by Ann » Tue Jul 23, 2013 10:26 am
Congratulations on having your processing of this galaxy chosen by HEIC, geckzilla.
NGC 524 is definitely an interesting galaxy (but then, most galaxies are).
NGC 524 is fascinatingly similar to
NGC 2787. Both galaxies are lenticular galaxies. Both have numerous thin dust lanes encircling their nuclei. Both are very red as galaxies go, which appears to be a common trait among lenticulars. Their B-V indexes appear to be even redder than the B-V colors of ellipticals, or at least I get that impression when I routinely check the colors of galaxies of various types.
So the B-V index of NGC 524 is 1.050, according to my software, and its U-B index is 0.600. That is really red. Fascinatingly, NGC 2787 is even redder, with B-V and U-B indexes of 1.060 and 0.670.
For comparison, we may look at the colors of giant elliptical galaxies M84, M86 and M87. Their B-V indexes are 0.980, 0.930 and 0.960, all just a tad bluer than the B-V indexes of NGC 524 and NGC 2787.
But the U-B indexes of these elliptical galaxies are generally redder than the U-B colors of lenticulars NGC 524 and 2787. The U-B indexes of M84, M86 and M87 are 0.700, 0.655 and 0.740.
A possible explanation for these colors is that the lenticulars contain a small population of young or moderately young blue stars, whose "blue contribution", however, is smaller than the "reddening contribution" of dust in the lenticulars. But the moderately young stars have light curves that peak in the ultraviolet part of the spectrum, so that their "ultraviolet contribution" is greater than their "blue contribution". Ellipticals, by contrast, generally lack both dust and young stars. Therefore the lenticulars are often redder in B-V than ellipticals, but often bluer in U-B than ellipticals.
In any case, it is not hard to believe that the dust arcs around the nuclei of NGC 1316 and NGC 2787 could be the remnants of these galaxies' spiral past.
Ann
Congratulations on having your processing of this galaxy chosen by HEIC, geckzilla.
NGC 524 is definitely an interesting galaxy (but then, most galaxies are). :wink: NGC 524 is fascinatingly similar to [url=http://heritage.stsci.edu/2002/07/index.html]NGC 2787[/url]. Both galaxies are lenticular galaxies. Both have numerous thin dust lanes encircling their nuclei. Both are very red as galaxies go, which appears to be a common trait among lenticulars. Their B-V indexes appear to be even redder than the B-V colors of ellipticals, or at least I get that impression when I routinely check the colors of galaxies of various types.
So the B-V index of NGC 524 is 1.050, according to my software, and its U-B index is 0.600. That is really red. Fascinatingly, NGC 2787 is even redder, with B-V and U-B indexes of 1.060 and 0.670.
For comparison, we may look at the colors of giant elliptical galaxies M84, M86 and M87. Their B-V indexes are 0.980, 0.930 and 0.960, all just a tad bluer than the B-V indexes of NGC 524 and NGC 2787.
But the U-B indexes of these elliptical galaxies are generally redder than the U-B colors of lenticulars NGC 524 and 2787. The U-B indexes of M84, M86 and M87 are 0.700, 0.655 and 0.740.
A possible explanation for these colors is that the lenticulars contain a small population of young or moderately young blue stars, whose "blue contribution", however, is smaller than the "reddening contribution" of dust in the lenticulars. But the moderately young stars have light curves that peak in the ultraviolet part of the spectrum, so that their "ultraviolet contribution" is greater than their "blue contribution". Ellipticals, by contrast, generally lack both dust and young stars. Therefore the lenticulars are often redder in B-V than ellipticals, but often bluer in U-B than ellipticals.
In any case, it is not hard to believe that the dust arcs around the nuclei of NGC 1316 and NGC 2787 could be the remnants of these galaxies' spiral past.
Ann