Since the 1970s, astronomers have observed that supermassive black holes (SMBHs) reside at the centers of most massive galaxies. In some cases, these black holes accelerate gas and dust from their poles, forming relativistic jets that can extend for thousands of light-years. Using the NASA/ESA Hubble Space Telescope, a team of astronomers observed the jet emanating from the center of M87, the supermassive galaxy located 53.5 million light-years away. To their surprise, the team observed nova erupting along the jet’s trajectory, twice as many as they observed in M87 itself.
Continue reading “Jets From Supermassive Black Holes Create New Stars Along Their Trajectory”Scientists Develop a Novel Method for Detecting Supermassive Black Holes: Use Smaller Black Holes!
In 1974, astronomers Bruce Balick and Robert L. Brown discovered a powerful radio source at the center of the Milky Way galaxy. The source, Sagittarius A*, was subsequently revealed to be a supermassive black hole (SMBH) with a mass of over 4 million Suns. Since then, astronomers have determined that SMBHs reside at the center of all galaxies with highly active central regions known as active galactic nuclei (AGNs) or “quasars.” Despite all we’ve learned, the origin of these massive black holes remains one of the biggest mysteries in astronomy.
The most popular theories are that they may have formed when the Universe was still very young or have grown over time by consuming the matter around them (accretion) and through mergers with other black holes. In recent years, research has shown that when mergers between such massive objects occur, Gravitational Waves (GWs) are released. In a recent study, an international team of astrophysicists proposed a novel method for detecting pairs of SMBHs: analyzing gravitational waves generated by binaries of nearby small stellar black holes.
Continue reading “Scientists Develop a Novel Method for Detecting Supermassive Black Holes: Use Smaller Black Holes!”The JWST Reveals the Nature of Dust Around an Active Galactic Nuclei
Supermassive Black Holes (SMBHs) are located in the centers of large galaxies like ours. When they’re actively feeding, they produce more light and are called active galactic nuclei (AGN). But their details are difficult to observe clearly because large clouds of gas block our view.
The JWST was built just for circumstances like these.
Continue reading “The JWST Reveals the Nature of Dust Around an Active Galactic Nuclei”Little Red Dots in Webb Photos Turned Out to Be Quasars
In its first year of operation, the James Webb Space Telescope (JWST) made some profound discoveries. These included providing the sharpest views of iconic cosmic structures (like the Pillars of Creation), transmission spectra from exoplanet atmospheres, and breathtaking views of Jupiter, its largest moons, Saturn’s rings, its largest moon Titan, and Enceladus’ plumes. But Webb also made an unexpected find during its first year of observation that may prove to be a breakthrough: a series of little red dots in a tiny region of the night sky.
These little red dots were observed as part of Webb’s Emission-line galaxies and Intergalactic Gas in the Epoch of Reionization (EIGER) and the First Reionization Epoch Spectroscopically Complete Observations (FRESCO) surveys. According to a new analysis by an international team of astrophysicists, these dots are galactic nuclei containing the precursors of Supermassive Black Holes (SMBHs) that existed during the early Universe. The existence of these black holes shortly after the Big Bang could change our understanding of how the first SMBHs in our Universe formed.
Continue reading “Little Red Dots in Webb Photos Turned Out to Be Quasars”The Brightest Object Ever Seen in the Universe
It’s an exciting time in astronomy today, where records are being broken and reset regularly. We are barely two months into 2024, and already new records have been set for the farthest black hole yet observed, the brightest supernova, and the highest-energy gamma rays from our Sun. Most recently, an international team of astronomers using the ESO’s Very Large Telescope in Chile reportedly saw the brightest object ever observed in the Universe: a quasar (J0529-4351) located about 12 billion light years away that has the fastest-growing supermassive black hole (SMBH) at its center.
Continue reading “The Brightest Object Ever Seen in the Universe”Astronomers are Getting Really Good at Weighing Baby Supermassive Black Holes
In the 1970s, astronomers deduced that the persistent radio source coming from the center of our galaxy was actually a supermassive black hole (SMBH). This black hole, known today as Sagittarius A*, is over 4 million solar masses and is detectable by the radiation it emits in multiple wavelengths. Since then, astronomers have found that SMBHs reside at the center of most massive galaxies, some of which are far more massive than our own! Over time, astronomers observed relationships between the properties of galaxies and the mass of their SMBHs, suggesting that the two co-evolve.
