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NRAO Home > CASA > CASA Task Reference Manual |
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0.1.124 specflux
Requires:
Synopsis
Report spectral profile and calculate spectral flux over a user specified region
Arguments
Inputs |
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imagename |
| Name of the input image
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| allowed: | string |
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| Default: |
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region |
| Region selection. Default is to use the full image.
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| allowed: | any |
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| Default: | variant
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box |
| Rectangular region to select in direction plane. Default
is to use the entire direction plane.
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| allowed: | string |
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| Default: |
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chans |
| Channels to use. Default is to use all channels.
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| allowed: | string |
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| Default: |
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stokes |
| Stokes planes to use. Default is to use all Stokes planes.
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| allowed: | string |
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| Default: |
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mask |
| Mask to use. Default is none.
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| allowed: | string |
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| Default: |
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stretch |
| Stretch the mask if necessary and possible?
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| allowed: | bool | |
| Default: | False |
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function |
| Aggregate function to use for computing per channel
values. Supported values are ”flux density”, ”mean”,
”median”, ”sum”. Minimal match supported.
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| allowed: | string |
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| Default: | flux density |
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unit |
| Unit to use for the spectral flux calculation. Must be
conformant with a typical spectral axis unit.
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| allowed: | string |
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| Default: | km/s |
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major |
| Major axis of overriding restoring beam. If specified,
must be a valid quantity.
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| allowed: | any |
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| Default: | variant
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minor |
| Minor axis of overriding restoring beam. If specified,
must be a valid quantity
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| allowed: | any |
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| Default: | variant
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logfile |
| File which to write details. Default is to not write to a
file.
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| allowed: | string |
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| Default: |
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overwrite |
| Overwrite exisitng ouput file if it exists?
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| allowed: | bool |
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| Default: | False |
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record
Example
PARAMETER SUMMARY
imagename Name of the input (CASA, FITS, MIRIAD) image
region Region selection. Default is to use
the full image.
box Rectangular region to select in direction plane.
for details. Default is to use the entire direction plane.
chans Channels to use. Default is to use
all channels.
stokes Stokes planes to use. Default is to use
all Stokes planes.
mask Mask to use. Default is none.
stretch Stretch the input mask if necessary and possible. Only used if a mask is specified.
function Aggregate function to use for computing per channel values. Supported values are
"flux density", "mean", "median", "sum". Minimal match supported.
unit Unit to use for the spectral flux calculation. Must be conformant with a typical
spectral axis unit (ie something conformant with a velocity, frequency, or length).
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, must be a valid quantity
If specified, minor must also be specified. The overriding beam is used for computing
flux and flux density values. Ignored if the image brightness units do not contain
"/beam". Example "4arcsec".
minor Minor axis of overriding restoring beam. If specified, must be a valid quantity.
If specified, major must also be specified. See help on parameter major for details.
Example: "3arcsec".
logfile Name of file to which to write tabular output. Default is to not write to a file.
overwrite Controls if an already existing log file by the
same name can be overwritten. If true, the user is not prompted, the file
if it exists is automatically overwritten.
This application retrieves details of an image spectrum which has been integrated over a specified
region (or the entire image if no region has been specified).
One may specify which function to use to aggregate pixel values using the function parameter. Supported
values are "flux density", "mean", "median", and "sum". Minimal match is supported.
The spectral flux is reported in units flux density consistent with the image brightness unit times the
specified spectral unit (eg, Jy*km/s, K*arcsec2*km/s). If the units are K*arcsec2..., multiply the
reported value by 2.3504430539098e-8*d*d, where d is the distance in pc, to convert to units of K*pc2...
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.
# write spectrum to file that has been integrated over
# rectangular region, using only pixels with non-negative values.
# if the log file already exists, overwrite it with the new data.
specflux(imagename="my.im", box="10,10,45,50", mask="my.im>=0", unit="km/s", logfile="my.log", overwrite=True)
# Extract the spectral profile using "sum" as the aggregate function from a cube over a given region:
specflux(imagename="myimage.image", box="10,10,45,50", mask="my.im>=0", function="sum", unit="km/s", logfile="profile.log", overwrite=True)
# Calculate the integrated line flux over a given region and channel range
# (this value will be reported as "Total Flux" in the output of specflux)
specflux(imagename="myimage.image", region="myregion.crtf", chans="14~25", unit="km/s", logfile="integrated_line_flux.log", overwrite=True)
More information about CASA may be found at the
CASA web page
Copyright © 2016 Associated Universities Inc., Washington, D.C.
This code is available under the terms of the GNU General Public Lincense
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