specflux retrieves details of a multi-channel image spectrum which has been integrated over a given region (or the entire image by default). One may specify which function to use to combine the pixel values within the region using the function parameter. Supported values are 'flux density', 'mean', 'median', and 'sum'. Minimal match is supported. specflux also calculates spectrally integrated flux (brightness) values. 

The task uses the brightness units that are specified in the image header (e.g., Jy/beam or K). When 'flux density' is calculated, the resulting spectra are in units of Jy for cube units of Jy/beam and $K*arcsec^2$ for cube units of K. 

The spectral integral that specflux calculates is the sum of the spectrum multiplied by the channel width. The units are updated accordingly. 

If the units are $K*arcsec^2$, multiply the reported value by $2.3504\times10^{-8}\times d^2$, where $d$ is in pc, to convert from units of $K*arcsec^2$ to units of $K*pc^2$.

If provided, major and minor will be used to compute the beam size, and hence the per channel flux densities (if function="flux density"), overriding the input image beam information (if present).

The output of specflux is written to the CASA logger and an ASCII file if logfile is specified. 

 

Parameter descriptions

imagename

Name of the input image (CASA, FITS or MIRIAD images are accepted). 

region

Region selection, using a CASA region file. Default is the entire image. 

box

Rectangular spatial selection, if no region file is supplied. Default is the entire image.

chans

Spectral/channel selection, if no region file is supplied. Default is the entire channel range. 

stokes

Stokes selection, if no region file is supplied. Default are all Stokes planes. 

mask

An image mask file. Default is not to use a mask.  

stretch

If the image mask is a single plane and not a cube of the same dimension as the input data cube, stretch can by set to True to extend the mask to all planes. (Default: False)

function

Aggregate function to use for computing per channel values. Supported values are 'flux density', 'mean', 'median', 'sum'. Minimal match is supported.

unit

Unit to use for the spectral flux calculation. Must be conformant with a typical spectral axis unit. Velocity units may only be used if the spectral coordinate has a rest frequency and if it is $> 0$.

major

Major axis of overriding restoring beam. If specified, it must be a valid quantity (e.g., "4arcsec").

minor

Minor axis of overriding restoring beam. If specified, it must be a valid quantity (e.g., "3arcsec").

logfile

File which to write details. Default is to not write to a file.

overwrite

Overwrite exisitng logfile file if it exists. (Default: False)