Conclusion

Large sky surveys in the 21cm line will improve the measurement of the HI content of the Universe, and this value will find immediate use in anchoring theories of galaxy evolution. Telescopes with large beams will suffer from confusion, which will complicate the determination of the faint end slope of the HI-mass function. Observation of the low column density regime with cm is a new frontier that awaits exploration in the local universe and may be capable of sensing the tip of the ionized intergalactic cloud distribution.

© Copyright Astronomical Society of Australia 1997