[yt-users] Halo positions in merger trees

Stephen Skory stephenskory at yahoo.com
Thu Aug 6 08:06:08 PDT 2009


Jean-Claude,


> sphere = pf.h.sphere([0.5 0.5 0.5],1.0)
> hop_results = lagos.hop.HopList(sphere, 80.000000)
> 
> which I copied from the merger code, so the thresholds were the same,
> unfortunately.

Darn it. Another simple question is (and I'm guessing 'no' is the answer), are there stars in your simulation? If yes, did you do all the runs of HOP with them considered (or excluded)?

Are you comparing the same columns of the output of HOP? Are you sure you're not comparing the most-dense particle position to the calculated center of mass? In the text file output of HOP, the first columns of positions are the most-dense particle, while the merger tree should be using the center of mass (unless I've done something wrong!).

I'm thinking of what else could be going on...

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sskory at physics.ucsd.edu           o__  Stephen Skory
http://physics.ucsd.edu/~sskory/ _.>/ _Graduate Student
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