We report estimates of the cosmological parameters \Omega _ { m } and \Omega _ { \Lambda } obtained using supernovae ( SNe ) associated with gamma-ray bursts ( GRBs ) at redshifts up to 0.606 .
Eight high-fidelity GRB-SNe with well-sampled light curves across the peak are used .
We correct their peak magnitudes for a luminosity-decline rate relation to turn them into accurate standard candles with dispersion \sigma = 0.18 mag .
We also estimate the peculiar velocity of the low-redshift host galaxy of SN 1998bw , using constrained cosmological simulations .
In a flat universe , the resulting Hubble diagram leads to best-fit cosmological parameters of ( \Omega _ { m } , \Omega _ { \Lambda } ) = ( 0.58 ^ { +0.22 } _ { -0.25 } , 0.42 ^ { +0.25 } _ { -0.22 } ) .
This exploratory study suggests that GRB-SNe can potentially be used as standardizable candles to high redshifts to measure distances in the universe and constrain cosmological parameters .