Physical Quantities

A simulation output stores many different types of physical information about its matter components, e.g. gas, stars, dark matter, and supermassive black holes. The original snapshots contain basic information, such as positions and masses, and we refer to these as default snapshot quantities. After a galaxy/halo finder has been run, the resulting group catalogs aggregate these same fields, computing e.g. the total stellar mass of a galaxy by summing up the masses of its associated stars. We refer to these fields as default catalog quantities.

From these physical quantities, many others can be derived. These are value-added properties which are not output directly by the simulation, but must be calculated. For example, simple unit conversions (e.g. from code mass, to solar masses), fundamental derived quantities (e.g. pressure, given density and internal energy), non-trivial theoretical quantities (e.g. enclosed mass, gravitational free-fall time, or the ratio of gas cooling time to free-fall time), and post-processed quantities and observables (e.g. gas x-ray emission, stellar light and spectra, or ion abundances from photoionization modeling). These we refer to as custom snapshot quantities, and when the derived properties are for galaxies or halos instead of individual particles/cells, custom catalog quantities.

Default Snapshot Quantities

These are the fields which are directly available from the on-disk snapshot files themselves. For example, PartType0/StarFormationRate (for gas) or PartType4/Masses (for stars). For complete documentation of available fields, their definitions, and units, see

The temet.load.snap_fields module defines metadata associated with these fields, including a description (label for plotting), units, and default bounds.

Default Catalog Quantities

These are the fields which are directly available from the on-disk group catalog files themselves. Specifically, by the combination of the friends-of-friends (FoF) algorithm plus the Subfind algorithm, which identifies gravitationally bound structures: halos and subhalos. For example, SubhaloMass or Group_M_Crit200 are two common fields. For complete documentation of available fields, their definitions, and units, see

Adding New Custom Snapshot Quantities

Each custom field is generated by a function, and the name of the function is the name of the custom field. All such defined fields are recorded in a ‘registry’. To create a new custom field is simple: just define a function, and decorate it with the @snap_field decorator, as shown below. It must accept four ordered arguments: (sim, partType, field, args), and must return a numpy array of the requested values.

You can find all built-in custom quantities defined in the temet.load.snap_fields_custom module. If you are editing this package directly, or want to share your custom fields in the future, you can add to that file. But, you can also define your custom field in any file you want.

For example, to define a new custom field for the ‘spherical equivalent radius’ of a gas cell:

from temet.load.snapshot import snap_field

@snap_field
def cell_radius(sim, partType, field, args):
    # load and manipulate data, return
    vol = sim.snapshotSubset(partType, 'vol', **args)
    return (vol * 3.0 / (4*np.pi))**(1.0/3.0)

Important metadata should also be specified, just below (and outside) the function itself:

cell_radius.units = 'code_length'
cell_radius.label = 'Cell Radius'
cell_radius.limits = [-2.0, 2.0]
cell_radius.log = True

Note: units and label should correspond to the returned values. limits is a default suggestion for a [min,max] range for plotting, while log indicates if the value should in general be logged for plotting/display (usually True, and by default True if omitted, as our convention is to always return linear values).

You can also register the same derived field under one or more additional names (‘aliases’):

@snap_field(aliases=['cellrad','rcell'])
def cell_radius(sim, partType, field, args):
    # load and manipulate data, return
    # ...

Finally, you can define ‘wildcard’ fields which capture, and then handle, many different field names at once. For example, imagine you could compute the optical stellar spectrum for any star particle, and you wanted to define a new field of the form specmean_{wavemin}_{wavemax} which would return the mean flux between the two specified wavelengths, which are arbitrary inputs. If we had such a custom field, we could compute e.g. D4000 = specmean_4050_4250 / specmean_3750_3950} (indeed, we could then define yet another custom field called D4000 which did exactly this, automatically). To handle these two field names, or any others of the same form, we could define:

@snap_field(multi=True)
def specmean_(sim, partType, field, args):
    # get wavelengths out of field string
    _, wavemin, wavemax = field.split('_')

    # compute spectrum, measure mean in this wavelength window, and return
    # ...

In this case, any snapshot load request (e.g. sim.stars('specmean_5000,6000', haloID=10)) which contains the string specmean_ will get routed to this generator function. Note: in the case that multi is not a simple bool, but instead a string, then the value itself is used as the matching pattern (see cloudy_ for an example, which matches on spaces).

Adding New Custom Catalog Quantities

Custom fields for group catalog objects i.e. halos/subhalos are defined similarly to snapshot fields:

from temet.load.groupcat import catalog_field

@catalog_field
def my_ssfr(sim, field):
    """ Galaxy specific star formation rate, instantaneous (total subhalo SFR normalized by fiducial stellar mass)."""
    sfr = sim.subhalos("SubhaloSFR") # Msun/yr

    mstar = sim.subhalos("SubhaloMassInRadType")[:, sim.ptNum("stars")] # code mass
    mstar_msun = sim.units.codeMassToMsun(mstar)

    ssfr = sfr / mstar_msun

    return ssfr

my_ssfr.label = r"My sSFR"
my_ssfr.units = r"$\rm{yr^{-1}}$"
my_ssfr.limits = [-13.3, -8.0]
my_ssfr.log = True

The same alias and wildcard matching functionality is also available for catalog fields, via the @catalog_field decorator arguments.

Custom Catalog Quantities

The following halo/subhalo custom quantities are currently defined, in the temet.load.groupcat_fields_custom module, along with associated metadata including a description, units, reasonable bounds, and so on.

Field Name

Label

Units

Aliases

Description

d5_mstar_gthalf

\(d_{5}\)

code_length

d5_mstar_gt7, d5_mstar_gt8

Environment: distance to 5th nearest neighbor (subhalo) that has a stellar mass at least half of our own (default unless specified).

delta5_mstar_gthalf

\(\delta_{5}\)

delta5_mstar_gt7, delta5_mstar_gt8

Environment: overdensity based on 5th nearest neighbor (subhalo).

num_ngb_gthalf

\(\rm{N_{ngb,subhalos}}\)

num_ngb_gt7, num_ngb_gt8, num_ngb_gttenth

Environment: counts of nearby neighbor subhalos, within a given 3D specture, satisfying some minimum (relative) stellar mass criterion.

mass_ovi

\(\rm{M_{OVI}}\)

\(\rm{M_{sun}}\)

Total gas mass in sub-species: OVI.

mass_ovii

\(\rm{M_{OVII}}\)

\(\rm{M_{sun}}\)

Total gas mass in sub-species: OVII.

mass_oviii

\(\rm{M_{OVIII}}\)

\(\rm{M_{sun}}\)

Total gas mass in sub-species: OVIII.

mass_o

\(\rm{M_{O,gas}}\)

\(\rm{M_{sun}}\)

Total gas mass in sub-species: O.

mass_z

\(\rm{M_{Z,gas}}\)

\(\rm{M_{sun}}\)

Total gas mass in sub-species: Z.

mass_halogas

\(\rm{M_{halo,gas}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass.

mass_halogasfof

\(\rm{M_{halo,gas}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass. FoF-scope, centrals only.

mass_halogas_cold

\(\rm{M_{halo,gas,cold}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass. Only cold (log T < 4.5 K), star-forming gas at eEOS temp.

mass_halogas_sfcold

\(\rm{M_{halo,gas,sfcold}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass. Only cold (log T < 4.5 K), star-forming gas at cold temp.

mass_halogasfof_cold

\(\rm{M_{halo,gas,cold}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass. FoF-scope, centrals only. Only cold (log T < 4.5 K), star-forming gas at eEOS temp.

mass_halogasfof_sfcold

\(\rm{M_{halo,gas,sfcold}}\)

\(\rm{M_{sun}}\)

Total halo (0.15 < r/rvir < 1.0) gas mass. FoF-scope, centrals only. Only cold (log T < 4.5 K), star-forming gas at cold temp.

frac_halogas_cold

\(\rm{M_{halo,gas,cold} / M_{halo,gas}}\)

Fraction of halo (0.15 < r/rvir < 1.0) gas mass that is cold (log T < 4.5 K), star-forming gas at eEOS temp.

frac_halogas_sfcold

\(\rm{M_{halo,gas,sfcold} / M_{halo,gas}}\)

Fraction of halo (0.15 < r/rvir < 1.0) gas mass that is cold (log T < 4.5 K), star-forming gas at cold temp.

frac_halogasfof_cold

\(\rm{M_{halo,gas,cold} / M_{halo,gas}}\)

Fraction of halo (0.15 < r/rvir < 1.0) gas mass that is cold (log T < 4.5 K), star-forming gas at eEOS temp. FoF-scope, centrals only.

frac_halogasfof_sfcold

\(\rm{M_{halo,gas,sfcold} / M_{halo,gas}}\)

Fraction of halo (0.15 < r/rvir < 1.0) gas mass that is cold (log T < 4.5 K), star-forming gas at cold temp. FoF-scope, centrals only.

mass_smbh

\(\rm{M_{SMBH}}\)

\(\rm{M_{sun}}\)

Largest SMBH mass in each subhalo. Avoids summing multiple SMBH masses, if more than one present.

