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arXiv · 1711.01971

Radio emission from the X-ray pulsar Her X-1: a jet launched by a strong magnetic field neutron star?

J. van den Eijnden·N. Degenaar·T. D. Russell·J. C. A. Miller-Jones·R. Wijnands·J. M. Miller·A. L. King·M. P. Rupen
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Abstract

Her X-1 is an accreting neutron star in an intermediate-mass X-ray binary. Like low-mass X-ray binaries (LMXBs), it accretes via Roche-lobe overflow, but similar to many high-mass X-ray binaries containing a neutron star, Her X-1 has a strong magnetic field and slow spin. Here, we present the discovery of radio emission from Her X-1 with the Very Large Array. During the radio observation, the central X-ray source was partially obscured by a warped disk. We measure a radio flux density of $38.7 \pm 4.8$ $\mu$Jy at $9$ GHz but can not constrain the spectral shape. We discuss possible origins of the radio emission, and conclude that coherent emission, a stellar wind, shocks and a propeller outflow are all unlikely explanations. A jet, as seen in LMXBs, is consistent with the observed radio properties. We consider the implications of the presence of a jet in Her X-1 on jet formation mechanisms and on the launcing of jets by neutron stars with strong magnetic fields.

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J. van den Eijnden, N. Degenaar, T. D. Russell, J. C. A. Miller-Jones, R. Wijnands, J. M. Miller, A. L. King, M. P. Rupen. 2017-11-06. Radio emission from the X-ray pulsar Her X-1: a jet launched by a strong magnetic field neutron star?. https://doi.org/10.1093/mnrasl/slx180

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