Jets in neutron star X-ray binaries: a comparison with black holes

By Simone Migliari, R. Fender, Robert P. Fender. 2005

272 citations recorded by the source corpus.

We present a comprehensive study of the relation between radio and X-ray emission in neutron star (NS) X-ray binaries, use this to infer the general properties of the disc‐jet coupling in such systems and compare the results quantitatively with those already established for black hole (BH) systems. There are clear qualitative similarities between the two classes of object: hard states below about 1 per cent of the Eddington luminosity produce steady jets, while transient jets are associated with outbursting and variable sources at the highest luminosities. However, there are important quantitative differences: the NSs are less radio loud for a given X-ray luminosity (regardless of mass corrections) and they do not appear to show the strong suppression of radio emission in steady soft states that we observe in BH systems. Furthermore, in the hard states, the correlation between radio and X-ray luminosities of the NS systems is steeper than the relation observed in BHs by about a factor of 2. This result strongly suggests that the X-ray emission in the BH systems is radiatively inefficient, with an approximate relation of the form L X ∝ ˙ m 2 , consistent with both advection-dominated models and the jetdominated scenario. In contrast, the jet power in both classes of object scales linearly with accretion rate. This constitutes some of the first observational evidence for the radiatively inefficient scaling of X-ray luminosity with accretion rate in accreting BH systems. Moreover, based on simultaneous radio/X-ray observations of Z-type NSs (the brightest of our Galaxy, always near or at the Eddington accretion rate), we draw a model that can describe the disc‐ jet coupling in such sources, finding a possible association between a particular X-ray state transition [horizontal branch to normal branch] and the emission of transient jets.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/a48d3c236a2099329bdf7bde9e1027489b120fe1

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Citations in the corpus

Short-duration gamma-ray bursts with extended emission from protomagnetar spin-down (2007, background): “Although jets from NS X-ray binaries are in general less powerful than their BH counterparts (Migliari & Fender 2006), the NS X-ray binary Circinus X-1 produces one of the most relativistic microquasar jets known (Fender et al. 2004).”
Radiatively efficient accreting black holes in the hard state: the case study of H1743-322 (2011, methodology): “Based on the radio/X-ray correlation alone and considering the results of Migliari & Fender (2006), the 1.4 power-law index could suggest that the accreting compact object is a neutron star.”
Jets from black hole X-ray binaries: testing, refining and extending empirical models for the coupling to X-rays (2009, background): “A +1.4 index is in fact as expected for jets from a radiatively efficient accretion flow (e.g. Heinz & Sunyaev 2003; see Migliari & Fender 2006 for the possible case of such an index for neutron stars) and so this is not quite ruled out.”
Radio Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications (2006, background): “2 in Migliari & Fender 2006).”
Detecting gravitational wave emission from the known accreting neutron stars (2008, methodology): “The source is located in 18 The distance of 6.4 ± 0.6 kpc derived by Penninx (1989), cited incorrectly as 9.2 ± 0.7 kpc by Fender & Hendry (2000); Migliari & Fender (2006) is highly model-dependent.”
Evaluating Spectral Models and the X-Ray States of Neutron Star X-Ray Transients (2007, background): “The hard state of atoll sources is considered by some authors to be associated with a steady jet (e.g., Fender 2006; Migliari & Fender 2006).”
Global optical/infrared-X-ray correlations in X-ray binaries: quantifying disc and jet contributions (2006, methodology): “It was shown that the jet power is linearly proportional to the mass accretion rate in NSXBs and BHXBs in the hard state (Falcke & Biermann 1996; Migliari & Fender 2006; Körding, Fender & Migliari 2006) and the X-ray luminosity scales as LX ∝ ṁ and LX ∝ ṁ2 for radiatively efficient and…”
Discovery of Coherent Millisecond X-Ray Pulsations in Aquila X-1 (2007, background): “The 2-10 keV flux is∼ 8.8 × 10−9 erg s−1 cm−2 which corresponds, assuming a distance of 5 kpc (Jonker & Nelemans 2004) and a bolometric correction of 1.4 (Migliari & Fender 2006), to a bolometric luminosity of ∼ 3.7 × 1037 erg s−1 ∼ 0.15LE.”
The 'universal' radio/X-ray flux correlation : the case study of the black hole GX 339-4 (2012, background): “At a 1–10 keV luminosity above 4 × 1036 erg s−1, the group of outliers seems to be consistent with the track followed by H 1743−322 with a steeper correlation index of ∼ 1.4 (Coriat et al. 2011b), and also quite similar to the few reported neutron star systems (Migliari & Fender 2006).”
A radio-emitting outflow in the quiescent state of A0620−00: implications for modelling low-luminosity black hole binaries (2006, background): “Since neutron star X-ray binaries tend to be dimmer in the radio band (Migliari & Fender 2006), the measured radio flux is actually the lowest reported for a Galactic X-ray binary system.”
No evidence for black hole spin powering of jets in X-ray binaries (2010, background): “Note that X-ray binary systems with comparable properties but hos ing a neutron star instead of a black hole (candidate) also show jets, but with a lower ratio ofLradio to LX (Fender & Kuulkers 2001; Migliari & Fender 2006).”