# A high-magnetic-field radio pulsar survey with Swift/XRT

## TL;DR

This study conducted an X-ray survey of 21 high-magnetic-field radio pulsars using Swift/XRT, setting upper limits on their X-ray emission and exploring the conditions under which they exhibit magnetar-like properties.

## Contribution

It provides new X-ray upper limits for 21 high-B pulsars, including 6 newly observed, and analyzes the magnetic field threshold for magnetar-like behavior.

## Key findings

- No magnetar-like high-B PSRs were detected.
- High X-ray efficiency in high-B PSRs is limited to 11-29%.
- Magnetar-like properties likely appear when dipole magnetic field exceeds 10^{13.5} G.

## Abstract

We present the X-ray survey results of high-magnetic-field radio pulsars (high-B PSRs) with Swift/XRT. X-ray observations of the rotation-powered pulsars with the dipole magnetic field ${\it B_{\rm d}}$ near the quantum critical field ${\it B_{\rm q}}=4.4\times10^{13}$ G is of great importance for understanding the transition between the rotation-powered pulsars and the magnetars, because there are a few objects that have magnetar-like properties. Out of the 27 high-B PSRs that are in the ATNF pulsar catalogue but have not been reported or have no effective upper-limits in the X-ray bands, we analyze the Swift/XRT data for 21 objects, where 6 objects are newly observed and 15 objects are taken from the archival data. As a result, we have new $3\sigma$ upper-limits for all the 21 objects. Since the upper-limits are tight, we conclude that we do not find any magnetar-like high-B PSRs such as PSR J1819$-$1458. The probability of the high X-ray efficiency in the high-B PSRs is obtained to be $11\%-29\%$. Combining the previous observations, we discuss which parameter causes magnetar-like properties. It may be suggested that the magnetar-like properties appear only when ${\it B_{\rm d}}\gtrsim10^{13.5}$ G for the radio pulsar population. This is true even if the radio-quiet high-B RPP are included.