Cosmology with the 6dF Galaxy Survey UCT/ICRAR/APERTIF workshop, - PowerPoint PPT Presentation

The 6dF survey Correlation function 6dfGS → WALLABY Cosmology with the 6dF Galaxy Survey UCT/ICRAR/APERTIF workshop, South Africa, May 2010 Florian Beutler PhD supervisors: Peter Quinn, Lister Staveley-Smith Chris Blake, Heath Jones 04.05.2010 International Centre for Radio Astronomy Research Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 1

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. The two point correlation function. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. The two point correlation function. Redshift space distortions. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. The two point correlation function. Redshift space distortions. Estimate of Ω m . Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. The two point correlation function. Redshift space distortions. Estimate of Ω m . Testing General Relativity. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY Outline Program for the next 20min. The 6dF Galaxy Survey. The two point correlation function. Redshift space distortions. Estimate of Ω m . Testing General Relativity. Predictions for WALLABY using 6dFGS. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 2

The 6dF survey Correlation function 6dfGS → WALLABY What is 6dFGS? Spectroscopic survey of southern sky (17,000 deg 2 ). Primary sample from 2MASS with K tot < 12 . 75; also secondary samples with H < 13 . 0, J < 13 . 75, r < 15 . 6, b < 16 . 75. Median redshift 0.05 ( ≈ 150 Mpc). Effective volume ≈ 2 x 10 7 h − 3 Mpc 3 . 125.000 redshifts (137.000 spectra). Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 3

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY The correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 → A correlation function measures the degree of (galaxy) clustering on different scales. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 4

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY The correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 → A correlation function measures the degree of (galaxy) clustering on different scales. How do we measure that? Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 4

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY The correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 → A correlation function measures the degree of (galaxy) clustering on different scales. How do we measure that? 1 Create a mock catalogue: Random distribution of galaxies without any clustering. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 4

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY Two point correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 A correlation function measures the degree of clustering on different scales. How do we measure that? 1 Create a mock catalogue: Random distribution of galaxies without any clustering. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 7

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY Two point correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 A correlation function measures the degree of clustering on different scales. How do we measure that? 1 Create a mock catalogue: Random distribution of galaxies without any clustering. 2 Measure the distance between all galaxy pairs in your survey. → DD(s) and RR(s) Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 7

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY Two point correlation function What is a correlation function? dP = n 2 ( 1 + ξ ( r 12 )) dV 1 dV 2 A correlation function measures the degree of clustering on different scales. How do we measure that? 1 Create a mock catalogue: Random distribution of galaxies without any clustering. 2 Measure the distance between all galaxy pairs in your survey. → DD(s) and RR(s) 3 The correlation function can be calculated via ξ ( s ) = DD ( s ) RR ( s ) − 1 (In my analysis I used the Landy & Salay estimator) Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 7

6dF correlation function 2 10 10 1 (s) ξ -1 10 -2 10 -1 10 1 10 -1 s [h Mpc]

6dF 2D correlation function

Redshift space distortions

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 11

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. → We can measure the total mass in the Universe Ω m . Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 11

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. → We can measure the total mass in the Universe Ω m . 2. With a known Ω m General Relativity predicts how much distortion we have to expect. Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 11

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. → We can measure the total mass in the Universe Ω m . 2. With a known Ω m General Relativity predicts how much distortion we have to expect. → We can test General Relativity and alternative theories (DGP). Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 11

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. → We can measure the total mass in the Universe Ω m . 2. With a known Ω m General Relativity predicts how much distortion we have to expect. → We can test General Relativity and alternative theories (DGP). f ( z ) = β b = Ω γ m ( z ) Ω m = 0 . 33 ± 0 . 054 ⇒ f = growth rate, b ≈ 1 . 22, Ω m = ρ m ρ 0 Theoretical predictions for γ : Λ CDM: γ = 0 . 55 DGP: γ = 0 . 69 Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 11

6dF 2D correlation function 30 20 10 10 Mpc] 0 -1 1 [h π -10 -20 10 -1 -30 -30 -20 -10 0 10 20 30 r [h -1 Mpc] p Model free parameters: β, σ v , r 0 , γ

6dF 2D correlation function β = 0 . 44 ± 0 . 04 , σ v = 586 ± 51 , r 0 = 6 . 01 ± 0 . 09 , γ = 1 . 75 ± 0 . 03

6dF 2D correlation function β = 0 . 44 ± 0 . 04 , σ v = 586 ± 51 , r 0 = 6 . 01 ± 0 . 09 , γ = 1 . 75 ± 0 . 03

The 6dF survey Correlation function Redshift space distortions 6dfGS → WALLABY 6dF 2D correlation function Why is that interesting? 1. All redshift space distortions originate from gravitational interaction. With more mass in the Universe we expect more distortions. → We can measure the total mass in the Universe Ω m . 2. With a known Ω m General Relativity predicts how much distortion we have to expect. → We can test General Relativity and alternative theories (DGP). f ( z ) = β b = Ω γ m ( z ) Ω m = 0 . 33 ± 0 . 054 ⇒ f = growth rate, b ≈ 1 . 22, Ω m = ρ m ρ 0 Theoretical predictions for γ : Λ CDM: γ = 0 . 55 DGP: γ = 0 . 69 Florian Beutler Cosmology with the 6dF Galaxy Survey 04.05.2010 15