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Astronomers Discover Fading Radio Galaxies, Revealing Supermassive Black Hole Activity

Astronomers Discover Fading Radio Galaxies, Revealing Supermassive Black Hole Activity

Astronomers have identified a previously unknown population of 'radio galaxies' exhibiting fading 'radio lobes.' This discovery sheds light on the processes that occur when the supermassive black holes powering these vast outflows of plasma cease their activity. The research team investigated 14 candidate faded or remnant radio galaxies within the XMM–Newton Large-Scale Structure (XMM–LSS) field, a region of the sky extensively studied by the XMM-Newton X-ray spacecraft. Radio galaxies are characterized by their intense radio wave emissions and expansive gas lobes that can extend for millions of light-years. Remnant radio galaxies represent the final stage of their evolution, where the jets from the central active galactic nuclei (AGNs), fueled by supermassive black holes, have shut down. Consequently, these jets can no longer replenish the radio lobes, leading to their gradual fading. The study utilized the MeerKAT radio telescope in South Africa, the Jansky Very Large Array, and the LOFAR (Low-Frequency ...

James Webb Space Telescope Reveals Early Galaxies Larger Than Previously Thought Due to Hidden Stars

James Webb Space Telescope Reveals Early Galaxies Larger Than Previously Thought Due to Hidden Stars

The James Webb Space Telescope (JWST) has made a significant discovery regarding the early universe, revealing that the first galaxies were much larger and more massive than previously estimated. By studying nine early galaxies that have completed their intense star formation periods, astronomers found a much greater proportion of small, faint stars compared to modern galaxies like the Milky Way. This finding challenges previous assumptions that the proportion of stars of different masses remained constant throughout cosmic history. The JWST's sensitivity allowed researchers to detect these previously 'hidden stars,' which were overshadowed by more massive, brighter stars in earlier observations. This means that the total mass of these early galaxies is considerably higher than what was calculated based on their overall light spectrum, which is typically dominated by the most massive stars.

Descubren GJ 523b, una mega-Tierra que desconcierta a científicos

Descubren GJ 523b, una mega-Tierra que desconcierta a científicos

La mega-Tierra GJ 523b tiene 23 veces la masa de la Tierra, pero apenas 2.5 veces su diámetro. Su aparente falta de gas desconcierta a los científicos.

JWST Identifies Black Hole Disguised as Enormous Star in Early Universe

JWST Identifies Black Hole Disguised as Enormous Star in Early Universe

The James Webb Space Telescope (JWST) has identified a compact red source, MoM-BH*-1, in the early universe, approximately 660 million years after the Big Bang. Initially, its spectrum made it appear similar to an enormous star. However, astronomers, led by Rohan Naidu, determined that its total light output is roughly 100 billion times the Sun’s luminosity, a level unsustainable by any ordinary star. The preferred explanation is a feeding black hole surrounded by an extraordinarily dense envelope of hydrogen. The JWST's NIRSpec instrument observed a significant drop in measured flux between three and four micrometers, a feature known as the Balmer break. While stellar populations produce this break, MoM-BH*-1's break strength of 7.7 far exceeds the typical peak of 3 for a dust-free stellar population, or even 5 for an extreme population of A-type stars. This, combined with broad hydrogen emission and deep hydrogen absorption, led to the conclusion that a normal collection of stars could not explain the ob...

Record-Breaking Star S301 Offers New Insights into Milky Way's Supermassive Black Hole Spin

Record-Breaking Star S301 Offers New Insights into Milky Way's Supermassive Black Hole Spin

Astronomers have discovered a new record-breaking star, S301, which is the closest known star to the Milky Way's supermassive black hole, Sagittarius A*. Reported on August 19 in Nature, S301 reaches speeds of 25,000 kilometers per second, approximately 8% the speed of light. Its extreme proximity to Sagittarius A* makes it a unique tool for measuring the black hole's elusive characteristic: spin. Stefan Gillessen, an astronomer at the Max Planck Institute for Extraterrestrial Physics, highlighted the star's potential for understanding black hole physics. S301, about 50% larger than the sun, was first observed in 2023 by the GRAVITY+ collaboration using the European Southern Observatory’s Very Large Telescope Interferometer. By combining two subsequent years of observations with historical data dating back to 2017, astronomers mapped its 8.7-year, highly elongated orbit, which brings it within 1.7 billion kilometers of Sagittarius A*. This close orbit is crucial because the black hole's spin is expected to...

New Research Reveals Shorter, More Dynamic Afterlife for Black Hole Jets in Dying Radio Galaxies

New Research Reveals Shorter, More Dynamic Afterlife for Black Hole Jets in Dying Radio Galaxies

Recent research published in the journal Monthly Notices of the Royal Astronomical Society indicates that the afterlife of black hole jets in dying radio galaxies is shorter and more dynamic than previously understood. Scientists utilized multifrequency observations from surveys like MeerKAT MIGHTEE and uGMRT superMIGHTEE, along with data from LOFAR, GMRT, and the Jansky Very Large Array, to study 14 candidate remnant radio galaxies in the XMM–Newton Large-Scale Structure (XMM–LSS) field. These remnant galaxies represent the final stage of radio-galaxy evolution where the central active galactic nucleus (AGN) jets have ceased to replenish the radio lobes with energetic particles. The study confirmed 12 of the 14 candidates as genuine remnant radio galaxies, with two reclassified as active sources. A key finding is the relatively young age of these remnants, ranging from approximately 8 to 42 million years, with a median age of about 12 million years, suggesting a population of short-lived remnants that wer...

