麻豆淫院

Using the James Webb Space Telescope (JWST), astronomers from Canada and Switzerland have discovered a new galaxy, which received designation COSMOS2020-635829. The newfound object appears to undergo a ram pressure stripping of gas and therefore may be a "jellyfish" galaxy. The finding was detailed in a research paper June 17 on the arXiv pre-print server.

The so-called "jellyfish" galaxies exhibit long, trailing streams of gas and young stars extending from one side, which makes them morphologically resemble jellyfishes. They are usually found in galaxy clusters and when they move through an intracluster medium they are slowly stripped of gas. This process, known as ram pressure stripping (RPS), can trigger bursts of star formation in the stripped gas.

Now, a team of astronomers led by Ian D. Roberts of the University of Waterloo in Canada, reports the finding of a new galaxy, which seems to be of the jellyfish type. Using the high-resolution imaging acquired with JWST, they uncovered the presence of a symmetric stellar disk coupled to a unilateral tail of star-forming knots.

"We report the discovery of COSMOS2020-635829 as a likely jellyfish galaxy undergoing ram pressure stripping in a (proto)cluster at z > 1," the researcher wrote in the paper.

The observations found that COSMOS2020-635829 is associated with a cluster-mass, X-ray detected overdensity. Moreover, the galaxy showcases a one-sided collection of blue, star-forming extra-planar knots that are co-spatial with an ionized gas tail.

The star-forming knots in the tail have stellar masses of around 100 million solar masses and star-formation rates at a level of 0.1-1 solar masses per year. These knots, which host young stellar populations, account for about one percent of the stellar mass of COSMOS2020-635829.

According to the paper, COSMOS2020-635829 has a redshift of approximately 1.156, a stellar mass of about 10 billion solar masses, and a star-formation rate of some 100 solar masses per year. The X-ray luminosity of this galaxy was measured to be about 8 tredecillion erg/s.

The researchers note that COSMOS2020-635829 is among the strongest candidates for a jellyfish galaxy at a redshift higher than 1.0. Furthermore, the galaxy is so far the highest redshift example of a ram-pressure stripped ionized gas tail as well as extra-planar star formation.

According to the authors of the paper, their study could improve our understanding of the quenching mechanisms at work in the high-redshift universe.

"This work reinforces the notion that ram pressure stripping can perturb group and cluster galaxies at z > 1 and likely contributes to environmental quenching even near Cosmic Noon," the scientists conclude.

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