On the nature of long period radio pulsar GPM J1839$-$10: death line and pulse width

TL;DR

This paper investigates the death line and pulse width criteria for long period radio pulsars, suggesting that some may be magnetars or white dwarf pulsars rather than normal neutron star pulsars.

Contribution

It introduces pulse width as a new criterion for classifying long period pulsars and analyzes their position relative to the death line, proposing alternative natures for certain pulsars.

Findings

Long period pulsars GLEAM-X J162759.5-523504.3 and GPM J1839-10 likely are not normal pulsars.

These pulsars have large pulse widths and lie below the traditional death line.

They may be magnetars or white dwarf pulsars, but uncertainties remain.

Abstract

Recently another long period radio pulsar GPM J1839$-$10 is reported, similar to GLEAM-X J162759.5$-$523504.3. Previously, the energy budget and rotational evolution of long period radio pulsars had been considered. This time, the death line and pulse width for neutron star and white dwarf pulsars are investigated. The pulse width is included as the second criterion for neutron star and white dwarfs pulsars. It is found that: (1) PSR J0250+5854 and PSR J0901$-$4046 etc should be normal radio pulsars. They have narrow pulse width and they lie near the radio emission death line. (2) The two long period radio pulsars GLEAM-X J162759.5$-$523504.3 and GPM J1839$-$10 is unlikely to be normal radio pulsars. Their possible pulse width is relatively large. And they lie far below the fiducial death line on the $P-\dot{P}$ diagram. (3) GLEAM-X J162759.5$-$523504.3 and GPM J1839$-$10 may be magnetars or white dwarf radio pulsars. At present, there are many parameters and uncertainties in both of these two possibilities.