[daip] A question about HI image analysis in classical AIPS !!

[Everton Ludke]

Dear Sir,

    I got a quick question about classical AIPS.

    Let us suppose I want to get the total neutral hydrogen
mass of a galaxy from VLA HI observations.

    According to the AIPS Cookbook, one must produce the data
cube with MX or other imaging task. Then you must ALTDEF and
ALTSW to get the channel axis converted to a velocity axis.
Then, you BLANK the off-source pixels to magical values.

    After that, the cube axis must be inverted in order
with task TRANS, TRANSCOD='-312' to get the decreasing velocity
as first axis.  XMOM can be run afterwards to get the moment
images from that cube.

    My questions are:

  (a) How could we get the total neutral hydrogen mass
from the XMOM0 image ?

I believe that I must set some sort of box around the galaxy
and integrate the total HI flux with some aips task, but
I don't know which tasks must be used to get MHI in solar
masses from that map.

  (b) How to get the radial velocity profile of the rotation
curve with the XMOM1 image, without using GAL for model fitting ?

It seems to me that we must make a slice of XMOM1 image, specifying
a vector R from the centre of the galaxy to the desired point in an
edge of the galaxy disk. Again, which AIPS tasks must be used to
get V(R) from this image ?

Thanks in advance for the guidance.

Everton

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