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Plasma-magnetic field interactions
in pulsars and their environments

  • The Vela Pulsar, 1,000 light-years from Earth, by NASA's Chandra X-ray Observatory. / Credit: NASA

Studying the microphysics in plasma-field conditions and observing astronomical behaviours

This group is primarily focused on the study of the interaction between plasma and magnetic field, in particular this group investigates pulsar winds and the progenitor supernova remnant (SNR) looks for understanding pulsar magnetospheres.

What role does plasma and magnetic field interaction play in pulsars and their nebulae?

The evolution of astrophysical systems of all kinds, from planets to stars, to galaxies and clusters, are almost invariably linked to the magnitude and spatial distribution of their magnetic field. In many cases, the latter is the key player in dominating energy and momentum transport, in securing pressure balances, in releasing energy in flares or outbursts, or in accelerating leptons and hadrons to relativistic energies via reconnection or diffusive processes. The plasma-magnetic field interaction regulates the state and evolution of many, if not all, astrophysical settings. And for relativistic objects, those generating extreme environments within and surrounding them, all our understanding actually comes and goes with how well we are able to comprehend the microphysics of the interaction between plasma and magnetic field. It is this microphysics that finally leads to observable, multi-frequency events, which we are able to track. We focus on linking the modelling of the microphysics in different plasma-field conditions with the observation of overall astronomical behaviours.

Obvious environments where plasma and magnetic field interaction play a determining role are pulsars and their nebulae. Pressure balance between magnetic field and accretion flows determine here a plethora of not-well-understood phenomena, which even for the same system allow them to transition from one visibly-different state to another. The first transitional pulsar caught in the act of transitioning from one state to another was discovered here, at the Institute of Space Sciences. Transitional pulsars are one of the hottest topics in astrophysics today, linking problems that range from evolution of stars and binaries, to particle acceleration.

Illustration of a pulsar.

Focus

The physical processes we study are ruled by the interaction between plasma and magnetic field, among them:

  • Weak magnetic fields in low-density (pulsars winds and young SNRs), and high-density plasma (old SNRs evolving in dense clouds)
  • Medium magnetic fields in low-density (such the ones found in pulsar magnetospheres) and high-density plasma (X-ray binaries)
  • The highest magnetic fields in low-density plasma (like the ones found in magnetars).

In particular, we aim to investigate pulsar winds and the progenitor SNRs, through a) observations of the dynamical evolution and related energetic processes in SNRs and PWNe b) the development of state-of-the-art modelling of the plasma/magnetic interaction in PWNe -including detailed description of their expansion and dynamical interaction between SNR / PWN, or magneto-thermal evolution in pulsars- and young SNRs. With respect to SNRs, we also aim to understand acceleration of cosmic rays and hadronic interaction via deep observations of evolved SNRs interacting with molecular clouds. To further understand pulsars magnetospheres, we study their emission through a) determination of the phase-resolved spectral features of bright LAT pulsars, b) observations of the inverse Compton component at GeV/TeV energies similar to the one in the Crab pulsar and c) modelling the synchro-curvature radiation in gaps.

We investigate the link between LMXBs and binary MSPs through a) prompt multi-band follow-up of transient X-ray outbursts from new or known accreting neutron stars, b) optical monitoring of known binary MSPs in search for a state change, and c) theoretical modelling of the conditions for particle spectra and multifrequency emission along their different accretion phases.

Finally, we pursue the study of the multiband, steady and transient emission of strongly magnetised neutron stars through follow-up and modelling of their transient events, as well as the possible occurrence of such outbursts in lower magnetised pulsars.

 

Senior institute members involved

Meet the senior researchers who participate in this research line.

  • Diego F. Torres

    Diego F. Torres

  • Nanda Rea

    Nanda Rea

  • Daniele Viganò

    Daniele Viganò

    More theory and observations