imreframe

imreframe(imagename, output='', outframe='lsrk', epoch='', restfreq='')[source]

Change the frame in which the image reports its spectral values

[Description] [Examples] [Development] [Details]

Parameters

  • imagename (path) - Name of the input image

  • output (string=’’) - Name of the output image

  • outframe (string=’lsrk’) - Spectral frame in which the frequency or velocity values will be reported by default

    outframe = topo

    • epoch (string=’’) - Epoch to be associated with this image

    outframe = TOPO

    • epoch (string=’’) - Epoch to be associated with this image

    outframe = geo

    • epoch (string=’’) - Epoch to be associated with this image

    outframe = GEO

    • epoch (string=’’) - Epoch to be associated with this image

  • restfreq (string=’’) - restfrequency to use for velocity values (e.g “1.420GHz” for the HI line)

Description

The spectral values assigned to an object depend on the spectral reference frame. This task can change the frame in which the image reports its spectral values.

Parameter descriptions

imagename

Name of the input image.

output

Name of the output image. Default (no output) is to modify the input image.

outframe

Spectral frame in which the frequency or velocity values will be reported by default. See Spectral Frames for more information on the frame definitions.

Abbreviation

Definition

lsrk

local standard of rest (kinematic) - default

lsrd

local standard of rest (dynamic)

bary

barycentric

geo

geocentric

topo

topocentric

galacto

galactocentric

lgroup

local group

cmb

Cosmic Microwave Background dipole

epoch

Epoch to be associated with this image (only with outframe=’geo’ or ‘topo’). For example: ‘2000/12/25/18:30:00.10’.

restfreq

Rest-frequency to use for velocity value. For example: restfreq=’1.420405752GHz’ for the HI 21cm line of neutral hydrogen. The default is to use the rest-frequency already present in the input image.

Examples

To change the spectral reference frame of an image (‘linecube.image’) to the Local Group reference frame using the rest-frequency values already stored in the original image, and then save the output image into a new image (‘linecube_new.image’):

imreframe(imagename='linecube.image',
          output='linecube_new.image' outframe='lgroup')

To change the spectral reference frame of an image that contains the NH 3 (1,1) line into the barycentric values, and overwrite the input image:

imreframe(imagename='NH3_cube.image', outframe='bary',
          restfreq='23.694496GHz')
Development

No additional development details

Parameter Details

Detailed descriptions of each function parameter

imagename (path) - Name of the input image
output (string='') - Name of the output image
outframe (string='lsrk') - Spectral frame in which the frequency or velocity values will be reported by default
epoch (string='') - Epoch to be associated with this image
restfreq (string='') - restfrequency to use for velocity values (e.g “1.420GHz” for the HI line)