smbh_mdot

\(\rm{\dot{M}_{SMBH}}\)

\(\rm{M_{sun} / yr}\)

Largest SMBH Mdot in each subhalo.

smbh_lum

\(\rm{L_{AGN,bol}}\)

\(\rm{erg / s}\)

l_bol, l_agn

Bolometric luminosity of largest SMBH in each subhalo.

fgas_r200

\(\rm{f_{gas}(<r_{200c})}\)

Gas mass fraction (= Mgas/Mtot) within the virial radius, r200c. FoF-scope approximation.

fgas_r500

\(\rm{f_{gas}(<r_{500c})}\)

Gas mass fraction (= Mgas/Mtot) within r500c. FoF-scope approximation.

sfr

\(\rm{SFR_{<30kpc},instant}\)

\(\rm{M_{sun}\, yr^{-1}}\)

sfr_30pkpc, sfr_30pkpc_instant

Galaxy star formation rate (instantaneous, within 30pkpc aperture).

sfr_10myr

\(\rm{SFR_{10Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (full subhalo) averaged over the past 10 Myr.

sfr_30pkpc_10myr

\(\rm{SFR_{<30kpc,10Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (30pkpc) averaged over the past 10 Myr.

sfr_50myr

\(\rm{SFR_{50Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (full subhalo) averaged over the past 50 Myr.

sfr_30pkpc_50myr

\(\rm{SFR_{<30kpc,50Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (30pkpc) averaged over the past 50 Myr.

sfr_100myr

\(\rm{SFR_{100Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (full subhalo) averaged over the past 100 Myr.

sfr_30pkpc_100myr

\(\rm{SFR_{<30kpc,100Myr}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Star formation rate (30pkpc) averaged over the past 100 Myr.

sfr_10_100_ratio

\(\rm{SFR_{10Myr}}\) / \(\rm{SFR_{100Myr}}\)

sfr_10_100

Ratio of SFR_10Myr / SFR_100Myr (full subhalo) as a burstyness indicator.

ssfr_30pkpc

\(\rm{sSFR}\)

\(\rm{yr^{-1}}\)

ssfr_30pkpc_instant

Galaxy specific star formation rate [1/yr] (sSFR, instantaneous, SFR and M* within 30kpc).

ssfr_30pkpc_10myr

\(\rm{sSFR, 10Myr}\)

\(\rm{yr^{-1}}\)

Galaxy specific star formation rate [1/yr] (sSFR, 10 Myr, SFR and M* within 30kpc).

ssfr_30pkpc_50myr

\(\rm{sSFR, 50Myr}\)

\(\rm{yr^{-1}}\)

Galaxy specific star formation rate [1/yr] (sSFR, 50 Myr, SFR and M* within 30kpc).

ssfr_30pkpc_100myr

\(\rm{sSFR, 100Myr}\)

\(\rm{yr^{-1}}\)

Galaxy specific star formation rate [1/yr] (sSFR, 100 Myr, SFR and M* within 30kpc).

sfr_surfdens

\(\rm{\Sigma_{SFR}}\)

\(\rm{M_\odot \, yr^{-1} \, kpc^{-2}}\)

sfr_surfdens_30pkpc_instant

Star formation surface density (instantaneous, SFR and M* within 30kpc).

sfr_surfdens_30pkpc_10myr

\(\rm{\Sigma_{SFR}}\)

\(\rm{M_\odot \, yr^{-1} \, kpc^{-2}}\)

Star formation surface density (10 Myr, SFR and M* within 30kpc).

sfr_surfdens_30pkpc_50myr

\(\rm{\Sigma_{SFR}}\)

\(\rm{M_\odot \, yr^{-1} \, kpc^{-2}}\)

Star formation surface density (50 Myr, SFR and M* within 30kpc).

sfr_surfdens_30pkpc_100myr

\(\rm{\Sigma_{SFR}}\)

\(\rm{M_\odot \, yr^{-1} \, kpc^{-2}}\)

Star formation surface density (100 Myr, SFR and M* within 30kpc).

szy_r500c_3d

\(\rm{Y_{SZ,r500}^{3d}}\)

\(\rm{Mpc^2}\)

Sunyaev Zeldovich y-parameter within r500c (3d).

szy_r500c_2d

\(\rm{Y_{SZ,r500}^{2d}}\)

\(\rm{Mpc^2}\)

Sunyaev Zeldovich y-parameter within r500c (2d).

xray_r500

L \(_{\rm X}\) Bolometric ( \(R_{500c}\) )

\(\rm{erg/s}\)

Bolometric X-ray luminosity (simple free-free model), within r500c.

xray_subhalo

L \(_{\rm X}\) Bolometric

\(\rm{erg/s}\)

Bolometric X-ray luminosity (simple free-free model), within full subhalo.

xray_05_2kev_r500

L \(_{\rm X,r500}^{\rm 0.5-2 keV}\)

\(\rm{erg/s}\)

X-ray luminosity 0.5-2.0 keV (APEC model), within r500c in 3D.

xray_05_2kev_r500_halo

L \(_{\rm X,r500}^{\rm 0.5-2 keV}\)

\(\rm{erg/s}\)

X-ray luminosity 0.5-2.0 keV (APEC model), within r500c in 3D (FoF-scope).

xray_01_24kev_r500_halo

L \(_{\rm X,r500}^{\rm 0.1-2.4 keV}\)

\(\rm{erg/s}\)

X-ray luminosity 0.1-2.4 keV (APEC model), within r500c in 3D (FoF-scope).

xraylum_r500c_2d

\(\rm{L_{X,r500}^{2d}}\)

\(\rm{erg/s}\)

X-ray luminosity (0.5-2.0 keV) within r500c (2d).

xray_peak_offset_2d

\(\rm{\Delta_{X-ray,galaxy}^{2d}}\)

\(\rm{kpc}\)

xray_peak_offset_2d_rvir, xray_peak_offset_2d_r500

Spatial offset between X-ray (0.5-2.0 keV) emission peak and galaxy (SubhaloPos). In 2D projection.

tcool_halo_ovi

\(\rm{t_{cool,halo,OVI}}\)

\(\rm{Gyr}\)

Mean cooling time of halo gas, weighted by OVI mass.

p_sync_ska

\(\rm{P_{sync,VLA}}\)

\(\rm{W / Hz}\)

p_sync_ska_eta43, p_sync_ska_alpha15

Synchrotron power radio emission (SKA model).

p_sync_vla

p_sync_vla_eta43, p_sync_vla_alpha15

Synchrotron power radio emission (VLA model).

lum_civ1551_outercgm

\(\rm{L_{CIV 1551} (R_{200c}/2 - R_{200c})}\)

\(\rm{erg/s}\)

CIV 1551 luminosity in the outer CGM.

lum_civ1551_innercgm

\(\rm{L_{CIV 1551} (20 kpc - R_{200c}/2)}\)

\(\rm{erg/s}\)

CIV 1551 luminosity in the inner CGM.

lum_heii1640_outercgm

\(\rm{L_{HeII 1640} (R_{200c}/2 - R_{200c})}\)

\(\rm{erg/s}\)

HeII 1640 luminosity in the outer CGM.

lum_heii1640_innercgm

\(\rm{L_{HeII 1640} (20 kpc - R_{200c}/2)}\)

\(\rm{erg/s}\)

HeII 1640 luminosity in the inner CGM.

mg2_lum

\(\rm{L_{MgII}}\)

\(\rm{erg/s}\)

MgII emission, total luminosity.

mg2_lumsize

L \(_{\rm MgII}\) Half-light Radius

kpc

MgII emission, size (half-light radius).

mg2_lumsize_rel

L \(_{\rm MgII}\) Half-light Radius / R \(_{\rm 1/2,\star}\)

MgII emission, size (half-light radius) relative to stellar half mass radius.

mg2_m20

MgII Emission M \(_{\rm 20}\) Index

MgII emission, M20 statistic.

mg2_concentration

MgII Emission Concentration (C)

MgII emission, concentration statistic.

z_stars_masswt

\(\rm{Z_{\star,masswt}}\)

\(\rm{Z_{\odot}}\)

Stellar metallicity (no radial restriction), mass weighted.

z_stars_1kpc_masswt

\(\rm{Z_{\star,masswt}}\)

\(\rm{Z_{\odot}}\)

Stellar metallicity (within 1 kpc, fof-scope), mass weighted.

z_stars_2rhalfstarsfof_masswt

\(\rm{Z_{\star,masswt}}\)

\(\rm{Z_{\odot}}\)

Stellar metallicity (within 2rhalfstars of fof, and fof-scope), mass weighted.

z_stars_fof_masswt

\(\rm{Z_{\star,masswt}}\)

\(\rm{Z_{\odot}}\)

Stellar metallicity (full fof-scope), mass weighted. All satellites have same value as their central.

z_gas_sfrwt

\(\rm{Z_{gas,sfrwt}}\)

\(\rm{Z_{\odot}}\)

Gas-phase metallicity (no radial restriction), mass weighted.

z_stars_halo

\(\rm{Z_{stars,halo}}\)

\(\rm{Z_{\odot}}\)

Mean stellar metallicity in the halo (0.15 < r/rvir < 1.0), mass weighted.

