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 the distribution of hydrogen gas and star formation across this early epoch. It does so by observing carbon monoxide emission lines, which provide a window into the EoR.
Selina Yang, a doctoral student at Cornell University, leads the research team behind TIME. In a press release, Yang explains the LIM technique, likening it to observing a city from a distance. Instead of counting individual streetlights, LIM measures the overall brightness of an entire city, offering a more comprehensive view of 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 can only identify specific galaxies, TIME can detect the presence of galaxies and their brightness, even if they are too dim to resolve individually.
The first 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 nucleus. The study verifies TIME's hyperspectral imaging capabilities and demonstrates its ability to measure molecular gas in Sgr A. This initial test observation compares the results with previous measurements from other tools and methods.
TIME's unique approach lies in its ability to measure the abundance of different 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 linked to the environments where stars are born.
The research team observed three regions near the Milky Way's galactic nucleus: the Circumnuclear Disk (CND) and a pair of gas clouds. These clouds serve as analogs for early starburst galaxies and are rich in the emission bands of interest to the TIME project. The CMZ, a heavily observed region, provided an excellent opportunity to validate TIME's results against existing observations.
The authors express satisfaction with TIME's initial commissioning observations, highlighting its ability to acquire and process broadband millimeter-wave spectral maps of complex astrophysical regions, even under challenging conditions. Despite initial skepticism about foreground contamination, TIME has proven its capability to recover both continuum and spectral-line signals, paving the way for future extragalactic surveys.
In conclusion, TIME represents a significant advancement in our quest to understand the early Universe. Its unique approach to line-intensity mapping and its ability to measure molecular gas in various regions make it a powerful tool for astronomers. As TIME continues its commissioning and future observations, it will undoubtedly unlock new insights into the cosmos' most fascinating era.
