Thermal X-ray emission from a baryonic jet: a self-consistent multicolour spectral model

Abstract

We present a publicly-available spectral model for thermal X-ray emission from a baryonic jet in an X-ray binary system, inspired by the microquasar SS 433. The jet is assumed to be strongly collimated (half-opening angle $\Theta \sim 1°$) and mildly relativistic (bulk velocity $\beta =V_b/c\sim 0.03-0.3$). Its X-ray spectrum is found by integrating over thin slices of constant temperature, radiating in optically thin coronal regime. The temperature profile along the jet and corresponding differential emission measure distribution are calculated with full account for gas cooling due to expansion and radiative losses. Since the model predicts both the spectral shape and luminosity of the jet's emission, its normalisation is not a free parameter if the source distance is known. We also explore the possibility of using simple X-ray observables (such as flux ratios in different energy bands) to constrain physical parameters of the jet (e.g. gas temperature and density at its base) without broad-band fitting of high-resolution spectra. We demonstrate this approach in application to Chandra HETGS spectra of SS 433 in its 'edge-on' precession phase, when the contribution from non-jet spectral components is expected to be low. Our model provides a reasonable fit to the 1-3 keV data, while some residuals remain at higher energies, which may be partially attributed to a putative reflection component. Besides SS 433, the model might be used for describing jet components in spectra of other Galactic XRBs (e.g. 4U 1630-47), ULXs (e.g. Holmberg II X-1), and candidate SS 433 analogues like S26 in NGC7793 and the radio transient in M82.

14 pages, 9 figures, accepted for publication in MNRAS. The presented model is publicly available at http://hea133.iki.rssi.ru/public/bjet

References in corpus (7)

• The Nature of SS433 and the Ultraluminous X-ray Sources
• An overview of jets and outflows in stellar mass black holes
• NuSTAR, XMM-Newton and Suzaku Observations of the Ultraluminous X-ray Source Holmberg II X-1
• The ASTRO-H X-ray Astronomy Satellite
• Determining the Nature of the SS 433 Binary Using an X-ray Spectrum During Eclipse
• The unusual radio transient in M82: an SS 433 analogue?
• X-ray variability of SS433: effects of the supercritical accretion disc

Cited by in corpus (14)

• The SRG X-ray orbital observatory, its telescopes and first scientific results
• Ultraluminous X-Ray Sources
• NuSTAR reveals the hidden nature of SS433
• Is SS 433 a misaligned ultraluminous X-ray source? Constraints from its reflected signal in the Galactic plane
• Observable Emission Features of Black Hole GRMHD Jets on Event Horizon Scales
• An upper limit on nickel overabundance in the supercritical accretion disk wind of SS 433 from X-ray spectroscopy
• Diagnostics of Parameters for the X-ray Jets of SS 433 from High-Resolution Chandra Spectroscopy
• A NuSTAR view of SS433: Precessional evolution of the jet-disk system
• X-ray Variability of SS 433: Evidence for Supercritical Accretion
• X-ray panorama of the SS433/W50 complex by SRG/eROSITA
• Identification of X-ray lines in the spectrum of the arcsec-scale precessing jets of SS 433
• Arcsecond-Scale X-ray Imaging and Spectroscopy of SS 433 with Chandra HETG
• PeV particle acceleration and non-thermal emission in the `minimalist' model of the extended jets in W50/SS433
• Constraints on the collimated X-ray emission of SS 433 from the reflection on molecular clouds