Sentences with phrase «dark halo»

There is a fairly obvious dark halo around the root tip we can easily see.

So they plump for a model in which the brown dwarfs revealed by microlensing are part of the relatively small but heavy spheroid, while the even heavier extended dark halo is made up of the more exotic particles variously known as WIMPs or cold dark matter.

But the relative scarcity of quasars at these larger distances may be only an illusion, caused by dusty dark haloes that block the light of the farthest objects in the Universe.

The dust may shed light on the nature of the mysterious dark haloes.

«Either there are not as many dark halos as our theory predicts, or star formation is hugely inefficient or easily suppressed within very low mass halos.»

Formation of galaxies like the Milky Way is thought to proceed through the hierarchical assembly of dark matter, forming dark halos, and through the subsequent infall of gas and star formation affected by gravity.

They argue that the brown dwarfs are in fact members of a much smaller spherical distribution of matter around the centre of the Galaxy, which they call the spheroid in order to avoid confusion with the extended dark halo.

But dusty dark haloes could mean that astronomers have only a partial view of the Universe, because dust obscures distant objects.

The dust Zaritsky has found may hold the key to probing the mysterious dark haloes, because astronomers could map the haloes by observing the amount of dust at different positions around spiral galaxies.

Some researchers suggested the dark halo consisted of ordinary material that simply didn't emit light.

This was the first time that astronomers had identified a component of the Galaxy's dark halo, and some speculated that the halo could be composed almost entirely of these objects.

This spheroid (unlike the dark halo) does contain a few visible stars, and its presence (like the dark halo) is required to explain details of the rotation of the visible part of the Galaxy, the relatively thin disc in which most stars live.

Mike Turner of Fermilab, Chicago, has already pointed out that the observed microlensing events seem to be too rare to fit the idea of a dark halo full of brown dwarfs.

On the other hand, we see no stars at all out in the fringes of the dark halo.

Standard models of galaxy formation in the context of the so - called cold dark matter (CDM) theory predict the presence of hundreds of small dark halos orbiting in a Milky Way - sized dark halo and a comparable number of luminous satellite companions.

The filter disks circled in red hold new forms of erythromycin created by University at Buffalo researchers, and the dark halo around them indicates that the drug has seeped out of the disk to kill the surrounding bacteria.

The glow seemed consistent with the size and shape of the matter needed to make ngc 5907 spin the way it does, so astronomers hoped that this might be the first sign that the dark halos were made of ordinary stars and planets — albeit faint ones — rather than exotic, yet - to - be discovered particles.

The Milky Way's dark halo extends at least 100 000 light years from the centre.

Zaritsky estimates that the dust in one of the dark haloes adds up to at least 300 million solar masses.

Dust has been detected in the dark haloes surrounding two large spiral galaxies.

He found that, on average, the galaxies viewed through the dark haloes looked redder than those farther out.

He estimates that more than 99 per cent of the hydrogen gas in the dark haloes is ionised and so can not be detected by means of radio waves.

This is a large amount of dust, but it makes up only a fraction of a dark halo's total mass of some 1000 billion solar masses.

Both lines of sight pass well outside the galaxies» discs, but the first goes through their dark haloes.

Zaritsky suspects that hydrogen gas exists in the dark haloes but that it has been ionised by ultraviolet radiation from stars.

As Sagittarius approached the Milky Way, passed through its disk, and circled back again, the dark halo of Sagittarius would have slammed into the plane of the Milky Way twice, knocking the disk askew and stirring up the formation of its spiral arms.

But the dark matter hypothesis is uncomfortable, to say the least: not only do astronomers have no idea what constitutes dark matter, they also have no idea how a dark halo might form.

Astronomers have then been able to discover that most of the mass in our Galaxy is not producing light of any kind and is in a dark halo around the visible parts of the Galaxy.

«The masses of these dark halos varied from small to large, and so the galaxies that formed within them also vary in such a manner,» Yozin explains in an email interview.

In 2006, a team of scientists (including Jürg Diemand, Michael Kuhlen, and Piero Madau) modelled the process by which dark matter «clouds» are attracted to form the Milky Way's dark halo (Diemand et al, 2006).

Infection trapped deep in this buried root tip is eating away the bone at the tip of the retained root, causing the dark halo.