Using the GRAVITY+ instrument at the Very Large Telescope Interferometer (VLTI), a team from the Max Planck Institute for Extraterrestrial Physics (MPE) recently measured the mass of an SMBH in SDSS J092034.17+065718.0. At a distance of about 11 billion light-years from our Solar System, this galaxy existed when the Universe was just two billion years old. To their surprise, they found that the SMBH weighs in at a modest 320 million solar masses, which is significantly under-massive compared to the mass of its host galaxy. These findings could revolutionize our understanding of the relationship between galaxies and the black holes residing at their centers.
Continue reading “Astronomers are Getting Really Good at Weighing Baby Supermassive Black Holes”Sometimes Compact Galaxies Hide Their Black Holes
Quasars, short for quasi-stellar objects, are one of the most powerful and luminous classes of objects in our Universe. A subclass of active galactic nuclei (AGNs), quasars are extremely bright galactic cores that temporarily outshine all the stars in their disks. This is due to the supermassive black holes in the galactic cores that consume material from their accretion disks, a donut-shaped ring of gas and dust that orbit them. This matter is accelerated to close to the speed of light and slowly consumed, releasing energy across the entire electromagnetic spectrum.
Based on past observations, it is well known to astronomers that quasars are obscured by the accretion disk that surrounds them. As powerful radiation is released from the SMBH, it causes the dust and gas to glow brightly in visible light, X-rays, gamma-rays, and other wavelengths. However, according to a new study led by researchers from the Centre for Extragalactic Astronomy (CEA) at Durham University, quasars can also be obscured by the gas and dust of their entire host galaxies. Their findings could help astronomers better understand the link between SMBHs and galactic evolution.
Continue reading “Sometimes Compact Galaxies Hide Their Black Holes”New Stars Forming Uncomfortably Close to the Milky Way’s Supermassive Black Hole
Astronomers examining a star cluster near Sgr A*, the Milky Way’s supermassive black hole, found that the cluster has some unusually young members for its location. That’s difficult to explain since the region so close to the powerful black hole is infused with powerful radiation and dominated by the black hole’s extremely powerful gravitational force. According to our understanding of stellar formation, young stars shouldn’t be there.
Continue reading “New Stars Forming Uncomfortably Close to the Milky Way’s Supermassive Black Hole”A Black Hole Switched On in the Blink of an Eye
In 2019, a team of astronomers led by Dr. Samantha Oates of the University of Birmingham discovered one of the most powerful transients ever seen – where astronomical objects change their brightness over a short period. Oates and her colleagues found this object, known as J221951-484240 (or J221951), using the Ultra-Violet and Optical Telescope (UVOT) on NASA’s Neil Gehrels Swift Observatory while searching for the source of a gravitational wave (GW) that was thought to be caused by two massive objects merging in our galaxy.
Multiple follow-up observations were made using the UVOT and Swift’s other instruments – the Burst Alert Telescope (BAT) and X-Ray Telescope (XRT), the Hubble Space Telescope, the South African Large Telescope (SALT), the Wide-field Infrared Survey Explorer (WISE), the ESO’s Very Large Telescope (VLT), the Australia Telescope Compact Array (ATCA), and more. The combined observations and spectra revealed that the source was a supermassive black hole (SMBH) in a distant galaxy that mysteriously “switched on,” becoming one of the most dramatic bursts of brightness ever seen with a black hole.
Continue reading “A Black Hole Switched On in the Blink of an Eye”Pulsars Could Help Map the Black Hole at the Center of the Milky Way
The Theory of General Relativity (GR), proposed by Einstein over a century ago, remains one of the most well-known scientific postulates of all time. This theory, which explains how spacetime curvature is altered in the presence of massive objects, remains the cornerstone of our most widely-accepted cosmological models. This should come as no surprise since GR has been verified nine ways from Sunday and under the most extreme conditions imaginable. In particular, scientists have mounted several observation campaigns to test GR using Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way.
Last year, the Event Horizon Telescope (EHT) – an international consortium of astronomers and observatories – announced they had taken the first images of Sag A*, which came just two years after the release of the first-ever images of an SMBH (M87). In 2014, the European members of the EHT launched another initiative known as BlackHoleCam to gain a better understanding of SMBHs using a combination of radio imaging, pulsar observations, astrometry, and GR. In a recent paper, the BHC initiative described how they tested GR by observing pulsars orbiting Sgr A*.
Continue reading “Pulsars Could Help Map the Black Hole at the Center of the Milky Way”