The Sacale of the Universe

Sideline quasars helped to stifle early galaxy formation

University of Colorado Boulder astronomers targeting one of the brightest quasars glowing in the universe some 11 billion years ago say "sideline quasars" likely teamed up with it to heat abundant helium gas billions of years ago, preventing small galaxy formation.

CU-Boulder Professor Michael Shull and Research Associate David Syphers used the Hubble Space Telescope to look at the quasar -- the brilliant core of an active galaxy that acted as a "lighthouse" for the observations -- to better understand the conditions of the early universe. The scientists studied gaseous material between the telescope and the quasar with a $70 million ultraviolet spectrograph on Hubble designed by a team from CU-Boulder's Center for Astrophysics and Space Astronomy.

Ancient, highly active galaxies discovered

Pasadena, CA — Using information gathered from several telescopes, a team of astronomers, including Carnegie’s Eric Murphy, searched the sky for very rarely seen dusty starburst galaxies, formed soon after the Big Bang. These galaxies are characterized by an unusually high rate of star formation. They are much more abundant in the early Universe than previously thought. Two of those identified are among the oldest ever found, indicating that these dusty starbursts likely evolve into the most massive galaxies ever observed in the local Universe. The results are published online March 13 by Nature.

Surprising 'Mini' Supermassive Black Hole Found in Unlikely Home

Using NASA's Chandra X-Ray space telescope, astronomers have discovered one of the smallest supermassive black holes in middle of an unlikely host galaxy.

The little monster was spotted in NGC 4178, a spiral galaxy about 55 million light-years from Earth that is quite flat and lacks a concentration or bulge of stars at its center.

Theoretical models had predicted that bulges are necessary for supermassive black holes to form and grow. But the new observations from NGC 4178 and four other bulgeless galaxies where black holes have previously been found challenge these assumptions and suggest more than one mechanism is at work in forming supermassive black holes. Researchers have speculated that these behemoths could feed on the disks of galaxies or the haloes of mysterious dark matter that surround galaxies instead of a cluster of stars at the center.

Spectacol galactic în centrul Căii Lactee

Pregătiţi-vă de o experienţă "gastronomică" fascinantă în centrul galaxiei noastre. Evenimentul are în prim-plan o gaură neagră care ar putea devora cea mai mare parte a unui nor de praf şi gaz cunoscut drept G2, ce se apropie de aceasta.

O simulare pe un supercomputer pregătită de doi fizicieni de la Lawrence Livermore National Laboratory şi un fost coleg sugerează că o parte din G2 va supravieţui, deşi masa care va scăpa gravitaţiei găurii negre va fi de-a dreptul sfâşiată, lăsând norul de praf şi gaz sub o formă diferită şi cu o soartă pusă sub semnul întrebării.

Monster Galaxy May Have Been Stirred Up By Black-hole Mischief

Astronomers using NASA's Hubble Space Telescope have obtained a remarkable new view of a whopper of an elliptical galaxy that may have been puffed up by the actions of one or more black holes in its core.

Spanning a little more than one million light-years, the galaxy is about 10 times the diameter of our Milky Way galaxy. The bloated galaxy is a member of an unusual class of galaxies with a diffuse core filled with a fog of starlight where there would normally be a concentrated peak of light around a central black hole. Viewing the core is like seeing a city with no downtown, just houses sprinkled across a vast landscape.

Quasar May Be Embedded in Unusually Dusty Galaxy

Hubble astronomers have looked at one of the most distant and brightest quasars in the universe and are surprised by what they did not see: the underlying host galaxy of stars feeding the quasar. The best explanation is that the galaxy is shrouded in so much dust that the stars are completely hidden everywhere. Astronomers believe that the James Webb Space Telescope will reveal the galaxy.

All but the very first galaxies contain some dust-the early universe was dust-free until the first generation of stars started making dust through nuclear fusion. As these stars aged and burned out, they filled interstellar space with this dust as they lost their atmospheres.

Astronomers report dark matter 'halos' may contain stars, disprove other theories

Could it be that dark matter "halos" — the huge, invisible cocoons of mass that envelop entire galaxies and account for most of the matter in the universe — aren't completely dark after all but contain a small number of stars? Astronomers from UCLA, UC Irvine and elsewhere make a case for that in the Oct. 25 issue of the journal Nature.

Astronomers have long disagreed about why they see more light in the universe than it seems they should — that is, why the infrared light they observe exceeds the amount of light emitted from known galaxies.

Satellites watch stellar death throes

Astronomers think they have seen the flare of a dying star being eviscerated by a black hole. The signal, spotted by three different satellites, could shed light on the relationship between the smaller black holes seen in our own galaxy and the supermassive ones in distant reaches of the Universe.

The stellar victim was first seen1 in 2011 by Swift, a NASA satellite designed to spot bursts of high-energy photons known as γ-rays. For more than a month, Swift watched a signal from a distant galaxy, which eventually faded from view. Subsequent analysis showed that the γ-rays probably came from a star being ripped to pieces by a previously unknown black hole (see 'The awakening of a cosmic monster').

Grupul Local

Galaxia noastra, Calea Lactee, este membra a unui grup din apropiere care este compus din aproximativ 40 de galaxii cunoscute, numit Grupul Local. Numarul real ramane necunoscut, intrucat recensamantul a crescut in mod constant de-a lungul anilor, pe masura ce noi membri au fost identificati. Grupul Local contine galaxii de aproape toate tipurile, inclusiv galaxii spirala ca M31, M33 si, desigur, Calea Lactee. Acesta contine dec asemenea cateva galaxii neregulate luminoase (norii lui Magellan), cateva galaxii neregulate slab iluminate, galaxii pitice (nucleate, sferoidale, eliptice si de tip compact). Singurul tip important de galaxie care nu este reprezentat in Grupul Local este tipul eliptic.

