ATCA search for 21 cm emission from a candidate damped
نویسندگان
چکیده
We report a deep search for 21 cm emission/absorption from the z ∼ 0.101 candidate damped Lyman-α system towards PKS 0439−433, using the Australia Telescope Compact Array (ATCA). The spectrum shows a weak absorption feature — at the 3.3σ level — which yields a lower limit of 730 K on the spin temperature of the system. No H i emission was detected: the 3σ upper limit on the H i mass of the absorber is 2.25× 109M⊙, for a velocity spread of ∼ 70 km s. The low H i mass and the high spin temperature seem to rule out the possibility that the absorber is a large gas-rich spiral galaxy.
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