ultraluminous x ray source

In a dense cloud of gas and dust where massive stars are born, two young stars recently passed very close to each other. Their dance has lasted only about sixty years, and astronomers have now seen it in detail for the first time.

A little monster hides in a dwarf galaxy, and its neighbor feeds it. The satellite galaxy is slowly merging with a massive companion, and gas from the outer regions falls toward the center, where a black hole sits. By cosmic standards, it is not large: only 800 to 5000 solar masses, but its appetite is ferocious.

The night forest is full of fireflies, but before, we only saw those that happened to be in the beam of a flashlight. That was the case with ultraluminous X-ray sources: points in other galaxies that shine in X-rays more brightly than a stellar-mass black hole can steadily emit. Telescopes looked at galaxies chosen for other purposes, missing most of the fireflies.

The night forest is full of fireflies, but before, we only saw those that happened to be in the beam of a flashlight. That was the case with ultraluminous X-ray sources: points in other galaxies that shine in X-rays more brightly than a stellar-mass black hole can steadily emit. Telescopes looked at galaxies chosen for other purposes, missing most of the fireflies.

A synchrotron beam is like a jet of water from a hose: wide and awkward for fine work. To examine a tiny sample, you need a fine needle, not a hose. In the new setup, the needle is a glass capillary — a tube through which light glides, reflecting off the walls like a voice echoing down a long corridor.

A black hole is like a spinning top that never stops on its own. But if a cloud of ultra-light particles, bosons, forms around it, the picture changes. This "fog" acts like an invisible brake: the particles drain the hole's spin, slowing it down.

The Andromeda galaxy is our nearest large neighbor, and like the Milky Way, it has an invisible gaseous shroud. This shroud of extremely hot, rarefied gas extends for hundreds of thousands of light-years. Seeing it directly is nearly impossible — the gas is too faint.

A spinning top whirls so fast that the air around it starts to rotate in unison. A black hole behaves in much the same way: if it spins, it can transfer its energy to particles that happen to be nearby. This process is called superradiance: it's like an echo in the mountains, but instead of sound, new particles are born.

The cosmic detective story began with a quiet flash in the optical band. AT2019wzc slowly brightened and faded like a smoldering ember. But hidden inside was something more energetic — repeating soft X-ray bursts that astronomers call quasi-periodic eruptions. These eruptions last minutes to hours and repeat every few hours or days.

In the distant Cigar Galaxy, there is an unusual beacon. It doesn't shine in the usual sense: its rays are born in a scorching cloud around a black hole that is devouring matter from a companion star. Such objects are called ultraluminous X-ray sources. Their X-ray brilliance is so intense that it outshines entire galaxies. This cloud, the corona, is like a boiling cauldron.

In the dark outskirts of our Galaxy, far from bright star clusters, millions of black holes lurk. They are invisible: they don't shine and don't noticeably accrete matter. Conventional search methods, designed for dense stellar fields, are useless here. A different approach is needed. Astronomers have proposed using the very fabric of space as a detector.

A whirlpool gulps down water, but splashes most of it back out. That's roughly how a black hole behaves when too much matter falls onto it. In a new study, astrophysicists ran 32 computer simulations to understand how a black hole's parameters — mass, spin, and "appetite"—control these cosmic fountains.

At the centers of many galaxies lurk giant black holes. They are surrounded by dense clouds of hot plasma that emit a powerful X-ray glow.

A star wrapped in an invisible blanket warms up more than it should. That's exactly how ten red dwarfs look, which astronomers from the Hephaistos project have been monitoring. These stars lie within 300 parsecs (about 1000 light-years) of us and emit far more infrared energy than their modest sizes can explain.

In a distant galaxy about 290 million light-years away, the object HLX-1 lies hidden. It once flared brighter than hundreds of billions of suns, but now it has quieted down. From 2018 to 2022, the Hubble, Chandra, and Swift space telescopes tracked its fading.

Ten billion years ago, the universe was speckled with strange crimson sparks. The JWST spotted them in images at distant redshifts — compact sources blazing like entire galaxies yet no larger than a tiny central region. Astronomers nicknamed them “little red dots.” Their nature long defied explanation.

A spotlight blazes straight into your eyes, and a few steps away a tiny firefly flickers. That's roughly what it's like hunting for an Earth-like planet around a neighboring star: the planet is a hundred million to ten billion times fainter than its star, and in the sky they almost merge into a single point.

Within a field of view the size of a grain of sand held up to the eye, hundreds of galaxies lie hidden, smeared into arcs by the massive cluster Abell S1063.

In the centers of distant galaxies, X-ray 'beacons' sometimes light up. They don't flash randomly but on a strict schedule: every few hours or days. These bursts are called quasi-periodic eruptions (repeating at nearly regular intervals).

The giant galaxy cluster Abell S1063, lying 4 billion light-years away, works not just as a lens but as a gravitational well of time. Its mass bends space so sharply that photons from an era when the Universe was just 500 million years old slide along curved paths, like rays in slow motion, and converge on us magnified forty-three times.

