Abstract

In this talk, I will report our recent study on the impact of 1/f noise on constraining cosmological parameters using intensity mapping survey, primarily with SKA1 -MID Band 1.  We forecast constraints on cosmological parameters under the CPL mode using Fisher matrix. Without 1/f noise, we project constraints on the dark energy equation of state with (w_0 = -1+/-0.04, w_a = 0+/-0.11), and the HI mass bias b_HI = 1+/-0.02 for SKA1 -MID Band 1+ Planck.  A representative baseline 1/f noise model  degrades the measured HI power spectrum  by a factor of _{10 on average, with large variations in redshift and angular scales. Consequently, the constraints on cosmological parameters are degraded by a factor of} 2.5. In order to mitigate this, one requires a minimised 1/f noise spectral slope, a low knee frequency and a large telescope slew speed.  A correlation of 1/f noise in frequency space is also preferred.