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Modelling radio galaxies in simulations: CMB contaminants and SKA / Meerkat sources. by Fidy A. RAMAMONJISOA MSc Project University of the Western Cape. Supervisor : Prof Catherine Cress. SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09. - PowerPoint PPT Presentation
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by
Fidy A. RAMAMONJISOA
MSc Project
University of the Western Cape
Supervisor: Prof Catherine Cress
Modelling radio galaxies in simulations:
CMB contaminants and SKA / Meerkat sources
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
AimOne of CMB experiments goals
Counting clusters at different times (redshift)
Relevant to dark energy constraints
How?Use CMB observations
through Sunyaev- Zeldovich (SZ) effect
Counting is difficult because of point sources and radio sources
We aim at modelling spatial distribution (number density) and flux of radio sources using N-body
simulation
INTRODUCTION
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Inte
nsity
(M
Jy/s
r)
Frequency (GHz) -0.05
0.00
0.05
ACT frequencies
145 GHz decrement
218 GHz null
270 GHz increment
Credit: Spergel D.
e-
e-
e-
e-
e-
e-
e-
e-
e-
TTelectronelectron = 10 = 1088 K K
Hot electron gas
Sunyaez-Zeldovich effect (SZE) in galaxy clusters
Distortion of CMB black body by inverse Compton scattering
2A
eSZE
D
TMdT
redshift independent effect
SZ surveys detect clusters
Thermal SZ270-300 microKelvin
Kinetic SZ10-20 microKelvin
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Methodology
•Millennium Run and semi analytical modelsemi analytical model of galaxy formation and evolution (Croton et al. 2006, De Lucia & Blaizot 2007)
•Extend the semi analytical model to follow black hole follow black hole mass accretion and its conversion to radiationmass accretion and its conversion to radiation
Millennium Run: simulation of 1010 dark matter particles in a cubic region 500h-1Mpc on a side in the ΛCDM cosmological framework (Springel et al. 2005)
Particle mass:8.6x108h-1Mʘ
Outputs stored in a database: use Structured Query Language (SQL) to make a query
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
AGN feedbackRadiative accretion efficiency
(not yet well known)
Radio mode Quasar mode
SMBH growth triggered by mergers- cold disk gas driven onto black hole
(Kauffmann & Haeanelt 2000)
Hot gas from surrounding hot halo accretes onto SMBH
Efficient at
7.0z
sunBH MM 810
Efficient at
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
1z
2
1cML BHbol
)()(
)()(
21
21
ztzt
zMzMM BHBHBH
Find progenitors at z1of all galaxies at z2
bolfLL
24 Ld
LS
mJySS cut 1 cutL
BH Sfc
dM
2
241
Count radio source
MODELf fraction of conversion to radio
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Fossati G. et al. (1998)
Average SED of blazars grouped by powers
Redshift distribution of blazars normalized
Flux density limit 1 mJy at 2.7 GHz
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Results
Redshift distribution of blazars normalized
Flux density limit 1 mJy at 2.7 GHz
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
ResultsFossati G. et al. (1998)
Average SED of blazars grouped by powers
Redshift distribution of blazars normalized
Flux density limit 1 mJy at 2.7 GHz
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
ResultsFossati G. et al. (1998)
Average SED of blazars grouped by powers
200r
r
123 .10 HzWP
Total surface density of radio galaxies vs.
Simulation+observation
Lin & Mohr (2007)simulation
Luminosity
200r
r
at 1.4 GHz
ResultsRedshift up to 0.06Radio galaxies
galaxies
BL LacsFRI
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Results
200r
rsunMh 11410
sunMh 11410
Surface density of radio sources vs.
2<Mvir<6
6<Mvir<10Mvir>10
Unit:
200r
r
Radio sources are concentrated in low mass clusters
Density of radio sources maximum near the centre
123 .10 HzWPLuminosity
at 1.4 GHz
Redshift 0.05
sunMh 11410
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Temperature (microK) vs redshift z Flux (mJy) vs z
Temperature fluctuations and fluxes caused by blazars in clusters binned in cluster mass at 145 GHz
Results
CMB contamination by radio galaxies and quasars
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
Summary• The model is able to reproduce fairly well the observed redshift distribution of radio
sources
• The surface density of simulated blazars are in agreement with Lin & Mohr for small radial distance from the centre of the cluster.
• It predicts high concentration of radio sources close to the centre of clusters.
• Radio sources are more concentrated in low mass clusters .
• Contaminations by blazars are not negligible at local redshift (z<0.1).
• The average temperature fluctuation in CMB caused by BL Lacs is 5 microK at z=0.01
(almost at the same order as the kinetic SZ signature of an average cluster mass).
• At high redshift (z>1), the fluctuation in CMB temperature produced by blazars appears to be very significant (about 300-350 microK, similar to temperature fluctuations from the thermal SZ effect).
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09
References• Croton D. J., Springel V. et al., 2006, MNRAS, 365, 11
• Dunlop J. S., Peacock J. A., 1990, MNRAS 247, 19-42
• Marulli F., Bonoli S., Branchini E., Moscardini L., Springel V., 2007, MNRAS, submitted
• Lin Y. T., Mohr J. J., 2007, astro-ph/0612521v2
SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09