ATCA search for 21 cm emission from a candidate damped Ly-αabsorber at ${\vec z} = 0.101$

N. Kanekar, J. N. Chengalur, R. Subrahmanyan, P. Petitjean
2001 Astronomy and Astrophysics  
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 3.3 σ level --- which yields a lower limit of 730 K on the spin temperature of the system. No HI emission was detected: the 3σ upper limit on the HI mass of the absorber is 2.25 × 10^9 M_, for a velocity spread of ∼ 70 km s^-1. The low HI mass and the high spin
more » ... perature seem to rule out the possibility that the absorber is a large gas-rich spiral galaxy.
doi:10.1051/0004-6361:20000420 fatcat:tgvab76vsbbj7f2cuoqvnqfgqe