Simulations* in the radio waves Simulations* in the radio waves regime for ASKAPregime for ASKAP

*of galaxy formation*of galaxy formation

Claudia Lagos (ARC DECRA fellow)on behalf of ICRAR-theory group

Theory/computing group at ICRAR

Preparing the theory for ASKAP...

● What's available? – We are working in two fronts: SAMs and hydro-

dynamical simulations.

● Properties of galaxies in the HI regime to keep in mind:– Results from new generation of multi-purpose

lightcones

● Radio properties of galaxies currently available (HI emission, radio continuum) and in development (radio continuum, HI absorption)

We are exploiting two fronts of galaxy formation sims

Adrian Jenkins

2. Parallel approaches: hydro-dynamical simulations

1. Serial approaches: semi-analytic models

Credit: Rob Crain

Why would we want to exploit both techniques, rather than focus

on one only?

Difference between SAMs and hydro-sims

In SAMs we have integrated properties: Galaxy sizes, stellar and gas masses, SFRs, metallicities, etc. Image from Lagos et al. (2013). Similar information in other models (Fu et al.; Popping et al.; Croton et al.)

In hydro simulations we have the entire structure of galaxies (but volumes are much smaller). Images from Lagos et al. (2015b) and Trayford et al. (2015) (EAGLE)

Volumes simulated

P-Millennium (produced in Durham)(800Mpc)3 resolution down to Mhalo~5x109 Msun

Most amazing hydro-simulations!

This means that we expect 10s of millions of gas-rich galaxies in our SAMs vs. fewx1,000 in EAGLE

Semi-analytic models and Semi-analytic models and multi-purpose lightconesmulti-purpose lightcones

Multi-purpose lightcones...

Adrian Jenkins

Although lightcones can be produced for specific surveys, we are testing multi-purpose lightcones (stellar mass cut only)

SURFS suite (C. Power) GALFORM (C. Lagos)VELOCIraptor (P. Elahi)

The SURFS suite of N-body simulations

Elahi et al. (in prep.)

SURFS (Synthetic UniveRses For Surveys) Volumes varying within ~x75,000Resolutions varying within ~x150

First example of multi-purpose lightcones

Lagos et al. (2012) galform model on Millennium-2 (halos resolved down to 109Msun)

Advantage is that it reproduces several HI properties of galaxies (treatment of the ISM)Lagos et al. (2014a)

The HI of galaxies/groups in GALFORM

Brown et al. (2016; HI stacking of satellitegalaxies)

Eckert et al. (2016; cold baryons fraction in groups)

Martindale et al. (in prep.)

GALFORM model

The SED of galaxies in GALFORM

Applications to HI ASKAP surveys

We asked: (1) What is the HI mass distribution expected? (2) given a set of HI detections, how many GAMA (or optical/near-IR surveys)

counterparts would be found?

ALFALFA.40 (Papastergis+11)

Duffy+12We took galaxies with Speak>3

Unexplored territory

But half of the galaxies here!!

All galaxies observed

We can now ask how many counterparts in UV/optical/near-IR are expected based

on these improved models/resolution!

UV/Optical/near-IR counterparts

(2) given a set of HI detections, how many GAMA (or optical/near-IR surveys) counterparts would be found?

GA

MA

WA

VE

S

Sub

aru

r

HD

FMany r-band selected galaxies without HI detections.

Many HI-selected galaxies without r-band counterparts

See Elisabete's talk for the TAIPAN/WALLABY overlap

Our preliminary results call for a revision of what was done in Duffy+12, and the SAX lightcones (mainly due to improved resolution of the sims+ improved models)

Ongoing work (to be finalised during 2016)

(1) Absorption lines (using HI and velocity structure of galaxies in the model): from models+hydro-sims

Prochaska & Wolfe (1997)

Use the lessons from hydro-sims to estimate neutral gas in the cosmic web(Rahmati+15)

Ongoing work (to be finalised during 2016)

(2) Radio continuum (AGN radio core is already included), but we are working now on - radio continuum from star formation - radio continuum from diffuse emission- radio continuum from AGN/outflows

