Steve Rawlings2nd SKADS Workshop, Paris, October 2007 Science Simulations Steve Rawlings (Oxford)...
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Transcript of Steve Rawlings2nd SKADS Workshop, Paris, October 2007 Science Simulations Steve Rawlings (Oxford)...
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Science Simulations
Steve Rawlings (Oxford)
Richard Wilman, Sadegh Khochfar, Hans-Rainer Klöckner, Tom Mauch, Lance Miller,
Danial Obreschkow (Oxford)
Matt Jarvis (Herts),Filipe Abdalla (UCL)
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
In this talk......
• Emphasise how imminent delivery of SKADS `simulated skies’ will provide standard input for quantified comparison of `competing’ SKA design concepts - needs high quality product, i.e. refereed papers (mostly to be published by next DS2-T1 meeting; Jan 2008)
• Use `continuum’ simulations (not described elsewhere) as example - last chance for input!
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
DS2-T1 Short-Term Deliverables: T0=July2006
• Continuum Surveys – Oxford, Leiden, (Herts, UCL):
Richard Wilman (Oxford); simulation deliverable T0+18
Ilse van Bemmel (Leiden); deliverable to be finalised (MeqTree Ionosphere module?)
• Line HI Surveys – Oxford, Groningen, Swinburne
Danail Obreschkow (Oxford); simulation deliverable T0+12
Rense Boomsa (Groningen); deliverable to be finalised (High-res HI module?)
• Magnetism – Cambridge, Bonn
Martin Krause+replacement (Cambridge); simulation deliverable T0+18
Tigran Arshakian (Bonn); deliverable to be finalised (Galactic Foreground module?)
• Pulsar Surveys – Manchester
Roy Smits (Manchester), simulation deliverable T0+15
• EOR – Paris, Lisbon;
Paola Di Matteo (Paris), simulation deliverable T0+21
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Continuum simulations
• Rationale different from ‘Line’ approach (Obreschkow)
Not DM haloes from Millennium Simulation ascribed HI, star formation rates and AGN properties, because insufficient FOV for SKADS benchmark
• But 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’
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Basic methodology
(Δρ/ρ)DM evolved under linear theory in each 20 Mpc/h cell
Redshift In each cell, for each source type:
• Define DM halo mass for each source type and compute bias b(M,z)
• Compute mean number of sources above flux limit, n0, in absence of clustering
• Amplify fluctuations in underlying DM density field:
n/n0 ~ exp[ b(M,z) (Δρ/ρ)DM ]
• Poisson sample the LF
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Parent Source Types
• Radio-quiet quasars: Mhalo = 3E12/h M tied
to XLF of Ueda et al. (2003) • `FRI’ radio sources: Mhalo = 1E13/h M
Willott et al. (2001) 151 MHz LF
• `FRII’ radio sources: Mhalo = 1E14/h M Willott et al. (2001) 151 MHz LF
• Normal star-forming galaxies: Mhalo = 1E11/h M Yun et al. (2001) 1.4 GHz LF (low-L component) + PLE
• Starburst galaxies: Mhalo = 5E13/h M Yun et al. (2001) 1.4 GHz LF (high-L component) + PLE
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
• Double Schechter-fn fit representing normal galaxies and starbursts
• We assume LF flattens below L1.4 GHz = 1020.5 W/Hz and integrate down to 1019
W/Hz (SFR ~ 0.01 M/yr)
• No need for an extra population of normal galaxies via an optical LF (à la Hopkins/Windhorst)
L(60 μm)
‘normal’ galaxies
starbursts
Two populations of star-forming galaxies
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Results: 1.4 GHz source counts
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Results: HI mass functions
Log M(HI) = 0.48 + 0.44*log L1.4 GHz +- 0.3 dex scatter
From M(HI)-SFR relations of Lah et al. 2007, Doyle & Drinkwater 2006
Increasing z
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
March 2007 Release
• v2: 20 x 20 deg2 down to 1 micro-Jy @1.4 GHz • v3: 10 x 10 deg2 down to 10 nano-Jy @1.4 GHz• Simulations stop at z=4• Simple P(k), i.e. no Baryon Wiggles• See the WIKI for full details and catalogue
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Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Faint source uncertainty
Star-forming galaxies
AGN
Hopkins et al. 2000 model
• Models diverge below 1 micro-Jy due mainly to inclusion of an extra population of ‘normal galaxies’ in the Hopkins/Windhorst models
• This extra population may not be needed- at least locally, the radio LF of infrared-selected galaxies accounts for all normal galaxies
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Extensions: (i) small-scale clustering
• Aim, to `paint on ‘ clustering on co-moving scales < 20 Mpc/h (cell-size)
• Uses a smaller size cell (5 Mpc/h) and a ‘mass filtering’ method to identify cluster-sized over-densities (which we have checked follow Press-Schechter-like mass distributions)
• FRI/II sources (and relic/halo sources) added to the clusters following `known’ occupancies (although problem due to differences before/after virialization).
