Utilizing the 5-hundred-meter Aperture Spherical radio Telescope (FAST), Chinese language astronomers have detected a brand new galaxy, which obtained designation FAST J0139+4328. The newfound galaxy is remoted, has a comparatively low stellar mass, and is dominated by dark matter. The invention was detailed in a paper revealed February 6 on the arXiv pre-print server.
China’s FAST is the world’s largest single-dish radio telescope. Its sensitivity and glorious survey pace permits astronomers to check compact objects, gaseous galaxies, and the interstellar medium. The potential discoveries of FAST embrace 1000’s of recent pulsars, a whole bunch of 1000’s of recent impartial atomic hydrogen (HI) galaxies, or darkish galaxies that make up a part of the so-called lacking baryons.
Now, a staff of astronomers led by Jin-Lengthy Xu of the Chinese language Academy of Sciences in Beijing, reviews the discovering of 1 new darkish galaxy utilizing FAST. The invention is a results of analyzing the info from FAST’s HI survey and likewise from the Panoramic Survey Telescope and Fast Response System (Pan-STARRS).
“A significant scientific goal for this survey is to seek for darkish and weak galaxies making the most of excessive sensitivity of FAST and with a comparatively excessive velocity decision. On this Letter, based mostly on the HI survey utilizing FAST, we’ve got found an remoted darkish dwarf galaxy within the close by universe,” the researchers defined.
Initially, the staff detected some new impartial atomic hydrogen clouds within the native universe based mostly on the brand new FAST extragalactic HI survey knowledge. Among the many detected clouds, they recognized an remoted cloud, named FAST J0139+4328 in response to its coordinates, which has no optical counterpart.
Additional examination of FAST J0139+4328 discovered {that a} typical disk galaxy, nevertheless with an especially low absolute magnitude (upper limit absolute B-band magnitude of -10.0 magazine) and a stellar mass beneath 690,000 solar masses. The dynamical and baryonic lots of FAST J0139+4328 had been calculated to be about 5.1 and 0.11 billion solar lots, respectively, whereas the impartial atomic hydrogen mass of this galaxy was discovered to be at a stage of some 83 million solar lots.
The astronomers underlined that the dynamical mass to total baryonic mass ratio for FAST J0139+4328 is about 47± 27, which means that on this galaxy dark matter dominates over baryons. All in all, the outcomes point out that FAST J0139+4328 is an remoted gas-rich and darkish dwarf galaxy positioned some 94 million gentle years away.
The authors of the paper famous that their discovery marks the primary time when a gas-rich remoted darkish galaxy has been detected within the close by universe. They added that FAST J0139+4328 seems to have a rotating disk of gasoline however is starless. This, along with the truth that dark matter dominates in FAST J0139+4328, might recommend that this darkish galaxy is within the earliest stage of the galaxy formation.
Extra info:
Jin-Lengthy Xu et al, Discovery of an remoted darkish dwarf galaxy within the close by universe, arXiv (2023). DOI: 10.48550/arxiv.2302.02646
Journal info:
arXiv
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Chinese language astronomers uncover an remoted darkish dwarf galaxy (2023, February 14)
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