E.P.J. van den Heuvel University of Amsterdam George Miley and the discovery of Micro-quasars (X-ray binaries with bimodal relativistic jets) Leiden, June 11, 2013

Early in 1971 Braes and Miley started observing X-ray sources with the Westerbork Synthesis Radio Telescope (WSRT), at 1415 MHz

1973 Cambridge Conference on the “Physics and Astrophysics of Compact Objects”: Luc Braes is in the 2 nd row, 4 th from the left

In 1971, the only known X-ray source that showed (variable) radio emission was Scorpius X-1, discovered by Andrew and Purton, 1968, and further studied by Ables (1969). Observations by Hjellming and Wade (1971,ApL 164,L1) and confirmed by Braes and Miley (1971, A&A 14, 160) showed it to have a triple structure, resembling a little Quasar

Braes & Miley 1972 IUA Symp.

Braes and Miley (1971,Nature 232,246, 1415 MHz) and Hjellming and Wade, 1971, ApJ 168, L21, 2695 MHz) independently discovered a weak radio source that had appeared in the X-ray error box of Cyg X-1 in early April The precise WSRT position left the 9 th magnitude star HD as the sole possible optical candidate of the RADIO Source. BUT WAS THIS THE X-RAY SOURCE?

Webster and Murdin (1971, Nature) identified the radio source with the 9 th magnitude O9.7 Iab blue supergiant star HD , and discovered in Nov this star to be a 5.6 day period spectroscopic binary with a radial velocity amplitude of 64 km/sec (now: 72km/s) [Nature, 7 Jan.1972]. Assuming a “normal” mass of 30 Msun for the supergiant, one finds (since there are no X-ray eclipses), that the minimum mass of the unseen companion is > 6 Msun. As this is larger than the upper mass limit of 3.4 Msun of neutron stars, the companion, if it is the X-ray source, must be a BLACK HOLE.(In the paper they still allow also a supergiant mass 10Msun, which gives a companion>2 Msun)

From B.Louise Webster and Paul Murdin, Nature 235,37 (7 Jan 1972), Received 17 Nov Orb. Period 5.6 days, velocity ampl. 64 km/s

The first pulsating and eclipsing binary X-ray source, Centaurus X-3, was discovered in November 1971 by the UHURU team. The doppler motion showed the companion to be a massive star > 16Msun, and the eclipse duration indicated that the star is a blue supergiant, like HD This made the possibility that Cyg X-1 is a black hole in a similar binary system, suddenly very likely.

The appearance of the radio source of Cyg X-1 just after the X-ray transition

The discovery of this coincidence, made by the UHURU team in the spring of 1972, showed that the radio and the X-ray source are the same object, and that Cyg X-1 indeed is a High-Mass X-ray binary, and that it most likely contains a black hole

Nature The second great discovery of Braes and Miley: the strong and highly variable radio source Cygnus X-3. As its radio spectral evolution after a large radio outburst exactly follows a “van der Laan-model”for an expanding bubble of relativistic electrons with magnetic fields, this is the first “Micro-Quasar” ( 22 years before this name was invented) Nature 237, 506, 30 June 1972

Cyg X-3 is a 4.8- hour period X-ray binary, and is a 4.8 hour period IR source, at a distance of 10 Kpc. In 1993 van Kerkwijk et al. (Nature) found it to have a Wolf-Rayet (He *) companion. It has radio jets. It is at times the brightest radio source in the sky.

March 27 April 03 April 09 April 16 April 23 April 27 Radio outburst of the black-hole X-ray binary GRS in 1994: Blobs moving on the sky with apparently super-luminal velocities 1,2c to 1,7c (VLA). This is a well-known relativisitic “projection” effect, seen in quasar jets. This led to the name Micro-quasar (Mirabel and Rodriguez, 1994, Nature 371,46)

Microquasar GRS : Black hole >10 solar masses with an ~2 solar mass K-giant companion in 33,5 day orbit

The black-hole X-ray binary GRS : radio blobs moving out with relativistic velocities (VLA) The blobs move on the sky with apparently superluminal velocities (1,2c to 1,7c), this is a well-known relativistic “projection”effect seen also in quasar-jets. This led to the name “Micro-quasar” (Mirabel and Rodriguez 1994,Nature 371,46)

SS433 Vermeulen,Schilizzi Multi-wavelength campaign on the May/June 1987 outburst WSRT, with NHO and Calar Alto (Spain), Russian 6m Telescope, Bologna, NRAO, Sydney Univ., NRL, etc. (Vermeulen et al.A&A 270,177,1993) SS 433 The Mother of all Micro-quasars A ~10 Msun Black hole with ~15 Msun donor, in 13d orbit (Fabrika &Cherepaschuk 2013) Discovered by Bruce Margon (1978)

Westerhout 50, the”beam bag” produced by the precessing beams of SS433

Optical behaviour of SS 433 during the May/June 1987 campaign, Aslanov, Cherepaschuck, Goranskij, Rakhimov and Vermeulen, AA 270, 200, 1993 [13-day binary]

Gallo, Fender, Kaiser, Russell, Morganti, Oosterloo and Heintz, 2005, Nature 436, 819: WSRT observations at 1.4 GHz: Discovery of the Jet-powered nebula of Cygnus X-1: Cygnus X-1 is a “Micro-Quasar”!

Gallo, Fender, Kaiser, Russell, Morganti, Oosterloo and Heintz 2005,Nature: WSRT Radio jet and jet-powered nebula of Cyg X-1 (1.4 GHz) [on Cover of Nature]: Cyg X-1 is a Micro- Quasar!!

H-alpha picture of the jet-powered nebula of Cyg X-1 taken with the Isaac Newton Telsc. (Gallo et al.,2005)

The jet-powered optical nebula of Cygnus X-1 (Russell, Fender, Gallo and Kaiser, 2008, MNRAS)

From Mirabel and Rodriguez 1999, Ann.Rev. A&A: Several sources to be added: e.g. Cyg X-1 (black Hole) and Sco X-1 (NS)

Conclusions Braes and Miley in did breakthrough work with the new WSRT on the discovery of the radio emission of accreting neutron stars and black holes in X-ray binaries: - Discovery of the triple “micro-quasar” structure of Sco X-1 (1971) -Discovery of the sudden radio appearance of Cyg X-1 in 1971, allowing its definitive identification with the first ever established black hole in an X-ray binary: HD (1972), (In 2005 found with WSRT to be a micro-quasar). -Discovery of the second “Micro-Quasar” Cygnus X-3 (1972) George: Many Thanks!