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Constraints on the Hubble constant from supernova Refsdal's reappearance
Patrick L Kelly1, Steven Rodney2, Tommaso Treu3
1Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN 55455, USA.
Science (New York, N.Y.)
|May 11, 2023
Summary
Astronomers used the lensed supernova Refsdal to measure the Universe's expansion rate. Time delays between supernova images yielded a precise Hubble constant value, aiding cosmological studies.
Area of Science:
- Cosmology
- Astrophysics
- Gravitational Lensing
Background:
- The Refsdal supernova provided a unique opportunity to study gravitational lensing.
- Supernova Refsdal appeared in multiple images due to lensing by a galaxy cluster.
Purpose of the Study:
- To perform a blinded measurement of the Hubble constant (H0).
- To utilize time delays between lensed supernova images for cosmological parameter estimation.
Main Methods:
- Employing gravitational lensing models of the galaxy cluster.
- Analyzing the time delays between the multiple images of the Refsdal supernova.
- Comparing results from eight different cluster lens models.
Main Results:
- Inferred a value for the Hubble constant (H0) using eight cluster lens models.
- Obtained a more precise H0 value using the two models most consistent with observations.
- Found that models assigning dark-matter halos to individual galaxies and the cluster best reproduced the observations.
Conclusions:
- Gravitationally lensed supernovae offer a novel method for measuring the Hubble constant.
- The study refines cosmological measurements by leveraging the Refsdal event.
- The distribution of dark matter within galaxy clusters impacts lensing effects and cosmological measurements.
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