# X-Ray spectral evolution of PSR~J2032+4127 during the 2017 periastron passage

## TL;DR

This study analyzes X-ray spectral data from multiple observatories to investigate how the spectral index of PSR J2032+4127 evolved during its 2017 periastron passage, revealing spectral softening and potential changes in shock-accelerated electrons.

## Contribution

It provides the first detailed spectral evolution analysis of PSR J2032+4127 during periastron using broad spectral coverage from multiple X-ray observatories.

## Key findings

- Spectral index softened after periastron
- Detected change in spectral parameters before and after passage
- Indications of altered physical state of shock-accelerated electrons

## Abstract

We report X-ray data analysis results obtained from Chandra, XMM-Newton, NuSTAR and Swift observations of PSR J2032+4127 taken before, during, and after the periastron on 2017 November 13. We found the first clear evidence of a change in the X-ray spectral index over the passage period, thanks to a broad and sensitive spectral coverage by XMM-Newton and NuSTAR. We analysed the joint XMM-Newton and NuSTAR observation epochs with power-law and broken power-law model. We have obtained change in spectral parameters before and after the periastron passage for both models. The spectra get softened after the passage. The evolution of the spectral index and break energy before and after the periastron may indicate a change in the physical state of shock-accelerated electrons.