Spiral Galaxy Photo Sheds New Light on Recent Star Explosion

A new, extremely deep photo of the site of a supernova explosion that was observed in 1957 has revealed X-rays emanating from the source.

The photo, taken by NASA's Chandra X-Ray space telescope, is the first to spot X-ray light coming from the remains of the dead star that sparked the explosion, and indicates that the supernova likely transformed the star into a pulsar.

Pulsars are super-dense, fast-rotating objects that have been compressed so tightly they are composed only of neutrons.

Galaxia Sombrero

Galaxia Sombrero (M104) este un obiect cu adevarat remarcabil, cu a sa proeminenta stralucitoare sectionata de un disc gros de praf. In taramul galaxiilor, forma sa deosebita este un adevarat simbol. Galaxia Sombrero este o galaxie luminoasa cu adevarat masiva, masa ei fiind echivalenta cu masa a 800 de miliarde de sori. 

Daca aceasta galaxie ar fi situata in clusterul Virgo, ea ar fi cel de-al treilea cel mai stralucitor membru. Faptul ca aceasta galaxie este pozitionata cu muchia spre noi i-a ajutat pe astronomi sa inteleaga organizarea materiei in galaxiile spirala.

Milky Way still recovering from mysterious impact, scientists say

For those of you worried about the nearby Andromeda galaxy colliding with our own Milky Way in the distant future, here’s a little perspective: Turns out our spiral galaxy is still reeling from a hard knock it suffered as recently as 100 million years ago  -- but it’s likely to recover just as quickly, say researchers at the Fermi National Accelerator Laboratory in Batavia, Ill.

Fermilab scientists looked at about 300,000 stars cataloged by the Sloan Digital Sky Survey – which has mapped a full 35% of the sky using an optical telescope in New Mexico – and noticed something strange: Some nearby stars north and south of the Milky Way’s plane were out of sync relative to one another.

Multi-Telescope View of Giant Black Hole Is 2 Million Times Sharper than Human Eye

Scientists using three telescopes spaced thousands of miles apart have caught the best look ever of the center of a distant quasar, an ultra-bright galaxy with a giant black hole at its core.

By linking powerful radio telescopes in Chile, Arizona and Hawaii together, astronomers created a deep-space observing system with 2 million times sharper vision than the human eye, which gave them the most detailed direct view ever of a supermassive black hole inside a galaxy 5 billion light-years from Earth.

Big Apple's Milky Way Galaxy: When Real Stars Shined Over NYC

With the bright moon out of our evening sky this week, it's a great time to get away from city lights and explore the beautiful summer Milky Way. But 35 years ago today, even New Yorkers got a glimpse of our home galaxy.

Today (July 13) marks the 35th anniversary of a night that I will always remember. At 9:29 p.m. EDT, lightning from a severe thunderstorm struck a power plant at Indian Point, New York. The result was sudden power failure that plunged all of New York City into darkness.

Black Hole Caught in a Stellar Homicide

This computer-simulated image shows gas from a star that is ripped apart by tidal forces as it falls into a black hole. Some of the gas also is being ejected at high speeds into space.

Using observations from telescopes in space and on the ground, astronomers gathered the most direct evidence yet for this violent process: a supermassive black hole shredding a star that wandered too close. NASA's orbiting Galaxy Evolution Explorer (GALEX) and the Pan-STARRS1 telescope on the summit of Haleakala in Hawaii were used to help to identify the stellar remains.

Glow in the dark

LAST week scientists at CERN, Europe's main particle-physics lab, finally ran the Higgs boson to ground. The discovery of the Higgs, whose existence was first predicted in 1964, is a powerful demonstration of the predictive powers of the Standard Model of particle physics. But other scientists have powerful theories of their own, even if they get less press than particle physicists do. A paper just published in the Monthly Notices of the Royal Astronomical Society reports another predictive triumph, this time for astronomers.

Black hole shines a light on dark galaxies

According to our best models, the early Universe was filled with clouds of gas that were the source of its current galaxies. However, not all of these protogalactic nebulas were massive enough to compress their gas sufficiently to make stars. This means a number of "dark galaxies" should exist: galaxy-sized clouds of gas with few or no stars. This lack of stars makes dark galaxies extremely hard to find, but a group of astronomers using the Very Large Telescope (VLT) in Chile have identified 12 candidates from the early days of the Universe. These results have the potential to fill in some of the observational gaps in our understanding of early galaxy formation and evolution.

Milky Way Galaxy at Its Best in July Night Sky

It's possible that most people on Earth have never seen the Milky Way, the galaxy in which we live. The Milky Way used to be a part of every human's life experience, but now that the majority of mankind lives in cities, with their light pollution, the Milky Way is rarely seen.

Our Milky Way galaxy is at its best for the next couple of weeks, but most of you will need to make a special effort to see it. It will probably require a drive of an hour or more to reach a dark enough location, where the Milky Way will be visible. Then it will require another 20 minutes for your eyes to become adjusted to the dark.

In a Cosmology Breakthrough, Astronomers Measure a Filament of Dark Matter

Dark Matter Filament This image shows the galaxy clusters Abell 222 and Abell 223 connected by a dark matter filament. The blue shading and the yellow contours indicate matter density. This image on the sky is about twice as big as the full moon. Jörg Dietrich, University of Michigan/University Observatory Munich

Invisible, cold dark matter plays a major role in the evolution of galaxies, according to modern cosmological theory. The most advanced simulations of cosmic evolution show stringy tendrils of mass — dark matter — connecting giant clusters of galaxies via a vast cosmic web. Now for the first time, astronomers have been able to detect one of these filaments, sussing out its location by watching it warp light.