Hydro-dynamical simulationsHydro-dynamical simulations

New generation of hydro-simulations

Large number of sub-grid physics module:→ Metal-dependent cooling→ Reionisation→ Star formation→ Stellar recycling→ Stellar feedback→ AGN feedback

(~700pc resolution, 1e6Msun,100Mpc box size)

Schaye et al.(2015); Vogelsberger (2014), Dubois et al. (2015), amongothers

Our group is extensively working with EAGLE and HORIZON-AGN

Cosmic density of gas in EAGLE

Atomic hydrogen-densityRahmati et al. (2015)

Molecular hydrogen-densityLagos et al. (2015b)

Extensive work in EAGLE partitioning the gas in HII/HI/H2Lagos et al. (2015b,2016a), Bahe et al. (2015), Crain et al. (2016), Rahmati et al. (2015,2016):- HI/H2 mass functions, gas fractions, scaling relations, relation with Mstellar and SFR at different redshfits, column density distributions (HI and high ionisation metals), etc.

The power of resolved galaxy structures

In hydro simulations we have the entire structure of galaxies. Images from Lagos et al. (2016a) and Trayford et al. (2015) (EAGLE)

Galaxies with the same stellar mass, SFR, HI and H2 masses but at different redshifts

Sizes/angular momentum extremely sensitive to accretion flows/compactness of galaxies

Lagos et al. (2016b):Using EAGLE (but similar results in Horizon-AGN)

The power of resolved HI maps...

Bahe et al. (2015): using EAGLE

Gas distribution extremely sensitive to the feedback+ISM modelling in a way that we can start using that information!

→ Our current strategy is to build-up a library of zoom-in simulations of groups and clusters (~10 to date) that can help up to:

(i) Capture the variety of environmental effects on the gas (WALLABY/DINGO)

(ii) Estimate the diffuse/radio continuum emission from groups/clusters (EMU)

→ Use “large” cosmological boxes (EAGLE/HORIZON-AGN) to:

(i) Characterise the nature of HI absorption lines (FLASH)

(ii) Study AGN outflows to estimate core radio emission + lobes emission (EMU)

Hydro-dynamical simulations...

We are doing this to help maximise the science We are doing this to help maximise the science outcome of the ASKAP surveys and so we are outcome of the ASKAP surveys and so we are ready to provide you with simulation data right ready to provide you with simulation data right here, right now!here, right now!

Gas mass functions in EAGLE

Lagos et al. (2015b)

Crain et al. (2016)

To study HI-selected galaxies in the entire range where observations exist, very high resolution is needed! (~250pc)

Radio diffuse emission in clusters

Power et al. (in prep.): Unveiling the diffuse radio emission from shocks in groups/clusters

Comparison with other publicly available models

Environment range probed

Murray, Power, Robotham (2014)

- HI gas-rich galaxies- SMGs and QSOs- ELGs

Fewx1,000

1

100

Clusters

LRGs

somex10,000

10s millions

- Quite obvious that clustering and LSS studies require SAs- Mocks should be (and will be) generated for large LSS surveys.

Semi-analytic models of galaxy formation

Adrian Jenkins

Semi-analytic models of galaxy formation

Running a suite of N-body simulations at ICRAR

Merger trees constructed using different algorithms (VELOCIraptor, SUBFIND)

Using GALFORM (different flavours and varying models)

Led by Chris Power Led by Pascal Elahi Led by Claudia Lagos

At the near-IR...

Many (~half) z-band selected galaxies without HI detections.

Many HI-selected galaxies without z-band counterpartsG

AM

A

Sub

aru

z

HS

T s

urve

ys

At the near-UV...

All NUV-selected galaxies (unless very faint) will have HI counterparts

GA

LEX

HS

T F

225W

1pc 100pc 100Mpc 1Gpc

Large

Large Scale Structure

ISM, star formationblack hole accretion

Semi-analytic models of galaxy formation

Hydro-dynamic simulationsof galaxy formation

Sub-grid physics

Summary of strengths and weaknesses of each technique...

Galaxy formation cares about all these scales