Infrared spectroscopy of NGC 1068
Spectroscopy of the nucleus of the nearby Seyfert 2 galaxy NGC 1068 has been obtained using the IRTF and the facility Cooled-Grating Array Spectrometer (CGAS). The wavelengths observed covered the expected wavelengths of the Bry (n = 7 → 4), Brα (n = 5 → 4), and the Pfβ (n = 7 → 5) hydrogen recombination lines between 2.2 μm and 4.6 μm. The CGAS has a 32-element InSb array multiplexed by a Reticon and was used at a resolution of ∼250 km s−1, allowing accurate determination of the line profiles and surrounding continua simultaneously. For example, the S/N at each spectral position in the Brα line spectrum was ∼100. The data show that the infrared lines are not more broadened than the optical hydrogen recombination lines, suggesting that the presence of an obscured Seyfert 1-like active nucleus is unlikely unless the visual extinction through any obscuring material present is larger than ∼100 mag.
KeywordsLine Spectrum Spectral Position Line Ratio Line Observation Visual Extinction
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