Constraining the Evolutionary Fate of Central Compact Objects: "Old" Radio Pulsars in Supernova Remnants

TL;DR

This study investigates whether certain old radio pulsars associated with supernova remnants could be descendants of central compact objects, but finds no evidence linking them, suggesting CCOs either activate late or stay radio-quiet.

Contribution

The paper provides the first systematic X-ray survey of radio pulsars in SNRs to test their connection to CCOs, offering new insights into neutron star evolution.

Findings

No anomalously high thermal X-ray luminosity detected in surveyed pulsars.

Results suggest these pulsars are unrelated to CCOs and are genuinely old.

Implication that CCOs either activate long after SNR dissipation or remain radio-quiet.

Abstract

Central compact objects (CCOs) constitute a population of radio-quiet, slowly-spinning ($\ge$100 ms) young neutron stars with anomalously high thermal X-ray luminosities. Their spin-down properties imply weak dipole magnetic fields ($\sim$$10^{10-11}$ G) and characteristic ages much greater than the ages of their host supernova remnants (SNRs). However, CCOs may possess strong "hidden" internal magnetic fields that may re-emerge on timescales $\gtrsim$10 kyr, with the neutron star possibly activating as a radio pulsar in the process. This suggests that the immediate descendants of CCOs may be masquerading as slowly spinning "old" radio pulsars. We present an X-ray survey of all ordinary radio pulsars within 6 kpc that are positionally coincident with Galactic SNRs in order to test the possible connection between the supposedly old, but possibly very young pulsars, and the SNRs. None of the targets exhibits anomalously high thermal X-ray luminosity, suggesting that they are genuine old ordinary pulsars unrelated to the superposed SNRs. This implies that CCOs are either latent radio pulsars that activate long after their SNRs dissipate or they remain permanently radio-quiet. The true descendants of CCOs remain at large.