Statistical tests of young radio pulsars with/without supernova remnants: implying two origins of neutron stars

Abstract

The properties of the young pulsars and their relations to the supernova remnants (SNRs) have been the interesting topics. At present, 383 SNRs in the Milky Way galaxy have been published, which are associated with 64 radio pulsars and 46 pulsars with high energy emissions. However, we noticed that 630 young radio pulsars with the spin periods of less than half a second have been not yet observed the SNRs surrounding or nearby them, which arises a question of that could the two types of young radio pulsars with/without SNRs hold the distinctive characteristics? Here, we employ the statistical tests on the two groups of young radio pulsars with (52) and without (630) SNRs to reveal if they share the different origins. Kolmogorov-Smirnov (K-S) and Mann-Whitney-Wilcoxon (M-W-W) tests indicate that the two samples have the different distributions with parameters of spin period (P), derivative of spin period ($\dot{P}$), surface magnetic field strength (B) and energy loss rate ($\dot{E}$). Meanwhile, the cumulative number ratio between the pulsars with and without SNRs at the different spindown ages decreases significantly after $\rm 10-20\, Kyr$. So we propose that the existence of the two types of supernovae (SNe), corresponding to their SNR lifetimes, which can be roughly ascribed to the low-energy and high-energy SNe. Furthermore, the low-energy SNe may be formed from the $\rm 8-12\, M_{\odot }$ progenitor, e.g., possibly experiencing the electron capture, while the main sequence stars of $\rm 12-25\, M_{\odot }$ may produce the high-energy SNe probably by the iron core collapse.

Initial periods and magnetic fields of neutron stars

“…There exists comparable number of objects with and without SNRs, both sharing quite similar values of 𝑃 and 𝑃 (see Fig. 1 in Cui et al 2021, also our Fig. 1).…”

“…It is worth to note that the hypothesis proposed by Cui et al ( 2021) can be criticised from two sides. On one side, the expected fraction of ecSN is not high enough to explain the formation of majority of PSRs without SNRs in the sample by Cui et al (2021). For isolated progenitors this fraction is expected to be ≈ 4% (Poelarends et al 2008).…”

“…Determination of initial parameters of NSs can significantly influence understanding of important details of their origin. Recently, Cui et al (2021) analysed a large sample of PSRs in SNRs and compared it with a sample of short period PSRs (𝑃 < 0.5 s) not associated with SNRs. These authors attribute difference between the two samples to the existence of two types of SN: low-energy and high-energy.…”

“…These NSs might form less noticeable (faster disappearing) SNR. This possibility was discussed by Cui et al (2021). We review the significance of this prospect for our own research in Section 5.4.…”

Long-period Pulsars as Possible Outcomes of Supernova Fallback Accretion

“…Moreover, only one third of the known young pulsars have a detected SNR remnant. The reasons for this are still a matter of debate and study, but the absence of detected SNRs for most neutron stars could simply indicate differences in the progenitor, supernova explosion and interstellar environment (see for example Gaensler & Johnston 1995;Cui et al 2021). We therefore do not consider the lack of SNR association as an issue for the validity of a fallback disk scenario.…”