Imagine a spotlight: if you look at it from the side, it glows dim red, but if you stare straight into it, it blinds you with white-blue light. That, according to new data, is exactly what the mysterious 'little red dots' in the early universe look like. They are giant black holes, objects with gravity so strong that even light cannot escape, turned edge-on to us.

A powerful spotlight flickers on and off. Light reflects off surrounding clouds, and by measuring the delay of the reflected signal, you can figure out how far away the clouds are. That's roughly how astronomers study the hot corona — a scorching cloud of plasma above the black hole at the center of an active galaxy. But there's a catch.

A giant baby planet is still pulling in leftover building material from its surrounding cloud. That's the scene the Hubble Space Telescope captured when it aimed its cameras at an object catalogued as SR 12 c. This companion planet orbits a young star at a wide distance — farther out than Neptune is from the Sun.

In galaxy NGC 3583, telescopes detected an unusual X-ray source: its brightness periodically spikes and then fades almost completely.

The story began with a puzzle: in the 1930s, Fritz Zwicky noticed that clusters of galaxies behave as if an enormous invisible mass is hidden within them. Half a century later, Vera Rubin confirmed that stars on the outskirts of galaxies rotate too fast to be held by visible matter alone.

In 1963, Maarten Schmidt unraveled the nature of quasars — distant active nuclei outshining entire galaxies. Since then, we've learned that at their hearts lurk supermassive black holes, converting infalling matter into blinding light.

Dark matter is an invisible substance that reveals itself only through gravitational effects: it bends the light of distant galaxies, much like an unseen window that alters the path of light rays.

The James Webb Space Telescope peered into the era when the expansion of the Universe stretched the light of distant objects into the red, and found a scattering of strange sources — 'little red dots'. Their spectra broke the usual patterns: they are blue in the ultraviolet, but deep red in the optical, as if seen through a cherry veil.

Nearly 12 billion years ago, when the Universe was experiencing the turbulent 'cosmic noon'—the era of record-breaking star formation — at the heart of one galaxy, the quasar WISSH13 was flaring up.

The Universe is pervaded by an invisible substance — ultralight dark matter, which doesn't collide with ordinary matter but can tremble like a taut string. Its oscillations alter the world's most fundamental properties: the electron charge, the speed of light — as if the tuning of a single cosmic note slightly drifts.

When the James Webb Space Telescope turned its gaze deep into time, astronomers expected to see familiar galaxies. Instead, the images were dotted with a scattering of bright, incredibly compact red dots.

The James Webb Space Telescope has spotted astonishing objects in the depths of space — tiny red dots that shine so brightly it's as if a spotlight were hidden inside a small bulb. These dots are not stars or galaxies in the usual sense, but rather 'cocoons' around supermassive black holes greedily gulping down surrounding gas.

The city has long been asleep: not a single lit window, not a single new house. Only in the very center, in one lone building, someone forgot to turn off a spotlight. That's what a galaxy looks like when stars are no longer born, yet its central black hole still shines.

A neutron star is a city the size of Manhattan, compressed to such a density that a teaspoon of its material weighs as much as Mount Everest. To understand what it's made of inside, scientists measure its radius. But there's a catch: many measurements suffer from systematic errors, like trying to measure the height of someone who keeps fidgeting and bending over.

Water plunges into an abyss, but part of it shoots back up — churning and foaming at the very edge. That's roughly how gas behaves as it flows onto a supermassive black hole when its stream becomes too dense. In a new study, scientists traced this picture using computer simulations.

The beacon flares up and then nearly goes out, even though the lamp inside burns steadily. That is exactly what astronomers saw when they pointed their telescopes at the galaxy I Zwicky 1. At its center sits a supermassive black hole that devours gas and dust so greedily that a scorching disk forms around it, shining brighter than an entire galaxy.

A powerful vacuum cleaner sucks in not only dust but also its own collection bag. That's roughly how a black hole behaves at the center of a 'red dot'—a distant galaxy where the glow comes not from the hole itself but from its dense gas shroud. This shroud is so thick it resembles a puffed-up cool star. And, like many stars, it has a magnetic field.

Dark matter has eluded direct observation so far, even though its gravity holds galaxies together. One hypothesis: it’s made of axions — ultra-light particles predicted by theory.

A dim lightbulb suddenly starts illuminating patterns on the wall that were invisible to the eye. That's roughly how astronomers look at distant dwarf galaxies — tiny stellar islands poor in heavy elements. In some of them, a faint violet glow of ionized helium has been spotted (a specific spectral line He II 4686 Å).

A swing swings higher and higher if you push it in rhythm. A similar mechanism kicks in when a dead star orbits a massive black hole shrouded in a cloud of ultralight particles. These particles are candidates for dark matter — the invisible substance that keeps galaxies from flying apart.