A Chandra Search for Coronal X Rays from the Cool White Dwarf GD 356

  title={A Chandra Search for Coronal X Rays from the Cool White Dwarf GD 356},
  author={Martin C.Weisskopf and Kinwah Wu and Virginia Trimble and Stephen L. O’Dell and Ronald F. Elsner and Vyacheslav E. Zavlin and Chryssa Kouveliotou},
  journal={The Astrophysical Journal},
We report observations with the Chandra X-ray Observatory of the single, cool, magnetic white dwarf GD 356. For consistent comparison with other X-ray observations of single white dwarfs, we also re-analyzed archival ROSAT dataforGD356(GJ1205),G99-47(GR290=V1201Ori),GD90,G195-19(EG250=GJ339.1),andWD2316+123, andarchivalChandradataforLHS1038(GJ1004)andGD358(V777Her).OurChandraobservationdetectedno X-rays from GD 356, setting the most restrictive upper limit to the X-ray luminosity from any cool… 
Hard X-Ray Emission Associated with White Dwarfs. IV. Signs of Accretion from Substellar Companions
With an effective temperature of ≃200,000 K, KPD 0005+5106 is one of the hottest white dwarfs (WDs). ROSAT unexpectedly detected “hard” (∼1 keV) X-rays from this apparently single WD. We have
A Chandra look at the X-ray faint millisecond pulsars in the globular cluster NGC 6752
We combine new and archival Chandra observations of the globular cluster NGC 6752 to create a deeper X-ray source list, and study the faint radio millisecond pulsars (MSPs) of this cluster. We detect
NuSTAR Hard X-Ray Survey of the Galactic Center Region. II. X-Ray Point Sources
We present the first survey results of hard X-ray point sources in the Galactic Center (GC) region by NuSTAR. We have discovered 70 hard (3–79 keV) X-ray point sources in a 0.6 deg^2 region around
The Chandra Local Volume Survey I: The X-ray Point Source Populations of NGC 55, NGC 2403, and NGC 4214
We present comprehensive X-ray point source catalogs of NGC~55, NGC~2403, and NGC~4214 as part of the Chandra Local Volume Survey. The combined archival observations have effective exposure times of
Deep XMM-Newton Observations of an X-ray Weak Broad Absorption Line Quasar at z = 6.5
We report X-ray observations of the most distant known gravitationally lensed quasar, J0439+1634 at z = 6.52, which is also a broad absorption line (BAL) quasar, using the XMM-Newton Observatory.
NuSTAR Hard X-ray Survey of the Galactic Center Region I: Hard X-ray Morphology and Spectroscopy of the Diffuse Emission
We present the first sub-arcminute images of the Galactic Center above 10 keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR J17456–2901 into non-thermal X-ray filaments, molecular
We present NuSTAR hard X-ray observations of three Type 2 quasars at z ≈ 0.4-0.5, optically selected from the Sloan Digital Sky Survey. Although the quasars show evidence for being heavily obscured,
The Massive Star-Forming Regions Omnibus X-Ray Catalog, Second Installment
We present the second installment of the Massive Star-forming Regions (MSFRs) Omnibus X-ray Catalog (MOXC2), a compilation of X-ray point sources detected in Chandra/ACIS observations of 16 Galactic
A catalog of X-ray point sources from two megaseconds of Chandra observations of the Galactic center
We present a catalog of 9017 X-ray sources identified in Chandra observations of a 2 ◦ × 0. 8 field around the Galactic center. This enlarges the number of known X-ray sources in the region by a
Dominance of magnetic cataclysmic variables in the resolved Galactic ridge X‐ray emission of the limiting window
The diffuse appearance of the Galactic ridge X-ray emission has been puzzling since its discovery due to the lack of compelling theories for sustainable hot diffuse X-ray emission in the Galactic


An X-ray survey of hot white dwarf stars - Evidence for a m(He)/n(H) versus Teff correlation
Observations of 13 white dwarf and subdwarf stars using the Einstein Observatory High Resolution Image are reported. Included are stars of classes DA, DB, DAV, sDO, and sDB, with optically determined
An upper limit to coronal X-rays from single, magnetic white dwarfs
Pointed ROSAT PSPC exposures of 9277 and 6992 sec, directed toward the nearby, single, cool, magnetic white dwarfs GR 290 and EG 250 yielded no counts significantly above the expected background
ROSAT Pointed Observations of Cool Magnetic White Dwarfs
Observational evidence for the existence of a chromosphere on the cool magnetic white dwarf GD 356 has been reported. In addition, there have been theoretical speculations that cool magnetic white
A soft X-ray survey of hot white dwarfs with Exosat
Broadband multicolor soft X-ray photometry of 34 hot white dwarfs is presented, obtained with the Low Energy Imaging Telescopes on Exosat. By combining the soft X-ray fluxes with measurements of the
Chandra Observations of Magnetic White Dwarfs and Their Theoretical Implications
Observations of cool DA and DB white dwarfs have not yet been successful in detecting coronal X-ray emission, but observations of late-type dwarfs and giants show that coronae are common for these
We have searched for X-ray emission from a sample of five nearby (6-2 pc), strongly magnetic (10-200 MG), relatively cool (6000-14000 K), single white dwarfs, two of which may possess coronae. We
Photospheric soft X-ray emission from hot DA white dwarfs
The Einstein Observatory's imaging proportional counter has detected 150-eV soft X-ray radiation from the four hot DA white dwarfs EG 187, Gr 288 and 289, and LB 1663. The observed pulse height
Detection of the First Coronal X-Ray Source about a White Dwarf
We present a ROSAT PSPC observation of the hot DO white dwarf KPD 0005+5106 which indicates that the X-ray radiation is coming from a hot corona about the star. This is quite novel, since all
The coolest DA white dwarfs detected at soft X-ray wavelengths
New soft X-ray/EUV photometric observations of the DA white dwarfs KPD 0631 + 1043 = WD 0631 + 107 and PG 1113 + 413 = WD 1113 + 413 are analyzed. Previously reported soft X-ray detections of three
Thermal cyclotron radiation by isolated magnetic white dwarfs and constraints on the parameters of their coronas
An efficient method for the detection and estimation of the parameters of the coronas of isolated white dwarfs possessing magnetic fields of about 107 G is tested. This method is based on the