Revisiting $γ$-Ray Orbital Modulation in the Redback Millisecond Pulsar PSR J2039-5617

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Zhang, Mengqing, Pei, Shengbin, Chang, Shan, Zhang, Pengfei
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917098344677376
author Zhang, Mengqing
Pei, Shengbin
Chang, Shan
Zhang, Pengfei
author_facet Zhang, Mengqing
Pei, Shengbin
Chang, Shan
Zhang, Pengfei
contents PSR J2039-5617 is a redback millisecond pulsar binary system consisting of a compact star with a mass of 1.1-1.6 $M_\odot$ and a low-mass companion of 0.15-0.22 $M_\odot$. For this binary, we performed a timing analysis using 16 years of data from the Fermi Large Area Telescope, covering the period from 2008 August to 2024 October. Our analysis detected an orbital modulation with a period of 0.2279781 days at a significance level of $\sim4σ$, which is in good agreement with previous findings. However, unlike previous reports, we identified a transition in the orbital modulation around 2021 August, after which the orbital signal disappeared. We speculate that the system may be undergoing a transition from a rotation-powered to an accretion-powered state at this epoch. Additionally, we conducted the phase-resolved and spectral analyses, and in the phase-resolved results, we observed an anti-correlation between its $γ$-ray and X-ray emissions, which consistent with the predictions of high-energy radiation models for such systems. We provide some predictive discussions based on the results of $γ$-ray data analysis, and future Fermi-LAT observations will determine whether these predictions hold true.
format Preprint
id arxiv_https___arxiv_org_abs_2511_17900
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Revisiting $γ$-Ray Orbital Modulation in the Redback Millisecond Pulsar PSR J2039-5617
Zhang, Mengqing
Pei, Shengbin
Chang, Shan
Zhang, Pengfei
High Energy Astrophysical Phenomena
PSR J2039-5617 is a redback millisecond pulsar binary system consisting of a compact star with a mass of 1.1-1.6 $M_\odot$ and a low-mass companion of 0.15-0.22 $M_\odot$. For this binary, we performed a timing analysis using 16 years of data from the Fermi Large Area Telescope, covering the period from 2008 August to 2024 October. Our analysis detected an orbital modulation with a period of 0.2279781 days at a significance level of $\sim4σ$, which is in good agreement with previous findings. However, unlike previous reports, we identified a transition in the orbital modulation around 2021 August, after which the orbital signal disappeared. We speculate that the system may be undergoing a transition from a rotation-powered to an accretion-powered state at this epoch. Additionally, we conducted the phase-resolved and spectral analyses, and in the phase-resolved results, we observed an anti-correlation between its $γ$-ray and X-ray emissions, which consistent with the predictions of high-energy radiation models for such systems. We provide some predictive discussions based on the results of $γ$-ray data analysis, and future Fermi-LAT observations will determine whether these predictions hold true.
title Revisiting $γ$-Ray Orbital Modulation in the Redback Millisecond Pulsar PSR J2039-5617
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2511.17900