REBELS-25 is a dynamically cold disk galaxy, observations find

A global crew of astronomers has noticed a high-redshift huge star-forming galaxy generally known as REBELS-25. They discovered that REBELS-25 is a dynamically chilly disk galaxy. This discovering was offered in a research paper revealed Might 9 on the pre-print server arXiv.

At a redshift of seven.31, which corresponds to a luminosity distance of about 236 billion light years, REBELS-25 is an infrared luminous galaxy. It has a stellar mass of some 8 billion solar lots and its star-formation charge is estimated to be at a stage of 199 solar lots per yr.

Not too long ago, a gaggle of astronomers led by Lucie E. Rowland of the Leiden College in The Netherlands, determined to carry out high-resolution and dust continuum observations of REBELS-25 as a way to shed extra gentle on its properties. For this function, they employed the Atacama Massive Millimeter/submillimeter Array (ALMA) in Chile.

“On this paper, we now have offered follow-up high-resolution (∼710 laptop) ALMA [CII] and dust (∼150????m) continuum observations of REBELS-25; a large star-forming galaxy at ????=7.31, initially focused as a part of the ALMA Reionization Period Vivid Emission Line Survey (REBELS) giant program (LP),” the researchers wrote.

The observations discovered that REBELS-25 has a comparatively low velocity dispersion of about 33 km/s and a excessive ratio of ordered-to-random movement—at a stage of 11.0. These outcomes point out that REBELS-25 is a dynamically chilly disk galaxy.

Nevertheless, though REBELS-25 appears to be dynamically chilly, the astronomers have noticed some proof of non-circular motions. These motions may very well be because of inflows or outflows, a minor merging element, in addition to because of a central bar or spiral arms.

The observations additionally discovered that REBELS-25 has a total dynamical mass of about 120 billion solar lots. Based mostly on this, the researchers estimated that the galaxy’s gasoline mass is a few 110 billion solar masses, however this result’s extremely unsure because of dust obscuration and requires additional research.

The authors of the paper underlined that their discovery makes REBELS-25 probably the most distant robustly confirmed chilly disk galaxies noticed thus far. They added that discovering such a really distant and really dynamically chilly disk galaxy challenges present theoretical predictions and simulations. It additionally means that such galaxies may very well be extra widespread within the high-redshift universe than beforehand thought.

“We due to this fact count on that future, excessive decision research of chilly gasoline kinematics at high-z will reveal much more chilly, huge disks. Particularly, ongoing ALMA observations of different REBELS galaxies will allow strong kinematic modeling of extra rotating disk candidates at ????∼6−8,” the scientists conclude.

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