SKADS Simulations (DS2 team)

• Box size: 500 h-1 Mpc (or ~700 Mpc) of which this is about 5-millionths of the corresponding sky area: ALMA & SKA both essential to study galaxies, but only SKA can generate the ‘billion-galaxy’ redshift surveys to probe the underlying cosmology

z = 1-1.1

Credit: Obreschkow

A fundamental experiment and not just dark energy (e.g. neutrino masses)

• If mis ~0.05 eV, SKA+Planck sufficient and necessary to measure it. With particle physics experiments, prospect of evidence for sterile neutrinos or

time evolution of neutrino mass. But all based on `perfect’ (catalogue) SKA survey: no longer adequate

Abdalla & Rawlings (2007)

1 yr 20,000 deg2

Abdalla, Blake & Rawlings (2009)

Large scales

s-cubed.physics.ox.ac.ukAll downloadable

will only discuss a sub-set: thanks to Matt Jarvis for some slides

Two types of SKADS extragalactic simulations

• ‘Line’ semi-analytic approach (Obreschkow PhD): SAX. DM haloes from Millennium Simulation. Ascribed HI and H2, star formation rates and AGN properties via physical prescriptions: provides insufficient FOV for SKADS benchmark

4x4 deg2 out to z~20 (HI/CO)~107 objects

star-formation continuum OKAGN continuum still under development

• ‘Continuum’ semi-empirical approach (Wilman):SEX. DM density field evolved under linear theory, populated with objects from known radio luminosity functions, and with other important physics (e.g. non-linear structures, source models) `pasted on’

currently 20x20 deg2 out to z~20 , ~2.5x108 simulated sources

80 kpc

500 M/pc2

H2

HI

Obreschkow & Rawlings, 2009, ApJ , 696L, 129

z=2z=0

Obreschkow & Rawlings, 2009, MNRAS, in press, arXiv:0908.0724

Application : dN/dz predictions for SKA and ALMA

Obreschkow et al. 2009c, ApJ,703, 1890

Obreschkow et al. (2009b), ApJ, 702, 1321

SKA, not ALMA, can do many deg2

• In ~100 days, phased arrays deliver >109 galaxies over ~20,000 deg2 to z~2 (and multiple P(k) to at least z~1)

Abdalla & Rawlings

Obreschkow et al

No evolution

• At z~0.1,1.4 h-1 com-kpc/arcsec

• 500 h-1 Mpc (log[k]=-1.9), 100 deg, z~0.15

• 100 h-1 Mpc (log[k]=-1.2), 20 degrees

• 30 h-1 Mpc (-0.67), 6 degrees

• Green curve: 20 arcmin (~1Mpc) resolution.

• 3 arcmin resolution only needs ~250m baselines.

• ASKAP will measure bias and detect BAOs: first time in HI

The Power Spectrum at z~0.1

Science with sub-phase-I AAs

1 yr 20,000 deg2

log(k) -0.7 to -1.6

k=0.2 down to 0.025

Key information comes from baselines below ~250 m

1% SKA with “just” 10 deg2

(and long baselines) is overkill

Can measure same P(k) as ASKAP (if in same hemisphere) with sub-phase-1 AA SKAs provided it can be calibrated, and ‘foregrounds’ removed

Science demonstration: <1% AAs can detect BAOs

2000 m2 (Tsys~50 K) with ~250 deg2 FOV, max baseline < 1km

split into ~9-15 stations - to be filled out to high filling factor by phase-I (analog/digital P&P)

Phase-1 (~10,000 m2) can get to z~0.7

Abdalla, Blake & Rawlings (2009)MNRAS in press, arXiv:0905.4311

Semi-Empirical eXtragalactic S3-SEX Simulation

Starting point: a z=0 (δρ/ρ)DM linear theory dark matter density field defined on a 550x550x1500 grid of 5 Mpc/h cells

Cosmology: H0=70 km/s/Mpc, ΩM=0.3, ΩΛ=0.7, σ8=0.74, BAO P(k)

Wilman et al. (2008) - MNRAS

In the ith cell, for each source population:

• Poisson sample the LF at L > Li

• In the limit (δρ/ρ)→0, (δn/n) → b(z)G(z)(δρ/ρ) (i.e. a linear bias model)

Redshift

ith cell, redshift zi

ΔΩ

Wilman et al. (2008)

