HI intensity mapping is a new observational technique to survey the large-scale structure of matter using the 21 cm emission line of atomic hydrogen ( HI ) .
In this work , we simulate BINGO ( BAO from Integrated Neutral Gas Observations ) and SKA ( Square Kilometre Array ) phase-1 dish array operating in auto-correlation mode .
For the optimal case of BINGO with no foregrounds , the combination of the HI angular power spectra with Planck results allows w to be measured with a precision of 4 \% , while the combination of the BAO acoustic scale with Planck gives a precision of 7 \% .
We consider a number of potentially complicating effects , including foregrounds and redshift dependent bias , which increase the uncertainty on w but not dramatically ; in all cases the final uncertainty is found to be \Delta w < 8 \% for BINGO .
For the combination of SKA-MID in auto-correlation mode with Planck , we find that , in ideal conditions , w can be measured with a precision of 4 \% for the redshift range 0.35 < z < 3 ( i.e. , for the bandwidth of \Delta \nu = [ 350 , 1050 ] MHz ) and 2 \% for 0 < z < 0.49 ( i.e. , \Delta \nu = [ 950 , 1421 ] MHz ) .
Extending the model to include the sum of neutrino masses yields a 95 \% upper limit of \sum m _ { \nu } < 0.24 eV for BINGO and \sum m _ { \nu } < 0.08 eV for SKA phase 1 , competitive with the current best constraints in the case of BINGO and significantly better than them in the case of SKA .