"Trees" connect halos at one output time with halos at the next output time.

Files:  e.g.   treel.0077  connects output 0077 with output 0084


Description:

1st entry : NH, number of halos identified at output 0084

    Loop from 1 to NH:

      Read I, MSS, IBND, NGAL

       I: halo index
       MSS: fof groupfinder mass
       IBND: particle index of the most-bound particle of the most 
             massive progenitor of this halo.
             (0 indicates that the halo had no progenitors in output time 0077) 
       NGAL: number of satellite galaxies in halo

       Loop from 1 to NGAL
       
          READ  ISAT
            
             ISAT: particle index of satellite galaxy

       endloop

    endloop


"field" galaxies (this is not essential information for using the trees):

   Read IFIELD, IDUM, MSS

     IFIELD: particle index of galaxy identified at any previous output, that is not
             contained in any halo at output time 0084 (Note that this list
             is cumulative). The program that constructs the trees does check to
             see whether any of the "field" galaxies re-enter halos at subsequent
             times. If so, they are deleted from the list and added to the correct
             halo.

     IDUM:   dummy index

     MSS:    Mass of halo if field galaxy was previously a central galaxy.
             "0" indicates that field galaxy was a satellite galaxy .
    
---------------------------------------------------------------------------------------------

Full list of simulation outputs:


         LCDM

     timestep     Z

     0024      12.15
     0026      11.28
     0029      10.66
     0031       9.99
     0035       9.35
     0039       8.75
     0043       8.18
     0048       7.65
     0052       7.14
     0058       6.67
     0064       6.22
     0070       5.80
     0077       5.41
     0084       5.03
     0092       4.68
     0101       4.35
     0111       4.04
     0121       3.75
     0132       3.47
     0143       3.21
     0156       2.97
     0173       2.74
     0192       2.52
     0211       2.32
     0232       2.12
     0254       1.94
     0280       1.77
     0311       1.61
     0341       1.46
     0373       1.31
     0405       1.18
     0439       1.05
     0476       0.93
     0519       0.82
     0565       0.72
     0612       0.62
     0671       0.52
     0731       0.42
     0797       0.35
     0870       0.27
     0938       0.20
     1014       0.13
     1092       0.06
     1178       0.00