host galaxy

At the center of nearly every large galaxy sits a supermassive black hole. It doesn't just devour infalling gas; it also blasts some of it back out in powerful jets. These jets act like giant pistons, shoving the surrounding gas and heating it. Astronomers have long suspected that this is how black holes keep galaxies from cooling into cold star factories.

A million orbits: the same score. Nine dark matter halos: nine orchestras without a conductor. All musicians play from the same notes, but in each hall the music sounds different: sometimes in tune, sometimes out of sync. Likewise, satellite galaxies falling into a host halo follow orbits that depend not only on mass but also on the shape of the invisible stage.

In a quiet back alley of a galaxy, where stars are rare and old, a light suddenly flares up, brighter than an entire galaxy. This is a Type Ia supernova: a thermonuclear explosion of a white dwarf that astronomers use as a standard candle to measure cosmic distances.

Two stars, AF Lep A and ε Indi A, have become the focus of close attention. Using the GHOST spectrograph on the Gemini telescope, astronomers split their light into colors and, from absorption lines, determined how much carbon, oxygen, sulfur, and thirteen other elements are in the stars' atmospheres.

A black hole with a mass of 35,000 Suns drifts through a galaxy's gas like a barge through fog. Its gravity rakes the material ahead of it, leaving a dense trail behind — a wake of gas. Some of that gas gets pulled into the black hole, and it grows.

The explosion of a massive star is not just a flash: it's a blow to the surrounding gas. But until now, no one had looked at how the gas itself moves at the sites of such explosions. Now astronomers have gathered data on 33 nearby supernovae and for the first time measured the turbulence of the cold molecular gas around them.

A star is not just a distant sun. It's a cradle for planets, and its light carries the birth story of the entire system. The chemical composition of a star is its DNA. Astronomers peer into this DNA to understand why some stars host rocky worlds like Earth, while others host gas giants.

A neutron star is the ultra-dense remnant of a supernova: the mass of the Sun packed into a sphere the size of a city. For billions of years, it travels through space, gathering around itself invisible matter, dark matter, which emits no light but pulls with gravity.

Layer by layer, artifact by artifact — an archaeologist reconstructs the history of an ancient settlement. Similarly, astrophysicists sifting through 259 records from LIGO–Virgo–KAGRA saw a clear layered structure among merging black holes.

1799 kilometers per second — that's the speed at which star S5-HVS1 is permanently leaving the galaxy. 4.8 million years ago, it was ejected from the center of the Milky Way during a close encounter with the supermassive black hole Sgr A*.

Eight hundred million years after the Big Bang, and at the heart of a young galaxy a monstrous engine is already throbbing. A black hole with a mass of ten billion suns devours matter so greedily that its radiation should outshine everything around it. But outside, silence.

Three invisible strings oscillate in the intergalactic void. This is not poetry, but a hypothesis about the nature of dark matter — an ultralight quantum field with spin 1, carrying three polarizations.

At the center of many galaxies lurks a black hole, wrapped in an invisible cloud — the halo of dark matter. This is not just a featureless mass: its density changes from the edge to the center, and the degree of this "compression" is called compactness.

The death of a massive star is not just the flash of a supernova, but also the birth of a black hole.

For decades astrophysicists painted a neat picture: a galaxy, like a giant carousel, spins in a unified rhythm, and the supermassive black hole at its center inherits that dance.

The light of a distant star briefly brightens when a massive invisible object passes between it and a telescope. This phenomenon, gravitational microlensing, acts as a natural telescope. Usually, the lens is a black hole, warping the spacetime around it.

Every fast radio burst is like a resounding strike of a bell in the void. And in its fading ring, the entire structure of space is encoded: over billions of light-years, the radio pulse is slightly delayed by every free electron it meets.

The focus is on a black hole, but not an ordinary one. It carries a magnetic monopole and is surrounded by a dilaton — a field that blurs the familiar boundaries of space. The authors tested how stable such a system is to thermal jolts. A magnetic monopole is a hypothetical particle with a single magnetic pole.

For 23 years, Hubble and James Webb have peered into the heart of Omega Centauri, a globular cluster where millions of stars crowd into a space just 150 light-years across. In this stellar beehive, the motion of the stars betrayed an invisible partner: a main-sequence star (one that has not yet left the main evolutionary branch) seemed to be tugged in a dance with an unseen weight.

The expansion of the universe, discovered by Edwin Hubble, gave us a picture of the young cosmos, but along with it — difficult questions.

