Spectra of four stationary galaxies in the protocluster QO-1000, with prominent absorption lines. Credit: Ito et al, 2023
An international team of astronomers reports the detection of a new protocluster of galaxies. The newly discovered protocluster, dubbed QO-1000, contains at least 14 giant stationary galaxies. The findings are detailed in a paper published on January 21st. arXiv preprint server.
Hundreds to thousands of galaxy clusters galaxy bound by gravity. They are the largest known gravitationally bound structures in the universe and could serve as excellent laboratories for studying galactic evolution and cosmology.
Astronomers are particularly interested in studying protoclusters of galaxies, the progenitors of galaxy clusters. Such objects found at high redshifts (greater than 2.0) may provide important information about the early stage of the Universe.
A new high-redshift protocluster has now been discovered by a group of astronomers led by Kei Ito of the University of Tokyo. The discovery is the result of analysis of data from the Cosmic Evolutionary Survey (COSMOS) and spectroscopic observations using the Keck I telescope.
“We search for the dense structure of stationary galaxies at z ~ 3 in the COSMOS field at ~ 2 degrees.2 It’s based on the predicted distribution of stationary galaxies,” the researchers explained.
As a result, they found an overdensity of 14 stationary galaxies at redshift 2.77. The protocluster, which received the designation QO-1000, contains four massive galaxies with specific low rates of star formation. The results suggest that this structure is at least 68 times denser in stationary galaxies than in common galaxies, and that the stationary part is about three times higher than this average redshift.
Astronomers have noted that the spectroscopically confirmed high stellar masses of QO-1000’s stationary galaxies indicate that they are hosted in giant halos. They added that the structure is likely hosted by a much more massive halo than other typical stationary galaxies with the same stellar mass.
As such, the researchers believe that QO-1000 is a more mature protocluster than most known protoclusters, possibly in a transitional stage from a star-forming protocluster to a local quenching cluster. I’m assuming it’s likely. According to the authors of the paper, their findings are even at redshifts of almost 3.0 proto cluster Galaxies can disappear and stationary galaxies can form dense structures. They hope that further study of the QO-1000 will help advance our knowledge of protocluster evolution.
“This structure would be an ideal laboratory for exploring the world. evolutionary history A (primordial) cluster of galaxies and the galaxies within it. A more detailed investigation of the member stationary galaxies within this structure will be done in future studies, including constraining the star formation history based on spectral and multiband photometry, and investigating morphology using HST/F160W images (3D- DASH Mowla et al. 2022 ), estimate dynamic masses and compare them with simulations,” the scientists concluded.
For more information:
Kei Ito et al, COSMOS2020: Discovery of a protocluster of huge quiet galaxies at z = 2.77, arXiv (2023). DOI: 10.48550/arxiv.2301.08845
Journal information:
arXiv
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Quote: New Protocluster of Massive Geostationary Galaxies Discovered (January 31, 2023) will be released on January 31, 2023 at https://phys.org/news/2023-01-protocluster-massive-quiescent- Taken from galaxies.html.
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