z_gas_halo

\(\rm{Z_{gas,halo}}\)

\(\rm{Z_{\odot}}\)

Mean gas metallicity in the halo (0.15 < r/rvir < 1.0), mass weighted.

veldisp

\(\rm{\sigma_{\star}}\)

\(\rm{km/s}\)

Stellar velocity dispersion (3D), within the stellar half mass radius.

veldisp1d

\(\rm{\sigma_{\star, 1D}}\)

\(\rm{km/s}\)

Stellar velocity dispersion (1D, from 3D), within the stellar half mass radius.

veldisp1d_05re

\(\rm{\sigma_{\star, 1D}}\)

\(\rm{km/s}\)

Stellar velocity dispersion (1D, from 3D), within 0.5 times the stellar half mass radius.

veldisp1d_10pkpc

\(\rm{\sigma_{\star, 1D}}\)

\(\rm{km/s}\)

Stellar velocity dispersion (1D, in z-direction), within 10pkpc.

veldisp1d_4pkpc2d

\(\rm{\sigma_{\star, 1D}}\)

\(\rm{km/s}\)

Stellar velocity dispersion (1D, in z-direction), within 4pkpc (~SDSS fiber low-z) in 2D.

veldisp_gas_01r500c_xray

\(\rm{\sigma_{gas, 1D, X-ray, <0.1\,r500c}}\)

\(\rm{km/s}\)

Gas velocity dispersion (1D, in z-direction), weighted by 0.2-2 keV X-ray luminosity, within 0.1r500c.

gas_vrad_2rhalf

Gas v \(_{\rm rad,ISM}\)

\(\rm{km/s}\)

Mean gas radial velocity within the galaxy (< 2rhalfstars), mass-weighted.

gas_vrad_halo

Gas v \(_{\rm rad,halo}\)

\(\rm{km/s}\)

Mean gas radial velocity the halo (0.15 < r/rvir < 1), mass-weighted.

rshock

\(\rm{R_{shock}}\)

\(\rm{kpc}\)

Virial shock radius, fiducial model choice.

rshock_rvir

\(\rm{R_{shock} / R_{vir}}\)

Virial shock radius, fiducial model choice. Normalized.

size_halpha

r \(_{\rm 1/2,H\alpha}\)

\(\rm{kpc}\)

Half-light radius of H-alpha emission, based on SFR empirical relation.

size_halpha_em

r \(_{\rm 1/2,H\alpha}\)

\(\rm{kpc}\)

Half-light radius of H-alpha emission, based on cloudy.

shape_q_sfrgas

q \(_{\rm SFRgas}\)

Iterative ellipsoid shape measurement: axis ratio (q) of star-forming gas.

shape_s_sfrgas

s \(_{\rm SFRgas}\)

Iterative ellipsoid shape measurement: sphericity (s) of star-forming gas.

shape_ratio_sfrgas

(s/q) \(_{\rm SFRgas}\)

Iterative ellipsoid shape measurement: ratio (s/q) of star-forming gas.

r80_stars

R \(_{\rm 80,\star}\)

\(\rm{kpc}\)

3D radius enclosing 80% of stellar mass, non-standard.

sigma1kpc_stars

\(\Sigma_{\rm 1,\star}\)

\(\rm{M_{\odot}\, kpc^{-2}}\)

Stellar surface density within a central 1 pkpc (2D projected) aperture.

rhalf_stars_fof

r \(_{\rm 1/2,\star}\)

\(\rm{kpc}\)

rhalf_stars_fof_code

Stellar half-mass radius, computed from all FoF-scope stars.

shape_q_stars

q \(_{\rm stars}\)

Iterative ellipsoid shape measurement: axis ratio (q) of stars.

shape_s_stars

s \(_{\rm stars}\)

Iterative ellipsoid shape measurement: sphericity (s) of stars.

shape_ratio_stars

(s/q) \(_{\rm stars}\)

Iterative ellipsoid shape measurement: ratio (s/q) of stars.

krot_stars

\(\kappa_{\rm stars, rot}\)

krot_stars1, krot_stars2

Galaxy disk kappa, fraction of stars in ordered rotation.

krot_gas

\(\kappa_{\rm gas, rot}\)

krot_gas1, krot_gas2

Galaxy disk kappa, fraction of gas in ordered rotation.

krot_oriented_stars

\(\kappa_{\rm stars, rot} (J_z > 0)\)

krot_oriented_stars1, krot_oriented_stars2

Galaxy disk kappa, fraction of stars in ordered rotation (J_z > 0).

krot_oriented_gas

\(\kappa_{\rm gas, rot} (J_z > 0)\)

krot_oriented_gas1, krot_oriented_gas2

Galaxy disk kappa, fraction of gas in ordered rotation (J_z > 0).

arot_stars

\(M_{\rm stars, counter-rot} / M_{\rm stars, total}\)

arot_stars1, arot_stars2

Galaxy disk, fraction of counter-rotating stars.

arot_gas

\(M_{\rm gas, counter-rot} / M_{\rm gas, total}\)

arot_gas1, arot_gas2

Galaxy disk, fraction of counter-rotating gas.

specangmom_stars

\(j_{\rm stars}\)

kpc km/s

specangmom_stars1, specangmom_stars2

Galaxy disk, specific angular momentum of stars.

specangmom_gas

\(j_{\rm gas}\)

kpc km/s

specangmom_gas1, specangmom_gas2

Galaxy disk, specific angular momentum of gas.

m_bulge_counter_rot

\(M_{\rm bulge}\)

\(M_\odot\)

M_bulge estimator: twice the counter-rotating stellar mass within the stellar half-mass radius.

bmag_sfrgt0_masswt

\(\rm{|B|_{ISM}}\)

\(\rm{\mu G}\)

bmag_sfrgt0_volwt

Mean magnetic field amplitude in the ISM (star-forming gas), full subhalo, mass or volume weighted.

bmag_2rhalf_masswt

\(\rm{|B|_{ISM}}\)

\(\rm{\mu G}\)

bmag_2rhalf_volwt

Mean magnetic field amplitude in the ISM (within 2rhalfstars), mass or volume weighted.

bmag_halo_masswt

\(\rm{|B|_{halo}}\)

\(\rm{\mu G}\)

bmag_halo_volwt

Mean magnetic field amplitude in the halo (0.15 < r/rvir < 1.0), mass or volume weighted.

bmag_r500_masswt

\(\rm{|B|_{r500c}}\)

\(\rm{\mu G}\)

bmag_r500_volwt

Mean magnetic field amplitude within r500c, mass or volume weighted.

bmag_halfr500_masswt

\(\rm{|B|_{0.5r500c}}\)

\(\rm{\mu G}\)

bmag_halfr500_volwt

Mean magnetic field amplitude within 0.5 * r500c, mass or volume weighted.

bmag_masswt

\(\rm{|B|}\)

\(\rm{\mu G}\)

bmag_volwt

Mean magnetic field amplitude (full subhalo), mass or volume weighted.

pratio_halo_masswt

\(P_{\rm B} / P_{\rm gas}\) (halo)

pratio_halo_volwt

Ratio of magnetic to thermal gas pressure in the halo (0.15 < r/rvir < 1.0), mass or volume weighted.

pratio_2rhalf_masswt

\(P_{\rm B} / P_{\rm gas}\) (ISM)

pratio_2rhalf_volwt

Ratio of magnetic to thermal gas pressure in the galaxy (r < 2rhalfstars), mass or volume weighted.

bke_ratio_halo_masswt

\(u_{\rm B} / u_{\rm KE}\) (halo)

bke_ratio_halo_volwt

Ratio of magnetic to kinetic energy in the halo (0.15 < r/rvir < 1.0), mass or volume weighted.

bke_ratio_2rhalf_masswt

\(u_{\rm B} / u_{\rm KE}\) (ISM)

bke_ratio_2rhalf_volwt

Ratio of magnetic to kinetic energy in the galaxy (r < 2rhalfstars), mass or volume weighted.

ptot_gas_halo

P \(_{\rm tot,gas}\)

\(\rm{K/cm^3}\)

Total gas thermal pressure in the halo (0.15 < r/rvir < 1.0).

ptot_b_halo

P \(_{\rm tot,B}\)

\(\rm{K/cm^3}\)

Total gas magnetic pressure in the halo (0.15 < r/rvir < 1.0).

m_bh

\(\rm{M_{BH}}\)

\(\rm{M_{\odot}}\)

Supermassive black hole mass (actual, i.e. starting from the seed mass).

bh_mdot_edd

\(\rm{\dot{M}_{BH} / \dot{M}_{Edd}}\)

Blackhole mass accretion rate normalized by its Eddington rate (for most massive BH in each subhalo).

bh_bollum

Blackhole \(L_{\rm bol}\)

erg/s

Blackhole bolometric luminosity (for most massive BH in each subhalo).

bh_bollum_basic

Blackhole \(L_{\rm bol}\) [basic]

erg/s

Blackhole bolometric luminosity, basic model (for most massive BH in each subhalo).

bh_eddratio

Blackhole \(\lambda_{\rm edd}\)

Blackhole Eddington ratio (for most massive BH in each subhalo).

