E.P.J. van den HeuvelUniversity 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 Astrophysicsof Compact Objects”: Luc Braes is in the 2nd row, 4th from the left

Braes &Miley1972IUASymp.

Braes and Miley (1971,Nature232,246, 1415 MHz) andHjellming and Wade, 1971, ApJ168, L21, 2695 MHz)independently discovereda weak radio source that had appeared in the X-ray error boxof Cyg X-1 in early April 1971.

The precise WSRT position leftthe 9th magnitude star HD226868 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 9th magnitude O9.7 Iab blue supergiant star HD 226868, and discovered in Nov. 1971 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 Msunof neutron stars, the companion, if it is the X-ray source, must be a BLACK HOLE .(In the paper they still allow also asupergiant mass 10Msun, which gives a companion>2 Msun)

From B.Louise Webster and Paul Murdin, Nature 235,37 (7 Jan 1972),Received 17 Nov. 1971. Orb. Period 5.6 days, velocity ampl. 64 km/s

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

March 27

April 03

April 09

April 16

April 23

April 27

Radio outburst of the black-hole X-ray binary GRS1915+105 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 quasarjets.

This led to the name Micro-quasar

(Mirabel and Rodriguez, 1994,Nature 371,46)

Microquasar GRS 1915+105: Black hole >10 solar masses with an ~2 solar mass K-giant companion in 33,5 day orbit

SS433 Vermeulen,Schilizzi

Multi-wavelength campaign on the May/June 1987 outburstWSRT, with NHO and Calar Alto (Spain), Russian 6m Telescope, Bologna, NRAO, Sydney Univ., NRL, etc. (Vermeulen et al.A&A 270,177,1993)

SS 433The Mother of all Micro-quasars

A ~10 MsunBlack hole with ~15 Msundonor, in 13dorbit (Fabrika&Cherepaschuk2013)

Discovered by Bruce Margon (1978)

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

Gallo, Fender, Kaiser, Russell, Morganti, Oosterloo and Heintz 2005,Nature: WSRT Radio jet and jet-powerednebula of Cyg X-1(1.4 GHz)[on Cover of Nature]:

Cyg X-1 is a Micro-Quasar!!

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)

ConclusionsBraes and Miley in 1971-1972 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: HD226868 (1972),

(In 2005 found with WSRT to be a micro-quasar).-Discovery of the second “Micro-Quasar” Cygnus X-3 (1972)

George: Many Thanks!