Discovery of Extended X-ray Emission around the Highly Magnetic Rratj1819–1458

We report on the discovery of extended X-ray emission around the high magnetic field Rotating Radio Transient J1819–1458. Using a 30 ks Chandra ACIS-S observation, we found significant evidence for extended X-ray emission with a peculiar shape: a compact region out to ∼5.5, and more diffuse emission extending out to ∼13 from the source. The most plausible interpretation is a nebula somehow powered by the pulsar, although the small number of counts prevents a conclusive answer on the nature of this emission. RRATJ1819–1458’s spin-down energy loss rate (Ėrot ∼ 3×10 erg s) is much lower than that of other pulsars with observed spin-down powered pulsar wind nebulae (PWNe), and implies a rather high X-ray efficiency of ηX ≡ Lpwn;0.5−8keV/Ėrot ∼ 0.2 at converting spin-down power into the PWN X-ray emission. This suggests the need of an additional source of energy rather than the spin-down power alone, such as the high magnetic energy of this source. Furthermore, this Chandra observation allowed us to refine the positional accuracy of RRATJ1819–1458 to a radius of 0.2, and confirms the presence of X-ray pulsations and the ∼1 keV absorption line, previously observed in the X-ray emission of this source. Subject headings: pulsar: individual (RRATJ1819–1458) — stars: magnetic fields — X-rays: stars