2021ApJ...911L...6B

We report on the 2020 reactivation of the energetic high magnetic field pulsar PSR J1846-0258 and its pulsar wind nebula (PWN) after 14 yr of quiescence with new Chandra and Green Bank Telescope observations. The emission of short-duration bursts from J1846-0258 was accompanied by an enhancement of X-ray persistent flux and significant spectral softening, similar to those observed during its first bursting episode in 2006. The 2020 pulsar spectrum is described by a power-law model with a photon index Γ = 1.7 ± 0.3 in comparison to a Γ = 1.2 ± 0.1 before outburst, and shows evidence of an emerging thermal component with blackbody temperature kT = 0.7 ± 0.1 keV. The 0.5-10 keV unabsorbed flux increased from 5.4_–0.5^+0.4 x 10^–12 erg cm^–2 s^–1 in quiescence to 1.3_–0.2^+0.3 x 10^–11 erg cm^–2 s^–1 following the outburst. We did not detect any radio pulsations from the pulsar at 2 GHz, and we place an upper limit of 7.1 µJy and 55 mJy for the coherent pulsed emission and single pulses, respectively. The 2020 PWN spectrum, characterized by a photon index of 1.92 ± 0.04 and X-ray luminosity of (1.2 ± 0.1) x 10³⁵ erg s^–1 at a distance of 5.8 kpc, is consistent with those observed before the outburst. An analysis of regions closer to the pulsar shows small-scale time variabilities and brightness changes over the 20 yr period from 2000 to 2020, while the photon indices did not change. We conclude that the outburst in PSR J1846-0258 is a combination of crustal and magnetospheric effects, with no significant burst-induced variability in its PWN based on the current observations.