FUSE Residual Wavelength Errors

A quality assessment of the FUSE data archive, including analyses of the systematic errors in the effective-area and wavelength calibrations have been conducted. The white dwarf KPD 0005+5106 was used as wavelength calibration target. Observed throughout the mission, the data from each observation were reduced independently. For each channel (LiF and SiC), detector segment (1A, 1B, 2A, and 2B), and aperture (LWRS, MDRS, and HIRS), all available spectra were shifted to a common wavelength zero point and combined into a single spectrum. These spectra were then fitted to an interstellar absorption model. The wavelength shifts necessary to align the spectra with the model are plotted in Figures F.1 through F.3 for LWRS; in Figures F.4 through F.7 for MDRS; and in Figures F.8 through F.11 for HIRS. The length of each horizontal line represents the wavelength span of one window. Several features seen in this plot are repeated in those for other channels and apertures. Most show a linear stretch in the wavelength scale of approximately 10 km s^-1 over an entire detector segment. Local distortions of 4 to 5 km s^-1 (about one CalFUSE pixel) over scales of a few Å are common. The apparent offset between the wavelength solutions of detector segments A and B (spanning 905-993 and 1003-1090 Å, respectively) may be spurious, as their spectra were shifted to common wavelength zero points independently.

**Figure F.1:** Residual wavelength errors in the LiF2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* LWRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/LWRS_LiF2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.2:** Residual wavelength errors in the SiC1 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* LWRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/LWRS_SiC1_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.3:** Residual wavelength errors in the SiC2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* LWRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/LWRS_SiC2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.4:** Residual wavelength errors in the LiF1 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* MDRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/MDRS_LiF1_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.5:** Residual wavelength errors in the LiF2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* MDRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/MDRS_LiF2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.6:** Residual wavelength errors in the SiC1 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* MDRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/MDRS_SiC1_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.7:** Residual wavelength errors in the SiC2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* MDRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/MDRS_SiC2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.8:** Residual wavelength errors in the LiF1 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* HIRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/HIRS_LiF1_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.9:** Residual wavelength errors in the LiF2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* HIRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/HIRS_LiF2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.10:** Residual wavelength errors in the SiC1 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* HIRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/HIRS_SiC1_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

**Figure F.11:** Residual wavelength errors in the SiC2 spectrum of the white dwarf KPD 0005+5106 observed through the *FUSE* HIRS aperture. Horizontal lines represent the width of a window over which wavelength errors differ by less than half a pixel.
$\begin{figure}\begin{center} \epsfig{figure=figs/HIRS_SiC2_wcal_resid.eps, width=0.8\linewidth}\end{center} \end{figure}$

Appendix FFUSE Residual Wavelength Errors

Appendix F
FUSE Residual Wavelength Errors