Infrared capabilities from JWST reveal the earliest galaxies in the young universe

Four distant galaxies in SMACS 0723. Analysis of the first-ever image from the James Webb Space Telescope shows that the infrared telescope reveals details of galaxies from when the universe was only about 1 billion years old. Left: The first image with four highlighted galaxies. On the right, the four galaxies, each seen with a different telescope or instrument. HST is the Hubble Space Telescope. JWST/NIRCam is the NIRCam instrument on the James Webb Space Telescope. JWST/MIRI is the MIRI instrument on the James Webb Space Telescope. A striking example is that galaxy ID 367 cannot be seen with Hubble. Credit: JWST/E. Iani & K. Caputi

Analysis of the very first image from the James Webb Space Telescope shows that the MIRI instrument developed in the Netherlands works even better than expected. Researchers from the University of Groningen have shown that the infrared telescope shows details of galaxies from a time when the universe was only about 1 billion years old. This period is important to astronomers because it was when the first galaxies formed. The analysis will be published shortly The Astrophysical Journal.

For the past 20 years, researchers have relied on infrared images from Spitzer. This telescope could only look back at long wavelengths to about 2 to 3 billion years after the Big Bang. “You would think that the 1 billion years that Webb takes off doesn’t matter that much,” says research leader Edoardo Iani (University of Groningen) “But you come right at the time when the first galaxies were formed. So we are very pleased with our findings.”

Infrared images from the James Webb Space Telescope allowed astronomers to discover undiscovered galaxies, among other things. They could also more accurately calculate how many stars were present in very young, distant galaxies. The reason previous Hubble Space Telescope estimates were inaccurate is that they didn’t capture much of the originally visible light because it was stretched by the expansion of the universe.

Co-author of the analysis Karina Caputi (University of Groningen) expects more and deeper images to become available soon. “Maybe that will allow us to penetrate a little bit into the Dark Ages. When we designed the MIRI instrument, we secretly hoped that we would achieve that, but now it looks like it’s really going to happen.”

Astronomers see infrared turn on in young universe

Webb’s first photo from early July 2022. The photo differs slightly from the photo used by the Groningen researchers. That of the Groningen researchers is tilted a few degrees to the right and has sharper colors thanks to improved image processing. Credit: JWST

About MIRI

MIRI was developed by NASA and ESA together with various European partners. The MIRI spectrometer was created thanks to the efforts of the Netherlands Research School for Astronomy (NOVA) and research institutes in the United Kingdom and Germany. Design and construction were carried out by the NOVA Optical-Infrared Group at ASTRON in Dwingeloo in collaboration with several other Dutch institutes and universities.

“A first look into the nature of JWST/MIRI 7.7 micron sources from SMACS 0723” has been accepted for publication in The Astrophysical Journal.

More information:
Edoardo Iani et al, A First Look into the Nature of JWST/MIRI 7.7 micron Sources from SMACS 0723, arXiv (2022). DOI: 10.48550/arxiv.2208.06364. Accepted for publication in The Astrophysical Journal.

Offered by the Netherlands Research School for Astronomy

Quote: Infrared Capabilities of JWST Reveal Earliest Galaxies in the Young Universe (2022, Nov. 16) Retrieved Nov. 16, 2022 from

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