Purple bulge
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by
joseph2237
Not sure what a purple bulge is?
Posted
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by
JeanTate
in response to joseph2237's comment.
It's hard to say, IMO. This being a CANDELS image, the RGB pixel values which produced 'purple' should be easy enough to find; however, ferreting out the cause may prove rather more challenging: is it an artifact, of any one of many kinds? a side-product of some simulation1? a fairly mundane combo of relatively bright foreground star with extended - but fainter - background galaxy? Something else?
1 I have no idea how many - if any - simulated/artificial CANDELS images there are
Posted
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by
vrooje
admin, scientist
At the moment there are no simulated CANDELS images, but eventually there will probably be some artificially redshifted images that go to the CANDELS redshifts, so then there will be.
This central source looks like it has a fairly bright point source in it, and in that case the blue can sometimes look like this. That's because the red and green images were taken with the same Hubble camera (the Wide Field Camera 3, or WFC3), but the blue image was taken with a different Hubble camera (the Advanced Camera for Surveys, ACS). And the specific shape a star has on the final image varies more between different cameras than between different filters on the same camera. So the red and green line up pretty well (though not perfectly) with each other, and the blue is different enough that it looks like a blotch on top of the other two filters.
I suspect there's a galaxy under there too, and it may be associated with the object above it, but I am not sure.
Posted