Difference image analysis

The interplay between the photometric scale factor and systematic photometric errors

D. M. Bramich, E. Bachelet, K. A. Alsubai, D. Mislis, N. Parley

Research output: Contribution to journalArticle

Abstract

Context. Understanding the source of systematic errors in photometry is essential for their calibration. Aims. We investigate how photometry performed on difference images can be influenced by errors in the photometric scale factor. Methods. We explore the equations for difference image analysis (DIA), and we derive an expression describing how errors in the difference flux, the photometric scale factor and the reference flux are propagated to the object photometry. Results. We find that the error in the photometric scale factor is important, and while a few studies have shown that it can be at a significant level, it is currently neglected by the vast majority of photometric surveys employing DIA. Conclusions. Minimising the error in the photometric scale factor, or compensating for it in a post-calibration model, is crucial for reducing the systematic errors in DIA photometry.

Original languageEnglish
JournalAstronomy and Astrophysics
Volume577
DOIs
Publication statusPublished - 1 May 2015

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image analysis
systematic errors
photometry
calibration

Keywords

  • Methods: data analysis
  • Techniques: image processing
  • Techniques: photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

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title = "Difference image analysis: The interplay between the photometric scale factor and systematic photometric errors",
abstract = "Context. Understanding the source of systematic errors in photometry is essential for their calibration. Aims. We investigate how photometry performed on difference images can be influenced by errors in the photometric scale factor. Methods. We explore the equations for difference image analysis (DIA), and we derive an expression describing how errors in the difference flux, the photometric scale factor and the reference flux are propagated to the object photometry. Results. We find that the error in the photometric scale factor is important, and while a few studies have shown that it can be at a significant level, it is currently neglected by the vast majority of photometric surveys employing DIA. Conclusions. Minimising the error in the photometric scale factor, or compensating for it in a post-calibration model, is crucial for reducing the systematic errors in DIA photometry.",
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author = "Bramich, {D. M.} and E. Bachelet and Alsubai, {K. A.} and D. Mislis and N. Parley",
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TY - JOUR

T1 - Difference image analysis

T2 - The interplay between the photometric scale factor and systematic photometric errors

AU - Bramich, D. M.

AU - Bachelet, E.

AU - Alsubai, K. A.

AU - Mislis, D.

AU - Parley, N.

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Context. Understanding the source of systematic errors in photometry is essential for their calibration. Aims. We investigate how photometry performed on difference images can be influenced by errors in the photometric scale factor. Methods. We explore the equations for difference image analysis (DIA), and we derive an expression describing how errors in the difference flux, the photometric scale factor and the reference flux are propagated to the object photometry. Results. We find that the error in the photometric scale factor is important, and while a few studies have shown that it can be at a significant level, it is currently neglected by the vast majority of photometric surveys employing DIA. Conclusions. Minimising the error in the photometric scale factor, or compensating for it in a post-calibration model, is crucial for reducing the systematic errors in DIA photometry.

AB - Context. Understanding the source of systematic errors in photometry is essential for their calibration. Aims. We investigate how photometry performed on difference images can be influenced by errors in the photometric scale factor. Methods. We explore the equations for difference image analysis (DIA), and we derive an expression describing how errors in the difference flux, the photometric scale factor and the reference flux are propagated to the object photometry. Results. We find that the error in the photometric scale factor is important, and while a few studies have shown that it can be at a significant level, it is currently neglected by the vast majority of photometric surveys employing DIA. Conclusions. Minimising the error in the photometric scale factor, or compensating for it in a post-calibration model, is crucial for reducing the systematic errors in DIA photometry.

KW - Methods: data analysis

KW - Techniques: image processing

KW - Techniques: photometric

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