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arXiv · 2504.06034

Distance to M87 as the Mode of the Modulus Distribution

Mariusz Tarnopolski
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Abstract

de Grijs and Bono (ApJS 2020, 246, 3) compiled a list of distances to M87 from the literature published in the last 100 years. They reported the arithmetic mean of the three most stable tracers (Cepheids, tip of the red giant branch, and surface brightness fluctuations). The arithmetic mean is one of the measures of central tendency of a distribution; others are the median and mode. The three do not align for asymmetric distributions, which is the case for the distance moduli $\mu_0$ to M87. I construct a kernel density distribution of the set of $\mu_0$ and estimate the recommended distance to M87 as its mode, obtaining $\mu_0 = \left(31.06~\pm~0.001\,\textrm{(statistical)}\,^{+0.04}_{-0.06}\,\textrm{(systematic)}\right)$~mag, corresponding to \linebreak $D=16.29^{+0.30}_{-0.45}$~Mpc, which yields uncertainties smaller than those associated with the mean and median.

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Mariusz Tarnopolski. 2025-04-08. Distance to M87 as the Mode of the Modulus Distribution. https://doi.org/10.3390/astronomy4020006

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