Xray binary jets a k a microquasars Rob

X-ray binary jets: a. k. a. microquasars Rob Fender (Southampton)

The jets from X-ray binaries are very similar to those from AGN: • Relativistic bulk motions with > 1 • Composition of relativistic ( > 100, in some cases >106) leptons – observed via their synchrotron radiation • Have an important feedback effect on their environment • Powered by central accreting black hole (or neutron star) • If we assume that this similarities have a common physical origin, we can use one to learn about the

GRS 1915+105: a super-Eddington 15 solar mass BH : MERLIN observations receding Daily images: Proper motions are so high (compare 10 s of mas/day with few mas/year) because of distance ratio (not mass scaling) 600 mas = 6000 A. U. at 10 kpc

Lorentz factors of XRBs estimated from limits on jet opening angle The jets may be just as relativistic as those from AGN XRB AGN (Jorstad) Miller-Jones, Fender & Nakar (2006)

Jet-blown bubbles in the ISM: Cygnus X-1 Emin ~ 1048 erg Gallo, Fender, Kaiser et al. 2005

What we’ve really learned that would have been difficult / impossible from AGN alone, is the properties of the disc: jet coupling in accreting black hole systems. AND… nearly everything we’ve learned from 10 solar mass BH seems to be applicable to supermassive BH in AGN… so far…

The life and times of a black hole X-ray binary… X-ray Luminosity / Eddington ~1. 0 ~0. 1 ~0. 01 <10 -6 X-ray soft spectrum hard spectrum Quiescence hardness

So what is the relation to jets ? X-ray Luminosity / Eddington ~1. 0 From quiescence to the brightest hard X-ray states, there seems to be a steady, powerful, jet. ~0. 1 ~0. 01 Steady jets (~1014 cm) <10 -6 X-ray soft spectrum hard spectrum Quiescence hardness

So what is the relation to jets ? In steady soft X-ray states there appears to be no jet produced X-ray Luminosity / Eddington ~1. 0 ~0. 1 ~0. 01 <10 -6 X-ray soft spectrum hard spectrum Quiescence hardness

Hard state: Lradio LX 0. 7 (and if Lradio PJ 1. 4 PJ LX 0. 5 ) Gallo, Fender & Pooley (2003) Fender et al. LX (Edd) Gallo, Fender et al. (2006

Why this relation to states ? MHD jets and B scale height ? B field "Corona" (base of jet? ) Low/hard X-ray state: ‘Power-law’ spectrum, cutoff ~100 ke. V Jets always present, lots of variability These are the states modeled as ADAFs Accretion disc B field High/soft X-ray state: ‘Thermal’ spectrum, no sign of jet (in radio) Very little variability Probably globally radiatively efficient [? ]

X-ray Luminosity / Eddington Early on in a major outburst, a large-scale, very powerful jet is produced… ~1. 0 Outburst ~0. 1 ~0. 01 Discrete ejections (up to parsec scales) <10 -6 X-ray soft spectrum hard spectrum Around this point strong and variable QPOs appear (e. g. Casello, Belloni & Stella 2005)

Powerful jets produced in transition from canonical ‘low/hard’ to ‘high/soft’ states… Corbel et al. 2002 Gallo et al. 2004 Fender, Belloni & Gallo (2004) See also Corbel et al. (2004); Homan & Belloni

What causes transient jet? GX 339 -4 radio flare This is formed as source moves between classical ‘hard’ and ‘soft’ Xray states. Fits to X-ray spectra invariably indicate that this corresponds to the point of minimum inner disc radius (which is often sustained for a period of >100 days) The optically thin radio flares occur around the time that the optically thick accretion disc reaches its innermost radius … but why ? ? ? (e. g. Zdziarski et al. 2004)

jet speed variations with Lx or state Fender, Belloni & Gallo (2004) (but see Heinz & Merloni) Jet velocity increases with increasing LX : but not clear if velocity function is a ‘step’ or smooth…

Disc moves in, jet increases Internal shock 1. ‘Hard’ X-ray state: steady, <2, self-absorbed jet >2 <2 2. Disc moves in, ‘softening’ the X-ray spectrum. A transient, high- flow collides with the slower pre-existing jet internal shocks. ‘Corona’, not disc, ejected (i. e. GRS 1915+105) ~1 Obviously you only get the shock when >0 (so only one flare per ‘cycle’) (almost like an ‘external’ shock with steady jet as ambient medium efficient) (see also Kaiser, Sunyaev & Spruit 2000; Vadawale et al. 2004; Turler et al. 2004)