bh_dedt

Blackhole \(\dot{E}_{\rm BH}\)

erg/s

Blackhole energy injection rate (for most massive BH in each subhalo).

bh_mode

Blackhole Mode [ 0=low/kinetic, 1=high/quasar ]

Blackhole feedback mode [0=low/kinetic, 1=high/quasar] (for most massive BH in each subhalo).

bh_cumegy_low

BH \(\int\) E \(_{\rm injected,low}\)

erg

Cumulative energy injected in the low (kinetic) accretion mode.

bh_cumegy_high

BH \(\int\) E \(_{\rm injected,high}\)

erg

Cumulative energy injected in the high (thermal/quasar) accretion mode.

bh_cummass_low

\(\int\) M \(_{\rm growth,low}\)

\(M_\odot\)

Cumulative mass accretion in the low (kinetic) accretion mode.

bh_cummass_high

\(\int\) M \(_{\rm growth,high}\)

\(M_\odot\)

Cumulative mass accretion in the high (thermal/quasar) accretion mode.

bh_cumegy_ratio

BH \(\int\) E \(_{\rm injected,high}\) / \(\int\) E \(_{\rm injected,low}\)

Ratio of cumulative energy injected in low vs. high accretion modes.

bh_cumegy_ratioinv

BH \(\int\) E \(_{\rm injected,low}\) / \(\int\) E \(_{\rm injected,high}\)

Ratio of cumulative energy injected in high vs. low accretion modes.

bh_cummass_ratio

BH \(\int\) M \(_{\rm growth,high}\) / \(\int\) M \(_{\rm growth,low}\)

Ratio of cumulative mass accretion in low vs. high accretion modes.

wind_vel

Wind Injection Velocity

km/s

Wind model: velocity at injection, from star-forming gas.

wind_etam

Wind Mass Loading \(\eta_{\rm M}\)

Wind model: mass loading at injection, from star-forming gas.

wind_dedt

Wind Energy Injection Rate \(\dot{E}_{\rm SN}\)

erg/s

Wind model: energy injection rate, from star-forming gas.

wind_dpdt

Wind Momentum Injection Rate \(\dot{P}_{\rm SN}\)

erg/s

Wind model: momemtum injection rate, from star-forming gas.

zform

\(\rm{z_{form}}\)

z_form

Formation redshift (of the halo), at which the subhalo had half of its current mass.

stellar_zform_vimos

\(\rm{z_{form,\star}}\)

Stellar formation redshift (mass-weighted mean), using the VIMOS slit aperture of stars.

stellarage

\(\rm{log t_{age,\star}\)

\(\rm{Gyr}\)

Mean stellar age (mass-weighted), all stars in subhalo.

stellarage_4pkpc

\(\rm{log t_{age,\star}\)

\(\rm{Gyr}\)

Mean stellar age (r-band luminosity weighted), including only stars within a 4 pkpc aperture.

fiber_

fiber_zred, fiber_mass, fiber_logzsol, fiber_tau, fiber_tage, fiber_dust1, fiber_dust2

Mock SDSS fiber spectrum MCMC fit quantities.

temp_halo

\(\rm{log T_{halo}}\)

\(\rm{K}\)

temp_halo_volwt

Mean gas temperature in the halo (0.15 < r/rvir < 1), mass or volume weighted.

nh_halo

\(\rm{log n_{H,halo}}\)

\(\rm{cm^{-3}}\)

nh_halo_volwt

Mean hydrogen number density in the halo (0.15 < r/rvir < 1), mass or volume weighted.

nh_2rhalf

\(\rm{log n_{H,ISM}}\)

\(\rm{cm^{-3}}\)

nh_2rhalf_volwt

Mean hydrogen number density in the galaxy (< 2rhalfstars), mass or volume weighted.

subhalo_id

Subhalo ID

subhalo_index, id, index

Subhalo ID/index.

central_flag

Central Flag (0=no, 1=yes)

cen_flag, is_cen, is_central

Subhalo central flag (1 if central, 0 if not).

contam_frac

Low-res Contamination Fraction

Subhalo contamination fraction (low-res DM to total DM particle count).

redshift

Redshift

Redshift, i.e. constant for all subhalos.

mhalo_200

Halo Mass \(\rm{M_{200c}}\)

\(\rm{M_{sun}}\)

mhalo_200_code, mhalo_200_parent, m200, m200c, mhalo

Parent halo total mass (\(\rm{M_{200,crit}}\)). Only defined for centrals: satellites are assigned a value of nan (excluded by default), unless ‘_parent’ is specified in the field name, in which case satellites are given the same host halo mass as their central.

mhalo_500

Halo Mass \(\rm{M_{500c}}\)

\(\rm{M_{sun}}\)

mhalo_500_code, mhalo_500_parent, m500, m500c

Parent halo total mass (\(\rm{M_{500,crit}}\)). Only defined for centrals: satellites are assigned a value of nan (excluded by default).

mhalo_vir

Halo Mass \(\rm{M_{vir}}\)

\(\rm{M_{sun}}\)

mhalo_vir_code, mhalo_vir_parent

Parent halo total mass (\(\rm{M_{vir}}\)). Defined by \(\rm{M_{\Delta}}\) where \(\Delta\) is the overdensity based on spherical tophat collapse. Only defined for centrals: satellites are assigned a value of nan (excluded by default).

rhalo_200

\(\rm{R_{halo,200c}}\)

\(\rm{kpc}\)

rhalo_200_code, rhalo_200_parent, rhalo, r200, rhalo_200, rvir

Parent halo virial radius (\(\rm{R_{200,crit}}\)). Only defined for centrals: satellites are assigned a value of nan (excluded by default).

rhalo_500

\(\rm{R_{halo,500c}}\)

\(\rm{kpc}\)

rhalo_500_code, rhalo_500_parent, r500, rhalo_500

Parent halo \(\rm{R_{500,crit}}\) radius. Only defined for centrals: satellites are assigned a value of nan (excluded by default).

vhalo

\(\rm{v_{200,halo}}\)

\(\rm{km/s}\)

v200, vvir

Parent halo virial velocity (\(\rm{V_{200}}\)). Only defined for centrals: satellites are assigned a value of nan (excluded by default).

halo_numsubs

\(\rm{N_{sub}}\) in Halo

halo_nsubs, nsubs, numsubs

Total number of subhalos in parent dark matter halo. A value of one implies only a central subhalo exists, while a value of two indicates a central and one satellite, and so on. Only defined for centrals: satellites are assigned a value of nan (excluded by default).

virtemp

\(\rm{T_{vir}}\)

\(\rm{K}\)

tvir

Virial temperature of the parent halo (satellites have NaN).

distance

Radial Distance

\(\rm{kpc}\)

rdist_code, rdist, rdist_rvir, distance_code, distance_rvir

Radial distance of satellites to center of parent halo (centrals have zero).

mhalo_subfind

Subhalo Mass \(\rm{M_{grav}}\)

\(\rm{M_{sun}}\)

Parent dark matter (sub)halo total mass, defined by the gravitationally bound mass as determined by Subfind.

mstar1

\(\rm{M_{\star}}\)

\(\rm{M_{sun}}\)

Galaxy stellar mass, measured within the stellar half mass radius.

mstar2

\(\rm{M_{\star}}\)

\(\rm{M_{sun}}\)

Galaxy stellar mass, measured within twice the stellar half mass radius.

mstar_tot

\(\rm{M_{\star}}\)

\(\rm{M_{sun}}\)

Galaxy stellar mass, total subhalo/subfind value.

mstar_fof

\(\rm{M_{\star,fof}}\)

\(\rm{M_{sun}}\)

Galaxy stellar mass, total halo (FoF) value. All satellites have same value as their central.

mgas1

\(\rm{M_{gas}}\)

\(\rm{M_{sun}}\)

Galaxy gas mass (all phases), measured within the stellar half mass radius.

mgas2

\(\rm{M_{gas}}\)

\(\rm{M_{sun}}\)

Galaxy gas mass (all phases), measured within twice the stellar half mass radius.

mgas_tot

\(\rm{M_{gas}}\)

\(\rm{M_{sun}}\)

Galaxy gas mass, total subhalo/subfind value.

mdm_tot

\(\rm{M_{DM}}\)

\(\rm{M_{sun}}\)

Galaxy DM mass, total subhalo/subfind value.

mstar_100pkpc

\(\rm{M_{\star, <30kpc}}\)

\(\rm{M_{sun}}\)

mstar_100kpc

Galaxy stellar mass, measured within a fixed 3D aperture of 100 physical kpc.

mstar_30pkpc

\(\rm{M_{\star, <30kpc}}\)

\(\rm{M_{sun}}\)

mstar_30kpc

Galaxy stellar mass, measured within a fixed 3D aperture of 30 physical kpc.

mstar_5pkpc

\(\rm{M_{\star, <5kpc}}\)

\(\rm{M_{sun}}\)

Galaxy stellar mass, measured within a fixed 3D aperture of 5 physical kpc.

mgas_5pkpc

\(\rm{M_{gas, <5kpc}}\)

\(\rm{M_{sun}}\)

Galaxy gas mass, measured within a fixed 3D aperture of 5 physical kpc.

