Related papers: Discovery of a Magnetic Double-Faced DBA White Dwa…
We report our findings on a spectroscopic survey of seven unresolved DA+DB binary white dwarf candidates. We have discovered extreme spectroscopic variations in one of these candidates, SDSS J084716.21+484220.40. Previous analysis failed to…
Optical spectrophotometry and circular spectropolarimetry are presented for several candidate magnetic white dwarfs that were identified during the Hamburg/ESO survey for bright QSOs. HE 1211-1707 and HE 1043-0502 are rare examples of white…
Four magnetic white dwarfs have been found in the course of the Hamburg/ESO Survey for bright QSOs. The objects have been selected as QSO candidate on the basis of its blue continuum and the apparent absence of strong hydrogen or helium…
We present our findings on the spectral analysis of seven magnetic white dwarfs that were presumed to be double degenerates. We obtained time-resolved spectroscopy at the Gemini Observatory to look for evidence of binarity or fast rotation.…
We report the discovery of spectroscopic variations in GD 323, the prototypical DAB white dwarf. Simultaneous optical spectroscopic observations over five consecutive nights of GD 323 and of PG 1234+482, a non-variable comparison DA white…
The magnetic white dwarf SDSS J121209.31+013627.7 exhibits a weak, narrow Halpha emission line whose radial velocity and strength are modulated on a period of ~90 minutes. Though indicative of irradiation on a nearby companion, no cool…
Fifty-two magnetic white dwarfs have been identified in spectroscopic observations from the Sloan Digital Sky Survey (SDSS) obtained between mid-2002 and the end of 2004, including Data Releases 2 and 3. Though not as numerous nor as…
We report the discovery of a nearby massive white dwarf with He-H atmosphere. The white dwarf is located at a distance of $74.5\pm0.9$ pc. Its radius, mass, effective temperature, H/He ratio and age are $R=2500\pm100$ km, $M=1.33\pm0.01$…
We model the structure of the surface magnetic fields of the hydrogen-rich white dwarfs in the SDSS. We have calculated a grid of state-of-the-art theoretical optical spectra of hydrogen-rich magnetic white dwarfs with magnetic field…
Two recently discovered white dwarfs, WDJ041246.84$+$754942.26 and WDJ165335.21$-$100116.33, exhibit H$\alpha$ and H$\beta$ Balmer line emission similar to stars in the emerging DAHe class, yet intriguingly have not been found to have…
We present phase resolved FUV HST FOS spectra of the rapidly rotating, highly magnetic white dwarf RE J0317-853. Using these data, we construct a new model for the magnetic field morphology across the stellar surface. From an expansion into…
We report the discovery of a strong magnetic field in the unique pulsating carbon-atmosphere white dwarf SDSS J142625.71+575218.3. From spectra gathered at the MMT and Keck telescopes, we infer a surface field of B_s ~1.2 MG, based on…
We present the discovery of photometric variability in the DQ white dwarf SDSS J103655.39+652252.2 (SDSS J1036+6522). Time-series photometry reveals a coherent monoperiodic modulation at a period of 1115.64751(67) s with an amplitude of…
We present a follow-up analysis of the unique magnetic luminosity-variable carbon-atmosphere white dwarf SDSS J142625.71+575218.3. This includes the results of some 106.4 h of integrated light photometry which have revealed, among other…
G183$-$35 is an unusual white dwarf that shows an H$\alpha$ line split into five components, instead of the usual three components seen in strongly magnetic white dwarfs. Potential explanations for the unusual set of lines includes a double…
We present a physical characterization of TMTS J00063798+3104160 (J0006), a rapidly rotating,ultra-massive white dwarf (WD) identified in high-cadence light curves from the Tsinghua University-Ma Huateng Telescope for Survey (TMTS). A…
White dwarf atmospheres are subjected to gravitational potentials around $10^5$ times larger than occur on Earth. They provide a unique environment in which to search for any possible variation in fundamental physics in the presence of…
We have applied the method of Zeeman tomography to analyze the surface magnetic field structures of the white dwarfs PG 1015+014 and HE 1045-0908 from spin-phase resolved flux and circular polarization spectra obtained with FORS1 at the ESO…
We present phase-resolved spectroscopy of two new short period low accretion rate magnetic binaries, SDSSJ125044.42+154957.3 (Porb = 86 min) and SDSSJ151415.65+074446.5 (Porb = 89 min). Both systems were previously identified as magnetic…
Photometric variability in massive, magnetic white dwarfs (WDs) on the timescales of less than a few hours is oft interpreted as being due to magnetic spots on the surface of a rotating star. Increasingly, numbers of these short period…