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By using the Keck telescope and HIRES spectrograph we have detected Na I D absorption lines in the spectrum of the QSO PKS 2020$-$370 (V = 17.5, z = 1.048) due to the galaxy Klemola 31A (z = 0.0288). The PKS 2020$-$370 line of sight is near an apparent spiral arm only 20{\tt"} from the nucleus of Klemola 31A which corresponds to 17 kpc ($\rm H_o$ = 50 $\rm km~s^{-1}~Mpc^{-1}$). The spectrum of PKS 2020$-$370 has strong Ca II absorption lines ($\rm W_{\lambda}$ $\approx$ 350 m\AA \ for the K line) at the galaxy redshift (Boksenberg et al, 1980, ApJ, 242, L145), but previous attempts to detect Na I have resulted in upper limits (Boisse et al. 1988, A\&A, 191, 193, Womble, 1992, thesis UCSD). We observed PKS 2020$-$370 with HIRES in May 1994 at a resolution of 8 $\rm km~s^{-1}$ FWHM for a total of 90 minutes. The Na I D doublet is detected with a total $\rm W_{\lambda}$ for the Na I 5891.6 \AA \ (vac) absorption line of about 160 m\AA . The absorption appears as two main velocity components separated by 23 $\rm km~s^{-1}$. The optically thin estimate for N(Na I) = 1.0 $\times$ $10^{12}$ $\rm cm^{-2}$ gives an estimated N(Ca II)/N(Na I) = 5. This value suggests that the gas in Klemola 31A along the QSO line of sight is ``halo like''. Along ``disk like'' lines of sight where Ca is thought to be depleted onto grains in our Galaxy, the N(Ca II)/N(Na I) ratio is usually small ($\le$ 1). Other QSO--galaxy pairs often show disk like N(Ca II)/N(Na I) ratios when the line of sight intersects starlight at 25 mag per sq. arcsec (Womble, 1992 thesis UCSD). The PKS 2020$-$370 sightline is near the optical extent of Klemola 31A but the N(Ca II)/N(Na I) is consistent with the sightline passing through two clouds in the halo.
This research has been supported in part by NASA NAS5--29293 and NAG5--1630.
