ABC doesn't add up

The ABC science news is usually quite good, but I just got very confused over a story they have about the size of spiral galaxies. The article describes research recently published in the Astrophysical Journal (ApJ) which makes use of Gemini South telescope based in Chile. There is a pre-print of the paper at the arXiv if you want to read it for yourself. The researchers studied the density of stars as they moved outwards from the middle of a nearby (6 million light years away) spiral galaxy named NGC 300. They were looking for an obvious break in the density but were unable to find one - it was just a smooth exponential decrease. This implies that spiral galaxies could be bigger than currently thought.

What confused me were the last few sentences:

Bland-Hawthorn says the findings also have other implications for astronomy. "It has big consequences for the early universe," he says. NGC 300 has a high redshift, he says, which means we are seeing it as it was early in the universe."We are suggesting the galaxies in the early universe were also very big."And given the universe was an even more violent place in its youth, this makes the question of how large flat disc galaxies form even more of a mystery.


According to the NASA Extragalactic Database (NED), and indeed the published paper, NGC 300 is quite near and has a tiny redshift of 0.00048 (accuracy to the last decimal place). So, the last few sentences about it having a high redshift, and thus we would be seeing it early in the Universe (which is 13.7 billion years old), don't make much sense to me. The quote doesn't feature in the original Gemini press release though so I'm guessing the reporter had a horrific accident with cut and paste.

Posted in astro blog by Stuart on Thursday 11th Aug 2005 (11:05 UTC) | Permalink
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