|
ИСТИНА |
Войти в систему Регистрация |
Интеллектуальная Система Тематического Исследования НАукометрических данных |
||
Spectral properties of NS X-ray binary 4U1705-44 with BeppoSAX and RXTE. Quasi-constancy of the spectral index vs accretion rateтезисы доклада
- Авторы: Seifina E., Titarchuk L.
- Сборник: Radiation mechanisms of astrophysical objects: classics today
- Тезисы
- Год издания: 2015
- Место издания: Saint-Petersburg
- Первая страница: 113
- Последняя страница: 113
- Аннотация: We present an analysis of the X-ray spectral properties observed from the atoll-source 4U1705-44 during evolutions between island and banana states. We analyze observations using the RXTE and BeppoSAX. We find that the X-ray broad-band energy spectra during all spectral states can be adequately reproduced by a model, consisting a low-temperature Blackbody component, two Comptonized components arising from the seed photons coming from NS atmosphere at a temperature kTs1 ≈ 1.5 keV (herein Comptb1) and a second resulting from the seed photons of Ts2 = 1.1 ÷ 1.3 keV coming from the disk (herein Comptb2). We also include an iron-line (Gaussian) component in the spectra. The data analysis using this model indicates that the photon power-law index Γ1 of our model is almost constant (Γ1 ≈ 2) for all spectral states. Another parameter, Γ2 demonstrates a two-phase behavior depending on the spectral state. Γ2 is quasi-constant at Γ2 ≈ 2 when the electron temperature kT(2)e < 80 keV and Γ2 is less than 2, namely in the range of 1.3 < Γ2 < 2, when kT(2)e > 80 keV. We also detect a decrease of kTs2 from 1.3 keV to 1.1 keV during this high electron temperature phase. This phase is similar to that was previously found in the Zsource Sco X-1. We interpret the decreasing index phase using a model in which a high radiation pressure from the NS causes an expansion of the Compton cloud similar to that found previously in Sco X-1 during the Flaring branch.
- Добавил в систему: Сейфина Елена Викторовна