Dwarf Ghost PEARLSDG. Credit: NASA, ESA, CSA, Jake Summers (ASU), Jordan CJ D’Silva (UWA), Anton M. Koekemoer (STScI), Aaron Robotham (UWA) and Rogier Windhorst (ASU).
Galaxies are like star islands overflowing with stars. We observe very different galaxies, large, small, furiously active and very quiet and unobtrusive. Sometimes, however, we find a galaxy that defies our understanding, or our models of galaxy evolution. Since the start of the Webb telescope, galactic oddities have increased.
Timothy Carleton. Kredit: Arizona State University.
Tim Carleton from the American Arizona State University and his team recently searched a certain cluster of galaxies as part of the Prime Extragalactic Areas for Reionization and Lensing Science project, or PEARLS. Outside the main field of view, in places where nothing should actually be, they discovered a dwarf galaxy, which is quite different from our ideas about dwarf galaxies.
It’s called PEARLSDG, and despite a detailed survey, it doesn’t appear to be close to any other galaxies. She is alone in space. At the same time, practically no new stars are born there. PEARLSDG is a remarkable case of an isolated and quiescent dwarf galaxy.
Logo. Kredit: Arizona State University.
As Carleton points out, we’ve only found such galaxies extremely rarely so far. Until now, scientists have imagined dwarf galaxies as either isolated and sustaining distinct new star formation or interacting with a more massive nearby galaxy. PEARLSDG turns these ideas on their head. It is isolated and at the same time contains only old stars.
At the same time, we observe this galaxy at a distance of 98 million years. The Webb Telescope can see individual stars there, so we have a relatively decent picture of the PEARLSDG galaxy. She is really weird.
Carleton et al. used a wide range of data, in addition to NIRCam Webb observations, spectroscopic data from the DeVeney Optical Spectrograph at Arizona’s Lowell Discovery Telescope, archival data from the Galex and Spitzer space observatories, and data from the ground-based Sloan Digital Sky Survey and Dark Energy Camera Legacy Survey.
Observations of the PEARLSDG galaxy will influence how we understand the evolution of galaxies. At the same time, it is possible that there are many similar isolated and quiet galaxies in the universe without the formation of new stars, for which we can now search.
Video: Dwarf galaxy discovered at Andromeda’s edge could be ‘fossil’ of first galaxies
Literature
Arizona State University 28. 1. 2024.
Astrophysical Journal Letters 961: L37.
2024-02-07 15:07:24
#PEARLSDG #galaxy #exist
