madbadgalaxyman
23-05-2011, 12:22 AM
Here's another interesting Ultraviolet image obtained from the GALEX satellite by means of the GalexView "virtual telescope" interface.
This image is about as clean as GALEX images can get, as the raw data is unbelievably ratty; the actual images that are displayed by GalexView range from incredibly noisy and out-of-focus to fairly sharp. However, GALEX lets us discover things that no eye has seen before!!
Here is the Eastern side of M81, showing the dwarf irregular galaxy Holmberg IX (alias UGC 5336), which could well be closely associated with M81. As usual, the brightness of dwarf irregulars is massively increased when we view them in these ultraviolet images...... so "HO IX" really jumps out at you.
There is a possible case for interaction between HO IX and M81, judged from this image.
94512
Here is the northernmost part of M81 showing apparent knots of star formation all over the field, a long way from the bright part of the galaxy. As we all know, star formation requires cold interstellar gas as a fuel, and I see some tentative correspondence between these knots and features in the distribution of cold atomic hydrogen gas that extends between the galaxies M81 and M82 and NGC 3077.
[[ However, my available HI (21cm)(cold atomic hydrogen) images are at very low resolution ]]
94513
Madbadgalaxyman's "astro-provocation" of the day:
Is that a dwarf galaxy forming on the NE Side of M81?
Here is an image of the southern part of M81, again showing UV -luminous knots extending way into the field. Hard to imagine how this could happen except through galaxy interactions.
94514
_____________________________
The outermost regions of M81 are very peculiar in the UV....
I have never seen anything like it in the optical regime!
I have just realized that there was a fairly recent paper written showing an exact correspondence between some of these outermost star-forming knots and concentrations in the unusual inter-galaxy gas that pervades the M81 galaxy group.
Cheers, madbadgalaxyman
This image is about as clean as GALEX images can get, as the raw data is unbelievably ratty; the actual images that are displayed by GalexView range from incredibly noisy and out-of-focus to fairly sharp. However, GALEX lets us discover things that no eye has seen before!!
Here is the Eastern side of M81, showing the dwarf irregular galaxy Holmberg IX (alias UGC 5336), which could well be closely associated with M81. As usual, the brightness of dwarf irregulars is massively increased when we view them in these ultraviolet images...... so "HO IX" really jumps out at you.
There is a possible case for interaction between HO IX and M81, judged from this image.
94512
Here is the northernmost part of M81 showing apparent knots of star formation all over the field, a long way from the bright part of the galaxy. As we all know, star formation requires cold interstellar gas as a fuel, and I see some tentative correspondence between these knots and features in the distribution of cold atomic hydrogen gas that extends between the galaxies M81 and M82 and NGC 3077.
[[ However, my available HI (21cm)(cold atomic hydrogen) images are at very low resolution ]]
94513
Madbadgalaxyman's "astro-provocation" of the day:
Is that a dwarf galaxy forming on the NE Side of M81?
Here is an image of the southern part of M81, again showing UV -luminous knots extending way into the field. Hard to imagine how this could happen except through galaxy interactions.
94514
_____________________________
The outermost regions of M81 are very peculiar in the UV....
I have never seen anything like it in the optical regime!
I have just realized that there was a fairly recent paper written showing an exact correspondence between some of these outermost star-forming knots and concentrations in the unusual inter-galaxy gas that pervades the M81 galaxy group.
Cheers, madbadgalaxyman