Deep XMM-Newton Spectroscopic and Timing Observations of the Isolated Radio Millisecond Pulsar PSR J0030+0451

TL;DR

This paper reports deep X-ray observations of the isolated millisecond pulsar PSR J0030+0451, revealing its thermal emission characteristics, pulse profile, and constraints on neutron star radius, enhancing understanding of neutron star surface properties.

Contribution

It provides detailed spectroscopic and timing analysis of PSR J0030+0451, including thermal modeling and neutron star radius constraints, which are novel for this pulsar.

Findings

Thermal emission modeled with a two-temperature surface fit.

Pulsed fraction of 60-70% in 0.3-2 keV band.

Neutron star radius constrained to >10.7 km at 95% confidence.

Abstract

We present deep XMM-Newton EPIC spectroscopic and timing X-ray observations of the nearby solitary radio millisecond pulsar, PSR J0030+0451. Its emission spectrum in the 0.1-10 keV range is found to be remarkably similar to that of the nearest and best studied millisecond pulsar, PSR J0437-4715, being well described by a predominantly thermal two-temperature model plus a faint hard tail evident above ~2 keV. The pulsed emission in the 0.3-2 keV band is characterized by two broad pulses with pulsed fraction ~60-70%, consistent with a mostly thermal origin of the X-rays only if the surface polar cap radiation is from a light-element atmosphere. Modeling of the thermal pulses permits us to place constraints on the neutron star radius of R>10.7 (95% confidence) and R>10.4 km (at 99.9% confidence) for M=1.4 M_sun.