ESA /NASA Hubble: The third way of galaxies - lenticular

Credit: ESA/Hubble & NASA

The subject of this image is NGC 6861, a galaxy discovered in 1826 by the famed Scottish astronomer James Dunlop.

Almost two centuries later we now know that NGC 6861 is the second brightest member of a group of at least a dozen galaxies called the Telescopium Group, otherwise known as the NGC 6868 Group, in the small constellation of Telescopium (The Telescope).

The famed Scottish astronomer James Dunlop Credit: Wiki

This NASA/ESA Hubble Space Telescope view shows some important details of NGC 6861. One of the most prominent features is the disc of dark bands circling the centre of the galaxy.

These dust lanes are a result of large clouds of dust particles obscuring the light emitted by the stars behind them.

Dust lanes are very useful for working out whether we are seeing the galaxy disc edge-on, face-on or, as is the case for NGC 6861, somewhat in the middle. Dust lanes like these are typical of a spiral galaxy.

The dust lanes are embedded in a white oval shape, which is made up of huge numbers of stars orbiting the centre of the galaxy. This oval is, rather puzzlingly, typical of an elliptical galaxy.

So which is it, spiral or elliptical? The answer is neither! NGC 6861 does not belong to either the spiral or the elliptical family of galaxies.

It is a lenticular galaxy, a family which has features of both spirals and ellipticals.

The relationships between these three kinds of galaxies are not yet well understood. A lenticular galaxy could be a faded spiral that has run out of gas and lost its arms, or the result of two galaxies merging.

Being part of a group increases the chances for galactic mergers, so this could be the case for NGC 6861.

Eta Carinae and the Expanding Homunculus Nebula

Eta Carinae and the Expanding Homunculus Nebula 

Image Credit: Hubble, NASA, ESA; Processing & Copyright: First Light, J. L. Dauvergne, P. Henarejos

How did the Eta Carinae star system create this unusual expanding nebula? No one knows for sure.

About 170 years ago, the southern star system Eta Carinae (Eta Car) mysteriously became the second brightest star system in the night sky.

Twenty years later, after ejecting more mass than our Sun, Eta Car unexpectedly faded. Somehow, this outburst appears to have created the Homunculus Nebula.

The three-frame video features images of the nebula taken by the Hubble Space Telescope in 1995, 2001, and 2008.

The Homonculus nebula's center is lit by light from a bright central star, while the surrounding regions are expanding lobes of gas laced with filaments of dark dust.

Jets bisect the lobes emanating from the central stars. Expanding debris includes streaming whiskers and bow shocks caused by collisions with previously existing material.

Eta Carinae still undergoes unexpected outbursts, and its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.

Hubble Image: Capturing the Egg Nebula

Credit: NASA /ESA /Hubble Heritage Team (STScI/AURA). Acknowledgment: W. Sparks (STScI) & R. Sahai (JPL)

This colourful image shows a cosmic lighthouse known as the Egg Nebula, which lies around 3000 light-years from Earth.

The image, taken with the NASA/ESA Hubble Space Telescope, has captured a brief but dramatic phase in the life of a Sun-like star.

The Egg Nebula is a 'preplanetary nebula'. These objects occur as a dying star's hot remains briefly illuminates material it has expelled, lighting up the gas and dust that surrounds it.

These objects will one day develop into planetary nebulas which, despite the name, have nothing at all to do with planets.

They gained their rather misleading title because when they were discovered in the 18th century they resembled planets in our Solar System when viewed through a telescope.

Although the dying star is hidden behind the thick dust lane that streaks down the centre of this image, it is revealed by the four lighthouse-like beams clearly visible through the veil of dust that lies beyond the central lane.

The light beams were able to penetrate the central dust lane due to paths carved out of the thick cloud by powerful jets of material expelled from the star, although the cause of these jets is not yet known.

The concentric rings seen in the less dense cloud surrounding the star are due to the star ejecting material at regular intervals, typically every hundred years, during a phase of the star's evolution just prior to this preplanetary nebula phase.

These dusty shells are not usually visible in these nebulas, but when they are it provides astronomers with a rare opportunity to study their formation and evolution.

The fleeting nature of this phase in a star's life, which occupies only a few thousand of the star's few billion years of existence, and the fact that they are fairly faint make it rare to capture them in action. In fact, the Egg Nebula, the first of its kind to be identified, was discovered only 40 years ago.

This image was taken with Hubble's Advanced Camera for Surveys. Artificial colours are used to represent how the light from the star reflects off the dust, this can tell scientists about the physical properties of the dust.

The image combines observations with three different polarising filters, each showing light vibrating at a specific orientation.

The three filters have been coloured red, blue and green, and all three observations were made at a wavelength of 0.606 microns. The image spans 1.2 light-years. North is to the right and east is up.

Hubble observations cast more doubt on Globular clusters formation

This NASA/ESA Hubble Space Telescope image shows four globular clusters in the dwarf galaxy Fornax. 

Credit: NASA, ESA, S. Larsen - