[yt-users] Velocity dispersion profile

[Jun-Hwan Choi]

Hi YT users,

I would like to make a (spherical and/or cylindrical) profile of the
velocity dispersion.
In order to do so, I need to compute the mean velocity (BulkVelocity) for a
given shell (or ring), and pass this value to newly defined velocity
dispersion field, and then make a profile for the velocity dispersion field.
Is there a particular way in yt to handle this?

Junhwan

P.S.: A few weeks ago I posted a similar question and Matt gave me a
following hint.
@derived_field(name = "deltaLocalCircularVelocity")
def delta_LocalCircularVelocity(fi
eld, data):
 fn, x, cv = data.get_field_parameter("local_circular_velocity")
 cv0 = na.interp(data[fn].ravel(), x, cv)
 cv0 = cv0.reshape(data[fn].shape)
 delta_cv = cv0 - data["LocalCircularVelocity"]
 return delta_cv

You'll need to do something like this on the data object from which
you are getting your data:

 sp.set_field_parameter("local_circular_velocity",
     (fn, prof[fn], prof["LocalCircularVelocity"]))

However, it does not work for me and it is also complicate to understand
and modify it.



-- 
--------------------------------------------------------------
Jun-Hwan Choi, Ph.D.
Department of Physics and Astronomy, University of Kentucky
Tel: (859) 897-6737        Fax: (859) 323-2846
Email: jhchoi at pa.uky.edu   URL: http://www.pa.uky.edu/~jhchoi
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