Median Statistics Estimate of the Distance to M87

IF 3.3 3区物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS

Publications of the Astronomical Society of the Pacific Pub Date : 2024-03-05 DOI:10.1088/1538-3873/ad220e

Nicholas Rackers, Sofia Splawska, Bharat Ratra

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引用次数: 0

Abstract

de Grijs & Bono compiled 211 independent measurements of the distance to galaxy M87 in the Virgo cluster from 15 different tracers and reported 31.03 ± 0.14 mag as the arithmetic mean of a subset of this compilation as the best estimate of the distance. We compute three different central estimates—the arithmetic mean, weighted mean, and the median—and corresponding statistical uncertainty for the full data set as well as three sub-compilations. We find that for all three central estimates the error distributions show that the data sets are significantly non-Gaussian. As a result, we conclude that the median is the most reliable of the three central estimates, as median statistics do not assume Gaussianity. We use median statistics to determine the systematic error on the distance by analyzing the scatter in the 15 tracer subgroup distances. From the 211 distance measurements, we recommend a summary M87 distance modulus of

31.08−0.04+0.05

(statistical)

−0.06+0.04

(systematic) mag, or combining the two errors in quadrature

31.08−0.07+0.06

mag, rounded to 16.4 ± 0.5 Mpc, all at 68.27% significance.

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距离 M87 的中位数统计估计值

de Grijs & Bono汇编了室女座星系团中M87星系距离的211个独立测量值，这些测量值来自15个不同的追踪器，并报告说31.03 ± 0.14 mag是这个汇编子集的算术平均值，是距离的最佳估计值。我们计算了三个不同的中心估算值--算术平均值、加权平均值和中位数，以及完整数据集和三个子汇编的相应统计不确定性。我们发现，对于所有三种中心估计值，误差分布都表明数据集明显是非高斯的。因此，我们得出结论，中位数是三个中心估计值中最可靠的，因为中位数统计不假定高斯性。通过分析 15 个示踪剂子群距离的散布情况，我们利用中位数统计来确定距离的系统误差。根据 211 个距离测量值，我们建议 M87 的距离模数为 31.08-0.04+0.05（统计误差）-0.06+0.04（系统误差）mag，或者将两个误差四舍五入为 31.08-0.07+0.06 mag，四舍五入为 16.4 ± 0.5 Mpc，显著性均为 68.27%。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Publications of the Astronomical Society of the Pacific 地学天文-天文与天体物理

CiteScore

6.70

自引率

5.70%

发文量

103

审稿时长

4-8 weeks

期刊介绍： The Publications of the Astronomical Society of the Pacific (PASP), the technical journal of the Astronomical Society of the Pacific (ASP), has been published regularly since 1889, and is an integral part of the ASP''s mission to advance the science of astronomy and disseminate astronomical information. The journal provides an outlet for astronomical results of a scientific nature and serves to keep readers in touch with current astronomical research. It contains refereed research and instrumentation articles, invited and contributed reviews, tutorials, and dissertation summaries.