A survey called GLIMPSE – Galactic Legacy Infrared mid-Plane Survey Extraordinaire has been making use of the Very Large Array and the Spitzer space telescope to seek out large concentrations of ionised hydrogen gas. These H II regions (like the Orion Nebula) are potentially areas where stars are forming and ionising hydrogen. To find out how many were, the Greenbank Radio Telescope took a look and found 448 new star forming regions, showing the signature of hydrogen ions recombining with electrons to form neutral hydrogen. These included 25 H II regions located at a galactic radius greater than that of our own solar system, bringing the total known at these distances to 27.
The Parkes radio telescope has also been performing a Galactic All-Sky survey to determine how many big blobs of gas are out there. Most conglomerations of gas should occur in the vicinity of the bar in the nucleus of the galaxy, where gas and dust are funelled toward the middle. However, it has been hypothesised that stars forming in these mixes lead to supernovae that blast great blobs of matter out of the plane of the disc of the galaxy. Some of these then come to rest further out, back in the plane, as completely disconnected blobs (as opposed to smooth variations in gas and dust concentrations). The survey with Parkes aimed to show that the blobs, which were known about, were in the right place and the right size to be explained this way. This could also explain how so many metals (atoms with atomic numbers greater than those of hydrogen or helium) came to be mixed into the outer arms of the galaxy, when there was unlikely to have been sufficient star formation and destruction there to have created the metals in situ.
Both of these were presented at the 216th American Astronomical Society meeting in Miami, Florida and reported in Astronomy Now.