Astronomy and Astrophysics – Astrophysics
Scientific paper
2008-05-21
Astronomy and Astrophysics
Astrophysics
accepted for publication in MNRAS (Letters), 5 pages, 4 figures. Small changes to improve the text and the figures. Some furth
Scientific paper
10.1111/j.1745-3933.2008.00519.x
Peculiar velocities of galaxies hosting Type Ia supernovae generate a significant systematic effect in deriving the dark energy equation of state w, at level of a few percent. Here we illustrate how the peculiar velocity effect in SN Ia data can be turned from a 'systematic' into a probe of cosmological parameters. We assume a flat Lambda-Cold Dark Matter model (w=-1) and use low and high redshift SN Ia data to derive simultaneously three distinct estimates of the matter density Omega_m which appear in the problem: from the geometry, from the dynamics and from the shape of the matter power spectrum. We find that each of the three Omega_m's agree with the canonical value Omega_m=0.25 to within 1 sigma, for reasonably assumed fluctuation amplitude and Hubble parameter. This is consistent with the standard cosmological scenario for both the geometry and the growth of structure. For fixed Omega_m = 0.25 for all three Omega_m's, we constrain gamma = 0.72 +/- 0.21 in the growth factor Omega_m(z)^gamma, so we cannot currently distinguish between standard Einstein gravity and predictions from some modified gravity models. Future surveys of thousands of SN Ia, or inclusion of peculiar velocity data, could significantly improve the above tests.
Abate Alexandra
Lahav Ofer
No associations
LandOfFree
The Three Faces of Omega_m: Testing Gravity with Low and High Redshift SN Ia Surveys does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Three Faces of Omega_m: Testing Gravity with Low and High Redshift SN Ia Surveys, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Three Faces of Omega_m: Testing Gravity with Low and High Redshift SN Ia Surveys will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-289595