by Ann » Sat May 09, 2015 5:41 am
This is a fascinating group of galaxies, and they are definitely perturbed! Except M65, that is. That galaxy looks remarkably serene and symmetric. Not too much is going on inside it, either. There are some young stars in it, but no pink emission nebulas, to the best of my knowledge. Unsurprisingly, this galaxy is a full magnitude
fainter in far infrared light than in blue light, which is typical of dust-poor (and inefficiently star-forming) galaxies. By contrast, richly star-forming M66 is a full magnitude
brighter in far infrared than in blue light.
But there was
a supernova in M65 in 2013, and fascinatingly, it was a Type II supernova, resulting from a massive star undergoing core collapse. So M65 is not totally devoid of young massive stars.
M66, on the other hand, is absolutely contorted by the tidal forces working on it. Interestingly, all the star formation takes place in the dusty inner parts of it, while at the same time there are huge relatively bright smooth outer features that appear to be made up almost entirely of old stars. Thee is a tendency in some galaxies to show star formation and dust only in its inner parts.
M64 is an extreme example of this, but M66 may be evolving towards to a similar state.
NGC 3628 is seen so (almost) perfectly edge on that there are not too many other bright galaxies rivaling it.
NGC 891 is the only even better example I can think of. But unlike NGC 891, NGC 3628 has extremely puffed-up disk endings. Also, unlike NGC 891, NGC 3628 has
a spectacular tidal tail.
Nice APOD!
Ann
This is a fascinating group of galaxies, and they are definitely perturbed! Except M65, that is. That galaxy looks remarkably serene and symmetric. Not too much is going on inside it, either. There are some young stars in it, but no pink emission nebulas, to the best of my knowledge. Unsurprisingly, this galaxy is a full magnitude [i]fainter[/i] in far infrared light than in blue light, which is typical of dust-poor (and inefficiently star-forming) galaxies. By contrast, richly star-forming M66 is a full magnitude [i]brighter[/i] in far infrared than in blue light.
But there was [url=http://i2.wp.com/astrobob.areavoices.com/files/2013/04/M65-reddened-Bill-Williams-MarchMarch-311.jpg?resize=584%2C404]a supernova in M65 in 2013[/url], and fascinatingly, it was a Type II supernova, resulting from a massive star undergoing core collapse. So M65 is not totally devoid of young massive stars.
M66, on the other hand, is absolutely contorted by the tidal forces working on it. Interestingly, all the star formation takes place in the dusty inner parts of it, while at the same time there are huge relatively bright smooth outer features that appear to be made up almost entirely of old stars. Thee is a tendency in some galaxies to show star formation and dust only in its inner parts. [url=http://apod.nasa.gov/apod/ap070802.html]M64[/url] is an extreme example of this, but M66 may be evolving towards to a similar state.
NGC 3628 is seen so (almost) perfectly edge on that there are not too many other bright galaxies rivaling it. [url=http://apod.nasa.gov/apod/ap100225.html]NGC 891[/url] is the only even better example I can think of. But unlike NGC 891, NGC 3628 has extremely puffed-up disk endings. Also, unlike NGC 891, NGC 3628 has [url=http://apod.nasa.gov/apod/ap070727.html]a spectacular tidal tail[/url].
Nice APOD!
Ann