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Beam profile sensitivity of WMAP CMB power spectrum Utane Sawangwit & Tom Shanks Durham University.

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Presentation on theme: "Beam profile sensitivity of WMAP CMB power spectrum Utane Sawangwit & Tom Shanks Durham University."— Presentation transcript:

1 Beam profile sensitivity of WMAP CMB power spectrum Utane Sawangwit & Tom Shanks Durham University

2 Standard  CDM Model - Issues!  Dark matter – exotic particles as yet undetected!   ⇒ 1 in 10 100 fine-tuning coincidence – anthropic?  Even though inflation was set up to get rid of fine-tuning!   has wrong sign for string theory – Anti-de Sitter v. de Sitter  Standard inflation model ⇒ 10^10 77 Universes!  Wrong mass function for galaxies!  Downsizing observed v. bottom-up hierarchy predicted  Feedback - more energy now used in preventing stars form than in forming them under gravity

3 WMAP 5-Year CMB Map

4 WMAP 5-Year Power Spectrum Universe comprises: ~72% Dark Energy ~24% CDM ~4% Baryons (Hinshaw et al. 2003, 2006, 2008, Spergel et al. 2003, 2006, 2008)

5 And yet…….

6 Sensitivity of WMAP C l to beam Raw C l result Final C l result

7 WMAP beams (Page et al 2003)

8 WMAP5 point sources  390 sources detected (5sigma) in K/Ka/Q/V/W  Complete down to ~1Jy  373/390 have 5GHz counterparts  Flat spectrum, = -0.09  We only use compact sources (5 GHz GB6/PMN) Wright et al. (2009)

9 WMAP5 Radio Source Profiles Gaussian Jupiter beam Radio sources

10 Comparison with ground-based fluxes

11 Potential problems with RS beam  Radio Source Clustering?  Estimate based on bright NVSS source clustering...  …suggests clustering is unlikely explanation  But what about the CMB fluctuations – Eddington effect? - referee

12 New: “CMB-free” point sources CMB-free WMAP5 source detection, Chen & Wright 2009

13 New: NVSS 1.4GHz point sources

14 New: Monte Carlo Simulations

15 Simulations: known source positions

16 Source detection  Filter the weighted map with  (Wright et al. 2009, Tegmark et al. 1998) W V Q Ka K

17 Simulations: after source detection

18 WMAP5 Radio Source Profiles Gaussian Jupiter beam Radio sources

19 De-beamed power spectra Gaussian Radio sources Jupiter

20 WMAP peak moved to l=330

21 A diy beam that works!

22 Conclusions   CDM assumes “undiscovered physics” + very finely- tuned + problems in many other areas  Model gained overwhelming support from WMAP  But WMAP power spectra highly sensitive to beam  Radio sources indicate wider beams than expected  Systematic errors on WMAP C l may therefore increase  May reduce constraints on simpler models

23 Example simpler model: low H 0,  baryon =1 Shanks (1985) - if H o <40kms -1 Mpc -1 then:  X-ray gas → DM in Coma, M vir /M X =15h 1.5  Inflationary  baryon =1 model in better agreement with nucleosynthesis  Light element abundances   baryon h 2 <0.06   baryon  1 starts to be allowed for low h  Inflation+EdS =>   =1 => Globular Cluster Ages of 13- 16Gyr require H o <40kms -1 Mpc -1  But the first acoustic peak is at l=330, not l=220

24 ‘Do it Yourself’ (DIY) WMAP beam  b S (  ) is the beam and b l is the beam transfer function  To get the “true” power spectrum, C l, divide the raw power spectrum, C l ’, by b l 2  Alternatively to get the beam function b l 2, divide raw by true power spectum!

25 Beam transfer functions  diy beam functions – divide low H 0 C l by raw WMAP C l & square root  Power-law radio source beam fits give too much power at l>300  Need spike in b l

26 Ed Witten -“Strings 2001” http://theory.tifr.res.in/strings /Proceedings/witten/22.html String theory prefers a negative  (anti-de Sitter!) rather than the observed positive 


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