Extended Data Fig. 6: NICER PDS of various types of noise.
From: Evidence for a compact object in the aftermath of the extragalactic transient AT2018cow
They both track the particle background. (c) The average PDS of 0.0-0.2 keV events. These are the optical light leak events. (d) The average PDS derived from trumpet-rejected events. These are the off-axis events that track the cosmic X-ray and other sources in the FoV. In all cases, the frequency resolution, the number of spectra averaged and the frequency rebinning is same as the left panel of Fig. 1. The red shaded rectangle shows the location of the 224 Hz QPO. The dashed horizontal line indicates the expected Poisson noise level of 2. All the errorbars represent the 1-σ uncertainties.
