Kinetic ‘jets’ from fast-moving pulsars

Some fast-moving pulsars, such as the Guitar and the Lighthouse, exhibit asymmetric non-thermal emission features that extend well beyond their ram pressure confined pulsar wind nebulae (PWNe). Based on our 3D relativistic simulations, we analytically explain these features as kinetically streaming pulsar wind particles that escaped into the interstellar medium (ISM) due to reconnection between the PWN and ISM magnetic fields. The structure of the reconnecting magnetic fields at the incoming and outgoing regions produces highly asymmetric magnetic bottles therefore and result in asymmetric extended features. For the features to become visible, the ISM magnetic field should be sufficiently high, BISM > 10 $\mu$G. We also discuss archival observations of PWNe displaying evidence of kinetic jets: the Dragonfly PWN (PSR J2021 + 3651), G327.1–1.1, and MSH 11–62, the latter two of which exhibit symmetric ‘snail eyes’ morphologies. We suggest that in those cases the pulsar is moving along the ambient magnetic field in a frisbee-type configuration.

Properties of MHD turbulence and its consequences for the ISM and ICM

It is well known that the interstellar (ISM) and intergalactic (ICM) media are threaded by large scale magnetic fields. The understanding of its role on the dynamics of the media is, however, still in progress. For the ISM, magnetic fields may control or, at least, play a major role on the turbulence cascade leading to the star formation process. The ICM, on the other hand, is assumed to be thermally dominated but still the magnetic field may play an important role on the processes of acceleration and propagation of cosmic rays. In this work we provide a review of the latest theoretical results on the evolution of MHD turbulence under collisional and collisionless plasma approaches.

ISM turbulence driven by the magnetorotational instability

We have performed numerical simulations which were designed to further our understanding of the turbulent interstellar medium (ISM). Our simulations include a multi-phase thermodynamic model of the ISM, magnetic fields, and sheared rotation, allowing us to study the effects of the magnetorotational instability (MRI) in an environment containing high density cold clouds embedded in a warm, low density, ambient medium. These models have shown that the MRI is indeed a significant source of turbulence, particularly at low mean densities typical of the outer regions of the Milky Way, where star formation rates are low, but high levels of turbulence persist. Here, we summarize past findings, as well as our most recent models which include vertical stratification, allowing us to self-consistently model the vertical distribution of material in the disk.