Open AccessThe radio luminosity of persistent X‐ray binaries
Author(s) -
Fender R. P.,
Hendry M. A.
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03443.x
Subject(s) - physics , astrophysics , accretion (finance) , neutron star , pulsar , black hole (networking) , luminosity , astronomy , eddington luminosity , x ray binary , compact star , outflow , x ray pulsar , galaxy , computer network , routing protocol , routing (electronic design automation) , meteorology , computer science , link state routing protocol
We summarize all the reported detections of, and upper limits to, the radio emission from persistent (i.e. non‐transient) X‐ray binaries. A striking result is a common mean observed radio luminosity from the black hole candidates (BHCs) in the low/hard X‐ray state and the neutron star Z sources on the horizontal X‐ray branch. This implies a common mean intrinsic radio luminosity to within a factor of 25 (or less, if there is significant Doppler boosting of the radio emission). Unless coincidental, these results imply a physical mechanism for jet formation that requires neither a black hole event horizon nor a neutron star surface. As a whole the populations of Atoll and X‐ray pulsar systems are less luminous by factors of ≳5 and ≳10 at radio wavelengths than the BHCs and Z sources (while some Atoll sources have been detected, no high‐field X‐ray pulsar has ever been reliably detected as a radio source). We suggest that all of the persistent BHCs and the Z sources generate, at least sporadically, an outflow with physical dimensions 10 12 cm; that is, significantly larger than the binary separations of most of the systems. We compare the physical conditions of accretion in each of the types of persistent X‐ray binary and conclude that a relatively low (10 10 G) magnetic field associated with the accreting object, and a high (0.1 Eddington) accretion rate and/or dramatic physical change in the accretion flow, are required for formation of a radio‐emitting outflow or jet.