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Related papers: Cool white dwarfs as standards for infrared observ…

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We present a comparative study of effective temperatures determined from the hydrogen Balmer lines and from the UV energy distribution for 140 DA white dwarfs drawn from the IUE archive. Our results indicate that the optical and UV…

Astrophysics · Physics 2009-11-13 C. -P. Lajoie , P. Bergeron

A total of 81 DA white dwarfs have been observed with the Cosmic Origins Spectrograph on the Hubble Space Telescope in a snapshot program. The targets were selected to be in the $T_{\rm eff}$ range from 17000 - 25000 K, where optical metal…

Solar and Stellar Astrophysics · Physics 2012-09-27 Detlev Koester , Boris Gänsicke , Jonathan Girven , Jay Farihi

A detailed analysis of halo white dwarf candidates is presented, which is based on model atmosphere fits to observed energy distributions built from photoelectric or photographic magnitudes. Most of the candidates identified in reduced…

Astrophysics · Physics 2009-11-07 P. Bergeron

As they evolve, white dwarfs undergo major changes in surface composition, a phenomenon known as spectral evolution. In particular, some stars enter the cooling sequence with helium atmospheres (type DO) but eventually develop hydrogen…

Solar and Stellar Astrophysics · Physics 2020-10-07 A. Bédard , P. Bergeron , P. Brassard , G. Fontaine

This paper reports follow-up photometric and spectroscopic observations, including warm Spitzer IRAC photometry of seven white dwarfs from the SDSS with apparent excess flux in UKIDSS K-band observations. Six of the science targets were…

Solar and Stellar Astrophysics · Physics 2012-06-06 J. Farihi , B. T. Gänsicke , P. R. Steele , J. Girven , M. R. Burleigh , E. Breedt , D. Koester

Near-infrared photometry and spectroscopy is obtained for a heterogeneous sample of nearby white dwarfs with possible excess flux as identified primarily in the Two Micron All Sky Survey. Among the sample of 43 stars are a number of white…

Solar and Stellar Astrophysics · Physics 2012-06-06 J. Farihi

The absolute calibration of space-borne instruments in the soft X-ray regime rests strongly on model spectra of hot white dwarfs. We analyze the Chandra LETG+HRC-S observations of the white dwarfs HZ43 A and Sirius B and of the neutron star…

Astrophysics · Physics 2011-03-31 K. Beuermann , V. Burwitz , T. Rauch

We have cross-correlated the 2dF QSO Redshift Survey (2QZ) white dwarf catalog with the GALEX 2nd Data Release and the Sloan Digital Sky Survey (SDSS) data release 5 to obtain ultraviolet photometry (FUV, NUV) for approximately 700 objects…

Astrophysics · Physics 2007-05-23 Adela Kawka , Stephane Vennes

We present high resolution Hubble Space Telescope ultraviolet spectroscopy of the dwarf nova EK TrA obtained in deep quiescence. The Space Telescope Imaging Spectrograph data reveal the broad Ly-alpha absorption profile typical of a…

Astrophysics · Physics 2009-11-06 B. T. Gaensicke , P. Szkody , E. M. Sion , D. W. Hoard , S. Howell , F. H. Cheng , I. Hubeny

We report on photometric and spectroscopic observations of white dwarf companions to four binary radio millisecond pulsars, leading to the discovery of companions to PSRs J0614-3329, J1231-1411 and J2017+0603. We place limits on the…

High Energy Astrophysical Phenomena · Physics 2015-12-09 C. G. Bassa , J. Antoniadis , F. Camilo , I. Cognard , D. Koester , M. Kramer , S. R. Ransom , B. W. Stappers

We present a method which uses colour-colour cuts on SDSS photometry to select white dwarfs with hydrogen rich (DA) atmospheres without the recourse to spectroscopy. This method results in a sample of DA white dwarfs that is 95% complete at…

Solar and Stellar Astrophysics · Physics 2012-08-01 J. Girven , B. T. Gaensicke , D. Steeghs , D. Koester

We investigate the far-infrared (IR) dust emission for 20 local star forming galaxies from the Key Insights on Nearby Galaxies: A Far-IR Survey with Herschel (KINGFISH) sample. We model the far-IR/submillimeter spectral energy distribution…

We present the results of our analysis of six orbits of HST/STIS time-tagged spectroscopy of the intermediate polar, EX Hydrae. The high time and wavelength resolution of the HST/STIS spectra provided an excellent opportunity to study the…

Astrophysics · Physics 2009-11-07 K. E. Belle , S. B. Howell , E. M. Sion , K. S. Long , P. Szkody

We have conducted a spectroscopic survey of over 1300 bright (V < 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook & Sion catalog. The complete results from our survey, including the spectroscopic…

Solar and Stellar Astrophysics · Physics 2015-05-30 Alexandros Gianninas , Pierre Bergeron , Maria Teresa Ruiz

We present optical spectroscopy and near-infrared photometry of 126 cool white dwarfs in the Sloan Digital Sky Survey (SDSS). Our sample includes high proper motion targets selected using the SDSS and USNO-B astrometry and a dozen…

Interferometric radius measurements provide a direct probe of the fundamental parameters of M dwarfs, but is within reach for only a limited sample of nearby, bright stars. We use interferometrically-measured radii, bolometric luminosities,…

Solar and Stellar Astrophysics · Physics 2015-06-23 Elisabeth R. Newton , David Charbonneau , Jonathan Irwin , Andrew W. Mann

White dwarfs with infrared excess emission provide a window into the late stages of stellar evolution and the dynamics of circumstellar environments. Using data from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), we…

We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly$\alpha$ absorption profile and we measure the white dwarf effective…

The measurement of precise absolute fluxes for stellar sources has been pursued with increased vigor since the discovery of the dark energy and the realization that its detailed understanding requires accurate spectral energy distributions…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Ralph C. Bohlin , Karl D. Gordon , P. -E. Tremblay

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

Solar and Stellar Astrophysics · Physics 2015-06-17 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , B. Freytag