A global staff of astronomers has used the James Webb House Telescope (JWST) to watch a luminous dusty star-forming galaxy often called GN20. Outcomes of the observational marketing campaign, printed April 26 on the arXiv preprint server, ship essential insights into the stellar construction of this galaxy.
At a redshift of 4.05, GN20 is among the most luminous dusty star-forming galaxies (DSFGs) identified to this point. GN20 is positioned in a protocluster or galaxy overdensity, has an infrared luminosity of some 18.6 solar luminosities, and a star formation price (SFR) of about 1,860 solar masses per yr. The molecular gasoline distribution on this galaxy exhibits a clumpy stellar structure with a diameter of roughly 45,600 light years and kinematics according to that of a large rotating disk.
Lately, a gaggle of astronomers led by Luis Colina of the Spanish Astrobiology Middle in Madrid, Spain, determined to carry out mid-infrared observations of GN20, aiming to shed extra gentle on its properties. For this function they used JWST’s Mid-Infrared Instrument (MIRI).
“GN20 JWST imaging was obtained on November 23–24, 2022, utilizing the MIRI imager (MIRIM, Bouchet et al, 2015) within the F560W filter as a part of the European Consortium MIRI Assured Time (program ID 1264),” the researchers defined.
The observations discovered that GN20 has a stellar construction characterised by a luminous (with an absolute magnitude of -22.35) unresolved nucleus and a diffuse prolonged envelope. This stellar construction is forming new stars at a continuing, excessive price of about 500 solar plenty per yr, for a interval of 100 million years.
The nucleus is lower than 2,600 gentle years in measurement, carries 9% of the total flux and coincides with the compact, chilly dust nuclear emission. The stellar envelope has an efficient radius of about 11,740 gentle years, and its place agrees with that of the carbon monoxide molecular gasoline, however its centroid is offset by roughly 3,300 gentle years from the stellar nucleus. This offset could also be a results of a current gravitational encounter or merger.
By analyzing the JWST photographs, the staff additionally recognized extra faint stellar clumps that seem like related to a few of the ultraviolet and carbon monoxide-clumps. Furthermore, the astronomers discovered that the stellar nucleus seems to have the best focus of cold dust however not the biggest focus of molecular gasoline.
Summing up the outcomes, the authors of the paper famous that GN20 has all of the properties wanted to evolve into a large quiescent galaxy at intermediate redshift.
“It’s a giant, luminous galaxy at z = 4.05 concerned in a brief and large starburst centered within the stellar nucleus and prolonged over all the galaxy, out to radii of 4 kpc, and sure induced by the interplay or merger with a member of the proto-cluster,” the researchers defined.
Extra info:
L. Colina et al, Uncovering the stellar construction of the dusty star-forming galaxy GN20 at z=4.055 with MIRI/JWST, arXiv (2023). DOI: 10.48550/arxiv.2304.13529
Journal info:
arXiv
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JWST observations unveil stellar construction of star-forming galaxy GN20 (2023, Might 10)
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