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Gravitationally lensed supernovae could clarify the Hubble tension
Summary
JWST's VENUS survey found two strongly lensed supernovae, SN Ares and SN Athena, whose multiple images will arrive years to decades apart and offer an independent timing experiment to inform measurements of the Hubble Constant.
Content
Astronomers using the James Webb Space Telescope's VENUS survey reported two strongly lensed supernovae, SN Ares and SN Athena, whose light is magnified and split by foreground galaxy clusters. The Hubble Constant is the measured rate of the Universe's expansion and different methods currently give differing values, a situation called the Hubble Tension. Because strong gravitational lensing produces multiple images that arrive at different times, repeat images of these supernovae set up a natural timing experiment. The findings were presented at the 247th Meeting of the American Astronomical Society.
Key facts:
- SN Ares and SN Athena were discovered in JWST VENUS observations of the MJ0308 and MJ0417 galaxy clusters.
- SN Ares exploded when the Universe was about 4 billion years old; SN Athena exploded when the Universe was about 6.5 billion years old.
- Massive galaxy clusters are acting as strong gravitational lenses that split and magnify the supernova light into multiple images.
- Predicted reappearance times are roughly 2–3 years for a repeat image of SN Athena and about 60 years for a repeat image of SN Ares.
- Researchers say measuring the time delays between images and comparing them to predictions can provide an independent constraint relevant to the Hubble Constant and related cosmological questions.
Summary:
These lensed supernovae create a timing experiment because different light paths produce measurable delays; comparing predicted and observed delays can inform measurements of the Hubble Constant and tests of cosmological models. Astronomers will use current observations to predict when the next images should arrive and then wait for those reappearances, with Athena expected in a few years and Ares in about sixty years.
