Hubble Volume Mock Catalogues

Catalogue Format

 The catalogues are available as gzipped files.
Once gunzip'ed they are simple ASCII tables consisting
of a header followed by 6 columns of data.

Column 1: id   - An integer identifying the particle in the
                 orginal Hubble Volume simulation. This is of 
                 little use unless you have access to the 1 Billion
                 particle Hubble Volume simulation data.
                    Note that galaxies with the same ID number
                 (or one that just differs by a sign) are the
                 same particle in the orginal N-body simulation
                 and so have identical positions etc. This occurs
                 as a consequence of how we model biasing and the
                 selection function. Together these factors give us
                 a probability, P, that each simulation particle is 
                 to be included as a galaxy in the mock catalogue.
                 We then draw a random integer, I, from a Poisson 
                 distribution with mean P and include I copies
                 of the particle in the mock catalogue. Typically,
                 P<<1 and I=0 or 1, but close to the observer and
                 in highly biased regions P can approach or exceed
                 1 and so I>1 can occur resulting in the multiple
                 copies. For most analysis this causes no problems
                 at all. However in certain applications it maybe
                 necessary to either:
                   i) Randomly perturb the positions of multiple copies 
                 do that they are not exactly coincident. Perturbing by
                 around 10s of kpc is perfectly valid as this is below
                 the resolution of the simulation.
                   ii) Keep only one of the N copies but give it weight
                  N .

                  Also note that by applying a low redshift but most
                  of these duplcated particles can be excluded.

Column 2: ra  - Right Ascension in radians in the interval 0 to 2Pi.
                (For PSCz we instead list galactic longitude, l .)

Column 3: dec - Declination in radians.
                (For PSCz we instead list galactic latitude, b .)

Column 4: mag - Apparent magnitude  (B_J for APM/2dF, K for 6dF)
                (For PSCz we instead list 60 micron flux in mJy.)

Column 5: zz  - Redshift in the CMB frame.

Column 6: zhub - Hubble Flow redshift in the CMB frame. Ie with the
                 effect of the galaxy's peculiar velocity removed.

Note that you can convert from the CMB to LG frame by 
subtracting the velocity of the observer from each galaxy.
The observers velocity is in the direction of the real CMB dipole
ie l=276 deg b=30 deg and its magnitude is given by 
vobs=sqrt(vxobs**2+vyobs**2+vzobs**2), where vxobs etc are listed
in the catalogue header. Note that vobs = 625 +/- 25 km/s as
this is one of the constraints applied when choosing the observer.


# ng=     198642
#  xobs= 1360.500  yobs= 1307.400  zobs=  739.100 Mpc/h
# vxobs= -345.000 vyobs=  306.000 vzobs= -394.000 km/s
# mockseed=    -359078
#  omega0=      1.000
# lambda0=      0.000
# sigma_8=      0.600
# basis:    0.24802  -0.21798   0.94391  
#          -0.90198  -0.40743   0.14291   
#           0.35343  -0.88684  -0.29767
#  id            ra               dec        mag     zz       zhub  
 672624919  3.7005867986427 -0.4782340482322 11.467  0.03182  0.02946
 672624913  3.6476975167684 -0.5123586137846 12.467  0.03202  0.02899
 672624914  3.6531152419017 -0.5007377672143 11.420  0.03055  0.02822
 672624892  3.5813182714546 -0.5173702293422 13.340  0.03078  0.02853