Title：Uncovering the Absorbed Atomic Universe using the [OI] 63 and 145µm lines, and implications of self-absorbed [CII]

报告人：Dr. Carlos De Breuck（European Southern Observatory (ESO)）

Abstract：Using the ALMA Band 10 and 9 receivers, we have found that the [OI] 63µm line is strongly self-absorbed in a sample of 12 dusty star forming galaxies at z=4–6 selected from the South Pole Telescope. We find that the emission only escapes the interstellar and circumstellar environment of these galaxies through narrow escape channels. We argue that the [OI] 63µm emission is strongly absorbed along the line of sight by sub-thermal, oxygen rich clouds. Our results are compatible with hydrodynamical simulations, predicting that the 63µm line can lose 90 to 99% of its flux, while optically thin lines such as [OI] 145µm and [NII] 205µm are not affected. We will present examples of four sources where both [OI] lines have been observed, predicting equivalent hydrogen column densities of 10^23 cm^2 of the foreground material. Intriguingly, the [CII] 158µm line can also be affected by these self-absorption effects, albeit to a lesser extent than the [OI] 63µm. We will illustrate this [CII] self-absorption using a comparison of velocity profiles of [OI] 63 and 145 µm data, which shows that in some cases, half of the flux can be reduced. This effect is thus important to consider when analyzing [CII] data.

时间：2026年11月9日（周一）10:30

地点：紫台 5-216会议室

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