In this review talk I cover some recent developments in understanding the role that magnetic fields play in cataclysmic variables. I discuss the recent DNO QPO unification models; the disk-magnetosphere boundary; some issues concerning the soft blackbody component and the nature of the X-ray spectra in MCVs; whether the SW Sex stars are magnetic, and finally I mention the weird behavior of FS Aur and HS 2331+3905.

I present, brief status reports on three large observational projects that are designed to test our current understanding of the evolution of cataclysmic variables (CVs): The spectroscopic selection of new CVs in the Hamburg Quasar Survey, the search for pre-CVs based on Sloan colours and UK Schmidt/6dF multiobject spectroscopy, and the identification of CVs that descended from supersoft X-ray binaries using a HST/STIS far-ultraviolet spectroscopic survey.

We present an analysis of Rapid Keck Spectroscopy of the CVs AM Her (polar) and SS Cyg (dwarf nova). We decompose the spectra into constant and variable components and identify different types of variability in AM Her with different characteristic timescales. The variable flickering component of the accretion disc flux md the observational characteristics of a small flare in SS Cyg are isolated.

The FUSE and HST spectra of dwarf novae in outburst, and of nova-like variables exhibit a wide range of characteristics. In a few systems, there are obvious signatures of a fast wind in the form of P-Cygni-like profiles of OVI and other relatively high ionization state ions. But this is rare. More common are systems with FUV spectra, showing a complex mixture of high and low ionization state lines. Here we describe attempts to reproduce the spectra using a Monte Carlo radiative transfer code developed to model bi-conical winds in disk systems.

We present orbital trailed spectrograms of XTE J1118+480 taken at the rise to outburst maximum in 2000. These show an evolving S-wave feature arising from the stream impact on the edge of the eccentric precessing disc. By comparing the observed S-waves with those generated in an SPH simulation, we deduce the disc precession phases corresponding to our observations. Hence we infer changes in the disc precession period around the outburst maximum: taken at face value our spectroscopy suggests a precession period temporarily as short as 20 days.

We find that the quiescent accretion disk of U Gem has a complicated structure. Along to the bright spot originating in the region of interaction between the stream and the disk particles, there are also explicit indications of spiral shocks. The Doppler map and the variations of the peak separation of the emission lines are indicative.

I present preliminary results from the: VLT+FORS2 time resolved spectroscopy of the newly discovered cataclysmic variable (CV) Hα0242-28.

In the proceedings of this, and of several recent close binary conferences, there have been several contributions describing smoothed particle hydrodynamics simulations of accretion disks. It is opposite therefore to review the numerical scheme itself with emphasis on its advantages for disk modelling, and the methods used for modelling viscous processes.

We discovered that the short period cataclysmic variable FS Aur at some epochs shows a photometric period close to the orbital. It exceeds the orbital period by ∽2%, which is a sign of the presence of a permanent superhump in the system. Superhumps tend to appear near short, low amplitude outbursts. We assume that FS Aur possesses a large thermally stable accretion disc and that the outburst may be due to the variable mass transfer rate. This, however, does not alter our previous explanation of yet another, 2.4 times longer than orbital, photometric period of FS Aur, found earlier, and persistently observed in its light curves.

We condueted XMM observations of 5 faint Polars discovered by the Sloan Digital Sky Survey. The X-ray fluxes and spectra show a variety of shock regimes. The lowest accretor has X-ray properties consistent with an origin on the secondary star. The light curves of all systems show large variability, with one showing a deep eclipse, and with some evidence for orbital-related variations in 2 others.

A simple model of the boundary layer and accretion disk wind of dwarf novae in outburst is briefly described and applied to the Chandra Low Energy Transmission Grating spectra of WZ Sge and SS Cyg in outburst.

From a 45ks Chandra observation of V42G Oph we have obtained high-resolution X-ray spectra at moderate signal-to-noise, and a, good quality, uninterrupted lightcurve. The spectra are reasonably fit with a cooling flow model, similar to EX Hya and U Gem. Our analysis of the Chandra and additional X-ray/optical lightcurves reveals a persistent modulation at 4.2 hr from 1988 to 2003, likely the white dwarf spin period indicating an intermediate polar nature for V426 Oph.

I present the key results of extensive optical spectroscopy obtained during the first three weeks of the 2001 super-outburst of WZ Sge. A sequence of Doppler maps of the accretion flow in various lines was constructed, and used to create real-time movies of WZ Sge as it evolved through the outburst. Main results include the detection of two-armed spiral asymmetries in the disk, emission from the irradiated donor star and an extended stream of emission around day 19 of the outburst that bears the hallmarks of a mass-transfer burst event.

