IIHE invited seminar: The LOFAR EoR project: science goals, foregrounds, processing challenges and status
by
Prof.Ger de Bruyn(ASTRON)
→
Europe/Brussels
Jean Sacton Seminar room (1G003) (IIHE, VUB)
Jean Sacton Seminar room (1G003)
IIHE, VUB
Description
abstract: The LOFAR EoR project set out to measure the spatial power
spectrum (PS) of redshifted HI signals in the redshift range from z =
6 to 11.4. WMAP and Planck data suggest that this redshift range will
cover the most interesting phases of the Epoch of Reionization, a key
phase in the history of the Universe when most of the hydrogen
re-ionized. Among the main questions we are after are the redshift
evolution of the spatial PS and what it might tell us about the
sources of reionization. Following an introduction about our current
thinking of what happened, mostly based on simulations, I will
concentrate on our observational project.
The data taking, in two windows centered on the North Celestial Pole
and the source 3C196, started in earnest in Dec 2012. Thusfar we have
accumulated about 2000 h of data. The project faces a wide variety of
challenges. Many of these had been expected and are well understood.
Among these are RFI, ionospheric effects, calibrating and processing a
Petabyte of data, and dealing with (polarized) Galactic foregrounds.
Constructing an accurate high resolution sky model and solving for
direction-dependent complex gains (due to time-varying station beams
and ionospheric turbulence) have proved more difficult and time
consuming. I will describe and illustrate these challenges and how we
are trying to solve them. In the mean time we are collecting
interesting results on ancillary science related to Galactic and
extragalactic foregrounds, especially as regards to their
polarization. I will conclude with the project status and timeline.