Open AccessX‐ray flux related timing and spectral features of 2S 1417−62
Author(s) -
Çağdaşİnam S.,
Baykal Altan,
Matthew Scott D.,
Finger Mark,
Swank Jean
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07478.x
Subject(s) - physics , astrophysics , accretion (finance) , flux (metallurgy) , pulsar , spectral index , spectral line , x ray pulsar , power law , pulse (music) , light curve , astronomy , optics , statistics , materials science , mathematics , detector , metallurgy
Rossi X‐ray Timing Explorer ( RXTE ) observations of the X‐ray transient pulsar 2S 1417 − 62 between 1999 November and 2000 August with a total exposure of ∼394 ks have been analysed. Observations include a main outburst followed by a series of mini outbursts. Changes in pulse morphology and pulse fraction were found to be related to the changes in X‐ray flux. Particularly low X‐ray flux regions were found to have significantly lower pulse fractions with different pulse morphologies. The 3–60 keV Proportional Counter Array (PCA) High‐Energy X‐ray Timing Experiment (HEXTE) main outburst spectrum was modelled with an absorbed power‐law model with high‐energy cut‐off and a Gaussian iron line complex feature. Using the same spectral model, individual 3–20 keV PCA spectra were found to be softer and less absorbed in low X‐ray flux regions between outbursts. Spectral studies showed that hydrogen column density was correlated, and the power‐law index was anticorrelated with the 3–20 keV X‐ray flux. X‐ray flux related spectral and timing features in 2S 1417 − 62, except for low X‐ray flux regions, were interpreted as a sign of disc accretion with a similar accretion geometry with a varying mass accretion rate (), whereas spectral and timing features of the low X‐ray flux regions were interpreted as a sign of possible temporary accretion geometry change prior to the next periastron where increases again to restore the original accretion geometry.