• Star-formation to be suppresed in cluster cores.
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Extension (ii) FRI/II structures: simple
prescriptions
PLS
PLS
FRI:
Log R(core:lobe) = 10.8 – 0.55logL151 + scatter
Γ=6 (for beaming)
FRII:
Log R(core:lobe) = -2 + scatter
Γ=8.5 for beaming
Hotspot:lobe ratio ~ 0.4*logL178 + const
• Cores and hotspots: point sources •lobes: uniform ellipses with varying axial ratio
• Pick-out blazars, core-dominated quasars, quasars and radio galaxies by angle
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Extensions: (iii) multi-frequency information
• SF-galaxies: -thermal free-free emission (α=0.1) -synchrotron emission (α=0.75 + scatter)
-free-free absorption for starbursts (τff=1 at 1 GHz) -dust emission
• Radio-loud AGN:-distribution in intrinsic linear size (ie simple radio source evolution model), spectral curvature (including CSS/GPS sources) -core-lobe-hotspot morphologies and flux division (lobes modelled as ellipses; spectral gradients+IC losses; environmental asymmetries) -Beaming of the steep-spectrum parent population (checked for consistency with high-frequency source counts)
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Extensions: (iv) Full P(k)
Now (thanks to Filipe Abdalla) with added wiggles
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Simulation Deliverable (1st Dec release)
• 20 x 20 deg2 (released as overlapping 4x4 deg2 tiles plus catalogues)
• Flux densities at 151 MHz, 610 MHz, 1.4 GHz, 5 GHz and 20 GHz• All sources included down to limits of LF (allowing user to add own
flux density limits)• Simulation performed out to high-z (z~10)• Galaxy clusters with assigned radio source content• Realistic source morphologies and SEDs: cores,lobes,hotspots, a
simple source evolution and a beaming model
Wilman et al, 2007
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
Catalogue format
• A common standard for SKADS extragalactic simulation catalogues • Galaxy index to identify sub-component sources
(cores/lobes/hotspots) to parent galaxy• Source type (AGN/SF) and sub-component type• Cluster Index • Millennium catalogue halo and galaxy indices• Continuum I[QUV] flux densities @0.15, 0.61, 1.4, 5 and 20 GHz• HI fluxes and profile descriptions• Morphological info: ellipse PA, major+minor axes
Steve Rawlings2nd SKADS Workshop, Paris, October 2007
MAIN TABLE#0 Unique source index#1 Cluster index (0-no member, cluster index#2 Galaxy index (0-cluster halo, otherwise number)#3 SF type (0-no SF, 1-normal SF, 2-SB)#4 AGN type (0-no AGN, 1-RQQ, 2-FRI, 3-FRII)#5 Structure type (1-core, 2-lobe, 3-hotspot, 4-SFdisk, 5-HI disk, 6-diffuse halo)#6 RA#7 DEC#8 Redshift (cosmological)#9-11 Shape (PA, major axis, minor axis) (arcsec)#12-27 Cont FD IQUV (200MHz, 1GHz, 5 GHz, 25 GHz) x4#28-33 HI Flux IQUV, centre apparent velocity, linewidth#34 Millennium galaxy index#35 Millennium halo index
MILLENNIUM TABLE#1 Unique source index#2 Millennium galaxy index#3 Millennium halo index
CLUSTER TABLE#1 Cluster index#2 RA centre#3 DEC centre#4 Redshift#5 mass#6 Radius#7 Velocity dispersion