By 2027,NASA’s Roman to Use Rare Events to Calculate Expansion Rate of Universe.

 

Hubble captures a galaxy’s gravity in a massive cluster, creating multiple images of a distant supernova within MACS J1149.6+2223, over 5 billion light-years away. Inset reveals arrows pointing to multiple copies of Supernova Refsdal, situated 9.3 billion light-years from Earth.

The Nancy Grace Roman Space Telescope, slated for launch by May 2027, will become a crucial tool for astronomers delving into the profound mystery of the universe’s expansion rate. Armed with the capability to scrutinize vast portions of the sky, astronomers plan to utilize Roman’s extensive image data to identify and study gravitationally lensed supernovae. This novel approach offers a unique perspective on measuring the universe’s expansion rate, contributing valuable insights to our understanding of the cosmos.

Astronomers face a cosmic conundrum as various techniques yield diverse values for the Hubble constant, generating what’s known as the Hubble tension. The Nancy Grace Roman Space Telescope, set to launch by May 2027, will embark on extensive cosmological investigations, focusing on the enigmatic dark energy’s impact on the universe’s evolving expansion. Employing both traditional and innovative approaches, astronomers will leverage Roman’s ability to scrutinize gravitationally lensed supernovae. This geometric method provides an alternative to brightness-based techniques, adding a unique perspective to unravel the mysteries of the universe’s expansion.

Roman promises to revolutionize the study of gravitationally lensed supernovae, presenting an unparalleled opportunity to delve into their mysteries. Lou Strolger of the Space Telescope Science Institute (STScI), leading the team for Roman’s study of these elusive objects, emphasizes their rarity and challenges in detection. With a vast field of view and high-resolution repeated imaging, Roman’s capabilities enhance the chances of discovering and studying more gravitationally lensed supernovae. Currently, astronomers have identified only eight such phenomena, and Roman’s advanced capabilities aim to contribute significantly to expanding this knowledge.

Gravitational lensing, a phenomenon central to Roman’s study, involves the bending of light from a stellar explosion as it travels to Earth through the gravitational field of a galaxy or galaxy cluster. This process creates multiple images of the supernova in the sky, with variations in arrival times due to different paths. By precisely measuring these time delays, scientists can deduce distances that play a crucial role in determining the Hubble constant.

This novel approach, distinct from conventional methods, offers a unique perspective on addressing discrepancies in measurement techniques and contributing insights to the ongoing exploration of cosmic mysteries. Justin Pierel of STScI, collaborating with Lou Strolger, emphasizes the potential of this approach to illuminate the reasons behind diverse measurement outcomes.

Finding the Needle in the Haystack: Unraveling Mysteries with NASA’s Roman Space Telescope.

Roman’s extensive surveys are set to revolutionize our understanding of the universe, surpassing the capabilities of the Hubble Space Telescope. With the ability to capture more than 100 times the area of Hubble in a single image, Roman will offer a comprehensive view of cosmic landscapes. Justin Pierel, co-lead on the program, likens the difference to seeing the entire forest in a single snapshot instead of gathering several pictures of trees. The High Latitude Time Domain Survey, part of Roman’s mission, will repeatedly observe the same sky area, generating over 5 billion pixels of data each time to explore transient astronomical phenomena.

A team led by Strolger and Pierel at the Space Telescope Science Institute (STScI) is taking strides to identify gravitationally lensed supernovae in Roman’s data. With funding from NASA’s Research Opportunities in Space and Earth Science (ROSES) Nancy Grace Roman Space Telescope Research and Support Participation Opportunities program, the team is preparing tools for efficient detection of these rare events. Their proactive approach aims to streamline the process, ensuring that the vast amount of data generated by Roman doesn’t go underutilized when it becomes available. The project involves collaboration among researchers from various NASA centers and universities across the country.

The team led by Strolger and Pierel at the Space Telescope Science Institute (STScI) is approaching the preparation in multiple stages. They are developing data reduction pipelines specifically tailored for the automatic detection of gravitationally lensed supernovae in Roman imaging. To enhance the training of these pipelines, the researchers will generate simulated imaging, creating 50,000 simulated lenses since only 10,000 actual lenses are currently known. The data reduction pipelines complement those designed for studying dark energy with Type Ia supernovae. Strolger emphasized Roman’s significance as the first opportunity to establish a gold-standard sample of gravitationally lensed supernovae, ensuring effective utilization of its enormous potential for cosmology.

The Nancy Grace Roman Space Telescope is overseen by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in collaboration with NASA’s Jet Propulsion Laboratory and Caltech/IPAC in Southern California, the Space Telescope Science Institute in Baltimore, and a science team composed of scientists from diverse research institutions. Key industrial partners include Ball Aerospace and Technologies Corporation in Boulder, Colorado; L3Harris Technologies in Melbourne, Florida; and Teledyne Scientific & Imaging in Thousand Oaks, California.