1 / 14

by Fidy A. RAMAMONJISOA MSc Project University of the Western Cape

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.

dora
Download Presentation

by Fidy A. RAMAMONJISOA MSc Project University of the Western Cape

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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

  2. Counting is difficult because of point sources and radio sources We aim at modelling spatial distribution (number density) and fluxof radio sources using N-body simulation Aim INTRODUCTION One of CMB experiments goals Use CMB observations through Sunyaev- Zeldovich (SZ) effect Counting clusters at different times (redshift) How? Relevant to dark energy constraints SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  3. redshift independent effect 0.05 Cosmic Microwave Background Hot electron gas Intensity (MJy/sr) e- 0.00 e- e- e- Cluster -0.05 Frequency (GHz) e- ACT frequencies e- e- e- 145 GHz decrement 218 GHz null 270 GHz increment e- Telectron = 108 K Sunyaez-Zeldovich effect (SZE) in galaxy clusters SZ surveys detect clusters Distortion of CMB black body by inverse Compton scattering Thermal SZ270-300 microKelvin Kinetic SZ10-20 microKelvin Credit: Spergel D. SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  4. Methodology • Millennium Run and semi analytical model of galaxy formation and evolution (Croton et al. 2006, De Lucia & Blaizot 2007) • Extend the semi analytical model to follow black hole mass 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

  5. AGN feedback Radiative accretion efficiency (not yet well known) Quasar mode Radio mode Hot gas from surrounding hot halo accretes onto SMBH SMBH growth triggered by mergers- cold disk gas driven onto black hole (Kauffmann & Haeanelt 2000) Efficient at Efficient at SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  6. Find progenitors at z1of all galaxies at z2 f fraction of conversion to radio MODEL Count radio source SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  7. Results Average SED of blazars grouped by powers Fossati G. et al. (1998) 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

  8. Results Average SED of blazars grouped by powers Fossati G. et al. (1998) 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

  9. Results Average SED of blazars grouped by powers Fossati G. et al. (1998) 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

  10. Results Simulation+observation Lin & Mohr (2007) Redshift up to 0.06 Radio galaxies galaxies simulation BL Lacs FRI Luminosity Total surface density of radio galaxies vs. at 1.4 GHz SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  11. Results • Radio sources are concentrated in low mass clusters • Density of radio sources maximum near the centre Redshift 0.05 2<Mvir<6 6<Mvir<10 Mvir>10 Unit: Luminosity at 1.4 GHz Surface density of radio sources vs. SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  12. Results CMB contamination by radio galaxies and quasars Flux (mJy) vs z Temperature (microK) vs redshift z Temperature fluctuations and fluxes caused by blazars in clusters binned in cluster mass at 145 GHz SKA 4 th annual Bursary Conference, Stellenbosch Institute for Advanced Study 03/12/09

  13. 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

  14. 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

More Related