Towards a unified model… As source softens, jet velocity increases abruptly, causing internal shock in jet More powerful, hard sources have more powerful, steady jets… 1915? Some sources do this more than once… 1859, 1550? Subsequently, soft states show no jet 1915: Fender & Belloni (2004) Only crossing the ‘jet line’ from hard to soft makes an outburst !! Crossing from soft to hard (e. g. quiescence) there is no shock Faint, hard source have steady, ~1 jets Generic: Fender, Belloni & Gallo (2004)

Some considerations, additions and refinement since the model came out…: 1. The HIDs are not always as simple as we show… but the general pattern is not strongly violated (Homan & Belloni 2005). Hard to soft transitions may occur at different luminosities, and the jet line transition may occur at a different hardness. 2. The timing properties of the sources also show a close association with jet production – in particular there may be particular QPOs associated with the transition around the ‘jet line’ (Homan & Belloni 2005; Remillard 2005; Casella et al. 2005) 3. Is there a fast spine even in the hard state ? This might reconcile XRBs with blazars and is included in the model of Petrucci et al. (2006, on astro-ph)

Luminosity / Eddington Relation to AGN ? Bright, radioquiet AGN (with old lobes? ) ~1. 0 Bright, Radio-loud AGN ~0. 1 ~0. 01 … and in here, is 3 C 120 ‘doing a 1915? ’ (Marscher) LLAGN <10 -6 Sgr A* <10 -9 X-ray soft hard Quiescence hardness

Where does all the power go ? using the disc-jet coupling to test advection The overwhelming majority of jet formation is taking place in the hard state, which is also the state modeled as being an ADAF…. (and also the state in which most black holes find themselves most of the time). Issues: • Are both processes (jet production and advection) occurring together ? probably • Do they dominate over radiation, so that accretion flow is radiatively inefficient ? maybe • Which one, jet or advection across event horizon, is the dominant sink for non-radiated accretion power ?

PJ QADAF The flow of energy around a black hole . m LX. m = LX + PJ + QADAF Eddington units What is major channel for energy release back to universe: photons ? Kinetic energy of the jet ? Is a significant amount of energy advected into black

X-ray binaries provide us with a further advantage over AGN: a control sample with very similar spacetime, but a solid surface: neutron stars Comparing the disc-jet coupling in BH and NS XRBs: BH: Lradio LX 0. 7 NS: Lradio LX~1. 4 which implies (with liberal use of Occam’s razor): . . BH: Pjet m , LX m 2 NS: Pjet m , LX m (Migliari & Fender 2005)

Quantifying what this all means… We (Koerding, Fender & Migliari) have developed a method to measure accretion rate from radio luminosity. We find that the normalisation is almost the same for BH and NS ( as noted previously: you don’t need a black hole to make a relativistic jet) Using this method, we can test the dependence of X-ray luminosity on accretion rate for any object for which we have a measure of LX and Lradio

Koerding, Fender & Migliari (2006) Using Lradio. as m tracer, BH are clearly radiatively inefficient

Well then, what about AGN… ? ?

How does this relate to the `fundamental plane’ (*) of black hole activity … ? Actually, the plane – almost exactly as measured -emerges as a natural and intuitive consequence: . 1. 4 IF Lradio m . and (LX /M) (m/M)2 then Lradio LX 0. 7 M 0. 7 which only differs from observed plane by M 0. 15 [* recently the subject of some Michigan-based scepticism]

With this M 0. 15 mass correction applied…:

Following this approach, we can establish (=we would claim) that all hard state BH (<2% Edd), whether XRB or AGN are jet-dominated advective systems in which: Pjet > LX and QADAF ~ Pjet Furthermore, the correspondence between hard state BH XRBs and (LL)AGN of widely varying masses implies that transition from radiatively efficient to inefficient accretion occurs at about the same Eddington ratio in all BH… (Koerding, Fender & Migliari 2006]

The Bottom Line: X-ray binary jets are very much like the jets from AGN: relativistic, powerful, powered by accretion By studying the temporal variability of XRBs we can gain insights into the response of an accreting black hole to a varying accretion rate which are impossible via the study of AGN alone The comparison with NS has proved invaluable, and has revealed that most accreting BH should be jet-dominated advective systems