OBJECTIVE BAYESIAN ANALYSIS OF ''ON/OFF'' MEASUREMENTS
Abstract
In highenergy astrophysics, it is common practice to account for the background overlaid with counts from the source of interest with the help of auxiliary measurements carried out by pointing offsource. In this ''on/off'' measurement, one knows the number of photons detected while pointing toward the source, the number of photons collected while pointing away from the source, and how to estimate the background counts in the source region from the flux observed in the auxiliary measurements. For very faint sources, the number of photons detected is so low that the approximations that hold asymptotically are not valid. On the other hand, an analytical solution exists for the Bayesian statistical inference, which is valid at low and high counts. Here we illustrate the objective Bayesian solution based on the reference posterior and compare the result with the approach very recently proposed by Knoetig, and discuss its most delicate points. In addition, we propose to compute the significance of the excess with respect to the backgroundonly expectation with a method that is able to account for any uncertainty on the background and is valid for any photon count. This method is compared to the widely used significance formula by Li andmore »
 Authors:
 Visiting Scientist, Department of Physics and Astronomy, UCL, Gower Street, London WC1E 6BT (United Kingdom)
 Publication Date:
 OSTI Identifier:
 22364784
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Astrophysical Journal; Journal Volume: 798; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANALYTICAL SOLUTION; APPROXIMATIONS; ASTROPHYSICS; ASYMPTOTIC SOLUTIONS; COMPARATIVE EVALUATIONS; COSMIC PHOTONS; GAMMA RADIATION
Citation Formats
Casadei, Diego, Email: diego.casadei@fhnw.ch. OBJECTIVE BAYESIAN ANALYSIS OF ''ON/OFF'' MEASUREMENTS. United States: N. p., 2015.
Web. doi:10.1088/0004637X/798/1/5.
Casadei, Diego, Email: diego.casadei@fhnw.ch. OBJECTIVE BAYESIAN ANALYSIS OF ''ON/OFF'' MEASUREMENTS. United States. doi:10.1088/0004637X/798/1/5.
Casadei, Diego, Email: diego.casadei@fhnw.ch. 2015.
"OBJECTIVE BAYESIAN ANALYSIS OF ''ON/OFF'' MEASUREMENTS". United States.
doi:10.1088/0004637X/798/1/5.
@article{osti_22364784,
title = {OBJECTIVE BAYESIAN ANALYSIS OF ''ON/OFF'' MEASUREMENTS},
author = {Casadei, Diego, Email: diego.casadei@fhnw.ch},
abstractNote = {In highenergy astrophysics, it is common practice to account for the background overlaid with counts from the source of interest with the help of auxiliary measurements carried out by pointing offsource. In this ''on/off'' measurement, one knows the number of photons detected while pointing toward the source, the number of photons collected while pointing away from the source, and how to estimate the background counts in the source region from the flux observed in the auxiliary measurements. For very faint sources, the number of photons detected is so low that the approximations that hold asymptotically are not valid. On the other hand, an analytical solution exists for the Bayesian statistical inference, which is valid at low and high counts. Here we illustrate the objective Bayesian solution based on the reference posterior and compare the result with the approach very recently proposed by Knoetig, and discuss its most delicate points. In addition, we propose to compute the significance of the excess with respect to the backgroundonly expectation with a method that is able to account for any uncertainty on the background and is valid for any photon count. This method is compared to the widely used significance formula by Li and Ma, which is based on asymptotic properties.},
doi = {10.1088/0004637X/798/1/5},
journal = {Astrophysical Journal},
number = 1,
volume = 798,
place = {United States},
year = 2015,
month = 1
}

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