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Crab Conv

NAME

crab_conv.pro - converts to and from crab units

USAGE

result = crab_conv( energy, low, high, [units], [direction] )

DESCRIPTION

This function converts a given energy to/from Crab units. It assumes the x-ray spectrum of the Crab is an unabsorbed powerlaw, I(E)=9.7*E^-1.1 keV s^-1 cm^-2 keV^-1. One "Crab unit" is the integral of the intensity over an energy range specified by "low" and "high".

ARGUMENTS (SWITCHES/FLAGS)

energy
The energy to be converted to/from Crab units

low
Lower limit of the energy band (in keV)

high
Higher limit of the energy band (in keV)

units
If 'kev' is given, the energy unit is kev/s/cm^2. Otherwise it is erg/s/cm^2.

direction
If -1 is given, converts to Crab units from the specified energy unit. Otherwise, converts from Crab units to the specified energy unit.

EXAMPLES

1. print, crab_conv( 7, 2.5, 20 ) 1.86343e-07

Converts an energy of 7 Crab units, detected over the range 2.5 to 20keV, into erg/s/cm^2

2. print, crab_conv( 30, 2.5, 20, 'kev', -1 ) 1.80538

Converts an energy of 30 keV/s/cm2, detected over the range 2.5 to 20keV, into Crab units.

BUGS

Please report problems to hauke.worpel@monash.edu

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