‘Spectro-temporal’ characteristics and disk-jet connection of the outbursting black hole source XTE J1859+226

Abstract

We re-investigated the 'spectro-temporal' behavior of the source XTE J1859+226 in X-rays during its outburst phase in 1999, by analysing the RXTE PCA/HEXTE data in 2-150 keV spectral band. Detailed analysis shows that the source evolves through different spectral states during its entire outburst as indicated by the variation in the spectral and temporal characteristics. Although the evolution pattern of the outburst followed the typical q-shaped profile, we observed an absence of 'canonical' soft state and a weak presence of 'secondary' emission during the decay phase of the outburst. The broad-band spectra, modeled with high energy cutoff, shows that the fold-energy increases monotonically in the hard and hard-intermediate states followed by a random variation in the soft-intermediate state. We attempted to estimate the mass of the source based on the evolution of Quasi-Periodic Oscillation (QPO) frequencies during rising phase modeled with the propagating oscillatory shock solution, and from the correlation of photon index and QPO frequency. It is also observed that during multiple ejections (observed as radio flares) the QPO frequencies are not present in the power spectra and there is an absence of lag in the soft to hard photons. The disk flux increases along with a decrease in the high energy flux, implying the soft nature of the spectrum. These results are the 'possible' indication that the inner part of the disk (i.e., Comptonized corona), which could be responsible for the generation of QPO and for the non-thermal Comptonized component of the spectrum, is disrupted and the matter gets evacuated in the form of jet. We attempted to explain the complex behavior of 'spectro-temporal' properties of the source during the entire outburst and the nature of the disk-jet connection before, during and after the ejection events in the context of two different types of accreting flow material, in presence of magnetic field.

Discovery of a quasi-periodic oscillation in the ultraluminous X-ray source IC 342 X-1: XMM–Newton results

“…Another important thing to note is that the hard Xray energy spectra of GBHBs (i.e., hard or intermediates states) have connection with the strong QPOs and compact radio jets observed in the sources (Radhika & Nandi 2014). The high energy spectral curvatures observed in GBHBs (in the range of 30 -100 keV) are the manifestation of optically thin corona with characteristic temperature of ∼ 100 keV (Remillard & McClintock 2006).…”

Dynamical structure of magnetized dissipative accretion flow around black holes

“…Depending on the flow parameters, namely angular momentum (λ), viscosity (αB), cooling efficiency factor (ξ) and β respectively, accreting matter changes its sonic state multiple times as it contains multiple sonic points. Flows of this kind are of special interest as they may contain shock wave which is perhaps essential to understand the spectral and timing properties of the black hole candidates (Chakrabarti & Manickam 2000;Nandi et al 2001aNandi et al ,b, 2012Radhika & Nandi 2014;Iyer et al 2015).…”

A study of the cross-correlation and time lag in black hole X-ray binary XTE J1859+226

“…The intensity is defined as the background subtracted light curve of 2−20 keV, the hardness is defined as the count-rate ratio of 6−20 keV/2−6 keV, and only data of PCU2 are used, which are the same as given by Radhika & Nandi (2014). …”

“…The evolution of correlations and long-term time lags along with the spectral states of BHXBs has never been investigated, and we select BHXB XTE J1859+226 as it evolved through a sequence of spectral states during the 1999−2000 outburst (Radhika & Nandi 2014). The observations and data reduction are described in Section 2.…”

“…Using RXTE data obtained during the whole 1999−2000 outburst, Radhika & Nandi (2014) studied the evolution of spectral and temporal properties associated with different spectral states to explore the accretion dynamics. Results from study for the variation of spectral and temporal properties show that the whole outburst of XTE J1859+226 evolved through seven state transitions: hard state → HIMS → SIMS → soft state → SIMS → HIMS → hard state (Radhika & Nandi 2014).…”