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Detection of thermonuclear X-ray bursts and dips from the X-ray binary 4U 1323-62 with Astrosat/LAXPC

Research in Astronomy and Astrophysics 2020年第6期20卷 281-292页

作者： Yashpal Bhulla Jayashree Roy s.n.a.jaaffrey Pacific Academy of Higher Education and Research University Udaipur-313003India Inter-University Center for Astronomy and Astrophysics Pune-411007India

Using data from the Large Area X-ray Proportional Counter(LAXPC)on the Astrosat satellite,we observed Type-1 thermonuclear X-ray bursts from the low mass X-ray binary neutron star 4 U *** of 4 U 1323-62 that were carried out during the performance verification phase of the Astrosat satellite indicated six thermonuclear X-ray bursts in a total effective exposure of^49.5 ks for about two consecutive *** time of the detected thermonuclear bursts is in accordance with the orbital period of the source,~9400 ***,the light curve of 4 U 1323-62 revealed the presence of two *** present the results from time-resolved spectroscopy performed during all of the six X-ray bursts and also report the detection of a known low frequency quasi-periodic oscillation(LFQPO)at^1 Hz from the ***,any evidence of kilohertz QPO was not *** have shown the burst profile at different energy *** a distance of 10 kpc,we observed a mean flux of^1.8×10^-9 erg cm^2 s^-*** radius of the blackbody is found to be highly consistent with the blackbody temperature and the blackbody flux of the bursts.

关键词： accretion-accretion disc-stars neutron star-X-rays binaries-X-rays thermonuclear bursts-individual 4U 1323–62

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Comprehensive spectral analysis of Cyg X-1 using RXTE data

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Research in Astronomy and Astrophysics 2012年第10期12卷 1427-1438页

作者： Rizwan shahid Ranjeev Misra s.n.a.jaaffrey Department of Physics M.L.Sukhadia UniversityUdaipur-313001India Inter University Centre for Astronomy and Astrophysics Pune-411007India

We analyze a large number （〉 500） of pointed Rossi X-Ray Timing Explorer （RXTE） observations of Cyg X- 1 and model the spectrum of each one. A subset of the observations for which there is a simultaneous reliable measure of the hardness ratio by the All sky Monitor shows that the sample covers nearly all the spectral shapes of Cyg X-1. Each observation is fitted with a generic empirical model consisting of a disk black body spectrum, a Comptonized component whose input photon shape is the same as the disk emission, a Gaussian to represent the iron line and a reflection feature. The relative strength, width of the iron line and the reflection parameter are in general correlated with the high energy photon spectral index F. This is broadly consistent with a geometry where for the hard state （low F ~ 1.7） there is a hot in- ner Comptonizing region surrounded by a truncated cold disk. The inner edge of the disk moves inwards as the source becomes softer till finally in the soft state （high F 〉 2.2） the disk fills the inner region and active regions above the disk produce the Comptonized component. However, the reflection parameter shows non-monotonic behavior near the transition region （F ~ 2）, which suggests a more complex geometry or physical state of the reflector. In addition, the inner disk temperature, during the hard state, is on average higher than in the soft one, albeit with large scatter. These inconsistencies could be due to limitations in the data and the empirical model used to fit them. The flux of each spectral component is well correlated with F, which shows that unlike some other black hole systems, Cyg X- 1 does not show any hysteresis be- havior. In the soft state, the flux of the Comptonized component is always similar to the disk one, which confirms that the ultra-soft state （seen in other brighter black hole systems） is not exhibited by Cyg X-1. The rapid variation of the Compton amplifica- tion factor with F naturally explains the absence of spec

关键词： accretion accretion disks -- X-rays: binaries

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Timing and spectral studies of Pulsar EXO2030＋375

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Chinese Physics Letters 2010年第2期27卷 334-337页

作者： shubhra Tiwari s. n. A. jaaffrey Rizwan s. Khan sushil K. Gandhi santvana Bapna Astronomy and Astrophysics Laboratory Department of Physics University College of Science M. L. Sukhadia University UDAIPUR (Raj.)-313001 India

We report the results of timing and spectral analysis of the x-ray pulsar EXO2030＋375. The observations were made using the Rossi x-ray timing explorer space satellite. The spectral analysis is carried out for the flux of x-ray energy range 3-30 keV. The x-ray continuum spectra of proportional counter array could be represented by a two-component model, a power law with an exponential cutoff at higher energies and a blackbody. An iron line at about 6.4-6.6 keV was also detected.

关键词： Atomic and molecular physics Astrophysics and astroparticles

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secondary X-Ray Environment in the Lower Atmosphere of the Earth during Monsoon season over Udaipur City （India） in July-september 2006

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Chinese Physics Letters 2009年第8期26卷 381-384页

作者： s. n. A. jaaffrey shubhra Tiwari Laboratory of Astronomy and Astrophysics Department of Physics University College of Science M. L. Sukhadia University UDAIPUR (Raj.)-313001 India

We present a study on the secondary x-rays of energy band 2-100 keV emitted by the intruded principal pollutant components （gases and minerals） brought up in the lower atmosphere by dust storms, monsoon drift and the gravitational pull on meteoritic showers. On the ground we employed a 1.5 × 1 inch^2 naI crystal in a scintillation detector, suitable for the energy range 2-100 keV of secondary x-rays, providing better energy resolution than a larger sized crystal. In order to eliminate the radioactive background of the Earth, the detector was well shielded on all sides with the help of the lead （Pb） container, except with *** open window at the top to permit only vertically incident secondary radiation. The results from the data analysis obtained during the monsoon over Udaipur city （India） during the period from July to september （2006） have revealed a linear correlation between dust storm cure monsoon clouds and observed luminosities of secondary x-ray radiation from intruded pollutants. We found intense flux of secondary x-rays from the intruded pollutants when heavy dust and monsoon clouds were brought up by dust storms and monsoon drift in the lower atmosphere over Udaipur city as compared to normal days. Thus, secondary x-rays in the environment provide a tool for investigation of local intrusive pollutant components in the lower atmosphere.

关键词： sea surface nonliear interaction numerical method

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