VizieR Online Data Catalog: Multiwavelength observations of GD 394 (Wilson+, 2019)

To test the accretion spot hypothesis, we obtained eight far-ultraviolet (FUV) spectra of GD 394 using the Space Telescope Imaging Spectrograph (STIS) onboard the Hubble Space Telescope (HST/STIS). The observations were taken between 2015 August 20 and 2015 August 21, timed to fully sample the 1.15d period seen in the EUV. The observations were taken with the FUV-MAMA detector in TIME-TAG mode, using the E140M grating covering the wavelength range 1144-1710Å with an average resolution of λ/91700 per pixel.

Optical spectroscopy was obtained on 2009 May 23, 2009 May 23, and 2015 November 15 using the High Resolution Echelle Spectrometer (HIRES) on the 10m W.M. Keck Telescope (Vogt et al. 1994SPIE.2198..362V) under Program IDs A284Hr, A284Hb, and N116Hb. On both nights 3x300s exposures were taken covering the wavelength range 3125-5997Å. On the first night an additional 3x300s exposures were taken covering the wavelength range 4457-7655Å using the GG475 filter. All of the exposures used the C5 aperture.

Further optical spectroscopy of GD 394 was obtained using the Intermediate dispersion Spectrograph and Imaging System (ISIS) on the 4.2m William Herschel Telescope (WHT) on 2007 August 6 and 2016 August 13. The 2007 observation used the R1200 grating to cover the wavelength ranges 4520-5262Å and 8260-9014Å, with a total exposure time of 2882s. The 2016 observations used the R600B+R gratings covering 3056-5409Å and 5772-9088Å with a total exposure time of 1800s.

In addition to the new observations described above, we utilized the following archival data sets: GD 394 was observed by the Far Ultraviolet Spectroscopic Explorer (FUSE) spacecraft on eight occasions; Shipman et al. (1995AJ....109.1220S) used the Goddard High Resolution Spectrograph (GHRS), one of the first-light instruments on HST, to observe GD 394 on 1992 June 18; GD 394 was also observed multiple times by the International Ultraviolet Explorer (IUE) and finally we retrieved an optical spectrum obtained by Gianninas, Bergeron & Ruiz (2011ApJ...743..138G) from the Montreal White Dwarf Database (MWDD, Dufour et al. 2017ASPC..509....3D) covering the wavelength range 3780-5280Å.

(4 data files).