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Computation and conversion of fluxes and magnitudes in ClassX software

Introduction

This document will describe the algorithms and procedures used in the ClassX project to compute magnitude values from flux measurements, and to convert flux measurements from one band system to another. The latter case only arises when converting data between the X-ray bands defined by the RASS and WGACAT catalogs.

The OC1 classifier used by ClassX typically uses magnitudes rather than fluxes to classify objects, to accommodate the large dynamic range of the energy fluxes of astronomical sources.

Algorithms

Assumptions

Flat energy distribution

Uniform channel width

RASS to WGACAT

WGACAT to RASS

Examples

RASS to WGACAT

WGACAT to RASS

Discussion

Comparison with actual values

Algorithm efficiency

Date of last modification: Wednesday, December 03, 2003
Responsible NASA official: Tom McGlynn
Curator: Eric Winter