snap.add.head.1: Add header information to particle data

In asgr/snapshot: Gadget N-body cosmological simulation code snapshot format 1 and 2 I/O utilities

Description

Function to add required header information to a Gadget format 1 particle data.frame. This has sensible defaults for a small galaxy merger style simulation

Usage

snap.add.head.1(part, Npart = 2, Massarr = 0, Time = 0, z = 0, FlagSfr = 0,
FlagFeedback = 0, FlagCooling = 0, BoxSize = 0, OmegaM = 0, OmegaL = 0,
h = 1, FlagAge = 0, FlagMetals = 0, NallHW = 0, flag_entr_ics = 0)

Arguments

part	Strictly speaking 'part' is passed through the function, but to make this a useful object 'part' should be a data.frame containing the main particle level information. Columns required are: ID particle ID x x position in units of Mpc y y position in units of Mpc z z position in units of Mpc vx x velocity in units of km/s vy y velocity in units of km/s vz z velocity in units of km/s Mass particle mass in units of Msun
Npart	The index on the Npart vector that should contain the particle number, where: gas [1] / collisionless particles [2:6]. The actual value is calculated based on the part data.frame provided with 'part', Nall is also calculated based on this number and not given as an option since the same index as Npart must be used
Massarr	The mass of the particles in the particle index provided to Npart
Time	Time of snapshot in units of km/s and kpc so 1 unit is ~10 Gyrs
z	Redshift of snapshot
FlagSfr	Star formation turned on/off
FlagFeedback	Feedback turned on/off
FlagCooling	Cooling turned on/off
BoxSize	Size of simulation box edge length in units of kpc
OmegaM	Omega matter of the simulation
OmegaL	Omega lambda of the simulation
h	Hubble constant divided by 100 used in the simulation
FlagAge	Stellar ages on/off
FlagMetals	Stellar metallacities on/off
NallHW	Tell Gadget to use large integers in the particle index provided to Npart- not usually necessary
flag_entr_ics	Entropy for gas on/off

Details

Nall is calculated based on Npart, and therfore it cannot be specified via an input argument. This increases the likelihood that a legal Gadget header will be produced.

Value

part

Strictly speaking 'part' is passed through the function, but to make this a useful object 'part' should be a data.frame containing the main particle level information. Assuming 'part' has been given a sensible input, columns provided are: ID particle ID x x position in units of Mpc y y position in units of Mpc z z position in units of Mpc vx x velocity in units of km/s vy y velocity in units of km/s vz z velocity in units of km/s Mass particle mass in units of Msun

head

A list containing various header information as list elements. These are: Npart Vector of length 6 containing the number of particles in this snapshot file, where: gas [1] / collisionless particles [2:6] Massarr Vector of length 6 containing the particle masses for the respective particle types in Npart Time Time of snapshot in units of km/s and kpc so 1 unit is ~10 Gyrs z Redshift of snapshot FlagSfr Star formation turned on/off Nall Vector of length 6 containing the number of particles in all snapshot files, where: gas [1] / collisionless particles [2:6] FlagFeedback Feedback turned on/off FlagCooling Cooling turned on/off NumFiles Number of files per snapshot- usually 1 BoxSize Size of simulation box edge length in units of kpc OmegaM Omega matter of the simulation OmegaL Omega lambda of the simulation h Hubble constant divided by 100 used in the simulation FlagAge Stellar ages on/off FlagMetals Stellar metallacities on/off NallHW Tell Gadget to use large integers for the respective particle types in Npart - not usually necessary flag_entr_ics Entropy for gas on/off

Author(s)

Aaron Robotham

See Also

snap.write.1, snap.read.1, snap.write.block.2,snap.read.2, snap.gen.param

Examples

## Not run: 
tempadd=snap.add.head.1(temp$part)

## End(Not run)

asgr/snapshot documentation built on Oct. 8, 2020, 2:52 p.m.