Black Holes Archives

July 20, 2022July 20, 2022 by Carolyn Collins Petersen

A Dormant Black Hole has Been Discovered Just Outside the Milky Way

What happens when a massive star dies? Conventional wisdom (and observational evidence) say that it can collapse to form a “stellar-mass” black hole. Astronomers detect black holes by the X-ray emissions they emit.

But, what if the black hole isn’t giving off high levels of X-ray emissions? Then, it could be a very rare object indeed: a dormant black hole. Not many of these have been seen. So, it’s exciting to know that a team of astronomers has found one. It’s called VFTS 243. They detected it in Very Large Telescope observations of stars in the Tarantula Nebula, in the neighboring Large Magellanic Cloud.

July 20, 2022July 20, 2022 by Carolyn Collins Petersen

We Finally Know Where the Highest Energy Cosmic Rays are Coming From: Blazars

Way out there in space is a class of objects called blazars. Think of them as extreme particle accelerators, able to marshall energies a million times stronger than the Large Hadron Collider in Switzerland. It turns out they’re the culprits in one of the great astrophysical mysteries: what creates and propels neutrinos across the universe at blazingly fast speeds? It turns out that the answer’s been there all along: blazars pump out neutrinos and cosmic rays. That’s the conclusion a group of astronomers led by Dr. Sara Buson of Universität Wurzburg in Germany came to as they studied data from a very unique facility here on Earth: the IceCube Neutrino Observatory in Antarctica.

July 14, 2022July 14, 2022 by Carolyn Collins Petersen

A Star Came too Close to a Black Hole and was Torn Apart. Surprisingly Little Actually Went In

Close-up of star near a supermassive black hole (artist’s impression). Credit: ESA/Hubble, ESO, M. Kornmesser

What happens when a star wanders too close to a supermassive black hole? The obvious story is that it gets sucked in, never to be seen again. Some of its material gets superheated on the way in and that gives off huge amounts of radiation—usually X-rays. That’s not a wrong explanation, just incomplete. There’s more to the story, thanks to a team of astronomers at the University of California at Berkeley. They used a specialized spectrograph at Lick Observatory to study a tidal disruption event. That’s where a star encountered a black hole. What they found was surprising.

July 6, 2022July 6, 2022 by Carolyn Collins Petersen

One Star Flies Past the Milky Way’s Black Hole at 3% the Speed of Light

Orbits of stars near Sagittarius A*. Credit: ESO/M. Parsa/L. Calçada

There’s a population of stars in the heart of our galaxy whipping around Sagittarius A* (the Milky Way’s central supermassive black hole). Astronomers just found the closest, fastest one (so far). It’s called S4716 and it orbits Sag A* once every four years. That makes it officially the fastest star moving at the heart of our galaxy. To give you some perspective, the Sun moves around the center of the galaxy at a much more leisurely pace once every 230 million years.

June 30, 2022July 11, 2022 by Carolyn Collins Petersen

Most Black Holes Spin Rapidly. This one… Doesn’t

This is the first image of Sgr A*, the supermassive black hole at the center of our galaxy. A reanalysis of EHT data by NAOJ scientist suggests its accretion disk may be more elongated than shown in this image. Image Credit: EHT

A Chandra X-ray Observatory view of the supermassive black hole at the heart of quasar H1821+643. Courtesy NASA/CXC/Univ. of Cambridge/J. Sisk-Reynés et al.

Black holes. They used to be theoretical, up until the first one was found and confirmed back in the late 20th Century. Now, astronomers find them all over the place. We even have direct radio images of two black holes: one in M87 and Sagittarius A* in the center of our galaxy. So, what do we know about them? A lot. But, there’s more to find out. A team of astronomers using Chandra X-ray Observatory data has made a startling discovery about a central supermassive black hole in a quasar embedded in a distant galaxy cluster. What they found provides clues to the origin and evolution of supermassive black holes.

June 27, 2022June 27, 2022 by Andy Tomaswick

Gaia Could Detect Free-Floating Black Holes Passing Near Stars in the Milky Way

The thing with black holes is they’re hard to see. Typically we can only detect their presence when we can detect their gravitational pull. And if there are rogue black holes simply traveling throughout the galaxy and not tied to another luminous astronomical, it would be fiendishly hard to detect them. But now we have a new potential data set to do so.

Gaia just released its massive 3rd data set that contains astrometry data for over 1.5 billion stars, about 1% of the total number of stars in the galaxy. According to a new paper by Jeff Andrews of the University of Florida and Northwestern University, it might be possible for Gaia to detect perturbances caused by a rogue black hole briefly interacting with one of the 1.5 billion stars in the catalog. Unfortunately, it’s just not very likely that any such interaction actually took place during Gaia’s observing time.

