MATINS

MATINS is a 3D numerical framework designed to model the magneto-thermal evolution within the crust of isolated neutron stars. It solves the induction equation in the crust, accounting for Ohmic dissipation and the Hall drift, to describe the evolution of the magnetic field. The induction equation is coupled to the 3D cooling model, which considers the local temperature evolution in the crust and treats the core as a single thermal cell, with an envelope model serving as a boundary condition. The code also computes the Tolman–Oppenheimer–Volkoff (TOV) structure, allowing the use of different tabulated cold-matter equations of state and stellar masses, applied consistently across the crust and core. In both regions, MATINS evaluates temperature-dependent microphysical properties that are crucial for accurately coupling thermal and magnetic evolution. Numerically, it employs a finite-volume scheme on a cubed-sphere grid, representing the stellar surface with six smoothly connected patches and avoiding the coordinate singularities present in standard spherical systems. The code can be used to model various observables of isolated neutron stars, including X-ray thermal emission, surface magnetic fields, and rotational properties.

Download

The public version of MATINS is available at:
https://github.com/ice-csic-astroexotic/MATINS

Documentation

A guide for the installation can be found in the README file.
A quick guide to the input of MATINS can be found in this document.

Contact

Should you encounter any issues or have questions, please feel free to email us at matins@ice.csis.es.

If you use MATINS in your research, we kindly ask you to:

  1. Cite the following publications in the text:

    Dehman C, Viganò D, Pons JA, and Rea N (2023) 3D code for MAgneto–Thermal evolution in Isolated Neutron Stars, MATINS: the magnetic field formalism, MNRAS 518 (1), pp. 1222–1242. DOI: 10.1093/mnras/stac2761.

    Ascenzi S, Viganò D, Dehman C, Pons JA, Rea N, and Perna R (2024) 3D code for MAgneto–Thermal evolution in Isolated Neutron Stars, MATINS: thermal evolution and light curves, MNRAS 533 (1), pp. 201–224. DOI: 10.1093/mnras/stae1749.
  2. Add the following sentence in the acknowledgment section of your publication:

    "MATINS has been funded by the European Research Council via the ERC Consolidator grant 'MAGNESIA' (No. 817661; PI: N. Rea)."

Cooling curve examples

The following examples illustrate cooling curves computed with the BSK24 equation of state over one million year for a neutron star of 1.6 M⊙, under varying surface magnetic field strengths ranging from 1012 G to 5×1015 G. The models assume a simple magnetic field configuration consisting of a poloidal dipole plus a toroidal quadrupole component, and include two types of magnetized envelope compositions: heavy-element and light-element envelopes.

The cooling curves and evolutionary track data are available for download here: