As part of the JWST COSMOS-Web survey, astronomers have announced the
finding of a new galaxy with the James Webb Space Telescope (JWST).
JWST-ER1, the newly discovered object, is a large, compact, inactive galaxy.
A article summarizing the results was posted on the pre-print service arXiv
on September 14.
Giant elliptical galaxies may have originated from large quiescent
galaxies, which are galaxies with a mass that has ceased to generate stars.
These objects may be essential to advancing our knowledge of the history of
galaxies since they generated stars sooner and accumulated their stellar
masses faster.
A group of astronomers from Yale University, led by Pieter van Dokkum, has
now reported the discovery of a new galaxy of this kind, designated
JWST-ER1. The Near Infrared Camera (NIRCam) on JWST was used to identify the
object as part of the ongoing COSMOS-Web, a large and deep survey of up to a
million galaxies. The "Einstein ring," a phenomena caused by gravitational
lensing that causes light to look as a ring, is one of JWST-ER1's most
notable characteristics.
"In the framework of the COSMOS-Web project, a public wide-area survey
using the F115W, F150W, F277W, and F444W filters, the galaxy and its ring
were identified in JWST NIRCam observations," the researchers said.
JWST-ER1 is made up of a full Einstein ring (JWST-ER1r) with two prominent
red concentrations and a compact early-type galaxy (JWST-ER1g), according to
NIRCam data. It was determined that the ring's center had a diameter of
around 1.54 arcseconds.
The new galaxy was discovered at 1.94 redshift, with a mass estimated at
650 billion solar masses and a radius of around 21,500 light years. The
findings indicate a low star-formation rate of four solar masses per year
and an age of 1.9 billion years. JWST-ER1 is a huge, inactive galaxy as a
result. In line with other inactive galaxies at comparable redshifts, it is
likewise rather compact.
Regarding the ring JWST-ER1r, the scientists discovered that it originates
from a background galaxy located at a photometric redshift of 2.98. Though
most of the known Einstein rings are incomplete, it unites a huge number of
them.
Additionally, the study discovered that JWST-ER1 is nearly perfectly
spherical and that the NIRCam imagery does not show any clear star-forming
areas, tidal tails, or other anomalies.
In order to determine if JWST-ER1 is the center galaxy of a cluster
progenitor or whether surrounding galaxies or structures along the line of
sight might contribute to its mass, the authors of the research suggest
doing more observations of JWST-ER1.
