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Name

eaglesnap - convert EAGLE hdf5 snapshots to NEMO snapshot format

Synopsis

eaglesnap [parameter=value]

Description

eaglesnap converts an HDF5 snapshot from the EAGLE simulation in a NEMO snapshot format. Various selections are possible: an X,Y,Z region, particle type (enforced), group and subgroup.

Currently only mass and phasespace coordinates are converted. This is still done in code units, in a future option conversion to astrophysical units will be possible.

debug=1 will also list the datasets contents of the HDF5 file.

Parameters

The following parameters are recognized in any order if the keyword is also given:
in=hdf_file
Input file (HDF5). Only one of the HDF5 parts needs to be given. The eagle_read access routines know how to find all of them. No default.
out=
Output file, in snapshot format. No default.
ptype=
Which particle type 0-5 (0=gas, 1=DM, 4=star, 5=BH) [0]
region=
Select rectangular region (xmin,xmax,ymin,ymax,zmin,zmax). If two values are given, they are xmin,xmax and replicated as a cube for Y and Z. If one value is given, this is xmax, and 0,xmax is selected and again replicated for Y and Z. [0,10,0,10,0,10]
group=
Select this group (-1 means all,1..NG are validm 2^30 is no group)) [-1]
subgroup=
Select this subgroup (-1 means all, 0..NSG-1 are valid, 2^30 is no subgroup) [-1]
units=
Convert to Mpc, Msol, .... - not implemented yet.
center=
If given, it will center the selected particles here (3 values, in code units), meaning the coordinated will be shifted such that the center will be (0,0,0). You will also need to specify a boxsize, since the grid is periodic. [Default: not used]
boxsize=
Size of the box if center= is used. This value is also inside the HDF file, but not available via read_eagle. Default: not used, required if center= is given.
dm=
A cheat by which the total dark matter (DM) mass can be set. Once eagle_read() can grab those from the header, this keyword will not be needed anymore and likely disappear. Current default: 1

Examples

Assuming you have a username/password for database access, the following commands show some of the things you can do
    wget --user=... --ask-password --content-disposition 
        "http://dataweb.cosma.dur.ac.uk:8080/eagle-snapshots//download?run=RefL0012N0188&snapnum=28"
    tar xvf RefL0012N0188_snap_028.tar
    h5dump -n RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
    eaglesnap RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
snap1  ptype=0 region=2
Data are taken from a typical co-moving cosmological grid. Objects near the edge, may seem to wind up in two places, as can be seen in the following example snapshot:
    eaglesnap RefL0012N0188/snapshot_028_z000p000/snap_028_z000p000.0.hdf5
snap2 0 group=2
    snapplot3 snap2 xrange=-10:10 yrange=-10:10 zrange=-10:10

See Also

snapshot(5NEMO) , eagle(5NEMO)
http://dataweb.cosma.dur.ac.uk:8080/eagle-snapshots/ - EAGLE snapshots
http://icc.dur.ac.uk/Eagle/index.php - The EAGLE Project
http://icc.dur.ac.uk/Eagle/database.php - EAGLE database access
https://github.com/jchelly/read_eagle - library used
https://kyleaoman.github.io/martini - MARTINI

Files


NEMO/usr/eagle    directory with support to install EAGLE tools
NEMO/src/nbody/io/eaglesnap.c    code for eaglesnap

Eagle5

This will be the section for eagle(5NEMO) , but now it’s here

RefL0012N0188 is the small volume (12Mpc) reference run. It has 29 slices in z, ranging from slice 0 at z=20 to slice 28 at z=0.0. Slice 27, the one but most recent slice, is at z=0.10. The number of particles is (188^3) 6,644,672 per species (gas and DM). At z=0 one can see 6,381,559 gas, 262380 stars, and 547 BH, this still 186 short, so did some merge? This means SFE = 4.0% Each snapshot comes in "nfiles" parts, e.g. snap_028_z000p000.0.hdf5, snap_028_z000p000.1.hdf5, ... snap_028_z000p000.15.hdf5. The read_eagle routines will automatically read of all these in order to populate the snapshot correctly.

Simulations with L=12, 25, 50, 100 co-moving Mpc are available.

Author

Peter Teuben

Update History


02-Nov-19    V0.1 Created        PJT


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