Fastest-known star zooms under Milky Way black hole's influence

Fastest-known star zooms under Milky Way black hole's influence

WASHINGTON, Aug 19 (Reuters) - Scientists have detected the fastest-known star, a stellar speedster that is zooming around the supermassive black hole residing at the center of our galaxy and might hold the key to measuring the spin of this celestial beast for the first time.

Telescope spies the fastest star in the Milky Way zipping around a black hole

Telescope spies the fastest star in the Milky Way zipping around a black hole

A telescope has spotted the fastest known star in the Milky Way

Hubble and James Webb Telescopes Collaborate to Capture 'Black Eye Galaxy' Image

Hubble and James Webb Telescopes Collaborate to Capture 'Black Eye Galaxy' Image

The Hubble Space Telescope and the James Webb Space Telescope (JWST) have collaborated to produce a composite image of the 'Black Eye Galaxy,' also known as Messier 64. This spiral galaxy is situated 17 million light-years from Earth in the constellation Coma Berenices. The galaxy is notable for its unique internal motion, where the gas in its outer regions rotates in the opposite direction to the gas and stars closer to its core. To create this detailed image, astronomers combined observations from JWST, which captured near and mid-infrared wavelengths, with Hubble's data from ultraviolet, visible, and near-infrared wavelengths. This joint effort showcases the complementary capabilities of these powerful space observatories.

Astronomers Detect Gravitational Lensing of Blazar Jet by Unseen Dark Matter Cluster

Astronomers Detect Gravitational Lensing of Blazar Jet by Unseen Dark Matter Cluster

Astronomers have found evidence that a plasma jet emanating from the distant blazar PKS 2233-148 has been gravitationally lensed. This phenomenon, predicted by Albert Einstein's theory of general relativity, occurs when a massive object warps space, altering the path of light. In this specific case, researchers observed a sudden deviation in the jet's expected trajectory and peculiarities in its gamma-ray curve. The blazar PKS 2233-148 is a type of quasar where supermassive black holes are surrounded by vast amounts of matter, with some material being ejected as plasma jets directed towards Earth. The team, led by Silke Britzen, reanalyzed data from the Very Long Baseline Array, the Fermi space telescope, and the Swift space observatory to track the jet's motion over time. The absence of any visible massive object, such as a galaxy or galaxy cluster, in the position to cause this lensing effect suggests that an invisible cluster of dark matter is responsible. Dark matter does not interact with electromagne...

Hubble and Gaia Telescopes Reveal Milky Way's Earliest Galactic Merger 11.8 Billion Years Ago

Hubble and Gaia Telescopes Reveal Milky Way's Earliest Galactic Merger 11.8 Billion Years Ago

Scientists, utilizing data from the Hubble and Gaia orbiting telescopes, have uncovered evidence that the Milky Way galaxy underwent its earliest known galactic merger approximately 11.8 billion years ago. This event occurred when the universe was less than 15% of its current age. The research, published in the journal Nature Astronomy, indicates that the Milky Way absorbed a smaller dwarf galaxy, which has been named Low-energy-Kraken-Heracles (LKH). At the time of the merger, the LKH dwarf galaxy contained stars with a mass equivalent to 500 million times that of the sun, making it about a quarter the size of the Milky Way. Researchers studied stellar clusters within the Milky Way's innermost 20,000 light-years, analyzing their age, chemical composition, and trajectory to reconstruct this ancient cosmic event. This discovery sheds light on the Milky Way's growth, demonstrating that it expanded not only through its own star formation but also by integrating smaller galaxies caught in its gravitational pul...

James Webb Space Telescope Reveals Distant Galaxies More Massive Than Previously Estimated

James Webb Space Telescope Reveals Distant Galaxies More Massive Than Previously Estimated

An international team of researchers, led by scientists at Leiden University, has utilized the James Webb Space Telescope (JWST) to discover that the most massive galaxies in the early universe contain a significantly higher proportion of small stars than previously assumed. This finding suggests that these distant galaxies are much more massive than initial measurements indicated, challenging existing models of galaxy formation. The team studied nine massive, mature galaxies that had ceased forming stars billions of years ago, combining deep JWST spectra with observations from the Very Large Telescope. By analyzing subtle differences in the light spectrum, they were able to reliably determine the proportions of tiny, faint stars and giant, bright stars within these galaxies for the first time. This research, published in Nature Astronomy, indicates that a large population of low-mass stars was previously concealed by the more luminous, massive stars.