Outstanding X-ray emission from the stellar radio pulsar CU Virginis

Abstract

We present X-ray observations of CU Vir performed with XMM-Newton and Chandra. With Lx = 3 x 10^28 erg/s the source is moderately X-ray bright, but its spectrum is extremely hard compared to other Ap stars. Spectral modelling requires multi-component models with predominant hot plasma at temperatures of about Tx = 25 MK or, alternatively, a nonthermal spectral component. The Chandra observations was performed six years later than the one by XMM-Newton, yet the source has similar X-ray flux and spectrum, suggesting a steady and persistent X-ray emission. To explain its full X-ray properties, a generating mechanism beyond standard explanations like the presence of a low-mass companion or magnetically confined wind-shocks is required. Magnetospheric activity might be present or, as proposed for fast rotating strongly magnetic Bp stars, the X-ray emission of CU Vir is predominantly auroral in nature.

Accepted for publication in A&A

References in corpus (6)

• Magnetic field topology of the unique chemically peculiar star CU Virginis
• X-rays from Magnetically Confined Wind Shocks: Effect of Cooling-Regulated Shock Retreat
• Stellar magnetosphere reconstruction from radio data. Multi-frequency VLA observations and 3D-simulations of CU Virginis
• The detection of variable radio emission from the fast rotating magnetic hot B-star HR7355 and evidence for its X-ray aurorae
• A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907
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