Related papers: Soft X-ray spectral variability of AM Herculis

High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-Newton observations of polars selected due to their ROSAT…

We have discovered a new AM Her system as the optical counterpart of the ROSAT All-Sky-Survey source RX J1016.9-4103 (= 1RXS J101659.4-410332). The X-ray spectrum is very soft and the X-ray intensity is strongly modulated with the orbital…

We report the identification of the ROSAT all-sky survey source 1RXS J154814.5-452845as new intermediate polar and present the results from follow-up optical and X-ray observations. The source shows pulsations with a period of 693 s both in…

Six high-resolution (\lambda/\Delta\lambda ~ 3000) far-UV (\lambda\lambda = 910-1210 \AA) spectra of the magnetic cataclysmic variable AM Herculis were acquired in 1996 November during the flight of the ORFEUS-SPAS II mission. AM Her was in…

Hard X-ray light curves and spectral parameters from our analysis of X-ray data of five AM Her type systems - V2301 Oph, V1432 Aql, EP Draconis, GG Leonis, V834 Cen, and one intermediate polar - TV Col, observed using the Rossi X-ray Timing…

We have made ROSAT PSPC and HRI X-ray observations to study the intracluster gas surrounding the powerful radio source Hercules A. The cluster is luminous in X-rays (L_bol = 4.8x10^37 W), and the host of the radio source is the central…

Recent observations with the XMM-Newton satellite confirmed the existence of the soft excess phenomenon in galaxy clusters, earlier discovered in several EUVE, ROSAT and BeppoSAX observations. Among the clusters for which XMM has reported…

We report the discovery of a new AM Herculis binary (polar) as the optical counterpart of the soft X-ray source RX J1724.0+4114 detected during the ROSAT all-sky survey. The magnetic nature of this V~17 mag object is confirmed by…

We present phase-resolved low resolution infrared spectra of AM Her and ST LMi, two low-field polars that we observed with SPEX on the IRTF. Optical/NIR lightcurves are also published to help constrain the viewing geometry and brightness of…

We present the results of timing and spectral analysis of X-ray high state observations of the high-mass X-ray pulsar SMC X-1 with Chandra, XMM-Newton, and ROSAT, taken between 1991 and 2001. The source has L_X ~ 3-5 x 10^38 ergs/s, and the…

Using the archival ROSAT observation of TT Ari, X-ray energy spectra in different orbital phases and power spectra of the intensity time series are presented. Spectral fits show that the source gets brighter during the observation. The…

A study of AM Her low states in September 1990 and 1991 and June-July 1997 is reported from a coordinated campaign with observations obtained at the Haute-Provence observatory, at the 6-m telescope of the Special Astrophysical Observatory…

We report observations of a new AM Herculis binary identified as the optical counterpart of the X-ray source RX J1313.2-3259, detected during the ROSAT All-Sky Survey (RASS). It has an orbital period of 251 min and is strongly modulated at…

We present a low-resolution discovery spectrum and CCD-photometry of the bright X-ray source 1RXS J012851.9-233931 found in the ROSAT All-Sky Survey. These first observations suggest that the source is an AM Herculis star (polar) accreting…

When accretion temporarily ceases in the polar AM Her, the emission line profiles are known to develop several distinct components, whose origin remains poorly understood. The new low-state spectra reported here have a more favorable…

In the EXOSAT and ROSAT eras a significant number of polars were found to show a soft/hard X-ray ratio much greater than that expected from the standard accretion shock model. This was known as the `soft X-ray excess'. We have made an…

Many X-ray accreting pulsars have a soft excess below 10 keV. This feature has been detected also in faint sources and at low luminosity levels, suggesting that it is an ubiquitous phenomenon. In the case of the high luminosity pulsars (Lx…

We have surveyed the optical linear polarization of a completely identified sample of 43 bright soft-X-ray-selected ROSAT AGN. Most (40) of these AGN show low polarization (<1%), and no clear optical reddening. This supports the suggestion…

Using XMM-Newton we have obtained the first X-ray observation covering a complete orbit of the longest period polar, V1309 Ori. The X-ray light curve is dominated by a short, bright phase interval with EPIC pn count rates reaching up to 15…

A detailed analysis of X-ray data from ROSAT, ASCA, XMM and RXTE for the asynchronous polar V1432 Aql along with Stokes polarimetry data from SAAO, is presented. Power spectra from long-baseline ROSAT data show a spin period of 12150s along…