The Tomographic Ionized-carbon Mapping Experiment (TIME) is a groundbreaking tool that promises to revolutionize our understanding of the early Universe. This innovative instrument, mounted on a 12-meter radio telescope at Kitt Peak Observatory in Arizona, employs a technique called line-intensity mapping (LIM) to gather light from numerous galaxies simultaneously. By focusing on specific spectral emission lines, TIME aims to unravel the mysteries of the cosmos' most critical period: the Epoch of Reionization (EoR).
The EoR marks a pivotal moment in the Universe's history when the first stars and galaxies ionized the intergalactic medium (IGM), transforming hydrogen from neutral to ionized and making the cosmos translucent. TIME's primary objective is to map hydrogen gas distribution and star formation across this era, providing a comprehensive view of the early Universe's evolution.
Selina Yang, a doctoral student at Cornell University, leads the research team behind TIME. In a press release, Yang explains the LIM technique, comparing it to observing a city from a distance. Instead of counting individual streetlights, TIME measures the overall brightness of an entire city, offering a more holistic perspective on the early Universe.
Abigail Crites, an assistant professor of physics at Cornell and the project's principal investigator, emphasizes TIME's ability to probe cosmic history over various timescales. Unlike traditional telescopes, which focus on individual galaxies, TIME identifies the presence of galaxies and their brightness, even if they are too dim to resolve individually.
The first preliminary results from TIME's commissioning run, published in The Astrophysical Journal, focus on Sagittarius A (Sgr A), a region near the Milky Way's galactic center. The study verifies TIME's hyperspectral imaging capabilities and demonstrates its ability to measure gas abundance and distribution.
TIME's unique approach lies in its ability to measure the abundance of various molecules by analyzing their unique spectral signatures, akin to reading barcodes. This technique is particularly valuable for studying early star formation, as certain molecules are closely tied to the environments where stars are born.
The research team, including co-author Dongwoo Chung, an assistant professor of astronomy at Cornell, chose Sgr A as a testbed for TIME's capabilities. By observing molecular gas at redshift zero, they aim to validate their measurements against previous observations at redshift two, ensuring the accuracy of their data.
TIME's observations targeted three regions near the Milky Way's nucleus: the Circumnuclear Disk (CND) and a pair of gas clouds resembling early starburst galaxies. These clouds, rich in emission bands, provide an excellent opportunity to study star formation and feedback processes in galactic nuclei.
The authors express satisfaction with TIME's initial commissioning observations, highlighting its ability to acquire and process broadband millimeter-wave spectral maps even under high-noise conditions. These results support the maturation of LIM, which initially faced skepticism due to foreground contamination concerns.
Despite the faint signal from early galaxies, TIME successfully recovers both continuum and spectral-line signals, validating its readiness for upcoming extragalactic CO and [C ii] surveys. This breakthrough technology paves the way for a deeper understanding of the early Universe, offering a more comprehensive view of the cosmos' evolution and the birth of stars.
