The x-RAY spectra of central compact objects (ccos) with weak magnetic fields, and quiescent magnetars with strong magnetic fields, are very similar despite the four orders of magnitude difference…

This is a $230,042 grant award from the National Aeronautics and Space Administration (NASA) to The Trustees of Columbia University in the City of New York for research on the magnetic field structure and evolution of young neutron stars. The grant funds the modeling and analysis of X-ray data to infer the surface temperature distributions and magnetic field topologies of central compact object (CCO) pulsars and magnetars. This research aims to provide insight into the populations and evolution of young neutron stars and potentially unify different classes of these objects. The grant does not have a set-aside designation and was awarded on February 17, 2016, with a completion date of May 21, 2019. Columbia University, a renowned private research institution, is the prime contractor for this grant, which is part of NASA's broader program focused on probing the magnetic structure of young neutron stars.

The x-RAY spectra of central compact objects (ccos) with weak magnetic fields, and quiescent magnetars with strong magnetic fields, are very similar despite the four orders of magnitude difference in their dipole magnetic field strengths. For CCO pulsars, the apparently localized surface emission indicated by their large pulsed modulation is difficult to reconcile with a surface b-field of only 3.E10 g. Recent work suggests that magnetar-strength b-fields might LIE buried in ccos by accretion during the formation of the NS. We propose to model the x-RAY pulse profiles and phase-resolved spectra of ccos to infer their surface temperature distributions, which must be controlled by their magnetic field geometry. Having measured the spin-down rates for all three CCO pulsars, we are now in a position to model their phase-dependent spectra using nearly 2 million seconds of x-RAY data available in the archive. We seek funding to refine and generalize our modeling of these data sets, expanding upon our methods that were previously applied to the transient anomalous pulsar AXP J1810-197 and the CCO PSR J0821-4300 in puppis a. By incorporating new theoretical results on the magnetic field structure of NSS and its evolution, we will infer possible magnetic field topologies. Magneto-thermal simulations suggest that the observed properties of ccos may be explained by strong toroidal field components in the NS crust. Probing the internal and external magnetic fields will provide important insight into the populations and evolution of young neutron STARS, and the possible unification of their different classes.