JWST’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) captured mosaic images in early January, which were made public by scientists from the COSMOS-Web program.

This first COSMOS-Web snapshot contains about 25,000 galaxies – an astonishing number larger than even what is in the Hubble Ultra Deep Field. It is one of the largest JWST images created to date. And yet it’s only 4 percent of the data we’ll get for the full survey. When finished, this deep field will be astonishingly large and overwhelmingly beautiful.

The images taken so far show incredible detail compared to those previously taken by other observatories, such as the Hubble Space Telescope and the Spitzer Space Telescope.

Compared to previous images taken by observatories such as the Hubble Space Telescope and the Spitzer Space Telescope, the images so far reveal amazing detail.

The first epoch of COSMOS-Web MIRI observations obtained on January 5-6, 2023
The first epoch of COSMOS-Web MIRI observations acquired on January 5-6, 2023. The MIRI data spans six visits and is divided into six non-overlapping tiles and includes data from both the MIRI imager and the Lyot Coronograph field of view. On the left is a comparison between Spitzer IRAC channel 4 (8 µm) data and MIRI 7.7 µm data in a 40” × 40” zoom panel. Image credit: COSMOS-Web/Kartaltepe, Casey, Harish, Liu, et al/RIT/UT Austin/IAP/CANDIDE

COSMOS-Web will conduct a broad and in-depth study of up to 1 million galaxies to map the oldest features of the universe. COSMOS-Web will map 0.6 square degrees of the sky with NIRCam over 255 hours of observation time, or roughly the area of ​​three full moons, and 0.2 square degrees with MIRI.

COSMOS-Web is the most extensive area that JWST will observe in its first year, allowing the study of galaxies in a wide variety of local environments.

COSMOS-Web has three primary scientific goals:

  1. Expanding our understanding of the Reionization Era, about 200,000 to 1 billion years after the Big Bang;
  2. identify and characterize early massive galaxies in the first 2 billion years; And
  3. Studying how dark matter has evolved with the stellar content of galaxies.

Santosh Harish, a postdoctoral research associate at RIT, said: “JWST has produced such stunning images of this region that sources are literally popping up in every little patch of the observed sky. What were considered compact objects based on the best images we had to date, with the JWST observations are now able to break these objects down into multiple components and in some cases even the complex morphology of these extragalactic sources to reveal. With these initial observations, we are just scratching the surface of what will come next year with the completion of this program.”

first era of COSMOS-Web NIRCam
The first era of COSMOS-Web NIRCam observations acquired on January 5-6, 2023, including the F115W, F150W, F277W, and F444W filters as a color composite. This data relates to six visits or referrals out of a total of 152 visits. The total area covered by NIRCam here is ∼77arcmin^2. The relative position of this mosaic in the survey is shown at the top left. At the lower left are several zoomed-in 10” x 10” cutouts and one 16” x 16” cutout showing specific galaxies selected from this initial data. Image credit: COSMOS-Web/Kartaltepe, Casey, Franco, Larson, et al./RIT/UT Austin/IAP/CANDIDE

The mosaics are made from six telescope alignments taken on January 5 and 6. In April and May, the telescope will perform 77 directions or nearly half of the field, and the final 69 directions are scheduled for December 2023 and January 2024.

Lead researcher Jeyhan Kartaltepe, an associate professor in the Rochester Institute of Technology’s School of Physics and Astronomy, said: “It is incredibly exciting to get the first data from the telescope for COSMOS-Web. Everything worked beautifully and the data is even better than we expected. We have worked hard to produce scientific-quality images for our analysis, and this is just a drop in the ocean of things to come.”

Magazine reference:

  1. Caitlin M. Casey, Jeyhan S. Kartaltepe et al. COSMOS-Web: An Overview of the JWST Cosmic Origins Survey. arXiv (2022). DOI: 10.48550/arxiv.2211.07865