1. Combining Different Measurements
Bob Nichol, ICG Portsmouth
Tommaso Giannantonio, H-J Seo, Dan Carson, Hubert Lampeitl*, Josh Frieman, Bruce Bassett, Mat Smith, Will Percival
(for SDSS Collaboration)
* see poster

2. BAO with Redshift Measure ratio of volume averaged distance
Flat CDM = 1.67
Systematics (damping, BAO fitting) also ~1Next set of measurements will need to worry about this
99.74% detection
z~0.2
143k + 465k
79k
z~0.35
Percival et al. (2006)
Percival et al. 2007

3. Cosmological Constraints
Flatness assumed, constant w
With CMB
Only D0.35 /D0.2 W
w= P/ 3 1
Favors w<-1 at 1.4 2 m

4. Cosmological Constraints
Flatness assumed
m = ± 0.018
w = ± 0.089
With CMB
Only D0.35 /D0.2 W W
w= P/ 3 1
D0.35 /D0.2 = 1.66 ± 0.01 2 m m

5. Discrepancy?
2.4 difference between SN & BAO. The BAO want more acceleration at z<0.3 than predicted by z>0.3 SNe
~1 possible from details of BAO damping - more complex then we thought
Assumption of flatness and constant w needs to be revisited

6. Revisit with SDSS SNe 500 Ia’s 102 from 05 LCDM line 2s contours
Only look at measurements at z<0.4
500 Ia’s
102 from 05
LCDM line
2s contours
q0 = (2s)
SDSS BAO points

7. Cosmological Constraints
Only look at measurements at z<0.4
ISW (z<0.4)
Peacock et al
Flat wCDM W
SNe
BAO
w= -1 (15% stat & sym)
SDSS BAO points

8. Curvature ISW (z<0.4) Peacock et al
Only look at measurements at z<0.4
ISW (z<0.4)
Peacock et al

9. Distance Duality
Returning to BAO and SN discrepancy?

10. Cosmic Chronometers 5500 LRGs Carson et al. (in prep)
Age of galaxies constraints age of universe (Jimenez & Loeb 2002)
5500 LRGs
Carson et al. (in prep)
(Using Thomas et al. models, marginalised over alpha-enhancement and metallicity)

11. Cosmic Chronometers II
Age of galaxies constraints age of universe (Jimenez & Loeb 2002)
ALL FLAT
raw t(z)
HST
TSR
ISW
WMAP

12. Differential Ages H(z)
We find H(z=0.2) ~ 80 +/- 12 km/s
Same value as Gaztanaga et al. but not yet competitive in error

13. Conclusions
Tension remains between BAO and SN (over same redshift range). But ~2s at best
Cosmic Chronometers provide constraints on age-redshift relation (thus h and Wm). Also provide constraints on H(z) but not yet competitive
BOSS could do much better, especially if we can do better on the stellar modeling (Maraston et al.)