June 27, 2022June 27, 2022 by Matt Williams

We Could Discover new Kinds of Particles Around Black Holes Through Gravitational Waves

The Laser Interferometer Space Antenna (LISA) consists of three spacecraft orbiting the sun in a triangular configuration. The LISA mission will study the mergers of supermassive black holes, test Einstein's theory of general relativity, probe the early Universe, and search for gravitational waves. As these passing waves ripple space and time, they will alter the lasers shining between the spacecraft, offering a different perspective on the Universe. LISA is scheduled for launch in 2015. Credit: NASA

On February 11th, 2016, researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) announced the detection of gravitational waves (GW) for the first time. As predicted by Einstein’s General Theory of Relativity, these waves result from massive objects merging, which causes ripples through spacetime that can be detected. Since then, astrophysicists have theorized countless ways that GWs could be used to study physics beyond the standard models of gravity and particle physics and advance our understanding of the Universe.

To date, GWs have been proposed as a means of studying Dark Matter, the interiors of neutron stars and supernovae, mergers between supermassive black holes, and more. In a recent study, a team of physicists from the University of Amsterdam and Harvard University has proposed a way where GWs could be used to search for ultralight bosons around rotating black holes. This method could not only offer a new way to discern the properties of binary black holes but could lead to the discovery of new particles beyond the Standard Model.

June 11, 2022June 11, 2022 by Nancy Atkinson

Hubble Pins Down the Mass of a Potential Free-Floating Black Hole That’s 5,000 Light-Years Away

This is an artist’s impression of a black hole drifting through our Milky Way galaxy. The black hole is the crushed remnant of a massive star that exploded as a supernova. The surviving core is several times the mass of our Sun. The black hole traps light because of its intense gravitational field. The black hole distorts the space around it, which warps images of background stars lined up almost directly behind it. This gravitational "lensing" effect offers the only telltale evidence for the existence of lone black holes wandering our galaxy, of which there may be a population of 100 million. The Hubble Space Telescope goes hunting for these black holes by looking for distortion in starlight as the black holes drift in front of background stars. Credit: ESA

Earlier this year, astronomers used microlensing and the Hubble Space Telescope to detect, for the first time, a rogue black hole that is about 5,000 lightyears away from Earth. Now, with more precise measurements, they have been able to determine an approximate mass of this hard-to-detect object. However, the surprisingly low mass means there’s a chance this object may not actually be a black hole.

May 27, 2022February 17, 2023 by Matt Williams

A new Quantum Technique Could Enable Telescopes the Size of Planet Earth

These annotated images, obtained with the GRAVITY instrument on ESO’s Very Large Telescope Interferometer (VLTI) between March and July 2021, show stars orbiting very close to Sgr A*, the supermassive black hole at the heart of the Milky Way. One of these stars, named S29, was observed as it was making its closest approach to the black hole at 13 billion kilometres, just 90 times the distance between the Sun and Earth. Another star, named S300, was detected for the first time in the new VLTI observations. To obtain the new images, the astronomers used a machine-learning technique, called Information Field Theory. They made a model of how the real sources may look, simulated how GRAVITY would see them, and compared this simulation with GRAVITY observations. This allowed them to find and track stars around Sagittarius A* with unparalleled depth and accuracy.

There’s a revolution underway in astronomy. In fact, you might say there are several. In the past ten years, exoplanet studies have advanced considerably, gravitational wave astronomy has emerged as a new field, and the first images of supermassive black holes (SMBHs) have been captured. A related field, interferometry, has also advanced incredibly thanks to highly-sensitive instruments and the ability to share and combine data from observatories worldwide. In particular, the science of very-long baseline interferometry (VLBI) is opening entirely new realms of possibility.

According to a recent study by researchers from Australia and Singapore, a new quantum technique could enhance optical VLBI. It’s known as Stimulated Raman Adiabatic Passage (STIRAP), which – in combination with pre-distributed entanglement – allows quantum information to be transferred without losses. When imprinted into a quantum error correction code, this technique could allow for VLBI observations into previously inaccessible wavelengths. Once integrated with next-generation instruments, this technique could allow for more detailed studies of black holes, exoplanets, the Solar System, and the surfaces of distant stars.

May 26, 2022May 26, 2022 by Carolyn Collins Petersen

The Building Blocks for Supermassive Black Holes are Found in Dwarf Galaxies

The newly discovered massive black holes reside in dwarf galaxies, where their radiation competes with the light of abundant young stars. (Original image by NASA & ESA/Hubble, artistic conception of black hole with jet by M. Polimera.)

We all know that a humongous black hole exists at the center of our galaxy. It’s called Sagittarius A* (Sgr A* for short) and it has the mass of 4 million suns. We’ve got to see a radio image of it a few weeks back, showing its accretion disk. So, we know it’s there. Astronomers can chart its actions as it gobbles up matter occasionally and they can see how it affects nearby stars. What astronomers are still trying to understand is how Sgr A* formed.