A failed galaxy

If you look closely at the faint and fuzzy centre of this picture, you will find a ghostly galaxy — the not-so-spooky-sounding UDG4 — captured using ESO’s VLT Survey Telescope (VST). 

UDG stands for ultra-diffuse galaxy: objects as large as the Milky Way but with 100 – 1000 times fewer stars. These galaxies are extremely faint and lack star-forming gas, which makes them appear almost like a fluffy cosmic cloud, or a smudge in space. Their origins remain uncertain, but astronomers speculate that they could be “failed” galaxies that lost their gas supply early in their lifetimes. 

This image of UDG4 was taken as part of a study from a much larger program, the VST Early-type Galaxy Survey (VEGAS), which aims to investigate very faint structures in galaxy clusters — large groups of many galaxies bound together by gravity. The study, led by Enrichetta Iodice from the Istituto Nazionale di Astrofisica in Italy, has found several UDGs in the Hydra Cluster, but more observations are needed to elucidate their true nature.

Given their flimsy appearance, UDGs can be difficult to spot. Nevertheless, the VST, equipped with its OmegaCAM camera, provides exquisite sensitivity to light, allowing astronomers to study such elusive objects.

Припис:

ESO/Iodice et al.

Про зображення

ID:potw2122a
Тип:Спостереження
Дата релізу [date]:31 травня 2021 р. 06:00
Розмір:467 x 424 px

Про об’єкт

Назва:UDG4
Тип:Local Universe : Galaxy
Constellation:Hydra
Категорія:Galaxies

Формати зображень


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Координати

Position (RA):10 37 2.63
Position (Dec):-27° 12' 15.55"
Field of view:1.63 x 1.48 arcminutes
Орієнтація:Північ на 0.1° ліва від вертикалі

Кольори та фільтри

ДіапазонДовжина хвиліТелескоп
Оптичний
g
480 nmVLT Survey Telescope
OmegaCAM
Оптичний
g
480 nmVLT Survey Telescope
OmegaCAM
Оптичний
r
625 nmVLT Survey Telescope
OmegaCAM
Оптичний
r
625 nmVLT Survey Telescope
OmegaCAM