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The impact of highly magnetic neutron stars in the explosive and transient Universe

Periodic Reporting for period 1 - MAGNESIA (The impact of highly magnetic neutron stars in the explosive and transient Universe)

Reporting period: 2019-06-01 to 2020-11-30

The gravitational wave window is now open. It is then imperative to build quantitative models of neutron stars that use all the available tracers to constrain fundamental physics at the highest densities and magnetic fields. The most magnetic neutron stars, the magnetars, have been recently suggested to be powering a large variety of explosive and transient events. The enormous rotational power at birth, and the magnetic energy they can release via large flares, put the magnetars in the (yet) hand-wavy interpretations of gamma-ray bursts, the early phases of double neutron star mergers, super-luminous supernovae, hypernovae, fast radio bursts, and ultra-luminous X-ray sources. However, despite knowing about 30 magnetars, we are lacking a census of how many we expect within the pulsar population, nor we have robust constraints on their flaring rates. The recent discovery of transient magnetars, of magnetar-like flares from sources with measured low dipolar magnetic fields and from typical radio pulsars, clearly showed that the magnetar census in our Galaxy is largely under-estimated. This hampers our understanding not only of the pulsar and magnetar populations, but also of them as possibly related to many of Universe’s explosive events. MAGNESIA will infer a sound Magnetar Census via an innovative approach that will build the first Pulsar Population Synthesis model able to cope with constraints/limits from multi-band observations, and taking into account 3D magnetic field evolution models and flaring rates for neutron stars. Combining expertise in multi-band observations, numerical modeling, nuclear physics, and computation, MAGNESIA will solve the physics, the observational systematic errors, and the computational challenges that inhibited previous works, to finally constrain the spin period and magnetic field distribution at birth of the neutron star population.
Publication wise we had a very productive year despite having to set-up the group and the working groups in this first period. Between 01/06/2019 and 30/11/2020 we have published the following refereed papers (* are those led by the ERC MAGNESIA group):

[1]Papitto, A., “The INTEGRAL view of the pulsating hard X-ray sky: from accreting and transitional millisecond pulsars to rotation-powered pulsars and magnetars”, New Astronomy Reviews, vol. 91, 2020. doi:10.1016/j.newar.2020.101544.
*[2]Coti Zelati, F., “The new magnetar Swift J1830.7-0645 in outburst”, arXiv e-prints, 2020, ApJ in press.
[2]Israel, G. L., “X-ray and Radio Bursts from the Magnetar 1E1547.0-5408”, arXiv e-prints, 2020, ApJ in press.
*[3]Dehman, C., Viganò, D., Rea, N., Pons, J. A., Perna, R., and Garcia-Garcia, A., “On the Rate of Crustal Failures in Young Magnetars”, The Astrophysical Journal, vol. 902, no. 2, 2020. doi:10.3847/2041-8213/abbda9.
*[4]Borghese, A., “The X-Ray Reactivation of the Radio Bursting Magnetar SGR J1935+2154”, The Astrophysical Journal, vol. 902, no. 1, 2020. doi:10.3847/2041-8213/aba82a.
[5]Pilia, M., “The Lowest-frequency Fast Radio Bursts: Sardinia Radio Telescope Detection of the Periodic FRB 180916 at 328 MHz”, The Astrophysical Journal, vol. 896, no. 2, 2020. doi:10.3847/2041-8213/ab96c0.
*[6]Esposito, P., “A Very Young Radio-loud Magnetar”,The Astrophysical Journal, vol. 896, no. 2, 2020. doi:10.3847/2041-8213/ab9742.
*[7]Rea, N., “The X-Ray Outburst of the Galactic Center Magnetar over Six Years of Chandra Observations”, The Astrophysical Journal vol. 894, no. 2, 2020. doi:10.3847/1538-4357/ab8387.
[8]de Martino, D., “NuSTAR and Parkes observations of the transitional millisecond pulsar binary XSS J12270-4859 in the rotation-powered state”, Monthly Notices of the Royal Astronomical Society, vol. 492, no. 4, pp. 5607–5619, 2020. doi:10.1093/mnras/staa164.
*[9]Coti Zelati, F., “The long-term enhanced brightness of the magnetar 1E 1547.0-5408”, Astronomy and Astrophysics, vol. 633, 2020. doi:10.1051/0004-6361/201936317.
[10]Haggard, D., “Chandra Spectral and Timing Analysis of Sgr A*'s Brightest X-Ray Flares”, The Astrophysical Journal, vol. 886, no. 2, 2019. doi:10.3847/1538-4357/ab4a7f.
*[11]Papitto, A., “Pulsating in Unison at Optical and X-Ray Energies: Simultaneous High Time Resolution Observations of the Transitional Millisecond Pulsar PSR J1023+0038”, The Astrophysical Journal, vol. 882, no. 2, 2019. doi:10.3847/1538-4357/ab2fdf.
[12]Pizzocaro, D., “Detailed X-ray spectroscopy of the magnetar 1E 2259+586”, Astronomy and Astrophysics, vol. 626, 2019. doi:10.1051/0004-6361/201834784.
[13]Esposito, P., “Long X-ray flares from the central source in RCW 103. XMM-Newton and VLT observations in the aftermath of the 2016 outburst”, Astronomy and Astrophysics, vol. 626, 2019. doi:10.1051/0004-6361/201935412.
We expect to produce the first big search for pulsars in many archival astronomical databases, a 3D magneto-thermal code able to evolve the B and the kT history of neutron stars from birth to 1 Myr age, and a Population Synthesis code that will use Machine Learning to study the neutron star hidden population in our Galaxy.