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Diffuse Far-ultraviolet Observations of the Taurus Region

D. H. Lee·I. S. Yuk·H. Jin·K. I. Seon·J. Edelstein·E. J. Korpela·J. Adolfo·K. W. Min·K. S. Ryu·J. H. Shinn·E. F. van Dishoeck
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Abstract

Diffuse far-ultraviolet (FUV: 1370-1670 A) flux from the Taurus molecular cloud region has been observed with the SPEAR/FIMS imaging spectrograph. An FUV continuum map of the Taurus region, similar to the visual extinction maps, shows a distinct cloud core and halo region. The dense cloud core, where the visual extinction is A_v > 1.5, obscures the background diffuse FUV radiation, while a scattered FUV radiation is seen in and beyond the halo region where A_v < 1.5. The total intensity of H2 fluorescence in the cloud halo is I_{H2} = 6.5 x 10^4 photons cm^{-2} s^{-1} sr^{-1} in the 1370-1670 A wavelength band. A synthetic model of the H2 fluorescent emission fits the present observation best with a hydrogen density n_H = 50 cm^{-3}, H2 column density N(H2) = 0.8 x 10^{20} cm^{-2}, and an incident FUV intensity I_{UV} = 0.2. H2 fluorescence is not seen in the core presumably because the required radiation flux to induce fluorescence is unable to penetrate the core region.

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D. H. Lee, I. S. Yuk, H. Jin, K. I. Seon, J. Edelstein, E. J. Korpela, J. Adolfo, K. W. Min, K. S. Ryu, J. H. Shinn, E. F. van Dishoeck. 2006-02-01. Diffuse Far-ultraviolet Observations of the Taurus Region. https://doi.org/10.1086/505199

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