Related papers: An ultraluminous supersoft source with a 4 hour mo…
Tidal disruption events (TDEs) are usually discovered at X-ray or optical wavelengths through their transient nature. A characteristic spectral feature of X-ray detected TDEs is a "supersoft" X-ray emission, not observed in any other…
Ultraluminous X-ray Sources (ULXs) provide a unique opportunities to probe the geometry and energetics of super-Eddington accretion. The radiative processes involved in super-Eddington accretion are not well understood, and so studying…
Ultraluminous X-ray sources are considered amongst the most extremely accreting objects in the local Universe. The recent discoveries of pulsating neutron stars in ULXs strengthened the scenario of highly super-Eddington accretion…
We present a deep optical imaging campaign on the starburst galaxy NGC 4631 with CFHT/MegaCam. By supplementing the HST/ACS and Chandra/ACIS archival data, we search for the optical counterpart candidates of the five brightest X-ray sources…
In a canonical model, the progenitors of Type Ia supernovae (SNe Ia) are accreting, nuclear-burning white dwarfs (NBWDs), which explode when the white dwarf reaches the Chandrasekhar mass, M_C. Such massive NBWDs are hot (kT ~100 eV),…
We searched for X-ray counterparts of optical novae detected in M 31 and M 33. We combined an optical nova catalogue from the WeCAPP survey with optical novae reported in the literature and correlated them with the most recent X-ray…
We present the results obtained from detailed X-ray timing and spectral studies of X-ray pulsar Swift J0243.6+6124 during its giant and normal X-ray outbursts between 2017 and 2023 observed by the Neutron star Interior Composition Explorer…
Chandra observations of 17 nearby galaxies were analysed and 166 bright sources with X-ray counts > 100, were chosen for temporal analysis. Fractional root mean square variability amplitudes were estimated for lightcurves binned at ~ 4 ksec…
Super-soft X-ray sources were established as a heterogeneous class of objects from observations of the Large Magellanic Cloud (LMC). We have searched for new sources of this class in the X-ray images obtained from the XMM-Newton survey of…
Strongly magnetized, rapidly rotating massive white dwarfs (WDs) emerge as potential outcomes of double degenerate mergers. These WDs can act as sources of non-thermal emission and cosmic rays, gethering attention as WD pulsars. In this…
Ultraluminous X-ray sources (ULX) are off-nuclear point sources in nearby galaxies whose X-ray luminosity exceeds the theoretical maximum for spherical infall (the Eddington limit) onto stellar-mass black holes. Their luminosity ranges from…
We present the results of soft X-ray studies of the classical nova V2491 Cygni using the Suzaku observatory. On day 29 after outburst, a soft X-ray component with a peak at ~0.5 keV has appeared, which is tantalising evidence for the…
We report on a 40 ks long, uninterrupted X-ray observation of the candidate supergiant fast X-ray transient (SFXT) IGRJ16418-4532 performed with XMM-Newton on February 23, 2011. This high mass X-ray binary lies in the direction of the Norma…
In this study, we present a detailed analysis of public archival soft X-ray data on the classical nova V339 Delphini (Nova Del 2013) during its outburst, obtained using the {\it Chandra} High-Resolution Camera Spectrometer (HRC-S) and Low…
We present radio and X-ray observations of the nearby Type IIb Supernova 2013df in NGC4414 from 10 to 250 days after the explosion. The radio emission showed a peculiar soft-to-hard spectral evolution. We present a model in which inverse…
Two ultraluminous X-ray sources (ULXs) in the nearby Sb galaxy NGC 1313, named X-1 and X-2, were observed with Suzaku on 2005 September 15. During the observation for a net exposure of 28~ks (but over a gross time span of 90~ks), both…
Classical novae are known to demonstrate a supersoft X-ray source (SSS) state following outbursts, which is associated with residual thermonuclear burning on the white dwarf (WD) surface. During its all-sky survey (eRASS1), the eROSITA…
We report the results of Chandra and XMM-Newton observations of a new outburst of an ultra-luminous X-ray source in M101. During a Chandra monitoring observation of M101, M101 ULX-1 was found to be in outburst in 2004 December, the second…
We report the detection of coherent pulsations from the ultraluminous X-ray source NGC 7793 P13. The ~0.42s nearly sinusoidal pulsations were initially discovered in broadband X-ray observations using XMM-Newton and NuSTAR taken in 2016. We…
We present the results of high-quality XMM-NEWTON observations of a ULX in the galaxy NGC 4190. The detection of spectral cutoff in NGC 4190 ULX1 spectra rules out the interpretation of the ULX to be in a standard low/hard canonical…