Thursday, August 30, 2012


The BBC bobbled the subhead ("A space telescope has added to its list of spectacular finds, spotting millions of supermassive black holes and blisteringly hot, "extreme" galaxies."), but the WISE telescope seems to have found some interesting things anyway--and I couldn't resist the jargon. HOT Dust Obscured Galaxies. (Yes, scientists generally have a sense of humor.)

The report references 3 papers at arxiv, one of which describes the discovery of a hyperluminous (3x10^13 times the luminosity of the sun) infrared galaxy. There are some assumptions about the spectrum that may not be quite right, but they won't be wrong by more than a factor of a few: that thing emits a lot of energy. They estimate that this red-shifted (2.4= very distant) galaxy was generated new stars at a rate of 300million/year, or 200 times the rate in our galaxy. I wonder what the night sky would look like.

A second paper follows up with some other hyperluminous galaxies, and concludes that they don't seem to fit well "with existing galaxy templates, suggesting they are a new population with very high luminosity and hot dust. They are likely among the most luminous galaxies in the Universe. We argue that they are extreme cases of luminous, hot dust-obscured galaxies (DOGs), possibly representing a short evolutionary phase during galaxy merging and evolution".

The third paper describes how they use the spectra to try to tell which spots are Active Galactic Nuclei. The paper goes into gory detail about how they decided on the spectral selection rules. "Selecting sources with W1 − W2 ≥ 0.8 identifies 61.9 ± 5.4 AGN candidates per deg^2 at the 10σ". That 61.9 per square degree translates to about 2.5 million AGN they may see when they finish the scan.

Twinkle twinkle, little star, if you're so hot I'm glad you're far.

1 comment:

Texan99 said...

I never thought we'd get to the point in my lifetime when we could get enough data about other galaxies to become connoisseurs.