What do we know about cosmography
Abstract In the present paper, we investigate the cosmographic problem using the bias–variance trade-off. We find that both the z-redshift and the $$y=z/(1+z)$$ y = z / ( 1 + z ) -redshift can present a small bias estimation. It means that the cosmography can describe the supernova data more accurat...
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Online Access: | http://link.springer.com/article/10.1140/epjc/s10052-017-5005-4 |
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doaj-9d9a798f788e45598e5237361d0ed5872020-11-25T02:34:42ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522017-06-0177711210.1140/epjc/s10052-017-5005-4What do we know about cosmographyMing-Jian Zhang0Hong Li1Jun-Qing Xia2Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of ScienceKey Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of ScienceDepartment of Astronomy, Beijing Normal UniversityAbstract In the present paper, we investigate the cosmographic problem using the bias–variance trade-off. We find that both the z-redshift and the $$y=z/(1+z)$$ y = z / ( 1 + z ) -redshift can present a small bias estimation. It means that the cosmography can describe the supernova data more accurately. Minimizing risk, it suggests that cosmography up to the second order is the best approximation. Forecasting the constraint from future measurements, we find that future supernova and redshift drift can significantly improve the constraint, thus having the potential to solve the cosmographic problem. We also exploit the values of cosmography on the deceleration parameter and equation of state of dark energy w(z). We find that supernova cosmography cannot give stable estimations on them. However, much useful information was obtained, such as that the cosmography favors a complicated dark energy with varying w(z), and the derivative $${\text {d}}w/{\text {d}}z <0$$ d w / d z < 0 for low redshift. The cosmography is helpful to model the dark energy.http://link.springer.com/article/10.1140/epjc/s10052-017-5005-4 |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Ming-Jian Zhang Hong Li Jun-Qing Xia |
spellingShingle |
Ming-Jian Zhang Hong Li Jun-Qing Xia What do we know about cosmography European Physical Journal C: Particles and Fields |
author_facet |
Ming-Jian Zhang Hong Li Jun-Qing Xia |
author_sort |
Ming-Jian Zhang |
title |
What do we know about cosmography |
title_short |
What do we know about cosmography |
title_full |
What do we know about cosmography |
title_fullStr |
What do we know about cosmography |
title_full_unstemmed |
What do we know about cosmography |
title_sort |
what do we know about cosmography |
publisher |
SpringerOpen |
series |
European Physical Journal C: Particles and Fields |
issn |
1434-6044 1434-6052 |
publishDate |
2017-06-01 |
description |
Abstract In the present paper, we investigate the cosmographic problem using the bias–variance trade-off. We find that both the z-redshift and the $$y=z/(1+z)$$ y = z / ( 1 + z ) -redshift can present a small bias estimation. It means that the cosmography can describe the supernova data more accurately. Minimizing risk, it suggests that cosmography up to the second order is the best approximation. Forecasting the constraint from future measurements, we find that future supernova and redshift drift can significantly improve the constraint, thus having the potential to solve the cosmographic problem. We also exploit the values of cosmography on the deceleration parameter and equation of state of dark energy w(z). We find that supernova cosmography cannot give stable estimations on them. However, much useful information was obtained, such as that the cosmography favors a complicated dark energy with varying w(z), and the derivative $${\text {d}}w/{\text {d}}z <0$$ d w / d z < 0 for low redshift. The cosmography is helpful to model the dark energy. |
url |
http://link.springer.com/article/10.1140/epjc/s10052-017-5005-4 |
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