Galaxy Colours: Difference between revisions
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==Galaxy Colours== | ==Galaxy Colours== | ||
===Filters in HyperSuprimeCame on Subaru=== | ===Filters in HyperSuprimeCame on Subaru=== | ||
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When we refer to colours we usually mean a combination of these filters to highlight whether a galaxy (or star) spectrum is "red" or "blue". This is also akin to the HR diagram for stars, which uses colours an an indicator of e.g. Temperature. | When we refer to colours we usually mean a combination of these filters to highlight whether a galaxy (or star) spectrum is "red" or "blue". This is also akin to the HR diagram for stars, which uses colours an an indicator of e.g. Temperature. | ||
Combining these you can see how they can be used to understands the SEDs of various objects | |||
[[File:Bowler-sed.jpg]] | |||
Taken from [https://arxiv.org/pdf/1411.2976.pdf Bowler et al. (2015)]. | |||
===Galaxy colour-magnitude diagram=== | ===Galaxy colour-magnitude diagram=== | ||
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[[File:Galaxy_color-magnitude_diagram.jpg]] | [[File:Galaxy_color-magnitude_diagram.jpg]] | ||
===Galaxy colour-colour diagram=== | |||
But you will also see colour-colour diagrams, which are often used to select certain galaxies at certain redshifts as they can pin-point where there are "breaks" in the galaxy spectral energy distribution. | |||
Revision as of 08:50, 19 November 2020
Galaxy Colours
Filters in HyperSuprimeCame on Subaru
Near-infrared filters on VISTA
When we refer to colours we usually mean a combination of these filters to highlight whether a galaxy (or star) spectrum is "red" or "blue". This is also akin to the HR diagram for stars, which uses colours an an indicator of e.g. Temperature.
Combining these you can see how they can be used to understands the SEDs of various objects
Taken from Bowler et al. (2015).
Galaxy colour-magnitude diagram
The most common plot in extragalactic astrophysics, is the colour-magnitude diagram, which plots a colour (blue-red filter) against a magnitude in one of the filters. The y-axis is then the colour and the x-axis is the brightness.
Galaxy colour-colour diagram
But you will also see colour-colour diagrams, which are often used to select certain galaxies at certain redshifts as they can pin-point where there are "breaks" in the galaxy spectral energy distribution.