期刊
ASTRONOMY & ASTROPHYSICS
卷 560, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201321880
关键词
cosmology: observations; cosmological parameters; large-scale structure of Universe; supernovae: general
资金
- CNRS/IN2P3 in France
- CNRS/INSU in France
- CNRS/PNC in France
- DFG [TRR33]
- National Natural Science Foundation of China [10903010]
- Bonn-Cologne Graduate School of Physics and Astronomy
- Lyon Institute of Origins [ANR-10-LABX-66]
- Office of Science, Office of High Energy and Nuclear Physics
- Office of Advanced Scientific Computing Research, of the U.S. Department of Energy (DOE) [DE-FG02-92ER40704, DE-AC02-05CH11231, DE-FG02-06ER06-04]
- Gordon & Betty Moore Foundation
- National Science Foundation [AST-0407297, 0087344, 0426879]
- France-Berkeley Fund
- Region Rhone-Alpes
- Office of Advanced Cyberinfrastructure (OAC)
- Direct For Computer & Info Scie & Enginr [0426879] Funding Source: National Science Foundation
- Office of Advanced Cyberinfrastructure (OAC)
- Direct For Computer & Info Scie & Enginr [0087344] Funding Source: National Science Foundation
Context. Our Local Group of galaxies appears to be moving relative to the cosmic microwave background with the source of the peculiar motion still uncertain. While in the past this has been studied mostly using galaxies as distance indicators, the weight of Type Ia supernovae (SNe Ia) has increased recently with the continuously improving statistics of available low-redshift supernovae. Aims. We measured the bulk flow in the nearby universe (0.015 < z < 0.1) using 117 SNe Ia observed by the Nearby Supernova Factory, as well as the Union2 compilation of SN Ia data already in the literature. Methods. The bulk flow velocity was determined from SN data binned in redshift shells by including a coherent motion (dipole) in a cosmological fit. Additionally, a method of spatially smoothing the Hubble residuals was used to verify the results of the dipole fit. To constrain the location and mass of a potential mass concentration (e. g., the Shapley supercluster) responsible for the peculiar motion, we fit a Hubble law modified by adding an additional mass concentration. Results. The analysis shows a bulk flow that is consistent with the direction of the CMB dipole up to z similar to 0 : 06, thereby doubling the volume over which conventional distance measures are sensitive to a bulk flow. We see no significant turnover behind the center of the Shapley supercluster. A simple attractor model in the proximity of the Shapley supercluster is only marginally consistent with our data, suggesting the need for another, more distant source. In the redshift shell 0.06 < z < 0.1, we constrain the bulk flow velocity to <= 240 km s(-1) (68% confidence level) for the direction of the CMB dipole, in contradiction to recent claims of the existence of a large-amplitude dark flow.
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