RGB composite images of A2744-GDSp-z4 in this sequence: RGB composite with F200W, F150W, F090W filters, midband RGB composite with F360M, F335M and F300M filters and RGB image with F444W, F356W and F277W filters. Credit: Jain et al., 2024.
Indian astronomers report the detection of a large new galaxy using the James Webb Space Telescope (JWST). The new galaxy, designated A2744-GDSp-z4, is relatively large and massive. The discovery was detailed in a paper published Dec. 6 on the preprint server. arXiv.
Large-design spiral galaxies are characterized by their prominent, well-defined arms, which rotate outward from a clear core. It is assumed that the arms of these galaxies are actually overly dense regions of the disk that trigger star formation when incoming matter is compressed into that region.
It is still unclear exactly when and how spiral galaxies first appeared in the early universe and these galaxies are generally rare at high redshifts. To date, only a few individual spirals have been found with a redshift greater than 3.0.
Today, a team of astronomers led by Rashi Jain from the National Center for Radio Astrophysics in India, reports the discovery of a new high redshift spiral using JWST. The new galaxy is of the large design subtype and was identified with a redshift of 4.03.
“In this article, we present the discovery, in the field of the Abell 2744 cluster, of a two-armed spiral galaxy, of great design, with a redshift of z ∼4, when the universe had only ∼1.5 billion years old is a large design spiral galaxy (GDSp) located in the A2744 field at z ∼4, we designate it as. A2744-GDSp-z4,” the researchers said. explain.
A2744-GDSp-z4 was first recognized as an unusual galaxy and its closer inspection revealed that it features a grandly designed spiral pattern with two well-formed spiral arms. The galaxy also features a bright central bulge and a large, extended disk about 32,000 light-years across.
According to the paper, A2744-GDSp-z4 has a stellar mass of about 14 billion solar masses and a star formation rate of 57.6 solar masses per year. The weighted age of the galaxy is 228 million years.
Astronomers calculated that the start of star formation in A2744-GDSp-z4 occurred about 839 million years after the Big Bang. Therefore, this means that A2744-GDSp-z4 assembled a mass of 10 billion solar masses in a few hundred million years and the age of the universe at the galaxy’s redshift was only about 1.5 billion years.
The authors of the paper pointed out that these results challenge current hierarchical models of galaxy formation and leave many questions open.
“How was A2744-GDSp-z4 able to acquire such a large disk in such a short time? How and when did the highly designed spiral arms appear? These questions could be answered by studying the dynamic state of this galaxy with future IFU JWST/NIRSpec observations,” the scientists wrote.
More information:
Rashi Jain et al, A grand design spiral galaxy 1.5 billion years after the Big Bang with JWST, arXiv (2024). DOI: 10.48550/arxiv.2412.04834
Journal information:
arXiv
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Quote: JWST discovers a massive, high-design spiral galaxy in the early universe (December 16, 2024) retrieved December 17, 2024 from
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