Related papers: Supersoft X-ray Sources. Basic Parameters

In the ROSAT Bright Survey (RBS) we have almost completely optically identified the brightest ~2000 high-galactic latitude sources from the ROSAT All-Sky Survey Bright Source Catalogue (1RXS). A small number of sources has empty X-ray error…

Super Soft X-ray Sources (SSS) are white dwarf (WD) binaries that radiate almost entirely below $\sim$1~keV. Their X-ray spectra are often complex when viewed with the X-ray grating spectrometers, where numerous emission and absorption…

We consider simultaneous optical data obtained during the recent X-ray turn-off of CAL83. Combining the optical behaviour with the observed X-ray decay time, we show that a model of cessation of steady nuclear burning is viable if the white…

RX J0947.0+4721 is a newly discovered example of a narrow-line Seyfert 1 type object with a quasar level luminosity (M_B = -24.8). It was detected in the ROSAT All-Sky Survey (RASS) and later in 17 pointed observations of the ROSAT Position…

We have made a deep search for radio emission from all the northern hemisphere supersoft X-ray sources using the VLA and MERLIN telescopes, at 5 and 8.4 GHz. Three previously undetected sources: T Pyx, V1974 Cygni and RX J0019.8+2156 were…

We monitored four supersoft sources - two persistent ones, CAL 83 and MR Vel, and the recent novae YZ Ret (Nova Ret 2020) and V1674 Her (Nova Her 2021) - with NICER. The two persistent SSS were observed with unvaried X-ray flux level and…

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 on the discovery of a periodic modulation in the bright supersoft X-ray source XMMU J004252.5+411540 detected in the 2000-2004 XMM-Newton observations of M31. The source exhibits X-ray pulsations with a period P~217.7 s and a…

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…

We report on the first spectral and timing characterization of the transient X-ray source 1RXS J194211.9+255552 using all available data from the Swift X-ray satellite. We used 10 years of hard X-ray data from the Burst Alert Telescope…

We have identified the ROSAT source RX J0039.2-5117 with the previously almost unknown `narrow line' Seyfert 1 galaxy WPVS007 (z=0.028). The X-ray source displays quite unusual properties for an AGN. It was bright and ultrasoft in the ROSAT…

We present results of an extensive study of the X-ray spectral properties of sources detected in the RIXOS survey, that is nearly complete down to a flux limit of 3e-14 cgs (0.5-2 keV). We show that for X-ray surveys containing sources with…

We have identified 127 discrete sources in a Chandra observation of M83, with a detection limit of ~ 3 x 10^{36} erg/s in the 0.3-8.0 keV band. We discuss the individual properties of about 20 bright sources with L_x >~ 10^{38} erg/s, and…

eROSITA is the soft X-ray instrument aboard the Spectrum Roentgen Gamma (SRG) satellite that is most sensitive in the energy range between 0.2 and 2.3 keV. Between December 2019 and December 2021, eROSITA completed four all-sky surveys…

We report on a BeppoSAX Low-Energy Concentrator Spectrometer (LECS) observation of the super-soft source (SSS) CAL83. The X-ray emission in SSS is believed to arise from nuclear burning of accreted material on the surface of a white dwarf…

The source XTE J1901+014 discovered by the RXTE observatory during an intense outburst of hard radiation and classified as a fast X-ray transient is studied. The source's spectral characteristics in the quiescent state have been…

We present results from an analysis of the broad-band, 0.3-195 keV, X-ray spectra of 48 Seyfert 1-1.5 sources detected in the very hard X-rays with the Swift Burst Alert Telescope (BAT). This sample is selected in an all-sky survey…

We present the ROSAT All-Sky Survey Bright Source Catalogue (RASS-BSC, revision 1RXS) derived from the all-sky survey performed during the first half year (1990/91) of the ROSAT mission. 18,811 sources are catalogued (i) down to a limiting…

We analyze the first X-ray observations with XMM-Newton of RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as…

Soft X-ray transients are systems that are detected when they go into an outburst, wherein their X-ray luminosity increases several orders of magnitude. These outbursts are markers of the poorly understood change in the spectral state of…