Search Publications
XMM-Newton's view of a RS CVn binary CF Tuc
Sriram, K.; Agrawal, Vivek K.; Lahiri, Deblina +1 more
Coronal emission exhibited by the chromospherically active binaries is important to understand the underlying mechanism. We report the X-ray spectral studies of an RS CVn source CF Tuc using XMM-Newton archival data. The light curve was found to be steady with no flaring activity and the source was in a quiescent X-ray emission state. The source s…
X-ray reprocessing: Through the eclipse spectra of low mass X-ray binaries with XMM-Newton
Paul, Biswajit; Aftab, Nafisa
Eclipsing X-ray binaries make an ideal condition to study reprocessed X-rays, as the X-rays detected during eclipse are purely reprocessed while the much brighter primary X-rays are blocked by the companion star. We carried out a comprehensive study of X-ray reprocessing with four eclipsing Low Mass X-ray Binary (LMXB) systems by comparing X-ray s…
Peculiar temporal and spectral features in highly obscured HMXB pulsar IGR J16320-4751 using XMM-Newton
Paul, Biswajit; Varun; Iyer, Nirmal
IGR J16320-4751 is a highly obscured HMXB source containing a very slow neutron star (Pspin ∼ 1300 sec) orbiting its supergiant companion star with a period of ∼9 days. It shows high column density (NH ∼ 2 - 5 × 1023cm-2) in the spectrum, and a large variation in flux along the orbit despite not being an…
The curvature emission model of peculiar isolated neutron star 2XMM J104608.7-594306
Chkheidze, N.; Machabeli, G.; Kevlishvili, N.
In the present paper we construct non-thermal emission theory, interpreting the observational properties of a newly discovered pulsar 2XMM J104608.7-594306 in X-rays that is believed to be thermally emitting isolated neutron star. A different approach of curvature emission scenario is considered, giving the spectral energy distribution that is in …
Variable absorption line in XTE J1810-197
Göğüş, Ersin; Güver, Tolga; Vurgun, Eda +1 more
We report the results of a long-term spectral and timing study of the first transient magnetar, XTE J1810-197 which was discovered in 2003, when its X-ray luminosity increased ≈ 100 fold. We fit X-ray spectra of all archival X-ray observations using a two-component blackbody model, where the cool component is most likely originating from the whole…
Post-flare formation of the accretion stream and a dip in pulse profiles of LMC X-4
Paul, Biswajit; Beri, Aru
We report here a pulse profile evolution study of an accreting X-ray pulsar LMC X-4 during and after the large X-ray flares using data from the two observatories XMM-Newton and RXTE. During the flares, the pulse profiles were found to have a significant phase offset in the range of 0.2-0.5 compared to the pulse profiles immediately before or after…
X-ray and optical orbital modulation of EXO 0748-676 : A co-variability study using XMM-Newton
Paul, Biswajit; Raman, Gayathri
We present a multi-wavelength timing study of the eclipsing low mass X-ray binary EXO 0748-676 (UY Vol) using XMM-Newton when the source was in a hard spectral state. The orbital optical and X-ray light curves show a fairly large amount of intensity modulation in the 7 observations taken during September-November, 2003, covering 36 complete binary…
Flux and spectral variability of the blazar PKS 2155 -304 with XMM-Newton: Evidence of particle acceleration and synchrotron cooling
Bhagwan, Jai; Papadakis, I. E.; Wiita, Paul J. +1 more
We have analyzed XMM-Newton observations of the high energy peaked blazar, PKS 2155 -304, made on 24 May 2002 in the 0.3-10 keV X-ray band. These observations display a mini-flare, a nearly constant flux period and a strong flux increase. We performed a time-resolved spectral study of the data, by dividing the data into eight segments. We fitted t…
Multiwavelength modelling the SED of supersoft X-ray sources I. The method and examples
Skopal, A.
Radiation of supersoft X-ray sources (SSS) dominates both the supersof X-ray and the far-UV domain. A fraction of their radiation can be reprocessed into the thermal nebular emission, seen in the spectrum from the near-UV to longer wavelengths. In the case of symbiotic X-ray binaries (SyXBs) a strong contribution from their cool giants is indicate…
Multiwavelength modeling the SED of supersoft X-ray sources. II. RS Ophiuchi: From the explosion to the SSS phase
Skopal, A.
RS Oph is a recurrent symbiotic nova that undergoes nova-like outbursts on a time scale of 20 yr. Its two last eruptions (1985 and 2006) were subject of intensive multiwavelengths observational campaign from the X-rays to the radio. This contribution aims to determine physical parameters and the ionization structure of the nova from its explosion …