|Submitter:||Ger de Bruyn|
|Description:|| On the 22d of Nov 2016 Ajinkya Patil defended his thesis with the title: LOFAR Epoch of Reionization: Statistical methods and First Results. Profs Saleem Zaroubi and Ger de Bruyn acted as promotors. The defence took place in the beautiful aula of the University of Groningen. |
Dr Patil's thesis is one of the many theses that have been delivered in the past 8 years at the University of Groningen on the subject of the LOFAR EoR project. However, it is the first that contains LOFAR results on the highly redshifted 21cm signals that we are aiming to detect.
His thesis contains a paper on the "variance statistic", an efficient way to constrain the redshift evolution of the HI signal, and a paper on the nature and possible cause of the systematic biases in the calibration. The latter reveal themselves as "excess noise" and have occupied us for several years. Both papers have already been published.
A thorough analysis of a single night of LOFAR data was presented in chapter 4 of his thesis. A journal version of that chapter, including all the details of the calibration and subsequent processing, has just been accepted for publication in the Astrophysical Journal (see arXiv 1702.08679). The limits on the spatial power spectra of HI signals for three redshift ranges centered at z=10.1, z=9.1 and z=8.3 are presented in Fig. 4.5 of his thesis and in Fig. 8 of the paper referenced above. These limits are still some factor away from a detection of the elusive signals. We are currently working on a paper with results based on many nights which we trust will produce significantly deeper limits.
At an age of only 25.5 years Ajinkya must have been the youngest PhD student to graduate in the history of the Kapteyn Astronomical Institute. Unfortunately, for us, he has decided to accept a job outside of astronomy. The EoR group is already missing him.