mdm_5pkpc

\(\rm{M_{DM, <5kpc}}\)

\(\rm{M_{sun}}\)

Galaxy dark matter mass, measured within a fixed 3D aperture of 5 physical kpc.

mtot_5pkpc

\(\rm{M_{total, <5kpc}}\)

\(\rm{M_{sun}}\)

Galaxy total mass (gas + stars + DM + BHs), measured within a fixed 3D aperture of 5 physical kpc.

mstar_mtot_ratio_5pkpc

\(\rm{M_{\star} / M_{total} (<5kpc)}\)

Ratio of galaxy stellar mass, to total mass, both measured within a 3D aperture of 5 physical kpc.

mstar2_mhalo200_ratio

\(\rm{M_{\star, <2r_{\star}} / M_{halo,200c}}\)

Galaxy stellar mass to halo mass ratio, the former defined as within twice the stellar half mass radius, the latter as M_200_Crit.

mstar30pkpc_mhalo200_ratio

\(\rm{M_{\star, <30pkpc} / M_{halo,200c}}\)

mstar_mhalo_ratio

Galaxy stellar mass to halo mass ratio, the former measured within a fixed 3D aperture of 30 physical kpc, the latter taken as M_200_Crit.

mstar_r500

\(\rm{M_{\star, <r500}}\)

\(\rm{M_{sun}}\)

Subhalo stellar mass (i.e. central+ICL, but no sats), measured within \(\rm{R_{500c}}\).

mgas_r500

\(\rm{M_{gas, <r500}}\)

\(\rm{M_{sun}}\)

Subhalo gas mass (all phases), measured within \(\rm{R_{500c}}\).

mgas_halo

\(\rm{M_{gas, halo}}\)

\(\rm{M_{sun}}\)

Halo-scale gas mass, measured within each FoF.

mhi

\(\rm{M_{HI, grav}}\)

\(\rm{M_{sun}}\)

Galaxy atomic HI gas mass (BR06 molecular H2 model), measured within the entire subhalo (all gravitationally bound gas).

mhi2

\(\rm{M_{HI, <2r_{\star}}}\)

\(\rm{M_{sun}}\)

Galaxy atomic HI gas mass (BR06 molecular H2 model), measured within twice the stellar half mass radius.

mhi_30pkpc

\(\rm{M_{HI, <30kpc}}\)

\(\rm{M_{sun}}\)

Galaxy atomic HI gas mass (BR06 molecular H2 model), measured within a fixed 3D aperture of 30 physical kpc.

mhi_halo

\(\rm{M_{HI, halo}}\)

\(\rm{M_{sun}}\)

Halo-scale atomic HI gas mass (BR06 molecular H2 model), measured within each FoF.

fgas1

\(\rm{f_{gas} = M_{\rm gas} / (M_{gas} + M_\star) (<r_{\star})}\)

fgas1_alt

Galaxy gas mass fraction (all phases), measured within the stellar half mass radius.

fgas2

\(\rm{f_{gas} = M_{\rm gas} / (M_{gas} + M_\star) (<2r_{\star})}\)

fgas2_alt

Galaxy gas mass fraction (all phases), measured within twice the stellar half mass radius.

fgas

\(\rm{f_{gas} = M_{\rm gas} / (M_{gas} + M_\star)}\)

fgas_alt

Galaxy gas mass fraction (all phases), measured within the entire subhalo.

fdm

\(\rm{f_{dm} = M_{\rm dm} / M_{\rm tot}}\)

Galaxy DM fraction, measured within the entire subhalo.

fdm1

\(\rm{f_{dm} = M_{\rm dm} / M_{\rm tot}}\)

Galaxy DM fraction, measured within the stellar half mass radius.

fdm2

\(\rm{f_{dm} = M_{\rm dm} / M_{\rm tot}}\)

Galaxy DM fraction, measured within twice the stellar half mass radius.

sfr1

\(\rm{SFR_{<r_{\star},instant}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Galaxy star formation rate (instantaneous, within one times the stellar half mass radius).

sfr2

\(\rm{SFR_{<2r_{\star},instant}}\)

\(\rm{M_{sun}\, yr^{-1}}\)

Galaxy star formation rate (instantaneous, within twice the stellar half mass radius).

sfr1_surfdens

\(\rm{\Sigma_{SFR,<r_{\star},instant}}\)

\(\rm{M_{sun}\, yr^{-1}\, kpc^{-2}}\)

Galaxy star formation rate surface density (instantaneous, within one times the stellar half mass radius).

sfr2_surfdens

\(\rm{\Sigma_{SFR,<2r_{\star},instant}}\)

\(\rm{M_{sun}\, yr^{-1}\, kpc^{-2}}\)

Galaxy star formation rate surface density (instantaneous, within twice the stellar half mass radius).

ssfr

\(\rm{sSFR_{<2r_{\star},instant}}\)

\(\rm{yr^{-1}}\)

Galaxy specific star formation rate [1/yr] (sSFR, instantaneous, both SFR and M* within 2rhalfstars).

ssfr_gyr

\(\rm{sSFR_{<2r_{\star}}}\)

\(\rm{Gyr^{-1}}\)

Galaxy specific star formation rate [1/Gyr] (sSFR, instantaneous, both SFR and M* within 2rhalfstars).

delta_sfms

\(\rm{\Delta SFMS}\)

dex

Offset from the star-formation main sequence (SFMS), taken as the clipped sim median, in dex.

z_stars

\(\rm{Z_{\star}}\)

\(\rm{Z_\odot}\)

Galaxy stellar metallicity, mass-weighted average of all star particles within 2rhalfstars.

z_gas

\(\rm{Z_{gas}}\)

\(\rm{Z_\odot}\)

Galaxy gas metallicity, mass-weighted average of all gas cells within 2rhalfstars.

z_gas_sfr

\(\rm{Z_{gas}}}\)

\(\rm{Z_\odot}\)

Galaxy gas metallicity, SFR-weighted average of all gas cells within 2rhalfstars.

size_stars

r \(_{\rm 1/2,\star}\)

\(\rm{kpc}\)

rhalf_stars, size_stars_code, rhalf_stars_code

Stellar half mass radius.

re_rvir_ratio

r \(_{\rm 1/2,\star}\) / R \(_{\rm vir,halo}\)

size_stars_rvir_ratio

Stellar half mass radius normalized by parent halo virial radius (r200c).

size_gas

r \(_{\rm 1/2,gas}\)

\(\rm{kpc}\)

rhalf_gas, size_gas_code, rhalf_gas_code

Gas half mass radius.

surfdens1_stars

\(\rm{\Sigma_{*,<r_{\star}}}\)

\(\rm{M_{sun}\, kpc^{-2}}\)

Galaxy stellar surface density (within the stellar half mass radius).

surfdens2_stars

\(\rm{\Sigma_{*,<2r_{\star}}}\)

\(\rm{M_{sun}\, kpc^{-2}}\)

Galaxy stellar surface density (within twice the stellar half mass radius).

surfdens1_dm

\(\rm{\Sigma_{DM,<r_{\star}}}\)

\(\rm{M_{sun}\, kpc^{-2}}\)

Galaxy DM surface density (within the stellar half mass radius).

vcirc

\(\rm{V_{circ}}\)

\(\rm{km/s}\)

vc, vmax

Maximum value of the spherically-averaged 3D circular velocity curve (i.e. galaxy circular velocity).

velmag

\(\rm{|V|_{subhalo}}\)

\(\rm{km/s}\)

vmag

The magnitude of the current velocity of the subhalo through the box, in the simulation reference frame.

spinmag

\(\rm{|S|_{subhalo}}\)

\(\rm{kpc km/s}\)

smag

The magnitude of the subhalo spin vector, computed as the mass weighted sum of all subhalo particles/cells.

m_v

M \(_{\rm V}\)

abs AB mag

m_u, m_b, m_r

V-band (B-band, r-band, …) magnitude (StellarPhotometrics from snapshot). AB system. No dust.

color_uv

(U-V) color

mag

color_vb

Integrated photometric/broadband galaxy colors, from snapshot. AB system. No dust.

massfrac_exsitu

Ex-Situ Stellar Mass Fraction

massfrac_exsitu2, massfrac_insitu, massfrac_insitu2

Postprocessing/StellarAssembly: ex-situ or in-situ stellar mass fraction. Within the stellar half mass radius, unless ‘2’ in field name, in which case within 2*rhalf.

mergers_mean_fgas

Mean Gas Fraction of Mergers

Postprocessing/MergerHistory: mean property (‘cold’ i.e. star-forming gas fraction) of mergers. Weighted by the maximum stellar mass of the secondary progenitors.

mergers_mean_z

Redshift

Postprocessing/MergerHistory: mean property (redshift) of all mergers this subhalo gas undergone. Weighted by the maximum stellar mass of the secondary progenitors.

mergers_mean_mu

Mean Stellar Mass Ratio of Mergers

Postprocessing/MergerHistory: mean property (stellar mass ratio) of mergers. Weighted by the maximum stellar mass of the secondary progenitors.

coolcore_flag

Cool-core Flag (0=CC, 1=WCC, 2=NCC)

Postprocessing/coolcore_criteria: flag (0=SCC, 1=WCC, 2=NCC) based on Lehle+24 tcool fiducial definition.

