#9 Renée Hložek - Axions, Tracing Dark Matter, Fate of the Universe
Dec 19, 2023
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Cosmologist Renée Hložek discusses axions, dark matter, dark energy, and unraveling the secrets of the universe. They explore the Atacama Cosmology Telescope, the Sunyev-Zaldovich effect, and the Ruben Observatory's capabilities. They also touch on self-interacting dark matter and upcoming missions in astronomy.
The Atacama Cosmology Telescope (ACT) offers improved resolution and insights into the cosmic microwave background (CMB) and clusters of galaxies.
The tension between measurements of the Hubble constant and CMB highlights the mysteries surrounding dark energy and dark matter.
Axions, as ultra-light particles, are a potential solution to the dark matter problem, and ongoing research aims to understand their behavior and impact on the universe.
Deep dives
Renee Kloschek's Work on Probing the Nature of the Universe
Renee Kloschek, an astronomy and astrophysics professor, is researching fundamental questions about the structure and nature of the universe. Her work focuses on exploring phenomena such as type 1A supernovae, the cosmic microwave background, and baryonic acoustic oscillations. Renee's expertise extends beyond her research, as she is also a skilled science communicator and has given TED talks on her work. In this podcast episode, she discusses some aspects of her research, including dark energy, dark matter, and the potential existence of axions.
ACT's Unique Approach to Measuring the Cosmic Microwave Background
The Atacama Cosmology Telescope (ACT) was used to measure the cosmic microwave background (CMB) in a different way compared to previous missions such as WMAP and Planck. ACT had larger telescopes, allowing for greater resolution and the ability to see smaller structures on the sky. Additionally, ACT's detectors could be continually updated and improved, resulting in the ability to add more frequencies and filters for a more comprehensive understanding of the CMB. ACT's observations also provided insights into the measurement of clusters of galaxies and their distinct signatures on the microwave light.
Hubble Tension and Exploring the Nature of Dark Matter and Dark Energy
The podcast episode delves into the unresolved tension between measurements of the Hubble constant at low redshift and those obtained from the cosmic microwave background (CMB). This tension highlights the mysteries surrounding dark energy and dark matter. Dark matter, while primarily responsible for the clumping of matter in the universe, does not completely align with the predictions of the Lambda Cold Dark Matter (LCDM) model on small scales. However, alternative dark matter models, such as the hypothetical axion particle, offer intriguing possibilities for better understanding the nature of dark matter and its behaviors. Furthermore, ongoing and upcoming telescopes, like the Vera Rubin Observatory, aim to improve measurements and provide additional insights into dark energy, potentially distinguishing it from a cosmological constant.
The Role of Axions in Cosmology
Axions, ultra-light particles that act like scalar fields, are considered as a potential solution to the dark matter problem. Researchers use observations and equations to determine the clumping and clustering signals of axions. Depending on the mass of the axion, its behavior and impact on the structure of the universe can vary. Through various comparisons and model building, scientists determine the mass ranges that are consistent with the observed data. However, a pure axion model is not favored due to its impact on high redshift galaxies and the Lyman alpha distribution in the universe. The search for axions and their role in the composition of the universe continues.
Ruben Observatory and Supernovae Surveys
The upcoming Ruben Observatory, equipped with a massive camera of 5,200 megapixels, will revolutionize cosmological surveys. With its ability to scan almost the entire sky every three days, it is expected to detect around 400,000 new objects, including type 1A supernovae, every night. This large-scale survey will provide an unprecedented amount of data, enhancing our understanding of dark energy and providing insights into the history and structure of the universe. Researchers anticipate that the vast amount of supernova data collected by Ruben Observatory will significantly improve the precision of distance measurements, enabling further constraints on cosmological models and potentially unveiling new physics.
In this week's episode, David is joined by Prof Renée Hložek from the University of Toronoto/Dunlap Institute. Renée is cosmologist studying the CMB, Type 1A Supernovae and baryonic acoustic oscillations. She's an Azrieli Global Scholar within the Canadian Institute for Advanced Research, a Senior TED fellow and a Sloan Research Fellow. Our conversation spans axions, dark matter, dark energy and most importantly how astronomers can unravel the secrets of the universe.
