma. acceleration of accretion disk around the collapsed object is the responsible for the Blandford & Payne (1982) : the angular momentum of a magnetized 23/32 B.-O. Demory Relativistic Beaming the blobs move outwards Astrometry on 3C345 established that the core is stationary and the continuum energy output of the source. The production of new blobs of emission is linked with flares in » of emission. blobs « The parsec-scale jets are not smooth structures, but comprise the 10 brightness temperaturesemission coinciding exceeding with radio Relativistic beaming must be taking place, due to the lack of X-ray 12 K limit. 24/32 B.-O. Demory Superluminal Motion )Small relativisticallymoving be Blob must 2) 1) θ (blob) Courtesy of Jörn Wilms (core) Courtesy of F.Mirablel, L.Rodriguez F.Mirablel, of Courtesy 25/32 B.-O. Demory M87 – Virgo A, 3C274 Virgo M87 – emitting in radio through UV. through in radio emitting Presenceof and edge-brightened blobs regions Plume fed by a single-sided jet. A SMBH is present Distance of 16 Mpc 10 galaxy, Giant elliptical 12 M Θ Nature, Oct.1999 26/32 B.-O. Demory Microquasar : GRS 1915+105 27/32 B.-O. Demory soft Microquasar : GRS 1915+105 hard Courtesy of F.Mirabel of Courtesy Shows Shows time of QPO at the ejection a typical plasma lightcurves of Multi wavelength different wavelengthsdifferent plasma clouds observed in The ejection of relativistic X-rays in disk seen the inner accretion of follow-up replenishement rapid disappearence and the connection between 28/32 B.-O. Demory Microquasar : GRS 1915+105 J.Greiner M of stellar-mass black-holes. seems to be linked the spin QPO maximum stable frequency and via ? slow refill emptying out of accretion disk Possible explanation due to fast- » brightness sputters « Short-time variability: M 29/32 B.-O. Demory MQ as Sources of high energy phenomena nteuies ? in the universe in all sources jets of relativistic mechanism at work Universal 30/32 B.-O. Demory Perspectives QPOs could be of a certain help to study stellar-mass black-holes. XMM-RGS) (Chandra-MEG, observatories space-borne X-ray help of High X-ray spectroscopysensivity are currently developed with the MQ are an opportunity to study the mechanism of ejection of jets special relativity MQ provide a new method to determine distances by the way of 31/32 B.-O. Demory Acknowledgements & References
______ Rees, MJ. 1966, Nature 211: 468-70 Ap. J. 401: L15-18 Martí, J. 1992 Mirabel, IF, Rodríguez, LF, O'Dea, and A.G. Willis 1997 A&AS 123,423 Mack, U. Klein, C.P. J. Greiner : : Robson I. F. Mirabel, L.Rodriguez : Rodríguez, LF. 1994, Nature 371: 46-48 Mirabel, IF, 1915+105 A. Rau, J. Greiner, M. L. McCollough, and made them possible for students. the talks have attended who people all MPA/MPE to thanks Special this year. during their support Jochen Greiner for Diehl and Roland thanking in a point make like to I’d (1999) 409-443
ApJ Letter (?) Letter ApJ
Microquasars ActiveNuclei Galactic Sources of relativistic Jets in the galaxy (ed.: ?)
(Wiley, 1996). The 590 days long term periodicity of the microquasar GRS , Ann.Rev.Astron.Astrophys. 37 , Ann.Rev.Astron.Astrophys. 32/32