coolcore_tcool

Central \(t_{\rm cool}\)

Gyr

tcool0

Postprocessing/coolcore_criteria: Lehle+24 central cooling time.

coolcore_entropy

Central \(K_0\)

keV cm \(^2\)

K0

Postprocessing/coolcore_criteria: Lehle+24 central cooling time.

coolcore_ne

Central \(n_e\)

cm \(^{-3}\)

Postprocessing/coolcore_criteria: Lehle+24 central electron number density.

coolcore_ne_slope

n_{rm e} slope ( \(\alpha\)

Postprocessing/coolcore_criteria: Lehle+24 central slope of number density.

coolcore_c_phys

C_{rm phys}

Postprocessing/coolcore_criteria: Lehle+24 X-ray concentration (40kpc vs 400kpc), physical.

coolcore_c_scaled

C_{rm phys}

Postprocessing/coolcore_criteria: Lehle+24 X-ray concentration (40kpc vs 400kpc), scaled.

peakoffset_xray

\(\Delta x_{\rm X-ray}\)

\(\rm{kpc}\)

peakoffset_xray_x, peakoffset_xray_y, peakoffset_xray_z

Postprocessing/released: Nelson+24 offsets of X-ray peaks [pkpc].

peakoffset_sz

\(\Delta x_{\rm SZ}\)

\(\rm{kpc}\)

peakoffset_sz_x, peakoffset_sz_y, peakoffset_sz_z

Postprocessing/released: Nelson+24 offsets of SZ peaks [pkpc].

fcirc_all_eps07o

\(\rm{f_{circ, \epsilon > 0.7}}\)

fcirc, fcirc_10re_eps07o

Postprocessing/circularities/: fraction of disk-stars (circularity > 0.7), all stars in subhalo.

fcirc_all_eps07m

\(\rm{f_{circ, \epsilon > 0.7 - \epsilon < -0.7}}\)

fcirc_10re_eps07m

Postprocessing/circularities/: fraction of disk-stars (circularity > 0.7), all stars in subhalo.

slit_vrot_halpha

\(V_{\rm rot, H\alpha}\)

km/s

Postprocessing/galskitkinematics/: Disk rotation velocity based on H-alpha emission.

slit_vrot_stars

\(V_{\rm rot, V-band}\)

km/s

Postprocessing/galskitkinematics/: Disk rotation velocity based on stellar light.

slit_vsigma_halpha

\(\sigma_{\rm vel, los, H\alpha}\)

km/s

Postprocessing/galskitkinematics/: Disk velocity dispersion based on H-alpha emission.

slit_vsigma_stars

\(\sigma_{\rm vel, los, V-band}\)

km/s

Postprocessing/galskitkinematics/: Disk velocity dispersion based on stellar light.

slit_voversigma_halpha

\(V_{\rm rot}\) / \(\sigma_{\rm vel,los}\) [H-alpha]

Postprocessing/galskitkinematics/: Disk rotational support (V/sigma) based on H-alpha emission.

slit_voversigma_stars

\(V_{\rm rot}\) / \(\sigma_{\rm vel,los}\) [V-band]

Postprocessing/galskitkinematics/: Disk rotational support (V/sigma) based on stellar light.

size2d_halpha

Projected 2D Size r \(_{\rm H-alpha,1/2}\)

kpc

Postprocessing/galsizes/: Galaxy disk size (from 2D projection) based on H-alpha emission.

size2d_stars

Projected 2D Size r \(_{\rm V-band,1/2}\)

kpc

Postprocessing/galsizes/: Galaxy disk size (from 2D projection) based on stellar light.

diskheight2d_halpha

Projected 2D Disk Height h \(_{\rm H-alpha,1/2}\)

kpc

Postprocessing/galsizes/: Galaxy disk scale-height (from 2D projection) based on H-alpha emission.

diskheight2d_stars

Projected 2D Disk Height h \(_{\rm V-band,1/2}\)

kpc

Postprocessing/galsizes/: Galaxy disk scale-height (from 2D projection) based on stellar light.

diskheightnorm2d_halpha

Normalized Disk Height \(\rm{(h/r)_{H-alpha}}\)

Postprocessing/galsizes/: Galaxy disk normalized scale-height (h/r) based on H-alpha emission.

diskheightnorm2d_stars

Normalized Disk Height \(\rm{(h/r)_{V-band}}\)

Postprocessing/galsizes/: Galaxy disk normalized scale-height (h/r) based on stellar light.

mstar_out_10kpc

Stellar Mass (r > 10 pkpc)

Msun

data.files/pillepich/: Stellar mass outside of 10 kpc.

d_minima

Distance to Nearest Void

Mpc

Postprocessing/disperse/: Distance to nearest cosmic web structure (minima = void), from disperse.

d_node

Distance to Nearest Halo

Mpc

Postprocessing/disperse/: Distance to nearest cosmic web structure (node = halo), from disperse.

d_skel

Distance to Nearest Filament

Mpc

Postprocessing/disperse/: Distance to nearest cosmic web structure (skel = filament), from disperse.

Custom Snapshot Quantities

The following particle/cell-level custom quantities are currently defined, in the temet.load.snap_fields_custom module, along with associated metadata including a description, units, reasonable bounds, and so on.

Field Name

Label

Units

Aliases

Description

mass_msun

Mass

\(\rm{M_{sun}}\)

Particle/cell mass in solar masses.

mass

High-Res Mass Fraction

masses

Particle/cell mass in code units, supporting constant-mass DM particles.

highres_massfrac

High-resolution mass normalized by total mass (applicable only to zooms).

velmag

Velocity Magnitude

\(\rm{km/s}\)

vmag

Magnitude of the gas velocity 3-vector.

subfind_vol

Subfind Volume

code_volume

subfind_volume

Particle ‘volume’ based on SubfindHsml of the N=64 nearest DM particles.

gravpot

Gravitational Potential

\(\rm{(km/s)^2}\)

gravpotential

Gravitational potential (from stored value in snapshot).

vesc

Escape Velocity

\(\rm{km/s}\)

escapevel

Escape velocity, based on the stored gravitational Potential.

dt

Timestep

\(\rm{yr}\)

dt_yr

Particle/cell total actual/effective timestep, from stored snapshot value.

temp

Gas Temperature

\(\rm{K}\)

temperature

Gas temperature.

temp_old

Gas Temperature (Uncorrected)

\(\rm{K}\)

Gas temperature (uncorrected values for TNG runs).

temp_sfcold

Gas Temperature

\(\rm{K}\)

Gas temperature, where star-forming gas is set to the sub-grid (constant) cold-phase temperature, instead of eEOS ‘effective’ temperature.

temp_sfhot

Gas Temperature

\(\rm{K}\)

Gas temperature, where star-forming gas is set to the sub-grid (constant) hot-phase temperature, instead of the eEOS ‘effective’ temperature. Use with caution.

twophase_coldfrac

SH03 Cold-phase Mass Fraction

Cold-phase mass (or density) fraction, for the SH03 two-phase ISM model. Note: is exactly 0.0 for non-starforming (SFR==0) gas cells, and typically of order ~0.9 for SFR>0 cells.

ne

Electron Number Density \(\rm{n_e}\)

\(\rm{cm^{-3}}\)

nelec

Electron number density, derived from (fractional) ElectronAbundance, handling runs without cooling.

ne_twophase

Hot-phase Electron Number Density \(\rm{n_e}\)

\(\rm{cm^{-3}}\)

Electron number density, where for star-forming gas cells we override the naive snapshot value, which is unphysically high, with a value based on the SH03 hot-phase mass only.

nh

Gas Hydrogen Density \(\rm{n_H}\)

\(\rm{cm^{-3}}\)

hdens

Hydrogen number density, derived from total Density.

xhi

Neutral Hydrogen Mass Fraction \(\rm{x_{HI}}\)

massfrac_hi

Neutral hydrogen fraction, relative to the total gas mass. No H2 model applied.

numdens

Gas Number Density

\(\rm{cm^{-3}}\)

Total gas number density, derived from total Density.

dens_critratio

\(\rm{\rho_{gas} / \rho_{crit}}\)

Mass density to critical density.

dens_critb

\(\rm{\rho_{gas} / \rho_{crit,b}}\)

Mass density to critical baryon density.

entropy

Gas Entropy

\(\rm{K\ cm^2}\)

ent, entr

Gas entropy, derived from (u,dens).

bmag

Magnetic Field Strength

\(\rm{Gauss}\)

bfieldmag

Magnitude of the gas magnetic field 3-vector in Gauss.

bmag_ug

Magnetic Field Strength

\(\rm{\mu G}\)

bfieldmag_ug

Magnitude of the gas magnetic field 3-vector in micro-Gauss.

b2

Magnetic Field Squared

code units

Magnitude squared of the gas magnetic field 3-vector (in code units).

va

Alfven Velocity

\(\rm{km/s}\)

vel_alfven

Magnetic Alfven-wave velocity.

cs

Sound Speed

\(\rm{km/s}\)

vel_sound, csound, csnd

Gas sound speed (hydro only version).

