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The results suggest a deeper investigation of Sgr A* may uncover hitherto undiscovered features.

The polarization of light and neat and strong magnetic fields of Sgr A*, and the fact that they closely resemble that of M87*, may indicate that our central black hole has been hiding a secret from us until now.

“We expect strong and ordered magnetic fields to be directly linked to the launching of jets as we observed for M87*,” Issaoun explained. “Since Sgr A*, with no observed jet, seems to have a very similar geometry, perhaps there is also a jet lurking in Sgr A* waiting to be observed, which would be super exciting!”

At the heart of a far-off galaxy, a supermassive black hole appears to have had a case of the hiccups. Astronomers from MIT, Italy, the Czech Republic, and elsewhere have found that a previously quiet black hole, which sits at the center of a galaxy about 800 million light years away, has suddenly erupted, giving off plumes of gas every 8.5 days before settling back to its normal, quiet state.

“Along with Sgr A* having a strikingly similar polarization structure to that seen in the much larger and more powerful M87* black hole, we’ve learned that strong and ordered magnetic fields are critical to how black holes interact with the gas and matter around them,” said Dr. Sara Issaoun.

A recent study published in The Astrophysical Journal Letters discusses the most recent image of the supermassive black hole, Sagittarius A* (Sgr A•, which is located approximately 27,000 light-years from Earth at the center of the Milky Way Galaxy. These new images that were obtained by Event Horizon Telescope (EHT) Collaboration are the first to identify the magnetic field lines of Sgr A* and comes after EHT first obtained images of Sgr A* in 2022. This study, which consists of more than 150 co-authors, holds the potential to help astronomers better understand the compositions of supermassive black holes throughout the universe.

For the study, the collaborative team of researchers used EHT to measure polarized light emitted by Sgr A*, which not only revealed the magnetic field lines for the first time, but also gained valuable insight into the properties and behavior of the magnetic field, as well. This study comes after astronomers previously identified the supergiant elliptical galaxy, M87*, was emitting powerful jets at nearly the speed of light after astronomers had discovered it also had large magnetic field lines. Therefore, researchers hope this recent study could produce the same long-term result.

Continue reading “Insights into Black Hole Feeding: Polarized Light Studies of Sgr A*” »

A new investigation into an obscure class of galaxies known as Compact Symmetric Objects, or CSOs, has revealed that these objects are not entirely what they seem. CSOs are active galaxies that host supermassive black holes at their cores. Out of these monstrous black holes spring two jets traveling in opposite directions at nearly the speed of light. But in comparison to other galaxies that boast fierce jets, these jets do not extend out to great distances—they are much more compact.

For many decades, astronomers suspected that CSOs were simply young and that their jets would eventually travel out to greater distances. Now, reporting in three different papers in The Astrophysical Journal, a Caltech-led team of researchers has concluded that CSOs are not young but rather lead relatively short lives.

Continue reading “Sleeping supermassive black holes awakened briefly by shredded stars” »

Astronomer Fred Hoyle supposedly coined the catchy term to ridicule the theory of the Universe’s origins — 75 years on, it’s time to set the record straight.

A UCL-led research team has used artificial intelligence (AI) techniques to infer the influence and properties of dark energy more precisely from a map of dark and visible matter in the universe covering the last 7 billion years.

The study, submitted to the Monthly Notices of the Royal Astronomical Society and available on the arXiv preprint server, was carried out by the Dark Energy Survey collaboration. The researchers doubled the precision at which key characteristics of the universe, including the overall density of dark energy, could be inferred from the map.

This increased precision allows researchers to rule out models of the universe that might previously have been conceivable.

An international piece of research, led by the Instituto de Astrofísica de Canarias (IAC) has found clues to the nature of some of the brightest and hottest stars in our universe, called blue supergiants. Although these stars are commonly observed, their origin has been an old puzzle that has been debated for several decades.

In the 1920s, Edwin Hubble and Georges Lemaitre made a startling discovery that forever changed our perception of the Universe. Upon observing galaxies beyond the Milky Way and measuring their spectra, they determined that the Universe was expanding. By the 1990s, with the help of the Hubble Space Telescope, scientists took the deepest images of the Universe to date and made another startling discovery: the rate of expansion is speeding up! This parameter, denoted by Lambda, is integral to the accepted model of cosmology, known as the Lambda Cold Dark Matter (LCDM) model.

Since then, attempts to measure distances have produced a discrepancy known as the “Hubble Tension.” While it was hoped that the James Webb Space Telescope (JWST) would resolve this “crisis in cosmology,” its observations have only deepened the mystery. This has led to several proposed resolutions, including the idea that there was an “Early Dark Energy” shortly after the Big Bang. In a recent paper, an international team of astrophysicists proposed a new solution based on an alternate theory of gravity that states that our galaxy is in the center of an “under-density.”

Continue reading “If Our Part of the Universe is Less Dense, Would That Explain the Hubble Tension?” »

Neutron star mergers are a treasure trove for new physics signals, with implications for determining the true nature of dark matter, according to research from Washington University in St. Louis.

On Aug. 17, 2017, the Laser Interferometer Gravitational-wave Observatory (LIGO), in the United States, and Virgo, a detector in Italy, detected gravitational waves from the collision of two neutron stars. For the first time, this astronomical event was not only heard in gravitational waves but also seen in light by dozens of telescopes on the ground and in space.

Physicist Bhupal Dev in Arts & Sciences used observations from this neutron star merger — an event identified in astronomical circles as GW170817 — to derive new constraints on axion-like particles. These hypothetical particles have not been directly observed, but they appear in many extensions of the standard model of physics.