@article{c3cb0d84dbe74176aeaa46f898246310,
title = "Resolved, expanding jets in the Galactic black hole candidate XTE J1908+094",
abstract = "Black hole X-ray binaries undergo occasional outbursts caused by changing inner accretion flows. Here we report high angular resolution radio observations of the 2013 outburst of the black hole candidate X-ray binary system XTE J1908+094, using data from the Very Long Baseline Array and European VLBI Network.We show that following a hard-to-soft state transition, we detect moving jet knots that appear asymmetric in morphology and brightness, and expand to become laterally resolved as they move away from the core, along an axis aligned approximately -11° east of north. We initially see only the southern component, whose evolution gives rise to a 15-mJy radio flare and generates the observed radio polarization. This fades and becomes resolved out after 4 days, after which a second component appears to the north, moving in the opposite direction. From the timing of the appearance of the knots relative to the X-ray state transition, a 90° swing of the inferred magnetic field orientation, the asymmetric appearance of the knots, their complex and evolving morphology, and their low speeds, we interpret the knots as working surfaces where the jets impact the surrounding medium. This would imply a substantially denser environment surrounding XTE J1908+094 than has been inferred to exist around the microquasar sources GRS 1915+105 and GRO J1655-40.",
keywords = "ISM: jets and outflows, Radio continuum: stars, Stars: individual: XTE J1908+094, X-rays: binaries",
author = "Rushton, {A. P.} and Miller-Jones, {J. C.A.} and Curran, {P. A.} and Sivakoff, {G. R.} and Rupen, {M. P.} and Z. Paragi and Spencer, {R. E.} and J. Yang and D. Altamirano and T. Belloni and Fender, {R. P.} and Krimm, {H. A.} and D. Maitra and S. Migliari and Russell, {D. M.} and Russell, {T. D.} and R. Soria and V. Tudose",
note = "Funding Information: We are deeply indebted to Peter Curran, who drove much of this work and was responsible for a significant amount of the data collation and interpretation before his death. His contributions to the field will be greatly missed by his many colleagues. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The EVN is a joint facility of independent European, African, Asian and North American radio astronomy institutes. Scientific results from data presented in this publication are derived from the following EVN project codes: RR007 and RR009. This work made use of the Swinburne University of Technology software correlator, developed as part of the Australian Major National Research Facilities Programme and operated under licence. APR acknowledges funding via an EU Marie Curie Intra-European Fellowship under contract no. 2012-331977. The work was also supported by ERC grant 267697 {\textquoteleft}4 PI SKY: Extreme Astrophysics with Revolutionary Radio Telescopes{\textquoteright}. JCAMJ is supported by an Australian Research Council Future Fellowship (FT140101082). This work was supported by Australian Research Council grant DP120102393. DA acknowledges support from the Royal Society. Publisher Copyright: {\textcopyright} 2017 The Authors.",
year = "2017",
month = jul,
day = "1",
doi = "10.1093/mnras/stx526",
language = "English (US)",
pages = "2788--2802",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",
}