The Possible Impact of GRB Detector Thresholds on Cosmological Standard Candles

Understand

GRB satellites are relatively inefficient detectors of dim hard bursts because they trigger on photon counts, which are number-biased against hard photons.

• Therefore, for example, given two bursts of identical peak luminosity near the detection threshold, a dim soft burst will be preferentially detected over a dim hard burst.
• This detector bias can create or skew an apparent correlation where increasingly hard GRBs appear increasingly bright.
• Although such correlations may be obfuscated by a middle step where GRBs need to be bright enough to have their actual redshifts determined, it is found that the bias is generally pervasive.