The classification scheme for Magnetic Cataclysmic Variables (MCVs) is addressed. When only ten or twenty MCVs had been discovered their classification was simple and based on direct observational properties. Now that the number of MCVs exceeds one hundred, the method of classification needs updating. One important consideration is the possibility that binaries might physically change their classification. For example will intermediate polars become polars as they evolve to shorter orbital periods? Or does a polar become an intermediate polar when synchronism is broken due to a nova?

I review X-ray observations of classical and recurrent novae in outburst, some of them recently done with Chandra and XMM-Newton for 12 objects. Significant X-ray flux is emitted by the nova shell, with a peak luminosity up to Lx = 1035 erg s–1 in the 0.2-10 keV range. In recurrent nova systems, or in novae hosting a red giant, the source of X-rays may be previous circumstellar matter shocked by the nova wind. However, for most classical novae, X-rays originate inside the nebula ejected in the outburst. The data indicate a very high fraction of shocked material, and a non-smooth, varying wind outflow. A nebular emission line spectrum is also observed at late phases. In about half of the observed novae, the central white dwarf appears as a very luminous supersoft X-ray source for 1 to 9 years after the outburst. It is the best type of object to study the characteristics of shell hydrogen burning on white dwarfs in single degenerate systems. Still incomplete statistics indicate that the duration of the supersoft X-ray phase is peaked around ≃2 years. The correlation of the X-ray light curve with the nova properties is not quite clear. Recently, “template grating spectra” with high S/N have been obtained for V4743 Sgr. The X-ray light curve of this nova reveals a rich and complex power spectrum, with signatures of non-radial g-mode oscillations of the white dwarf. The oscillations and the spectra allow to determine the properties of the shell hydrogen burning white dwarf.

In the course of a long-term project investigating classical novae with large outburst amplitudes, we have performed multi-wavelength photometry and optical spectroscopy of several old nova candidates. We here introduce the aim of the project, the search for low mass-transfer novae with short orbital periods, and explain the method to recover these old novae via their colour characteristics. Finally we concentrate on first results for selected objects in our sample.

We report the discovery of one unique cataclysmic variable drawn from the Hamburg Quasar Survey, HS 2331 + 3905. Follow-up observations obtained over three years unveiled a very unusual picture. The large amplitude 3.5 h radial velocity variations obtained from our optical spectroscopy is not the orbital period of the system, as one would normally expect. Instead, extensive CCD photometry strongly suggests that HS 2331 + 3005 is a short orbital period cataclysmic variable with Рorb = 81.09 min, containing a cold white dwarf which appears to exhibit ZZ Ceti pulsations.

We have undertaken a theoretical study of the impact of the accumulating envelopes on the thermal state of the underlying white dwarf (WD). This has allowed us to find the equilibrium WD core temperatures, the classical nova ignition masses and the thermal luminosities for WDs accreting at rates of 10–11 – 10–8M⊙ yr–1. These accretion rates are most, appropriate to WDs in cataclysmic variables (CVs) of (Porb ≲ 7 hr), many of which accrete sporadically as Dwarf Novae. Over twenty Dwarf Novae have been observed in quiescence, when the accretion rate is low and the WD photosphere is detected and Teff measured. Comparing our theoretical work to these observations allows us to constrain the WD mass and the time averaged accretion rate, ⟨Ṁ⟩. If ⟨Ṁ⟩ is that given by gravitational radiation losses alone, then the WD masses are > 0.8 M⊙. An alternative conclusion is that the masses are closer to 0.6M⊙ and ⟨Ṁ⟩ is 3-4 times larger than that expected from gravitational radiation losses.

We have obtained FUSE spectra of several dwarf novae which reveal the properties of their accreting white dwarfs, their rates of accretion during quiescence and the nature of their boundary layer/inner disk regions including accretion belts on the white dwarfs. Among the systems for which preliminary results will be presented are BV Cen, WW Ceti, EY Cyg, SS Aur and VW Hyi. The contribution of these FUSE studies to our understanding of disk accretion physics will be emphasized within the context of the white dwarf and boundary layer.

The 2001 outburst, of V445 Puppis is an unique object, that shows absence of hydrogen, enrichment of helium and carbon, slow decay of the light curve with a small amplitude. We have calculated theoretical light curves of helium novae to confirm that V445 Pup is the first example of helium nova. From the light curve fitting we conclude that the white dwarf is very massive ≥ 1.33M⊙.