In the silent theater of the cosmos, a star’s life plays out over billions of years. But sometimes an invisible director sneaks onto the stage — a primordial black hole.

A vast hall where hundreds of orchestras play at once. Amid this din, you need to pick out one specific duet — two supermassive black holes circling each other in a distant galaxy. That's how pulsar timing arrays work: they listen to the "hum" of the entire sky, created by gravitational waves from many such pairs.

The gravity of a black hole creates a curvature of spacetime, acting like a lens: light from a distant galaxy splits in two, stretching into arcs. Dark matter around the hole barely changes the picture, as if a transparent curtain was added to a window pane.

Black holes come in two types: tiny ones — the remnants of supernova explosions, and giants in the cores of galaxies. But where are the intermediate ones, with hundreds and thousands of solar masses? The answer may lie in star swarms, where black holes collide like balls on a billiard table and, merging, bulk up.

A research probe is planned for the nearest black hole — a region of spacetime whose gravity traps even light. After a hundred years of flight, the spacecraft will enter orbit around the mysterious object to answer a key question: are we looking at a black hole or a neutron star — the ultra-dense remnant of a massive star, compressed to nuclear…

When a neutron star and a black hole merge, they send out gravitational waves — ripples in spacetime that reach Earth. These ripples carry the imprint of their final dance: the orbit before the collision is often elongated, like an ellipse.

The cosmos is full of mimicry. The clearwing moth wears a wasp's mask, a harmless fly buzzes like a bee. And in the world of gravity, the role of impersonator is perhaps played by boson stars — colossal clumps of scalar field, indistinguishable from black holes.

A stellar river winds around the center of a distant galaxy like a glowing ribbon on an invisible frame. That frame is the dark halo: a vast cloud of invisible dark matter whose gravity holds stars and gas in place. If the halo is squashed like a pumpkin or stretched like a melon, the stellar stream will bend differently.

A tiny black hole zips through a gas cloud. Instead of swallowing the gas, it heats it up, like an iron left on a damp cloth. Radiation streams from the black hole, creating a hot spot — a region where the temperature is hundreds of times higher than in the surrounding space.

Recently, astronomers spotted three interstellar comets coming from deep space. One of them, 3I/ATLAS, turned out to be unexpectedly large: its nucleus is several kilometers across.

Gravitational wave detectors pick up a low-frequency hum, like the sound of a distant waterfall. The Webb telescope finds galaxies in the early universe with black holes that seem too massive for such a young age.

The Oort Cloud is a spherical swarm of trillions of icy bodies at the very edge of the Solar System, about a light-year from the Sun. These objects are almost motionless relative to one another until some gravitational disturbance breaks their calm.

At the center of the Milky Way lurks something invisible but extremely massive — about four million times heavier than the Sun. It is usually called a black hole and designated Sagittarius A*. But astronomers are not letting their guard down: what if it is not a hole but something more exotic, like a giant ball of ultralight particles — a boson star?

A baker adds more sugar to the dough, and the pie turns out different. So it is with a star: the composition of its "dough"—the cloud of gas and dust from which planets are born — determines what worlds will form around it.

Cosmologists have measured how fast distant galaxies are receding in different parts of the sky. To do this, they used two kinds of "cosmic rulers": galaxy clusters and a certain type of supernova explosion. Both methods showed the same thing: in one direction, the Universe is expanding slightly faster than in the opposite direction.

At the center of our Galaxy lurks the supermassive black hole Sagittarius A* — a heavyweight that holds stars in its grip. Astronomers dream of finding pulsars near it: these cosmic lighthouses emit radio pulses with the precision of atomic clocks.

Growing a galaxy is like a dance between two partners: at the center of nearly every large galaxy sits a supermassive black hole, and they grow together. But who leads?

The James Webb Space Telescope peered into the galaxy cluster AS1063 and spotted tens of thousands of globular clusters — dense stellar "knots" scattered throughout the cluster. Their positions matched the map of invisible mass, which is constructed from the bending of light from distant galaxies.

You can't see a black hole until a star wanders too close. Then tidal forces stretch the star like a cook rolling out dough, and some of the material falls into the hole, flaring up as a final goodbye. Such events, called tidal disruptions, are a rare chance to weigh a black hole that would otherwise remain invisible.

Deep in space, there's a cloud of gas that looks like a necklace with bright beads. This is the Necklace Nebula — the remains of a star that once swelled up and swallowed its neighbor. At the center, a pair remains: a small, hot star and its bloated companion, rich in carbon.