Today's Colloquium: The HI4PI Survey

© Benjamin Winkel & HI4PI collaboration

The image shows the column density of neutral atomic hydrogen in our galaxy, the Milky Way. It is one result of a new 21-cm spectroscopic survey of the full sky, the HI 4-PI Survey (HI4PI). The HI4PI data set was merged from two recent surveys, the Effelsberg-Bonn HI Survey, made with the 100-m radio telescope at Effelsberg/Germany, and the Galactic All-Sky Survey (GASS), observed with the

Parkes 64-m dish in Australia.

HI4PI is the most sensitive all-sky HI survey ever performed, offering high angular resolution and very accurate flux density calibration. It is furthermore corrected for stray radiation effects.