All Tables

Table 1: Observational details and target properties. The spectral types, intrinsic colours and reddenings are discussed in Sect. 4.2.
Table 2: Diffuse interstellar bands investigated in this study. The EW and associated statistical error $\sigma _{\it EW}$ (derived from the adjacent continuum) is quoted in mÅ (first part, Col. 5). Observed central wavelengths, heliocentric velocities and FWHM are given in Cols. 2-4, respectively. For non-detected DIBs upper limits are calculated adopting EW $_{\rm upper\ limit}$ = $2 \ \sigma _{\rm noise}$ FWHM $_{\rm DIB}$ , with $\sigma _{\rm noise}$ the noise in the spectral range of the expected DIB, and FWHM $_{\rm DIB}$ the full width at half maximum of the corresponding DIB observed toward AzV 456. For AzV 18 the first two values are derived from spectra obtained in 2001 and 2003, respectively. The third value is obtained from Welty et al. (2006). Our DIB equivalent widths for AzV 456 are consistent with those derived by Welty et al. (2006). The reported high upper limits for the 5780 Å are due to the lower signal-to-noise in the spectral range and its larger FWHM. The DIB spectral ranges are plotted in Fig. 3. The $\ensuremath {{E_{B-V}}}$ values were derived by subtracting the Milky Way foreground contamination from the line-of-sight reddening (see Sect. 4.2.1 and Table 1).
Table 3: Small Magellanic Cloud atomic column densities for Na I, Ca II and Ti II derived via the construction of apparent column density velocity profiles and subsequent line profile integration (v $\approx$ 80-200 km s^-1). The error in log N is 0.02 dex for Ti II and Ca II K, and $\approx$ 0.03-0.04 dex for the more saturation sensitive Na I D line. Line transition wavelengths and oscillator strengths are adopted from Morton (2003). For both Na I and Ca II the individual doublet line column densities are given, as well as the "optical depth - velocity'' corrected column densities (see text for details).
Table 4: Small Magellanic Cloud atomic hydrogen and molecularhydrogen column densities from different sources.
Table 5: Weak diatomic and atomic UV lines: CH, CH⁺, Ca I, K I and Na I toward AzV 456. The spectral lines are shown in Fig. 7. Central velocities v (km s^-1), equivalent widths EW (mÅ) and column densities log N (cm^-2) are listed.
Table 6: Reddening, total-to-selective extinction, visual extinction, atomic column density ratios, and gas-to-dust ratios for sightlines in the SMC. A higher Na I/Ca II ratio implies less Ca II liberated from dust grains by destructive processes and thus a more quiescent environment. A lower ratio thus indicates a more turbulent medium where dust grains are destroyed and Ca II is released into the gas phase. The Ti depletion level $\delta _{\rm Ti}$ gives a measure of the lock up of the refractory ion in grains. A higher Ti II/Ca II ratio indicates a stronger/harder UV field. $\ensuremath {{E_{B-V}}}$ is corrected for foreground reddening. $R_{\rm V}$ for AzV 65 and Sk 191 from Table 7, other values for $R_{\rm V}$ (and $A_{\rm V}$ ) from Gordon et al. (2003).
Table 7: J, H and K 2MASS photometry (Cutri et al. 2003), intrinsic colours (AN Cox [1] and Winkler [2]) and colour excesses for SMC targets AzV 65 and Sk 191. $R_{\rm V}$ is calculated from the colour excesses using the relationships derived by Fitzpatrick (1999).
Table 8: Galactic (foreground) atomic column densities derived via the construction of apparent column density velocity profiles and subsequent line profile integration. Error in log N is 0.02 dex for Na I, Ti II and Ca II K. Adopted line transition wavelengths and oscillator strengths from Morton (2003). Column densities toward Sk 191 and AzV 242 suffer significantly from line saturation. The smaller values for Ca II/Na I in the Galaxy are consistent with a higher UV in the SMC. Larger Galactic values for Ca II/Ti II by about 0.2 dex, indicate a higher sensitivity to the second ionisation potential in the SMC compared to the Galaxy.
Table 9: Physical properties and conditions of the interstellar medium in the lines-of-sight toward the SMC targets AzV 456 and AzV 18 (this work), the LMC target Sk-69 223 (Cox et al. 2006) and the Galactic targets HD 62542, HD 144217 ( $\sigma$ -type) and HD 149757 ( $\zeta$ -type). UV lines are indicated by (uv) and the weak and strong doublet lines by (w) and (s), respectively.