This directory contains initial conditions generated for
the EAGLE suite of simulations. The cosmology, resolution
and phases are the same as used in the original suite. The only
difference is the file format, adapted for SWIFT.

For standard runs, the code should be configured with

--with-subgrid=EAGLE-XL --with-hydro=sphenix --with-kernel=wendland-C2

(and any other optimization, library or compiler parameters specific
to your system.)

Compared to the original EAGLE runs of Schaye et al. 2015),
the following changes have been made (at standard resolution):

 - The flavour of SPH has been changed from the Pressure-Entropy
   "ANARCHY" implementation to the Density-energy based "SPHENIX"
   implementation of Borrow+20.
 - The dark matter softening lengths have been increased to 1.3
   pkpc and 3.32 ckpc. The comoving baryon softening lengths have
   been changed to 1.79 ckpc. This follows the recommendations of
   Ludlow et al. 2019. Old values were 0.7 pkpc and 2.69 ckpc for
   all the particle species.
 - The minimal smoothing length of SPH particles has been reduced
   to 0.01 of the softening length (was 0.1).
 - SPH particles reaching a mass larger than 7*10^6 Msun (~4x the
   initial gas particle mass) are now split into 2 equal mass
   particles within the smoothing length of the original particle.
 - The metallicity-dependent density threshold for star formation
   uses the smoothed metallicities and not the raw metallicities
   any more.
 - The cooling uses the Ploeckinger+20 tables including an updated
   UV background, newer version of CLOUDY and self-shielding
   (was using the Wiersma+09 tables before).
 - The redshift of H reionization has been lowered to 7.5 (from 11.5).
 - The entropy floor between n_H = 10^-5 and 10^-1 cm^3 at 8000K has
   been removed as the new cooling tables handle this correctly. The
   gamma=4/3 floor has been extended to lower densities
   (i.e. 800K at n_H = 10^-4 cm^-3) as a fail-safe.
 - Particles within 0.3 dex of the entropy floor get their
   subgrid properties (rho, T as well as the HI and H_2 frac) computed
   assuming pressure equilibrium.
 - Particles are star-forming if their subgrid temperature is below
   10^3 K OR if they are both colder than 10^4.5 K and have a subgrid
   number density above 10 cm^-3.
 - Particles can be star-forming if they are in an over-density of
   at least 100 (was 57.7).
 - Particles with a density above 10^5 cm^-3 are not turned into
   stars instantaneously any more.
 - The normalisation of the SF law at high densities has been corrected
   from the original code where the break in slope of the K-S law
   also led to a jump. This change of slope is not used anymore (was
   a K-S slope of 2 at volume particle densities > 10^3 cm^-3).
 - The minimal mass of SNII stars has been raised to 8 Msun (from 6).
 - The SNII feedback heats the particle closest to the star particle
   (was a random set of particles in the kernel).
 - The SNII feedback delay is done by sampling the stellar age
   distribution and not using a fixed delay of 30 Myr any more.
 - The density and metallicity used for the f_th scaling of the
   SNII feedback are now computed at the time of feedback from the
   gas neighbours and are not the birth quantities any more.
 - The halo mass for BH seeding has been lowered to 10^10 M_sun
   (from 10^10/h Msun).
 - The BH seed mass (subgrid mass at birth) has been lowered to
   10^4 Msun (from 10^5/h Msun).
 - The black hole accretion rate is now limited to 100% of the
   Eddington rate (from 100/h = 150 %).
 - The circular velocity threshold for BH mergers is measured
   at the actual distance linking the BHs not at the kernel support
   length any more.
 - When two BHs merge, the one with the largest subgrid mass swallows
   the other one (not the one with the largest ID anymore).
 - The BHs can reposition only onto gas particles and BH particles
   (not onto any type as before).
 - No limit is imposed any more on the velocity (w.r.t. the BH)
   of the gas particles onto which the BHs can reposition.
 - BHs of all masses can be repositioned (was limited to
   M_BH < 1.8*10^8 Msun).
 - BHs do not swallow gas particles any more. They nibble small
   amounts of mass from the eligible neighbours within their kernel.
 - Gas particles can be nibbled down to 50% of their initial mass.
 - The angular momentum term in the BH accretion model of
   Rosas-Guevara et al. (2015) is now switched off.
 - The BHs compute a time-step length based on their accretion rate
   with a minimum time-step length of 10^5 years.
 - The AGN feedback heats the particles closest to the BH particle
   (was a random set of particles in the kernel).
 - The AGN does not use a combination of probability and reservoir
   any more. Energy is accumulated and then used in a deterministic
   way once the threshold for feedback is reached.
 - The free parameters in the SN feedback efficiency function, boost
   of the AGN accretion, coupling efficieny, and AGN heating temperatures
   have been calibrated to match the z=0 stellar mass function, and
   mass-size relation. The procedure used to obtain the values of these
   parameters is described in Borrow et al. (in prep.)

The scripts in this directory download the tables required to
run the EAGLE model. Plotting scripts are also provided
for basic quantities.

To use the cooling model based on the Wiersma+09 tables, replace
EAGLE-XL by EAGLE in the configuration command line.

VELOCIraptor can be run on the output. The code is compiled
using

cmake -DVR_USE_GAS=ON -DVR_USE_STAR=ON -DV_USE_BH=ON

and run using

stf -C vrconfig_3dfof_subhalos_SO_hydro.cfg -i eagle_0036 -o halos_0036 -I 2

