The termination region of high-mass microquasar jets

Abstract

Context. The environment of high-mass X-ray binaries can be characterized either by the supernova remnant that forms these systems or by the wind from the companion massive star. These regions should be tenuous but very hot and surrounded by a dense and cold shocked ISM shell. The interaction between the jet and such a complex medium, also affected by the system proper motion, can lead to very different jet termination structures. Aims. The evolution of the jet termination regions during the life of a high-mass microquasar is simulated to improve our present understanding of these structures. Also, the evolving emission characteristics are modeled to inform potential observational campaigns of this class of object. Methods. We performed 2D numerical simulations of jets propagating in different scenarios, corresponding to different epochs after the formation of the high-mass X-ray binary, using the code Ratpenat. We also made simple estimates of the nonthermal emission that could be produced in the jet termination regions. Results. We find that, in the way through the hot and tenuous medium of the shocked wind/supernova ejecta, the jet suffers recollimation shocks in which it loses part of its thrust and ends in a strong shock inflating a hot cocoon. The jet head propagates with a speed that is similar to the medium sound speed, until it eventually reaches the denser and colder shocked ISM and the unperturbed ISM later on. In these last stages of evolution, the jet is significantly slowed down and can be disrupted. For relatively old sources, the microquasar peculiar velocity becomes important, leading to complete jet destruction. Extended nonthermal radiation can be generated in the jet termination regions, and hard X-rays and TeV photons are the wavelengths best suited for observing these structures.

Jet Stability, Dynamics and Energy Transport

“…Microquasar jets Inhomogeneities in the ambient medium can also have a strong effect on microquasar jets in high-mass X-ray binaries (HMXB) with typical powers (10 36−37 erg/s). 55 Such inhomogeneities are encountered by the jet in the transition between the unshocked and shocked stellar wind from the massive companion. Another change of ambient medium occurs for a young HMXB still embedded in the SNR, at the transition between the shocked wind and the shocked SNR, and finally from the latter to the interstellar medium (ISM) through the shocked ISM.…”

Large-scale flow dynamics and radiation in pulsarγ-ray binaries

“…Therefore, a significant fraction of the pulsar wind luminosity is reprocessed outside the binary system. Interestingly, this region may dominate the very high-energy output in pulsar gamma-ray binaries with high photon-photon absorption (see the discussion in Bosch-Ramon et al 2008).…”

“…Velázquez & Raga 2000;Heinz 2002;Heinz & Sunyaev 2002;Bosch-Ramon et al 2005;Zavala et al 2008;Bordas et al 2009;Bosch-Ramon et al 2011). On the other hand, PSR B1259−63 is a system formed by an O9.5 V star and a nonaccreting millisecond pulsar (Johnston et al 1992;Negueruela et al 2011).…”

Mapping jet–ISM interactions in X-ray binaries with ALMA: a GRS 1915+105 case study

“…For instance, given the possibility that the stellar wind may also be powering the Cyg X-1 bubble, the jet-driven shock velocity may have been overestimated, possibly explaining the stark contrast between the estimated shock velocity in the Cyg X-1 and IRAS 19132+1035 cases. A comparison between the observational characteristics of these interaction sites and numerical simulations of jet-ISM interactions in XRBs (e.g., Perucho & Bosch-Ramon 2008;Bordas et al 2009;Bosch-Ramon et al 2011) could help disentangle the complex processes that are driving such interactions. Performing numerical simulations of the jet-ISM interaction in IRAS 19132+1035 is beyond the scope of this work, but will be explored in future work.…”