Messier 110 (APOD 8 Sep 2006)

BMAONE23 · Post by **BMAONE23** » Fri Sep 08, 2006 1:41 pm

In today's APOD, M110, the caption talks about dust in the 7:00 & 11:00 positions that is part of the dwarf elliptical galaxy. If you look closely at the linked enlargement, it appears that there is also a similar but mirrored and shrunk dusty patches at the 1:00 & 5:00 positions but much smaller and closer to the galactic center. Is this just coincidence or possible lensing effect?

orin stepanek · Post by **orin stepanek** » Fri Sep 08, 2006 1:59 pm

http://antwrp.gsfc.nasa.gov/apod/ap060908.html

I believe you are seeing some dust lanes but a lot lighter than the two that were pointed out. Just an opinion.

Orin

brickc · Post by **brickc** » Fri Sep 08, 2006 5:14 pm

There is a typo in today's APOD: should be "elliptical"

I absolutely adore APOD.

iamlucky13 · Post by **iamlucky13** » Fri Sep 08, 2006 5:32 pm

I vote for coincidence. It's hard to tell, but the smaller blotches don't appear to have quite the same shape, and the 1 O'clock blotch is smaller proportionally compared to the 11 O'clock than the 5 is to the 7.

Would lensing be able to create double images? Also, M110 is very close to us. I'd be surprised if there were a significant hidden mass between here and there to accomplish the lensing.

astro_uk · Post by **astro_uk** » Fri Sep 08, 2006 5:57 pm

Its almost certain to be just more dust and gas. Its generally rare to find just one patch of dust in a galaxy (though some galaxies do show this NGC 3923 being one). I've tried to find some images of M110 (NGC 205) in other wavelength bands, as dust is generally less visible in infra-red and more obvious in the shorter wavelength ranges (i think thats the way around).

Check out this image for some real dust lanes

http://apod.nasa.gov/apod/ap050507.html
http://heritage.stsci.edu/2000/14/big.html

It is two almost exactly aligned galaxies, you can really see the dust in the front one.

Classycat · Post by **Classycat** » Fri Sep 08, 2006 7:00 pm

Please forgive a dumb question from an clueless astronomer wanna-be, but I was curious; are most of the other objects in this picture distant galaxies, or are they simply other stars in our own galaxy?

astro_uk · Post by **astro_uk** » Fri Sep 08, 2006 7:31 pm

The simple answer is that it depends.

In this image its almost certain that the vast majority are stars. But if the image was deep enough (long enough exposure) the majority of objects would probably be galaxies.

You can usually pick out the galaxies because they are not circular in shape, there is a good example of a background galaxy to the south of the large galaxy.

Classycat · Post by **Classycat** » Fri Sep 08, 2006 7:38 pm

Thank you!