Starship Asterisk*

re: http://antwrp.gsfc.nasa.gov/apod/image/ ... ndlerM.jpg

In the picture of these interacting galaxies, NGC5195 seems to have little or no detail. (A quick look elsewhere on the internet yielded no "better" images of this galaxy - not saying they're not out there, but I couldn't find any in a cursory search.)

Is this because there was no enhancing of that galaxy as there was for M51 (NGC5194), or is NGC5195 actually an "amorphous blob" type of galaxy?

If it as amorphous as it appears, is this likely to indicate that it is a very young, newly formed galaxy that hasn't yet developed a distinct structure, or what?

http://antwrp.gsfc.nasa.gov/apod/image/ ... ndlerM.jpg

The NGC5195 is believed to slide by, behind the NGC5194. An observation that supports this hypothesis is the amount of asymmetry in 94.

A simple test, you, every day reader of the APOD, can do at home, is fetch an overhead sheet. If you don't have such a sheet, -like me- use one of these transparent plastic bags which encase magazines, sent to you via snail mail. Press it flat on your monitor and draw the contours of the two spiral arms of 94 on this bag, with a felt tip pen! Mark carefully the center of the galaxy. Then rotate the plastic bag by 180 degrees around the galaxy center, until the drawn lines cover roughly the opposite spiral arms. The difference between the drawn lines and the actual spiral arms is a measure for the amount of asymmetry. I suppose that professional astronomers will use image processing techniques and express the amount of asymmetry into a number. We amateurs use an effective low tech solution.

Nevertheless in the lines drawn I did not notice a lot of asymmetry, so the distance between 94 and 95 must be large compared to the length scale of 94. This supports the hypothesis. Why?

Suppose 95 is in the same plane as 94. Then, the distance between the right spiral arm and 95 would have been 3 times smaller than the distance between the left spiral arm and 95. Expressed into attractive forces, it is nearly an order of magnitude. The asymmetry would have been considerable. This is in sharp contrast with the observation, so the assumption: "95 is in the same plane as 94" is not correct.

In spite of all theoretical aspects, which focus the attention to details and numbers, i DO appreciate M51 for its magnificent appearence. My favourite!

To me it looks like the smaller galaxy is the older as there are no dust lanes. It does; however, look like it has a larger core {black hole]. It also looks like it may be starting to feast on M51.
Orin

G'day from the land of ozzzzzzzzzzz

These links may help

http://www.robgendlerastropics.com/M51HST-Gendler.html

http://chandra.harvard.edu/photo/2002/0158/more.html

Atlas of Peculiar Galaxieshttp://en.wikipedia.org/wiki/Atlas_of_Peculiar_Galaxies

NGC 5195
http://en.wikipedia.org/wiki/NGC_5195

M51 and M51b are strongly interacting. According to current models, B came from behind M51, passed through the disk some 600 million years ago, was pulled back by gravity, and passed through again about 100 million years ago, to its current location behind M51. This caused strong distortions in both galaxies, though since M51 is far, far larger it was less affected. It is believed the well pronounced and spaced out spiral arms are caused by this interaction.

M51b is in fact an "amorphous blob", more or less, which is why you can't make out any structure. It is a small dwarf galaxy, much like our LMC, though larger. The gravitational interactions with M51 likely destroyed any structure it may have had.

All the red regions in the image are star forming nebulas, stirred up by the gravitational interactions. M51 is ablaze with star formation.

G'day from the land of ozzzzzz


Cursor control M51

http://chandra.harvard.edu/photo/2002/0158/zoom.html

You may find others through this link