SDSS DR9! Spectra galore!

[Nereid]

The ninth data release of the Sloan Digital Sky Survey - SDSS DR9 - was yesterday.

Here are some fun facts:
Sky coverage 14,555 square degrees
Catalog objects 932,891,133
Galaxy spectra 1,457,002
Quasar spectra 228,468
Star spectra 668,054

Most of what's new is the spectra, "more than 800,000 new galaxy, quasar and stellar spectra" in fact. This is due, in part, to BOSS (Baryon Oscillation Spectroscopic Survey); the replacement of the original SDSS spectrographs with the new BOSS ones means most of the new spectra are of considerably higher quality than those in DR8. However, there are other notable changes, from DR8, including the fixing of an astrometric error, and a new SSPP (SEGUE Stellar Parameters Pipeline).

[parejkoj]

I noted this in the "fun arxiv papers" thread. Repeating some of what I said there:

DR9 includes the data from all previous data releases, analyzed using the latest software pipelines, with spectra of about 1.5 million galaxies, 228 thousand quasars, and 668 thousand stars, in addition to the roughly a billion photometric sources.

If you want to do research in an astrophysics subject, there's probably data you can use in DR9. It's all there, and it's quite well documented, so dig in!

Edited to add: See Figure 5 of the DR9 paper for two examples of how much better the new BOSS spectrograph is.

[parejkoj]

If the data itself didn't catch your eye, maybe this flythrough of the local universe will. Each galaxy is placed at its measured position, and the pictures of the galaxies have the correct size, shape, and color. You can clearly make out the voids, walls, and clusters that define the large scale structure of the cosmos.

Pretty cool.