A meta-analysis of distance measurements to M87.

We obtain the median-, the arithmetic mean–, and the weighted mean–based central estimates for the distance to M87 using all the measurements collated in literature. We then reconstruct the error distribution for the residuals of the combined measurements and also split them based on the tracers used. We then check for consistency with a Gaussian distribution and other symmetric distributions such as Cauchy, Laplacian, and Student's- t distributions. We find that when we analyze the combined data, the weighted mean–based estimates show a poor agreement with the Gaussian distribution, indicating that there are unaccounted systematic errors in some of the measurements. Therefore, the median-based estimate for the distance to M87 would be the most robust. This median-based distance modulus to M87 is given by 31.08 ± 0.09 mag and 31.07 ± 0.09 mag, with and without considering measurements categorized as "averages," respectively. [ABSTRACT FROM AUTHOR]