PSR J1119–6127 and Its Pulsar Wind Nebula Following the Magnetar-like Bursts

Abstract

We present a Chandra Director's Discretionary Time observation of PSR J1119-6127 and its compact X-ray pulsar wind nebula (PWN) obtained on 27 October 2016, three months after the Fermi and Swift detection of millisecond bursts in hard X-rays, accompanied by 160 times increase in flux. This magnetar-like activity, the first observed from a rotation-powered radio pulsar, provides an important probe of the physical processes that differentiate radio pulsars from magnetars. The post-burst X-ray spectrum of the pulsar can be described by a single powerlaw model with a photon index of 2.0±0.2 and an unabsorbed flux of 5.7−12 ergs cm −2 s −1 in the 0.5-7.0 keV energy range. At the time of Chandra observations, the pulsar was still brighter by a factor of ∼22 in comparison with its quiescence. The X-ray images reveal a nebula brighter than in the pre-burst Chandra observations (from 2002 and 2004), with an unabsorbed flux of 2.2 +1.1 −0.9 ×10 −13 ergs cm −2 s −1 . This implies a current X-ray efficiency of ≈0.001 at a distance of 8.4 kpc. In addition, a faint torus-like structure is visible along the southeast-northwest direction and a jet-like feature perpendicular to the torus towards the southwest. The PWN is best fitted by an absorbed powerlaw with a photon index of 2.2±0.5 (post-burst). While the pulsar can still be energetically powered by rotation, the observed changes in PSR J1119-6127 and its PWN following the magnetar-like bursts point to an additional source of energy powered by its high-magnetic field.

Peculiar spin frequency and radio profile evolution of PSR J1119−6127 following magnetar-like X-ray bursts

“…While only a small portion of the spin-down energy goes into radio and X-ray, we could expect much stronger high energy emissions from the pulsar (e.g., γ-ray) if energy loss via high energy radiation is the main energy-loss mechanism. Such a high spin-down luminosity could also power strong relativistic particle outflows that can brighten the pulsar wind nebula (Blumer et al 2017).…”

Back to quiescence: post-outburst evolution of the pulsar J1119-6127 and its wind nebula

“…The pulsar's spectrum, obtained with Chandra three months after the outburst onset, was best described by a single PL model with Γ=2.0±0.2, softer than the value measured at the peak (Blumer at al. 2017).…”

“…The pre-burst image was made by combining the 2002 and 2004 observations, and shows a compact nebula of size 6 ′′ ×15 ′′ in the north-south direction . The 2016 burst image clearly shows a brighter nebula and small-scale fine structures (∼10 ′′ ) around the pulsar (see Blumer et al 2017 for details). The post-outburst image was made by combining all the four observations in 2019 and features a much fainter PWN, with elongated jet-like features along the north-south direction, similar to its pre-burst phase.…”

Planetary magnetosphere evolution around post-main-sequence stars

“…In contrast, neutron stars -the end products of stars with masses of 7 − 20M -do appear to emit winds (e.g. Blumer et al 2017;Enoto et al 2019;Hsiang-Yue & Chang 2021). The three planets known to orbit single pulsars were in fact the first three confirmed exoplanets (Wolszczan & Frail 1992;Wolszczan 1994), but are now known to be genuinely rare (as opposed to white dwarf planetary systems, which are common with an occurrence rate of 25-50 per cent; Koester et al 2014).…”