Galaxies

Blogs about galaxies, singles ones on in clusters

Some of the galaxies included in the DESI Legacy Imaging Surveys map (Image: DESI Legacy Imaging Surveys/LBNL/DOE & KPNO/CTIO/NOIRLab/NSF/AURA)

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The DESI Legacy Imaging Surveys team has released the largest 2D map of the universe. Consisting of 5.6 trillion pixels, this map includes nearly 4 billion celestial objects, ranging from asteroids to galaxies, as well as other objects such as stars, black holes, and more. It’s a vast archive spanning approximately three-quarters of the sky, useful for astronomical studies requiring information at optical and near-infrared frequencies. This result isn’t the final one, as the map will be used to determine the distances to objects such as quasars to construct a new map, this time 3D.

An archival image of the galaxy WISEA J014656.04-152214.7 and the location of the TDE 2025abcr event (above), as well as the same area imaged on December 14, 2025, with the tidal disruption event visible in the blue circle

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An article published in “The Astrophysical Journal Letters” reports the discovery of a supermassive black hole on the outskirts of its host galaxy WISEA J014656.04-152214.7, approximately 30,000 light-years from its center. A team of researchers found its traces thanks to a so-called tidal disruption event cataloged as TDE 2025abcr. Detected for the first time by the Zwicky Transient Facility (ZTF), thanks in part to a new artificial intelligence algorithm, the event was confirmed and studied for months in various electromagnetic bands using various instruments. This discovery supports the theory that wandering supermassive black holes can exist very distant from the center of a galaxy, where they normally reside.

The Sextans A galaxy. In the inset, in green, polycyclic aromatic hydrocarbons (Image NASA, ESA, CSA, Elizabeth Tarantino (STScI), Martha Boyer (STScI), Julia Roman-Duval (STScI); Image Processing: Alyssa Pagan (STScI))

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An article published in “The Astrophysical Journal” reports the results of a study of dust generated by red giant stars towards the end of their lives under conditions similar to those existing in the first galaxies of the universe. A team of researchers led by Claudio Gavetti of the Italian National Institute for Astrophysics and the University of Roma Tre used observations conducted with the James Webb Space Telescope to study the Sextans A dwarf galaxy, where the environment is very metal-poor. Observations of a quality unimaginable in the past allowed to understand how these stars produce cosmic dust in environments similar to those of the early universe.

Abell 2744-QS01. The insets show zooms of three separate views of QS01 generated by gravitational lensing

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Two articles, one published in the journal “Nature” and one in the “Monthly Notices of the Royal Astronomical Society”, report different aspects of a study of the supermassive black hole cataloged as Abell 2744-QSO1, or simply QSO1, indicating that it’s older than its host galaxy. A team of researchers used observations with the James Webb Space Telescope to study QSO1 and measured its mass at about 50 million times the Sun’s. This means it makes up at least two-thirds of the total mass of the galaxy, an anomaly that betrays its age and leaves open some possible hypotheses about its origin.

A 3D map of the local universe with the various galaxy superclusters. On the left is the Vela Supercluster

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An article submitted for publication in the journal “Astronomy & Astrophysics” reports the results of an astronomical study that used a hybrid technique to examine the Vela Supercluster. A team of researchers combined redshifts with the distances and peculiar velocities of galaxies within the Vela Supercluster to obtain a complete portrait of it, a result that was previously impossible due to its location, hidden by the Milky Way’s so-called zone of avoidance.

Key information was obtained using the SALT optical telescope and the MeerKAT radio telescope, both in South Africa. Given the importance of this nation in this research, the authors used the nickname Vela-Banzi, adding a term in Xhosa, a Bantu language, which means “revealing widely.”