Using the latest upper limits on the 21-cm power spectrum at z \approx 9.1 from the Low Frequency Array ( LOFAR ) , we explore regions of parameter space which are inconsistent with the data .
We use 21CMMC , a Monte Carlo Markov Chain sampler of 21CMFAST which directly forward models the 3D cosmic 21-cm signal in a fully Bayesian framework .
We use the astrophysical parameterisation from 21CMFAST , which includes mass-dependent star formation rates and ionising escape fractions as well as soft-band X-ray luminosities to place limits on the properties of the high- z galaxies .
Further , we connect the disfavoured regions of parameter space with existing observational constraints on the Epoch of Reionisation such as ultra-violet ( UV ) luminosity functions , background UV photoionisation rate , intergalactic medium ( IGM ) neutral fraction and the electron scattering optical depth .
We find that all models exceeding the 21-cm signal limits set by LOFAR at z \approx 9.1 are excluded at \gtrsim 2 \sigma by other probes .
Finally , we place limits on the IGM spin temperature from LOFAR , disfavouring at 95 per cent confidence spin temperatures below \sim 2.6 K across an IGM neutral fraction range of 0.15 \lesssim \bar { x } _ { \mathrm { H { \scriptscriptstyle I } } { } } \lesssim 0.6 .
Note , these limits are only obtained from 141 hrs of data in a single redshift bin .
With tighter upper limits , across multiple redshift bins expected in the near future from LOFAR , more viable models will be ruled out .
Our approach demonstrates the potential of forward modelling tools such as 21CMMC in combining 21-cm observations with other high- z probes to constrain the astrophysics of galaxies .