Talk:Galaxy color–magnitude diagram

Translated to French
This article has just been translated into french. Thank you to all the contributors to this original one. Hop ! Kikuyu3 (talk) 19:30, 21 June 2010 (UTC)

Relation to size - Magnitude diagram ?
On page 58 of Galaxy Formation & Evolution by Mo, van den Bosch, and White, a similar diagram, relating galaxy size to Luminosity, also shows a separation between Ellipticals (evidently redder, too), and Spirals (evidently bluer, too). If so, then, accordingly, the "Blue Cloud" also contains Irregular galaxies (as well as Spirals). Inexpertly, the "Blue" color reflects star formation, lacking in Ellipticals, with older stellar populations. 66.235.38.214 (talk) 05:45, 21 November 2012 (UTC)

Survey Bias?
Stephen A. Eales et al [2018] show that the distinct regions on the diagram are the result of optical surveys, while a submillimeter survey has almost the opposite distribution, with a "green mountain" instead of a "green valley". Thus, this diagram is not evidence for there being two distinct populations.

ExtonGuy (talk) 22:43, 6 September 2018 (UTC)

Is the colour plotted intrinsic or the doppler-shifted observation
Is the colour plotted, the intrinsic colour (that a co-moving observer would see) or the doppler-shifted observation ? How is the 'colour' defined, eg. a ratio between which two filters ? - Rod57 (talk) 17:04, 17 June 2021 (UTC)