The cosmic web in the GIMIC simulation - CLUES-Project

The cosmic web in the
GIMIC simulation
Ofer Metuki
Hebrew University
CLUES meeting 2013,
La Cristalera

Motivation
● We've known for a long time that
environment affects galaxy formation
and galaxy properties (Dressler 1980)

Motivation
● We've known for a long time that
environment affects galaxy formation
and galaxy properties (Dressler 1980)
● “Environment” is not well defined –
observers and theorists use different
definitions

Motivation
● We've known for a long time that
environment affects galaxy formation
and galaxy properties (Dressler 1980)
● “Environment” is not well defined –
observers and theorists use different
definitions
● HODs and SAMs rely on the fact that
all of the effect comes in indrectly
through the halo mass (and accretion
history)

The GIMIC simulation
● Resimulation of the Millenium run

The GIMIC simulation
● Resimulation of the Millenium run
● 5 regions of 18-25 Mpc/h radius, with
densities of -2 to +2 σ

The GIMIC simulation
● Resimulation of the Millenium run
● 5 regions of 18-25 Mpc/h radius, with
densities of -2 to +2 σ
● Full gas dynamics, feedback but no
AGN

The GIMIC simulation
● Resimulation of the Millenium run
● 5 regions of 18-25 Mpc/h radius, with
densities of -2 to +2 σ
● Full gas dynamics, feedback but no
AGN
● Intermediate resolution -
●
M DM =5.3×10 7 M ⊙
M gas =1.17×10 7 M ⊙

The GIMIC simulation
● Resimulation of the Millenium run
● 5 regions of 18-25 Mpc/h radius, with
densities of -2 to +2 σ
● Full gas dynamics, feedback but no
AGN
● Intermediate resolution -
M M gas =1.17×10 7 DM =5.3×10 7 M ⊙
M ⊙
● Star formation, stellar feedback,
radiative cooling, chemodynamics

The GIMIC simulation
● Halos and subhalos are found using
AHF

The GIMIC simulation
● Halos and subhalos are found using
AHF
● We only take halos > 10 10 M ⊙ for the
sake of numerical convergence

The GIMIC simulation
● Halos and subhalos are found using
AHF
● We only take halos > 10 10 M ⊙
● Galaxies are defined to be everything
within 10% of Rvir

The GIMIC simulation
● Halos and subhalos are found using
AHF
● We only take halos > 10 10 M ⊙
● Galaxies are defined to be everything
within 10% of Rvir
● Satellite galaxies reside in subhalos

The GIMIC simulation
● Halos and subhalos are found using
AHF
● We only take halos > 10 10 M ⊙
● Galaxies are defined to be everything
within 10% of Rvir
● Satellite galaxies reside in subhalos
● Galaxies (and satellites) must have at
least 10 star particles

The GIMIC simulation

The parent halo mass function
● Changes with web –
effect of environment
● Knots control high
masses, then filaments,
then sheets

The (central) luminosity function
● Very similar behaviour
to mass function
● Unrealistic “bump” a
feature of the GIMIC
simulations

Subhalo mass function
A clear trend with the
“web sequence”,
matches number of
positive eigenvalues

Satellite luminosity function
Same trend with web
sequence as in the
subhalos

Subhalo / satellite numbers
Subhalos
Satellites

Baryon fraction in luminous halos
Plots sit right on top of
each other!
Things change with
halo mass, but for a
given halo mass, no
change between web
elements.

L/M
L/Mvir
L/Mbar

Specific star formation rate
● Higher mass halos
have later SFR peak
● Highest mass bin
behaves differently, but
within each mass bin
almost no change
between web elements

Conclusions
●
●
●
●
The web affects mass functions – the
higher a halo is on the “web sequence”,
the more massive it is likely to be
Luminosity functions behave close to
mass functions
Subhalos show a clear trend with web
sequence
Satellite galaxies also follow the subhalos
they reside in

Conclusions
●
●
Other galaxy parameters depend on their
host halo mass, but not on their web
element
Good news for SAMs and HODS!