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40 Years of Microquasars

40 Years of Microquasars. Ralph Spencer Jodrell Bank Observatory School of Physics and Astronomy University of Manchester Ierapetra June 2014. Radio Emitting X-ray binaries (REXRB). 1968: discovery of radio emission from Sco X-1 (Andrew and Purton 1968)

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40 Years of Microquasars

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  1. 40 Years of Microquasars Ralph Spencer Jodrell Bank Observatory School of Physics and Astronomy University of Manchester Ierapetra June 2014

  2. Radio Emitting X-ray binaries (REXRB) • 1968: discovery of radio emission from Sco X-1 (Andrew and Purton 1968) • 1971: radio emission from X-ray binaries detected by Westerbork Array and GB Interferometer at ~ mJy levels (Braes and Miley 1971, Hjellming and Wade1971) April 1971 John applies to Jodrell Bank for a place on the MSc course, joins in Sept 1971

  3. Cygnus X-3 Goes Bang! • Jan 1972: Detection of Cyg X-3 with GBI (Hjellming and Wade 1972) 0.1-0.3 Jy at 11 and 4 cm • September 1972: –outburst on Cyg X-3 reaching > 20 Jy. Many observatories took part. Gregory et al 1972 Oct 1972 John starts PhD

  4. Nova Monoceros 1975 A0620-00 • Rapid increase in X-ray emission reported by Leicester group (Ariel) • Triggered radio obs at JBO (Davis et al. 1975) • Kuulkers et al. 1999 revisited data Oct 1975 John completes PhD

  5. X-Ray Binaries • ~300 X-ray emitting binary stars (XRBS) found in our own Milky Way galaxy, detected by X-ray satellites at ~1-10 kev (van Paradis 1995, Liu et al. 2000, 2001 catalogues) • High Mass ~ 10 Msun • Low Mass ~ 1 Msun • .All powered by accretion onto a compact object (neutron star or black hole). • Roche Lobe overflow or wind? • ~20 % have been found to have radio emission

  6. Low Mass XRBs • Companions around 1 Msun, with a neutron star or BHC secondary • Neutron star binaries • Type I X-ray bursts • Soft X-ray emission (few kev brightness temp.) • Short orbital period of < 12 hours • BHCs : no Type 1 bursts, hard X-rays, transients • X-ray colour-colour diagram useful diagnostic • Quasi period oscillations in X-ray intensity X-ray bursts from Circ X-1

  7. High Mass X-ray binaries: HMXRB • Indicators: • O, B, Be or Wolf-Rayet stellar spectrum • Strong flaring and absorption variability on a timescale of minutes • Transient outbursts • Hard 1-10 kev spectrum with a power law index at higher energies of ~0-1 • Periods range from 4.8 hrs (Cygnus X-3) to 187 days (Hen 715) • N- star or BHC compact secondaries • Generally wind fed.

  8. The discovery of radio jets • SS433 in 1979 • Moving optical lines suggest precessing jets at 0.26 c with a period of 162.5 days (Abell and Margon1979) • Cambridge 5km observations of compact objects < 1 arcsec, Ryle et al 1978 • Interesting X-ray behaviour – Dennis Walsh suggested we observed it at JB • Discovered extension in PA ~100 deg – jets? (Spencer 1979) Margon and Anderson 1989 MkI-Defford 74-cm 1979 visibility curve

  9. SS433 radio jets • Hjellming and Johnston 1981 VLA results • MERLIN 5 GHz Jowett PhD 1999 Stirling et al 2002

  10. Radio Emission • ~50 sources have radio emission • Most radio emitters are Low Mass XRBs with BHC I. Brown 2006 PhD Thesis

  11. Microquasars • Term first used by Martin Elvis 1984 “Microquasars and the X-ray Background” (Weak AGN) • First used in the context of X-ray binaries: Geldzahler, Fomalont and Cohen 1984, “Sco X-1 The Microquasar” • Now thought to be unrelated background sources VLA 4.8 GHZ

  12. Microquasars • Why microquasar? • Radio jets • Relativistic velocities • Powered by accretion • 106 times closer • Mirabel et al. 1992 1E1740.7-2942

  13. Number of papers with ‘microquasar’ in the title or abstract No. of papers Year

  14. Fundamental plane of black holes • Radio/X-ray correlation found in XRBS can be extended to AGN by the inclusion of a mass term. • Correlation very tight for LLAGN Merloni, Heinz et al. 2003, Falcke, Koerding, Markoff 2004, Koerding et al. 2006

  15. Some Individual Objects • Cygnus X-3 • SS433 • Cygnus X-1 • GRS1915+105 • Cygnus X-2

  16. Cygnus X-3 • Greenbank Interferometer Waltman et al 1995 • 1983 MERLIN 5 GHz – model fitting N-S double showed expansion at 0.3 c Johnston et al. 1983 • Infra red and radio flares Fender, Bell-Burnell, Ogley et al. 1994,1995, 1996, 2001 • 10 Msun WR star and 2.4 Msun BH Zdziarski et al. 2013 Fender et al 1996

