Wednesday, September 12, 2007

Small Galaxies


Small dark galaxies have been found surrounding our Milky Way. Since Fritz Zwicky in the 1930's, astronomers have suspected that galaxies are surrounded by hidden mass. Astronomer Vera Rubin reached a similiar conclusion based upon galaxy rotation rates. Theorists have believed that the galaxy is surrounded by hundreds of smaller galaxies. Since these are not visible, it was suggested that the dwarf galaxies are made entirely of dark mass.

Earlier this year astronomers reported on VIRGO H121, a Dark Galaxy. This galaxy could be found found only from its radio emissions. When VIRGO H121 was first noticed back in 2000, the astronomy community was very skeptical. Sometimes a new observation takes years to be accepted.

The dark halo surrounding our galaxy holds many dicoveries. Just one month ago astronomers found a Pulsar in Galactic Halo. Like pulsars within the galaxy, this object gives off rotating beams of radiation like a lighthouse. A pulsar's energy source has been a mystery, but the twin jets are like those given off by a Black Hole.

The dwarf galaxies were originally located using the Sloan Digital Sky Survey. Further observations with our Keck II telescope on Mauna Kea. These galaxies are 10,000 times smaller than the Milky Way. Since mass of the galaxies is 100 times greater than that of the stars alone, there must be further dark mass in their vicinity. Astronomers now believe that hundreds of these dark galaxies surround our Milky Way.

These results will be reported in the November 10 issue of Astrophysical Journal. Because these are distinct from dwarf galaxies, they have been nicknamed "hobbit galaxies." Will there be elf galaxies and orc galaxies?

Since every galaxy contains at its centre a massive Black Hole, it is logical to infer that dark galaxies contain them too. Hundreds of dark galaxies could signal thousands of Black Holes in the galactic halo. There could be still more surrounding the dwarf galaxies. Presence of Black Holes would also explain formation of globular clusters. Our Milky Way could be surrounded by a halo of Black Holes.

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9 Comments:

Anonymous a quantum diaries survivor said...

Hi Louise,

I think the picture you illustrate is a quite economical explanation of current observations. I also think that as more data on globulars is gathered, we will find out that black holes at their center are the rule and not the exception...

Cheers,
T.

11:54 AM  
Blogger Kea said...

Wow! That DM counting must be getting way out of hand for the SM! Thanks for keeping us posted.

11:58 AM  
Blogger alex kaplan said...

hi Louise,

would you mind please to add a link to my blog?

http://blackmonsters.blogsopt.com

11:59 PM  
Blogger L. Riofrio said...

For Tommaso: The blog tries to give economical explanations, though sometimes the math is simplified. I left a reply about the invitation to Iran.

For Kea: Your posts are enjoyed every day too. I often wish to be in your part of the world.

For alex: Working on that soon.

9:59 AM  
Blogger alex kaplan said...

thank you very much

3:43 AM  
Blogger Stephen said...

Zwicky was ignored in his time too. It's often said that this was because he insulted everyone around him. I might have liked him, as i enjoy being insulted. But, alas, we had no meaningful overlapping time.

5:45 AM  
Anonymous Viagra Online said...

we call then small, but maybe in this mini galaxies could be numberless life form, just remember the size is not the important issue.

6:27 AM  
Anonymous Invertir en oro said...

I woild like to know more about this topic because looks interesting.

5:07 AM  
Anonymous xlpharmacy said...

There are two scientific senses in which multiple universes are discussed. First, disconnected spacetime continua may exist; presumably, all forms of matter and energy are confined to one universe and cannot "tunnel" between them. An example of such a theory is the chaotic inflation model of the early universe. Second, according to the many-worlds hypothesis, a parallel universe is born with every quantum measurement; the universe "forks" into parallel copies, each one corresponding to a different outcome of the quantum measurement.

4:08 AM  

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