Broadband study of the Be X-ray binary RX J0520.5-6932 during its outburst in 2024
arXiv:2412.00960 · doi:10.1093/mnras/stae2676
Abstract
A new giant outburst of the Be X-ray binary RX J0520.5-6932 was detected and subsequently observed with several space-borne and ground-based instruments. This study presents a comprehensive analysis of the optical and X-ray data, focusing on the spectral and timing characteristics of selected X-ray observations. A joint fit of spectra from simultaneous observations performed by the X-ray telescope (XRT) on the Neil Gehrels Swift Observatory (Swift) and Nuclear Spectroscopic Telescope ARray (NuSTAR) provides broadband parameter constraints, including a cyclotron resonant scattering feature (CRSF) at 32.2(+0.8/-0.7) keV with no significant energy change since 2014, and a weaker Fe line. Independent spectral analyses of observations by the Lobster Eye Imager for Astronomy (LEIA), Einstein Probe (EP), Swift-XRT, and NuSTAR demonstrate the consistency of parameters across different bands. Luminosity variations during the current outburst were tracked. The light curve of the Optical Gravitational Lensing Experiment (OGLE) aligns with the X-ray data in both 2014 and 2024. Spin evolution over 10 years is studied after adding Fermi Gamma-ray Burst Monitor (GBM) data, improving the orbital parameters, with an estimated orbital period of 24.39 days, slightly differing from OGLE data. Despite intrinsic spin-up during outbursts, a spin-down of ~0.04s over 10.3 years is suggested. For the new outburst, the pulse profiles indicate a complicated energy-dependent shape, with decreases around 15 keV and 25 keV in the pulsed fraction, a first for an extragalactic source. Phase-resolved NuSTAR data indicate variations in parameters such as flux, photon index, and CRSF energy with rotation phase.
17 pages, 15 figures, accepted for publication in MNRAS
References in corpus (33)
- On the use of C-stat in testing models for X-ray spectra
- A model for cyclotron resonance scattering features
- The Einstein Probe Mission
- The ART-XC telescope on board the SRG observatory
- High variability in Vela X-1: giant flares and off states
- Pulse phase resolved analysis of the HMXB Cen X-3 over two binary orbits
- Outbursts Large and Small from EXO 2030+375
- Long-term change in the cyclotron line energy in Hercules X-1
- The 2019 super-Eddington outburst of RX J0209.6-7427: Detection of pulsations and constraints on the magnetic field strength
- First wide field-of-view X-ray observations by a lobster eye focusing telescope in orbit
- Can disk-magnetosphere interaction models and beat frequency models for quasi-periodic oscillation in accreting X-ray pulsars be reconciled?
- Spectral and temporal properties of RX J0520.5-6932 (LXP 8.04) during a type-I outburst
- The Swift-BAT monitoring reveals a long term decay of the cyclotron line energy in Vela X-1
- NuSTAR Discovery of a Cyclotron Line in the Be/X-ray Binary RX J0520.5-6932 During Outburst
- The Lobster Eye Imager for Astronomy Onboard the SATech-01 Satellite
- Long-term evolutions of the cyclotron line energies in Her X-1, Vela X-1 and Cen X-3 as observed with Swift/BAT
- Cyclotron lines: from magnetic field strength estimators to geometry tracers in neutron stars
- Chandra probes the X-ray variability of M51 ULX-7: evidence of propeller transition and X-ray dips on orbital periods
- Timing properties of the X-ray accreting pulsar 1A 0535+262 studied with Insight-HXMT
- Energy-resolved pulse profiles of accreting pulsars: Diagnostic tools for spectral features
- Long-term pulse profile study of the Be/X-ray pulsar SAX J2103.5+4545
- Discovery of Two Cyclotron Resonance Scattering Features in X-ray Pulsar Cen X-3 by Insight-HXMT
- A Bayesian approach for torque modelling of BeXRB pulsars with application to super-Eddington accretors
- RX J0529.8-6556: a BeXRB pulsar with an evolving optical period and out of phase X-ray outbursts
- On the cyclotron absorption line and evidence of the spectral transition in SMC X-2 during 2022 giant outburst
- Common patterns in pulse profiles of High Mass X-ray Binaries
- Cyclotron line evolution revealed with pulse-to-pulse analysis in the 2020 outburst of 1A 0535+262
- Optical and X-ray studies of Be/X-ray binary 1A 0535+262 during its 2020 giant outburst
- A high-mass X-ray binary pulsar 4U 1907+09 with multiple absorption-line features in the spectrum
- Neutron Stars in X-ray Binaries and their Environments
- An X-ray view of the 2021 outburst of SXP 15.6: constraints on the binary orbit and magnetic field of the Neutron Star
- One for the Future: measuring the mass transfer rate in the ULX M82 X-2 by using orbital period changes will take millenia
- Unveiling the origin of the optical/UV emission from the Galactic ULX Swift J0243.6+6124 during its 2017-2018 giant outburst