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

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.

arXiv comment5 pages, 2 figures; accepted for publication in MNRAS Letters

References in corpus (26)

• Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
• Modelling the behaviour of accretion flows in X-ray binaries
• A fundamental plane of black hole activity
• The MAXI Mission on the ISS: Science and Instruments for Monitoring All Sky X-Ray Images
• A Scheme to Unify Low-Power Accreting Black Holes - Jet-Dominated Accretion Flows and the Radio/X-Ray Correlation
• A universal radio/X-ray correlation in low/hard state black hole binaries
• The Swift/BAT Hard X-ray Transient Monitor
• Jets in neutron star X-ray binaries: a comparison with black holes
• Episodic Accretion on to Strongly Magnetic Stars
• The radio luminosity of persistent X-ray binaries
• Broad relativistic iron emission line observed in SAX J1808.4-3658
• Aquila X-1 from outburst to quiescence: the onset of the propeller effect and signs of a turned-on rotation-powered pulsar
• The quiescent X-ray emission of three transient X-ray pulsars
• Propeller effect in two brightest transient X-ray pulsars: 4U 0115+63 and V 0332+53
• Evolution of the radio - X-ray coupling throughout an entire outburst of Aquila X-1
• Disk-jet coupling in low-luminosity accreting neutron stars
• HZ Her: Stellar Radius from X-ray Eclipse Observations, Evolutionary State and a New Distance
• The large-scale jet-powered radio nebula of Circinus X-1
• The influence of spin on jet power in neutron star X-ray binaries
• Magnetic Field Upper Limits for Jet Formation
• Jet quenching in the neutron star low-mass X-ray binary 1RXS J180408.9$-$342058
• Continued decay in the cyclotron line energy in Hercules X-1
• The nature of the companion star in Circinus X-1
• Spectral Signature of Atmospheric Reflection in Hercules X-1/HZ Hercules During Low and Short-High States
• X-ray Spectral Evolution of Her X-1 in a Low State and the Following Short High State
• Radio emission from the high-mass X-ray binary BP Cru: first detection

Cited by in corpus (13)

• Accretion disks and coronae in the X-ray flashlight
• An evolving jet from a strongly-magnetised accreting X-ray pulsar
• A new radio census of neutron star X-ray binaries
• Hot disk of the Swift J0243.6+6124 revealed by Insight-HXMT
• Revisiting the archetypical wind accretor Vela X-1 in depth -- A case study of a well-known X-ray binary and the limits of our knowledge
• A re-establishing jet during an X-ray re-brightening of the Be/X-ray binary Swift J0243.6+6124
• A radio frequency study of the accreting millisecond X-ray pulsar, IGR J16597$-$3704, in the globular cluster NGC 6256
• Repeated transient jets from a warped disk in the symbiotic prototype Z And: A link to the long-lasting active phase
• X-Ray Views of Galactic Accreting Pulsars in High-Mass X-Ray Binaries
• Radio emission from colliding outflows in high-mass X-ray binaries with strongly magnetized neutron stars
• Optical IFU spectroscopy of a bipolar microquasar jet in NGC 300
• Constraining the origin of the long term periodicity of FRB 20180916B with Polarization Position Angle
• How to distinguish an actual astrophysical magnetized black hole mimicker from a true (theoretical) black hole