# Spectral and temporal changes associated with flux enhancement in 4U 1626-67 - Astrophysics > High Energy Astrophysical Phenomena

Spectral and temporal changes associated with flux enhancement in 4U 1626-67 - Astrophysics > High Energy Astrophysical Phenomena - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: 4U 1626-67 is an accretion powered X-ray pulsar that shows remarkably stableX-ray luminosity above hours timescale and gradual intensity variation on a fewyears timescale. Here we report a significant increase in the X-ray intensityin the long term RXTE-ASM light curve of 4U 1626-67. Similar enhancement in theX-ray flux has also been detected in the Swift-BAT light curve. The increase inthe X-ray flux took place over a long period of about 100 days and thereappears to be two episodes of flux enhancement. We have investigated thespectral and timing features of 4U 1626-67 during its current state of enhancedflux emission with data obtained from the Proportional Counter Array and theHigh-Energy X-ray Timing Explorer on board the Rossi X-ray Timing Explorer. Thesource has entered a new spin-up phase with a spin-up rate of 4.025 $\times$10$^{-13}$ Hz s$^{-1}$. The present spin-up rate is almost half of the earlierspin-up and spin-down trends. A significant excess in soft X-ray photonemission is observed during the enhanced flux state, which is similar to theenergy spectrum obtained during the spin-up era of the pulsar before 1990. Wealso report detection of a significant broadening in the wings of the 130 mHzpeak and a change in the shape of the continuum of the power spectrum.

Autor: Chetana Jain, Biswajit Paul, Anjan Dutta

Fuente: https://arxiv.org/