[BRIEF NOTE] On the Gaia map of the Milky Way Galaxy

In my morning links post, I mentioned that both Centauri Dreams and The Map Room reported. on the ESA’s Gaia satellite mapping project of the galaxy. Centauri Dreams had explained the import of this project.

The European Space Agency’s Gaia satellite has delivered a catalog of more than a billion stars — 1142 million, to be more specific — as it continues the work of mapping our galaxy in three dimensions. To be sure, we can expect much more from Gaia, but the September 14 data release is a milestone, offering distances and proper motion for more than 2 million stars. The mission’s first public release collects 14 months of data, from July 2014 to September 2015.

“The beautiful map we are publishing today shows the density of stars measured by Gaia across the entire sky, and confirms that it collected superb data during its first year of operations,” says Timo Prusti, Gaia project scientist at ESA.

To get an idea of Gaia’s long-term promise, recall that we are looking at the galaxy with Hubble-like precision. We may have more than a billion stars in today’s release, but 400 million of these are appearing in a catalog for the first time.

The image is downloadable in a variety of file sizes. Fifteen scientific papers describing the Gaia data are to appear in a special issue of Astronomy & Astrophysics. Those interested in digging into Gaia’s first data release can gain access here.

A collaboration of 450 scientists and software engineers known as the Gaia Data Processing and Analysis Consortium (DPAC) is charged with turning the satellite’s raw data into reliable stellar positions. ESA explains just how much of an upgrade Gaia represents in this news release, which discusses not only the billion-star catalog, but the two million stars represented both in Gaia’s work and the earlier Hipparcos catalogs, which are now more than two decades old. Combining the data allows scientists to sort out not just the physical movement of stars in the galaxy but also parallax effects caused by the star’s apparent position during a year-long Earth orbit of the Sun. A combined Tycho-Gaia Astrometric Solution is the result.

We live in a science fiction world.