will be interesting to study the detectability using imaging techniques. Some recent attempts have been made to understand the detection possibility of large ionized bubbles with LOFAR, MWA, GMRT [@kanan2007MNRAS.382..809D; @2008MNRAS.386.1683G; @2008MNRAS.391.1900D; @2009MNRAS.399L.132D; @2011MNRAS.413.1409M; @datta2012a; @Datta2012b]. In addition, @2012MNRAS.425.2964Z show that the redshifted 21-cm signal from the EoR can be detected in low-resolution images with LOFAR. Studies have also been done in the same context to detect the signal in post-reionization epochs with SKA1 [@2014JCAP...09..050V]. Our earlier work @ghara15c [hereafter paper I] investigated the detectability of very early sources like metal-free Population III (PopIII) stars, galaxies containing Population II (PopII) stars, mini-QSOs and high-mass X-ray binaries (HMXBs) in the presence of system noise and astrophysical foregrounds using a visibility based techniques. The study showed that the SKA1-low should be able to detect the signal from the sources like the PopII stars, mini-QSOs and HMXBs with $\sim 9-\sigma$ confidence by integrating the visibilities signal over all baselines and frequency channels within $\sim 1000$ hours of observation time.

Once the signal from the cosmic dawn is detected, the challenge would be to interpret it and understand the properties of the first sources and the surrounding IGM. One probably needs to use some 