mjeans

Jeans Mass

\(\rm{M_{sun}}\)

jeans_mass

Local (per-cell) Jeans mass.

tff_local

Free-fall Time

\(\rm{yr}\)

tff_cell

Local (per-cell) free-fall time.

volume

Gas Cell Volume

(code_length) \(^3\)

vol

Gas cell volume.

volume_cm3

Gas Cell Volume

\(\rm{cm^3}\)

vol_cm3

Gas cell volume [cm^3].

volume_kpc3

Gas Cell Volume

\(\rm{kpc^3}\)

vol_kpc3

Gas cell volume [kpc^3].

cellsize

Gas Cell Size

code_length

cellrad

Gas cell ‘size’ i.e. ‘cell radius’, defined as the radius of the volume equivalent sphere.

cellsize_kpc

Gas Cell Size

\(\rm{kpc}\)

cellrad_kpc

Gas cell size [kpc].

cellsize_ckpc

Gas Cell Size

\(\rm{ckpc}\)

cellrad_ckpc

Gas cell size [comoving kpc].

hsml

Smoothing Length

code_length

Smoothing length i.e. characteristic size, possibly for visualization purposes.

f_b

\(\rm{f_{b} / f_{b,cosmic}}\)

baryon_frac

Baryon fraction, defined as (gas+stars)/(gas+stars+DM), all estimated locally, then normalized to the cosmic baryon fraction.

pressure

Gas Pressure

\(\rm{K\ cm^{-3}}\)

gas_pres, gas_pressure, pres, p_gas, p_thermal

Gas thermal pressure.

pressure_mag

Gas Magnetic Pressure

\(\rm{K\ cm^{-3}}\)

mag_pres, magnetic_pressure, p_magnetic, p_b

Gas magnetic pressure.

pressure_ratio

\(\rm{\beta^{-1} = P_{B} / P_{gas}}\)

pres_ratio

Ratio of gas magnetic to thermal pressure (\(\beta^{-1}\)).

beta

\(\rm{\beta = P_{gas} / P_{B}}\)

Ratio of gas thermal to magnetic pressure (plasma \(\beta\)).

pressure_tot

Gas Total Pressure = \(\rm{P_{gas} + P_{B}}\)

\(\rm{K\ cm^{-3}}\)

p_tot, pres_tot, pres_total, pressure_total

Total (thermal+magnetic) gas pressure.

u_kinetic

Gas Kinetic Energy Density

\(\rm{erg\ cm^{-3}}\)

u_ke, kinetic_edens, kinetic_energydens

Kinetic, as opposed to thermal, energy density.

uratio_mag_ke

Gas ( \(\rm{u_{mag} / u_{ke}}\) ) Ratio

uratio_b_ke, u_b_ke_ratio, b_ke_edens_ratio

Ratio of gas magnetic to kinetic energy density.

tcool

Gas Cooling Time

\(\rm{Gyr}\)

cooltime

Gas cooling time (computed from saved GFM_CoolingRate), is np.nan if cell has net heating.

coolrate

Gas Cooling Rate

\(\rm{erg/s/g}\)

coolingrate

Gas specific cooling rate (computed from saved GFM_CoolingRate), is np.nan if cell has net heating.

heatrate

Gas Heating Rate

\(\rm{erg/s/g}\)

heatingrate

Gas specific heating rate (computed from saved GFM_CoolingRate), is np.nan if cell has net cooling.

netcoolrate

Gas Net Cooling Rate

\(\rm{erg/s/g}\)

Gas net specific cooling rate (computed from saved GFM_CoolingRate).

coolrate_powell

Powell Cooling Rate

\(\rm{erg/s/g}\)

Gas ‘cooling rate’ of Powell source term, specific (computed from saved DivB, GFM_CoolingRate).

dt_hydro

Gas Courant Timestep

\(\rm{yr}\)

dt_hydro_yr

Gas cell hydrodynamical (Courant) timestep.

tdep

Gas Depletion Time

\(\rm{Gyr}\)

depletion_time, tau_dep

Gas cell depletion time: cells with zero sfr given nan.

metaldens

Metal Density

\(\rm{g\ cm^{-3}}\)

dens_z, dens_metal

Total metal mass density.

h_massfrac

H Mass Fraction

Total hydrogen (H) mass fraction. This is a custom helper for MCST runs where this value is not directly stored for gas, but is split based on sub-species and ionization state.

he_massfrac

He Mass Fraction

Total helium (He) mass fraction. This is a custom helper for MCST runs where this value is not directly stored for gas, but is split based on sub-species and ionization state.

sz_y

Sunyaev-Zeldovich y-parameter

\(\rm{kpc^2}\)

sz_yparam, yparam

(Thermal) Sunyaev-Zeldovich y-parameter (per gas cell).

ksz_y

Kinetic SZ y-parameter

\(\rm{kpc^2/g}\)

ksz_yparam, ksz_y

(Kinetic) Sunyaev-Zeldovich y-parameter (per gas cell).

frm_x

Faraday RM

\(\rm{rad m^{-2}}\)

frm_y, frm_z

Faraday rotation measure -integrand- (ne*B_parallel) in [rad m^-2]. Must be integrated through all cells along a line of sight, as sum(integrand*dl) where dl is the pathlength through each cell in pc. Requires the B-field component ‘along the line-of-sight’ which must be axis-aligned and specified.

p_sync

Synchrotron Power

\(\rm{W/Hz}\)

p_sync_ska, p_sync_ska_eta43, p_sync_ska_alpha15, p_sync_vla

Radio synchrotron power (simple model).

halpha_lum

\(\rm{L_{H\alpha}}\)

\(\rm{10^{30}\ erg/s}\)

halpha, sfr_halpha

H-alpha line luminosity, simple model: linear conversion from SFR.

s850um_flux

\(\rm{S_{850\mu m}}\)

\(\rm{mJy}\)

submm_flux, s850um_flux_ismcut, submm_flux_ismcut

850 micron (sub-mm) flux (simple model).

xray_lum

\(\rm{L_{X,bolometric}}\)

\(\rm{10^{30}\ erg/s}\)

xray

Bolometric x-ray luminosity, simple bremsstrahlung (free-free) emission model only.

xray_lum_apecX

\(\rm{L_{X}}\)

\(\rm{10^{30}\ erg/s}\)

xray_lum_05-2kev, xray_flux_05-2kev, xray_lum_05-2kev_nomet, xray_flux_05-2kev_nomet, xray_counts_erosita, xray_counts_chandra, xray_lum_0.1-2.4kev, xray_lum_0.5-2.0kev, xray_lum_0.3-7.0kev, xray_lum_0.5-5.0kev, xray_lum_0.5-8.0kev, xray_lum_2.0-10.0kev

X-ray luminosity/flux/counts (the latter for a given instrumental configuration). If a decimal point ‘.’ in field, using my APEC-based tables, otherwise using XSPEC-based tables (from Nhut).

n_hi

\(\rm{N_{HI}}\)

\(\rm{cm^{-2}}\)

hi_column

Experimental: assign a N_HI (column density) to every cell based on a (xy) grid projection.

hi_mass

\(\rm{M_{HI}}\)

code_mass

mass_hi, h i mass, hi mass, h i numdens

Hydrogen model: atomic H (neutral subtracting molecular) mass calculation.

h2_mass

\(\rm{M_{H2}}\)

code_mass

mass_h2, h2mass

Hydrogen model: molecular H (neutral subtracting atomic) mass calculation.

mass_h_poppingX

\(\rm{M_{HI,H}}\)

code_mass

mhi_br, mhi_gk, mhi_kmt, mh2_br, mh2_gk, mh2_kmt

Pre-computed atomic (HI) and molecular (H2) gas cell masses (from Popping+2019).

numdens_h_poppingX

\(\rm{n_{HI,H}}\)

\(\rm{cm^{-3}}\)

nhi_br, nhi_gk, nhi_kmt, nh2_br, nh2_gk, nh2_kmt

Pre-computed atomic (HI) and molecular (H2) gas cell number densities (from Popping+2019).

mass_h_diemerX

\(\rm{M_{HI,H}}\)

code_mass

mhi_gd14, mhi_gk11, mhi_k13, mhi_s14, mh2_gd14, mh2_gk11, mh2_k13, mh2_s14

Pre-computed atomic (HI) and molecular (H2) gas cell masses (from Diemer+2019).

numdens_h_diemerX

\(\rm{n_{HI,H}}\)

\(\rm{cm^{-3}}\)

nhi_gd14, nhi_gk11, nhi_k13, nhi_s14, nh2_gd14, nh2_gk11, nh2_k13, nh2_s14

Pre-computed atomic (HI) and molecular (H2) gas cell number densities (from Diemer+2019).

wind_dedt

Wind Energy Injection Rate

\(\rm{10^{51}\ erg/s}\)

wind_edot, sn_dedt, sn_edot, sf_dedt, sf_edot

TNG/SH03 wind model: feedback energy injection rate.

wind_dpdt

Wind Momentum Injection Rate

\(\rm{10^{51}\ g\,cm\,s^{-2}}\)

wind_pdot, sn_dpdt, sn_pdot, sf_dpdt, sf_pdot

TNG/SH03 wind model: feedback momentum injection rate.

