can you see it?Recently discovered ultra-low-luminosity dwarf galaxy in the constellation Cetus | sorae Portal site to space

This is an image that captures a corner of “Cetacea”. The width is equivalent to about 1/10 of the apparent diameter of the full moon (field of view is 3.20 x 1.61 arcmin). If you look closely at the center of the image, you can see a faint nebula-like object. This object is called “Donatiello II” and is classified as an Ultra Faint Dwarf Galaxy (UFDG).

A dwarf galaxy is a general term for small galaxies that contain billions of stars or less. Dwarf galaxies are galaxies with low (dark) surface brightness, but ultra-low-luminosity dwarf galaxies, as their names suggest, are particularly faint types of dwarf galaxies. The dark dwarf galaxies are thought to be the oldest surviving galaxies and are expected to contain clues about the earliest stars that formed.

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Donatiello II is a galaxy recently discovered by Italian amateur astronomer Giuseppe Donatiello. Published from the project “Dark Energy Survey (DES)”, which was observed from 2013 to 2019 using the observation device “Dark Energy Camera (DECam)” of the Blanco 4m telescope at the Cerro Tololo Inter-American Observatory in Chile. Donatiello, who analyzed the data, found it very dark around the spiral galaxy NGC 253, also known as the Sculptor Galaxy, in the constellation Sculptor next to Cetus3. Discover two galaxies. These are all satellite galaxies (companion galaxies) of NGC 253 and have been named Donatiello II, Donatiello III, and Donatiello IV.

The image posted at the beginning was created from data acquired by the “Hubble” Space Telescope based on a proposal by a research team led by Burçin Mutlu-Pakdil of the University of Arizona. Observations using the Hubble Space Telescope have independently confirmed Donatiello’s discovery, according to the European Space Agency (ESA). It is said that the three galaxies discovered by Donatiello were overlooked by an algorithm that automatically searches for candidate galaxies from observational data, and for objects that are difficult to identify in this way, the old-fashioned method by human eyes is necessary. .

The first image was created based on data acquired by the Hubble Space Telescope’s Advanced Camera for Surveys (ACS), and was released by ESA on February 6, 2023 as one of the Hubble Space Telescope’s images of the week. Published by date.

[▲ Ultra-low-luminosity dwarf galaxy “Donatiello II” (enlarged image near the center of the original image) (Credit: ESA/Hubble & NASA, B. Mutlu-Pakdil; Acknowledgment: G. Donatiello)]

Source

• Image Credit: ESA/Hubble & NASA, B. Mutlu-Pakdil; Acknowledgment: G. Donatiello
• ESA/Hubble – Can You Spot It?
• According to Mutlu-Pakdil et al. – Hubble Space Telescope Observations of NGC 253 Dwarf Satellites: Three Ultra-faint Dwarf Galaxies (The Astrophysical Journal)
• Martinez-Delgado et al. – Tracing satellite planes in the Sculptor group – I. Discovery of three faint dwarf galaxies around NGC 253 (Astronomy & Astrophysics)

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