A prominent research theme at ASTRON involves the study of Cosmic Dawn (CD) and Epoch of Reionization (EoR) with LOFAR. These eras span the first billion years of the Universe’s history when the first stars and galaxies appeared and died, forming the first elements that make up everything that we see around us today. This period in the history of the Universe remains the least explored. Advancing our understanding of this early universe has been a primary motivation for the construction of the Square Kilometre Array.

Searching the 21-cm line

LOFAR is searching for the 21-cm line signal from diffuse neutral hydrogen between 110 and about 200 MHz, corresponding to a Cosmic time between 400 and 900 million years after the Big-Bang. More recently, the AARTFAAC system on LOFAR is also being used to search for similar signal from the earlier cosmic dawn epoch, about 200 million years after the big bang.

Most of the current group members are based at ASTRON and the Kapteyn Astronomical Institute of the University of Groningen, but the team involves members from e.g. the UK, Germany and Sweden.

Research staff

Andre Offeringa

Harish Vedantham

Latest tweets

Daily image of the week

On June 13-17, the LOFAR Family Meeting took place in Cologne. After two years LOFAR researchers could finally meet in person again. The meeting brings together LOFAR users and researchers to share new scientific results.

Our renewed ‘Melkwegpad’ (Milky Way Path) is finished! The new signs have texts in Dutch on the one side and in English on the other side. The signs concerning planets have a small, 3D printed model of that planet in their centre.
#Melkwegpad @RTVDrenthe

Daily image of the week

The background drawing shows how the subband correlator calculates the array correlation matrix. In the upper left the 4 UniBoard2s we used. The two ACM plots in the picture show that the phase differences of the visibilities vary from 0 to 360 degrees.

Daily image of the week: Testing with the Dwingeloo Test Station (DTS)
One of the key specifications of LOFAR2.0 is measuring using the low- and the highband antenna at the same time. For this measurement we used 9 lowband antenna and 3 HBA tiles.