  17. Relationship to X-rays • Ryle telescope and RXTE (Pooley) • Quenching of radio before outburst • Hardening of X-rays

  18. Radio/Hard X and γ-ray Quenching • Corbel et al 2012- hard X-rays and γ-rays suppressed just before a major flare

  19. Cygnus X-3 Images • Mioduszewski et al 2001 • 15 GHz VLBA • Evolving N-S jet • 2-sided N-S structure also seen in 5 GHz VLA images (AM). • Expansion at ~0.5 c • (Marti et al 2002) • www.aoc.nrao.edu/~amiodusz/ NB 90 deg rotation

  20. EVN at 5 GHZ 1st e-VLBI observations at 5 GHz Complex changes in the core- more to do!

  21. SS433 • Another WR star and compact companion • 24 Msun WR and 16 Msun BH • 162.5 d precession period • 13 d binary period • Proper motion if at 0.26 c gives distance of 4.6 kpc VLA 5 GHz Blundell and Bowler 2004

  22. The Ruff – Equatorial emission VLA, MERLIN VLBA 6 cm March 1998 Blundell et al 2001 MERLIN+EVN 18 cm June 1998 Stirling et al 2004 Present in ~25% of images, no obvious relationship to jet knots and PA Spencer 2006

  23. W50 and SS433 – the jets slow down? Velocity of filaments in the ears < 0.04c Goodhall et al. 2011 Fit to ephemeris including nutation suggests deceleration at 0.04c/yr Stirling et al. 2004 More observations needed!

  24. Cygnus X-1 – a radio jet in a persistent black hole XRB 15 Msun Black hole +19 Msun O star companion VLBA 8.4 GHz August 1998 -discovery of jet in Cyg X-1 on ~15 mas scale (Stirling et al 2001) VLBA 15 GHz Showing compact jet ~3 mas long Also a weak compact jet in the soft state (Rushton et al 2012 (in low/hard X-ray state)

  25. Optical line emission White: continuum Red: Ha Green: O[III] (Russell, Fender et al. 2007) Cyg X-1 Nebula 1.4 GHz Westerbork image Gallo et al 2005

  26. GRS1915+10510 Msun BH +2 Msun companion Superluminal expansion Mirabel & Rodriguez 1994 Fender et al 1999 0.9c, 11kpc

  27. Radio emission in plateau states (Migliari & Belloni 2003 Xray state χ) Rushton et al 2010

  28. 0.2-0.4 Jy Flares and 0.05-0.1 Jy plateaus Typically 1-3 months

  29. Flares decay in 3-4 days, followed by a suppressed flux before recovering Occurs during plateau state as well as at beginning or end

  30. GRS1915 – log normal flux distribution Compare with power law for Cyg X-3

  31. A Radio Jet in the Cyg X-2 Neutron Star X-ray BinarySpencer et al. MNRAS 435L, 48, 2013 Horizontal Branch (HB) - jet launched here Normal Branch (NB) - mass accretion rate increases Z-track on hardness-intensity diagram Flaring Branch (FB) - unstable nuclear burning on the neutron star 6 cm EVN 22 Feb 2013 Jet ejected SWIFT hardness – intensity diag. Source in HB 23 Feb 2013 Hard Apex - Jet ejected X-ray, UV and radio vs time 1.7 Msun neutron star and a 0.6 Msun companion

  32. To summarise so far • Radio emission can be relatively steady or in flares • Flaring often associated with the formation of relativistic jets on > 100 mas scales • Steady mas (10’s au) jets can also occur • At least one object shows precessing jets • Strong association with X-ray emission: jet-disk coupling • Changing accretion conditions have a causal relationship with the radio jets

  33. q- diagram or Turtles Head Gallo, Fender et al 2005

  34. Miller et al. 2012 model for CygX-1 >0.3c Radio wind 0.3c Reflected X-rays Hard X-rays O Star companion disk Magnetic loops Hot e+- plasma lifted by unstable loops formed by magnetic rotational instability

  35. GRS1915 evolution High Soft X-ray state No radio X-ray Intensity Flaring outburst with relativistic ejection Hardness Dominated by radiation form disk Low Hard X-rays Inner disk instability leads to major ejection Hot corona and jet formed - Blandford Znajek 1977 mechanism Stronger inner jet Weak inner jet Plateau state

  36. Future • Do all galactic XRBs have radio emission at some level? Need much better sensitivity to bring the 20% detections up! • Microquasars in other galaxies e.g. M31 (Middleton et al 2013), IC10 (Bernard et al 2008), NGC300 (Crowther et al. 2010) – should be lots, especially in star forming galaxies. • E.g. an equivalent 10 Jy flare in IC10 from a CygX-3 type object would give 240 microJy on Earth – can be studied with JVLA and e-MERLIN, but not quiescent emission • Relationship to ULXs – extending the fundamental plane • Need the SKA!!

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