# Discovery of Soft X-ray Pulsations from PSR J1231-1411 using NICER

## TL;DR

This paper reports the discovery of soft X-ray pulsations from the millisecond pulsar PSR J1231-1411 using NICER, revealing details about its emission and system geometry through combined X-ray, radio, and gamma-ray data analysis.

## Contribution

It presents the first detection of soft X-ray pulsations from PSR J1231-1411 and combines multi-wavelength data to analyze its emission properties and geometry.

## Key findings

- Detection of soft X-ray pulsations with a broad main pulse and faint interpulse.
- Spectral analysis indicates thermal emission from hot spots on the neutron star surface.
- Phase relationship analysis provides insights into the pulsar's emission geometry.

## Abstract

We report the discovery of soft X-ray pulsations from the nearby millisecond pulsar PSR J1231$-$1411 using NICER. The pulsed emission is characterized by a broad and asymmetric main pulse and a much fainter secondary interpulse, with a total pulsed count rate of 0.055 c s$^{-1}$ in the 0.35-1.5 keV band. We analyzed Fermi LAT data to update the pulse timing model covering 10 years of data and used that model to coherently combine NICER data over a year of observations. Spectral modeling suggests that the flux is dominated by thermal emission from a hot spot (or spots) on the neutron star surface. The phase relationship between the X-ray pulse and the radio and $\gamma$ rays provides insight into the geometry of the system.