Semi-Empirical eXtragalactic S3-SEX Simulation

Continuum source populations

• Radio-quiet AGN: Mhalo = 3x1012/h M • FRI radio sources: Mhalo = 1x1013/h M

• FRII radio sources: Mhalo = 1x1014/h M

• Normal SF galaxies: Mhalo = 1x1011/h M

• Starburst galaxies: Mhalo = 5x1013/h M

Wilman et al. (2008)

S3-SEX Example Use

Facilities for the next decade

eMerlin LOFAR EVLA KAT/ASKAP SKA2013 2020 2010

Spitzer SCUBA2 Herschel WISE ALMANow 2009 20102009

UKIDSS VISTA JWST ELTNow 2009 2013 2020

Near-IR

Mid/Far-IR

Radio

2010

SDSS1-2 Pan-STARRS SDSS-3 SkyM DES LSSTNow 2009 2010

Optical

2012

2011 2017

Facilities for the next decade

eMerlin LOFAR EVLA KAT/ASKAP SKA2013 2020 2010

Spitzer SCUBA2 Herschel WISE ALMANow 2009 20102009

UKIDSS VISTA JWST ELTNow 2009 2013 2020

Near-IR

Mid/Far-IR

Radio

2010

SDSS1-2 Pan-STARRS SDSS-3 SkyM DES LSSTNow 2009 2010

Optical

2012

2011 2017

3.5m primary

Launched in April 2009

Continuum capabilities from 70-550 microns

Herschel surveys relevant to SKA science

50 25

HerMES+PEP(the usual deep fields)

GOODS North / HDF North

GOODS South CDFS ECDFS

Lockman wide & deep

Extended Groth Strip

Bootes

XMM/VVDS

SWIRE fields (EN1, EN2, ES1)

Spitzer-FLS

AKARI SEP

Courtesy of S. Oliver

Herschel-ATLAS

• Local(ish) Galaxies

• Planck synergies

• Efficient lens survey

• Rare object science

• Large-scale structure

• Clusters

• Galactic science

Aim is to survey ~550 deg2 with Herschel at 110, 170, 250, 350 and 550mm. (600hrs allocated)

These will all be completed by 2012, so we can use them (and other wavelength surveys) to feed into the SKA sky simulations and give us a

better picture of the SKA-sky

Herschel-ATLAS

• Local(ish) Galaxies

• Planck synergies

• Efficient lens survey

• Rare object science

• Large-scale structure

• Clusters

• Galactic science

Aim is to survey ~550sq.deg with Herschel at 110, 170, 250, 350 and 550mm. (600hrs allocated)

But for now we go from the SKADS radio simulation to predict what Spitzer and Herschel have and will see…

Baseline model

• Starbursts follow FIR-radio correlation

• AGN given distribution in torus properties with FIR emission scaled with L(AGN)

Wilman et al. (2009)

Wilman et al. (2009)

Baseline model

• Starbursts follow FIR-radio correlation

• AGN given distribution in torus properties with FIR emission scaled with L(AGN)

Modification 1

• Starbursts follow FIR-radio correlation

• Evolution was PLE in a E-dS Cosmology.

• Use new prescription of PLE in -Cosmology for the 70 m population (Huynh et al. 2007)

Wilman et al. (2009)

Wilman et al. (2009)

Modification 1

• Starbursts follow FIR-radio correlation

• Evolution was PLE in a E-dS Cosmology.

• Use new prescription of PLE in -Cosmology for the 70um population (Huynh et al. 2007)

Modification 2

• New evidence suggests that higher-z sources have cooler SEDs (e.g. Symeonidis et al. 2009; peak of the thermal dust emission moves to longer wavelengths)• Results in a very slight modification to the FIR-radio relation

Wilman et al. (2009)

Mid-infrared redshift

distributions

Wilman et al. (2009)

Far-IR redshift distributions

35 mJy

Wilman et al. (2009)

Predictions for Herschel Surveys

250 m

Wilman et al. (2009)

Final Words• DS2-T1 Simulated Skies (continuum, lines, polarization,

pulsars) are available and being used by multi-waveband astronomers:

http://s-cubed.physics.ox.ac.uk

• DS2-T2 Data Simulation tools (e.g. MeqTrees, OSKAR) are available as packaged software products

• End-to-end simulations for early phases of SKA now underway (and for full SKA on s/computer)

• High filling factor mid-frequency AA (~1% SKAs) have the potential to do really important HI science; science and technical precursors for AAs

• ASKAP has run process defining Survey Science for dish precursors: MeerKAT, LoIs by March 2010

• Efforts to coordinate with science of ALMA/E-ELTMay 10-14 (Crete)