General

• Levine et al.
• http://arxiv.org/abs/0711.3478
• Simulation with high dynamic range (1E7) down to 0.1pc, i.e. to the accretion disk of a SMBH.
• Global instabilities make things quasi-stable locally due to turbulence.
• An exponential density profile for the gas in a disk arises naturally due to this.

Here and here. Funny as usual.

Things that happen when you neglect your blog #187: You find a finished article that you forgot to publish and which is quite outdated now. You now have to bite the bullet and publish it anyway, because you are to cheap to ditch it.

“You” in that case is, of course, me. So here it comes:

It has already been all over the news and blogs, but I cannot resist to comment a little more on the newly opened Galaxy Zoo.

The site shows galaxy images from the SDSS to the public and lets them classify them. Categories are very simple: spirals (subdivided into direction of rotation and edge-on), ellipticals, mergers and stars/unknown. The aim is, of course, to use the human brains’ excellent capability to recognise pattern, even if they are feeble. What a wonderful project! I am quite sure it will become popular and therefore successful.

As a “professional”, however, one gets into troubles when trying this myself. That’s because of a little too much background knowledge. Mainly, I find it hard to ignore the color of a galaxy or some other details that are visible. This probably biases my judgment more towards the “other” classification as compared to the more specific ones.

Everbody who reads the daily news on astrp-ph knows that there is a lot coming in and very little of it is really relevant for the own work.

I think I have found a decent solution to this. It uses Yahoo Pipes on the RSS feed from arxiv.org. Have a look at this screenshot from the interface:

It is as simple as telling Pipes to get the feed, filter it according to your needs and providing the output which you can in turn prenumerate with your favourite RSS or other news aggregator. I have created three such pipes for myself, one for a list of author names, one for keywords in the title or abstract and one for certain favourite astronomical objects that I work with.

This has reduced the number of papers that I have to check to around ten per day and the chances of them being relevant are usually quite good. Of course the results depend completely on your filter criteria and this whole thing might not be for you if you are afraid to miss something.

Well, to be honest, this blog has been kinda dead lately and the main reason for this is that the two most active bloggers of us write several other blogs, including a Swedish one about astronomy.

Therefore, I will from now on abuse this blog to very briefly mention the papers that I find interesting from the daily batch at astro-ph. By giving tags, I hope that I myself will be able to find things again after a while. I have no idea how interesting this will be to read for others, but that’s not for me to judge anyway…

The European Southern Observatory has (not before time) redesigned its website. Among the changes are a new tagline: Astronomy made in Europe. Now I know that a lot of ESO’s astronomy gets done in Garching in Germany, and plenty more at people’s home institutions, but the really cool stuff that ESO does gets done at its observatories in Chile. And in this postcolonial world, that is not Europe, no matter how regularly Kaffee und Kuchen is served at the ESO Guesthouse.

They found holes on Mars! What can have caused them?

(Pictures: NASA / JPL / U. Arizona and Flickr)