Astronomers from the COSMOS-Web program released mosaic images taken in early January 2023 by the Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) onboard the NASA/ESA/CSA James Webb Space Telescope.
The first epoch of COSMOS-Web NIRCam observations obtained on January 5 and 6, 2023, including the F115W, F150W, F277W, and F444W filters as a color composite. Image credit: COSMOS-Web / Casey et al. / RIT / UT Austin / IAP / CANDIDE.
“It’s incredibly exciting to get the first data from the telescope for COSMOS-Web,” said Dr. Jeyhan Kartaltepe, an astronomer at Rochester Institute of Technology and principal investigator of the COSMOS-Web program.
“Everything worked beautifully and the data are even better than we expected.”
“We’ve been working really hard to produce science quality images to use for our analysis and this is just a drop in the bucket of what’s to come.”
“This first snapshot of COSMOS-Web contains about 25,000 galaxies — an astonishing number larger than even what sits in the Hubble Ultra Deep Field,” added Dr. Caitlin Casey, an astronomer at University of Texas at Austin and principal investigator of the COSMOS-Web program.
“It’s one of the largest Webb images taken so far. And yet it’s just 4% of the data we will get for the full survey.”
“When it is finished, this deep field will be astoundingly large and overwhelmingly beautiful.”
COSMOS-Web aims to map the earliest structures of the Universe and will create a wide and deep survey of up to one million galaxies.
Over the course of 255 hours of observing time, the survey will map 0.6 square degrees of the sky with Webb’s NIRCam instrument, roughly the size of three full moons, and 0.2 square degrees with MIRI.
COSMOS-Web has three primary science goals:
(i) furthering our understanding of the Reionization Era, roughly 200,000 years to one billion years after the Big Bang;
(ii) identifying and characterizing early massive galaxies in the first 2 billion years;
(iii) and studying how dark matter has evolved with the stellar content of galaxies.
COSMOS-Web is the widest area Webb will observe in its first year, enabling the study of galaxies across a wide range of local environments.
The images taken so far show incredible detail when compared with those taken previously by other observatories such as the NASA/ESA Hubble Space Telescope and NASA’s Spitzer Space Telescope.
The mosaics were created from six pointings of the telescope taken January 5 and 6, 2023.
Webb will take 77 pointings, roughly half the field, in April and May, and the remaining 69 pointings are scheduled to take place in December 2023 and January 2024.
“Webb has delivered such stunning images of this region that sources are literally popping out in every small patch of the observed sky,” said Dr. Santosh Harish, an astronomer at Rochester Institute of Technology.
“What were thought to be compact objects based on the best images we had so far, the Webb observations are now able to resolve these objects into multiple components, and in some cases even reveal the complex morphology of these extragalactic sources.”
“With these first observations, we have just barely scratched the surface of what is to come with the completion of this program, next year.”
An overview of COSMOS-Web’s survey design, implementation, and outlook will be published in the Astrophysical Journal.
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Caitlin M. Casey et al. 2023. COSMOS-Web: An Overview of the JWST Cosmic Origins Survey. ApJ, in press; arXiv: 2211.07865
