New data from the James Webb Space Telescope (JWST) has revealed that the structures of galaxies in the early universe were much more diverse and mature than previously known. Scientists compared images of hundreds of galaxies taken by JWST for the Cosmic Evolution Early Release Science (CEERS) survey with corresponding images previously taken by the Hubble Space Telescope and presented the results at the 241st meeting of the American Astronomical Society.
The study examined 850 galaxies at redshift z three to nine, or as they were roughly 11-13 billion years ago. Associate Professor Ceyhan Kartaltepe of Rochester Institute of Technology’s School of Physics and Astronomy said JWST’s ability to see faint, high-redshift galaxies in sharper detail than Hubble allowed the research team to resolve more features and see a broad mix of galaxies, including many with mature features such as discs and spheroidal components.
“There have been previous studies that have highlighted that we see many disc galaxies at high redshift, which is true, but in this study we also see many galaxies with other structures, such as spheroids and irregular shapes, as we do at lower redshift.” , said Kartaltepe, lead author of the paper and a CEERS co-investigator. “This means that even at these high redshifts, the galaxies were already quite evolved and had a wide range of structures.”
The research results, which were published on ArXiv and accepted for publication in The Astrophysical Journal, demonstrate JWST’s advances in depth, resolution and wavelength coverage compared to Hubble. Of the 850 galaxies used in the study that were previously identified by Hubble, 488 were reclassified as having different morphologies after being shown in more detail with JWST. Kartaltepe said scientists are just beginning to take advantage of JWST’s impressive capabilities and are excited about what the upcoming data will reveal.
“This tells us that we still don’t know when the earliest galactic structures formed,” Kartaltepe said. “We still don’t see the first disk galaxies. We will need to study many more galaxies at even higher redshift to truly quantify at what point in time features such as discs were able to form.
The survey used an initial data set captured by CEERS when JWST first came online in June, but since then the survey has captured a total of 60 hours of observation, potentially providing thousands of high-redshift galaxies for further study. Kartaltepe said COSMOS-Web, the largest co-observer program selected for JWST’s first year, will provide an even larger sample through 255 hours of observing time with the telescope. COSMOS-Web began its observing campaign this month.
Several of Kartaltepe’s collaborators on the study were RIT students, including a Ph.D. in Astrophysical Sciences and Technology. students Caitlin Rose, Brittany Vanderhoof and Isabella Cox; imaging science Ph.D. student James Liu; and physics student Jayse Petersen.
To read the full study, go to the ArXiv website.
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