wind_vel

Wind Launch Velocity

\(\rm{km/s}\)

wind_launchvel

TNG/SH03 wind model: launch velocity.

wind_eta

Wind Mass Loading \(\rm{\eta_m}\)

wind_massloading, wind_etam

TNG/SH03 wind model: mass loading factor (at launch).

rad_fuv

FUV Radiation Energy Density

erg cm \(^{-3}\)

raddens_fuv, rad_fuv_habing, raddens_fuv_habing

Radiation energy density in FUV band (6 - 13.6 eV).

rad_lw

LW Radiation Energy Density

erg cm \(^{-3}\)

raddens_lw, rad_lw_habing, raddens_lw_habing

Radiation energy density in Lyman-Werner band (11.2 - 12.3 eV).

rad_fuv_lw_ratio

(FUV / LW) Radiation Ratio

Ratio of radiation energy density in FUV to Lyman-Werner band.

rad_fuv_uvb_ratio

(Local / UVB) FUV Radiation Ratio

Ratio of local to UVB radiation energy density in FUV band.

z_solar

Metallicity

\(\rm{Z_{sun}}\)

metal_solar

Metallicity in solar units.

sn_iaii_ratio_fe

Mass Ratio \(\rm{Fe_{SNIa} / {Fe}_{SNII}}\)

GFM_MetalsTagged: ratio of iron mass [linear] produced in SNIa versus SNII.

sn_iaii_ratio_metals

Mass Ratio \(\rm{Z_{SNIa} / Z_{SNII}}\)

GFM_MetalsTagged: ratio of total metal mass [linear] produced in SNIa versus SNII.

sn_ia_agb_ratio_metals

Mass Ratio \(\rm{Z_{SNIa} / Z_{AGB}}\)

GFM_MetalsTagged: ratio of total metal mass [linear] produced in SNIa versus AGB.

metalmass

Metal Mass

code_mass

mass_z, mass_metal, metalmass_msun

Total metal mass (convert GFM_Metals from fraction to mass).

star_age

Stellar Age

\(\rm{Gyr}\)

stellar_age

Age of stellar population (conversion of GFM_StellarFormationTime).

z_form

Stellar Formation Redshift

z_formation

Formation redshift of stellar population (conversion of GFM_StellarFormationTime).

stellar_masshist

Stellar mass histogram (binned by mass) for a given snapshot. MCST model.

bh_lbol

\(\rm{L_{bol}}\)

\(\rm{erg/s}\)

bh_bollum, bh_bollum_obscured

Black hole bolometric luminosity (optionally with obscuration).

bh_lbol_basic

\(\rm{L_{bol}}\)

\(\rm{erg/s}\)

bh_bollum_basic, bh_bollum_basic_obscured

Black hole bolometric luminosity (simple model, optionally with obscuration).

bh_lumedd

\(\rm{L_{edd}}\)

\(\rm{erg/s}\)

ledd, lumedd, edd_ratio, bh_ledd, eddington_lum

Black hole Eddington luminosity.

bh_eddratio

\(\rm{\lambda_{edd} = L_{bol} / L_{edd}}\)

eddington_ratio, lambda_edd, edd_ratio

Black hole bolometric luminosity (optionally with obscuration).

bh_mode

BH mode (0=low, 1=high)

Black hole accretion/feedback mode (0=low/kinetic, 1=high/quasar).

bh_dedt

BH Energy Injection Rate

\(\rm{erg/s}\)

bh_edot

Black hole feedback energy injection rate.

pos_relX

Halocentric Position

code_length

pos_rel_kpc, pos_rel_rvir

3D (xyz) position, relative to the halo/subhalo center.

vel_rel

Halo-Relative Velocity

\(\rm{km/s}\)

vrel, halo_vrel, halo_relvel, relative_vel

3D (xyz) velocity, relative to the halo/subhalo motion.

vel_rel_mag

Halo-Relative Velocity

\(\rm{km/s}\)

vrelmag, halo_vrelmag, relative_vmag

Magnitude of velocity, relative to the halo/subhalo motion.

radX

Radial Distance

code_length

halo_rad, rad_r500, rad_rvir, halo_rad_r500, halo_rad_rvir

3D radial distance from (parent) halo center.

rad_kpc

Radial Distance

\(\rm{kpc}\)

halo_rad_kpc, rad_kpc_linear

3D radial distance from (parent) halo center in [kpc].

dist_2dz

dist_2dz_r200, dist_2dz_r500

2D distance (i.e. impact parameter), projecting along z-hat, from (parent) halo center.

vradX

Radial Velocity

\(\rm{km/s}\)

halo_vrad, radvel, halo_radvel, vrad_vvir, halo_vrad_vvir, halo_radvel_vvir

Radial velocity, relative to the central subhalo and its motion, including hubble correction. Optionally normalized by the halo virial velocity. Convention: negative = in, positive = out.

angmomX

Specific Angular Momentum

\(\rm{M_{sun}\ kpc\ km/s}\)

j, specj, specangmom, angmom_mag, specj_mag, specangmom_mag

Angular momentum, relative to the central subhalo and its motion, including hubble correction, either the 3-vector or the specific magnitude (if field contains ‘_mag’).

menc

Enclosed Mass

code_mass

enclosedmass

Enclosed mass, i.e. total halo mass within the radial distance of each particle/cell.

menc_msun

Enclosed Mass

\(\rm{M_{sun}}\)

enclosedmass_msun

Enclosed mass, in solar masses.

tff

Gravitational Free-Fall Time

\(\rm{Gyr}\)

tfreefall, freefalltime

Gravitational free-fall time.

tcool_tff

\(\rm{t_{cool} / t_{ff}}\)

Ratio of gas cooling time to gravitational free-fall time.

menc_vesc

Escape Velocity

\(\rm{km/s}\)

Gravitational escape velocity (based on enclosed mass).

delta_rho

\(\delta \rho / <\rho>\)

Ratio of density to local mean density, delta_rho/<rho>, based on a spherically symmetric, halo-centric mass density profile. This is a special case of the below.

subhalo_id

Subhalo ID

subid, subhaloid

Parent subhalo ID, per particle/cell.

halo_id

Halo ID

haloid

Parent halo ID, per particle/cell.

sat_member

Satellite Member

True (1) if particle/cell belongs to a satellite subhalo, False (0) otherwise (central/inner fuzz/outer fuzz).

The following ‘wildcard’ fields match any field request whose name contains the pattern.

Field Name

Label

Units

Description

tau0_X

Optical Depth \(\rm{\tau_{X,0}}\)

Optical depth to a certain line, at line center.

metaldens_X

X Metal Density

\(\rm{g\ cm^{-3}}\)

Metal mass density for a given species, e.g. ‘metaldens_O’.

{ion} {num} mass

{ion} {num} Ionic Mass

\(\rm{M_{sun}}\)

CLOUDY-based photoionization calculation: total ionic mass (e.g. ‘O VI mass’, ‘Mg II mass’), for any known ion name and excited level number. Note: uses spaces in field name.

{ion} {num} frac

{ion} {num} Ionization Fraction

CLOUDY-based photoionization calculation: ionic mass fraction (e.g. ‘O VI frac’, ‘Mg II frac’), for a given ion name and excited level number. Note: uses spaces in field name.

{ion} {num} numdens

\(\rm{n_{\{ion\}\{num\}}}\)

\(\rm{cm^{-3}}\)

CLOUDY-based photoionization calculation: ionic number density (e.g. ‘O VI numdens’, ‘Mg II numdens’), for a given ion name and excited level number. Note: uses spaces in field name.

{line_name} flux

{line_name} Line Flux

\(\rm{photon/s/cm^2}\)

CLOUDY-based photoionization calculation: ion line emission flux (e.g. ‘H-alpha flux’, ‘O–6-1037.62A’), for a given line name. Note: uses spaces in field name.

{line_name} lum

{line_name} Luminosity

\(\rm{10^{30}\ erg/s}\)

CLOUDY-based photoionization calculation: ion line luminosity (e.g. ‘MgII lum’, ‘CVI lum’), for a given line name. Note: uses spaces in field name.

ionmassratio_X_Y

(X / Y) Mass Ratio

Ratio between two ionic masses, e.g. ‘ionmassratio_O6_O8’.

numratio_X_Y

\(\rm{[X/Y]_{}}\)

Metal abundance number density ratio e.g. ‘numratio_Si_H’, relative to solar, i.e. [Si/H].

massratio_X_Y

Mass Ratio \(\rm{(X/Y)_{}}\)

Metal abundance mass ratio e.g. ‘massratio_Si_H’, absolute (not relative to solar).

metalmass_X

X Metal Mass

code_mass

Metal mass for a given species (convert GFM_Metals from fraction to mass), e.g. ‘metalmass_O’ or ‘metalmass_Mg’ or ‘metalmass_Fe_msun’.

delta_X

\(\rm{\delta X / <X>}\)

Ratio of any particle/cell property to its local average, based on a spherically symmetric, halo-centric radial profile.

parent_subhalo_X

Parent Subhalo [X]

Any property of the parent subhalo, per particle/cell.

parent_halo_X

Parent Halo [X]

Any property of the parent halo, per particle/cell.