Systematic study of magnetar outbursts

We present the results of the systematic study of all magnetar outbursts observed to date through a reanalysis of data acquired in about 1100 X-ray observations. We track the temporal evolution of the luminosity for all these events, model empirically their decays, and estimate the characteristic decay time-scales and the energy involved. We study the link between different parameters (maximum luminosity increase, outburst peak luminosities, quiescent X-ray and bolometric luminosities, energetics, decay time-scales, magnetic field, spin-down luminosity and age), and reveal several correlations between different quantities. We discuss our results in the framework of the models proposed to explain the triggering mechanism and evolution of magnetar outbursts. The study is complemented by the Magnetar Outburst Online Catalog (http://www.magnetars.ice.csic.es), an interactive database where the user can plot any combination of the parameters derived in this work and download all reduced data.FCZ acknowledges funding in the framework of the Netherlands Organization for Scientific Research (NWO) Vidi award (PI: N. Rea) and the European COST Action MP1304 (NewCOMPSTAR), and is also supported by grants AYA2015-71042-P and SGR2014-1073

Unifying the observational diversity of isolated neutron stars via magneto-thermal evolution models

Observations of magnetars and some of the high magnetic field pulsars have shown that their thermal luminosity is systematically higher than that of classical radio-pulsars, thus confirming the idea that magnetic fields are involved in their X-ray emission. Here we present the results of 2D simulations of the fully coupled evolution of temperature and magnetic field in neutron stars, including the state-of-the-art kinetic coefficients and, for the first time, the important effect of the Hall term. After gathering and thoroughly re-analysing in a consistent way all the best available data on isolated, thermally emitting neutron stars, we compare our theoretical models to a data sample of 40 sources. We find that our evolutionary models can explain the phenomenological diversity of magnetars, high-B radio-pulsars, and isolated nearby neutron stars by only varying their initial magnetic field, mass and envelope composition. Nearly all sources appear to follow the expectations of the standard theoretical models. Finally, we discuss the expected outburst rates and the evolutionary links between different classes. Our results constitute a major step towards the grand unification of the isolated neutron star zoo.This research was supported by the grants AYA 2010-21097-C03-02 (DV, JAP, JAM); AYA2009-07391, AYA2012-39303, SGR2009-811, and iLINK 2011-0303 (NR); CONICET and PIP-2011-00170 (DNA); NSF grant No. AST 1009396 and NASA grants AR1-12003X, DD1-12053X, GO2-13068X, GO2-13076X (RP). DV is supported by a fellowship from the Prometeo program for research groups of excellence of the Generalitat Valenciana (Prometeo/2009/103) and NR is supported by a Ramon y Cajal Fellowship

Investigation of the High-energy Emission from the Magnetar-like Pulsar PSR J1119-6127 after the 2016 Outburst

PSR J1119-6127 is a radio pulsar that behaved with magnetar-like bursts, and we performed a comprehensive investigation of this pulsar using the archival high-energy observations obtained after its outburst in 2016 July. After the 2016 outburst, specific regions on the neutron star (NS) surface were heated up to >0.3 and >1 keV from similar to 0.2 keV. A hard nonthermal spectral component with a photon index <0.5 related to the magnetospheric emission can be resolved from the NuSTAR spectra above 10 keV. We find that the thermal emitting regions did not cool down and gradually shrank by about 20%-35% 4 months after the outburst. Hard X-ray pulsations were detected with NuSTAR immediately after the outburst at a 5 sigma confidence level and with a background-subtracted pulsed fraction of 40% +/- 10%. However, the signal became undetectable after a few days. Using Fermi data, we found that the gamma-ray emission in 0.5-300 GeV was suppressed along with the disappearance of the radio pulsations. This is likely caused by a reconfiguration of the magnetic field. We also discovered that the timing noise evolved dramatically, and the spin-down rate significantly increased after the 2016 glitch. We proposed that postoutburst temporal and spectral behaviors from radio to gamma-ray bands were caused by changes of the magnetosphere structure, pair plasma injection, and the shrinking emission sites on the NS