# AX J1910.7+0917: the slowest X-ray pulsar

## TL;DR

This paper reports the discovery of AX J1910.7+0917 as the slowest known X-ray pulsar with a 36,200-second period, highlighting its unique properties and spectral characteristics, and discussing its accretion mechanism.

## Contribution

It provides detailed observations and analysis of the slowest X-ray pulsar, including its period, spectrum, and variability, and interprets its long period within a quasi-spherical settling accretion model.

## Key findings

- Longest neutron star spin period observed at 36,200 seconds.
- Highly absorbed X-ray spectrum with variable flux over years.
- Consistent with a wind-fed, low luminosity accretion scenario.

## Abstract

Pulsations from the high mass X-ray binary AXJ1910.7+0917 were discovered during Chandra observations performed in 2011 (Israel et al. 2016). We report here more details on this discovery and discuss the source nature. The period of the X-ray signal is P=36200+/-110s, with a pulsed fraction, PF, of 63+/-4%. Given the association with a massive B-type companion star, we ascribe this long periodicity to the rotation of the neutron star, making AXJ1910.7+0917 the slowest known X-ray pulsar. We report also on the spectroscopy of XMM-Newton observations that serendipitously covered the source field, resulting in an highly absorbed (column density almost reaching 1e23cm-2), power law X-ray spectrum. The X-ray flux is variable on a timescale of years, spanning a dynamic range >60. The very long neutron star spin period can be explained within a quasi-spherical settling accretion model, that applies to low luminosity, wind-fed, X-ray pulsars.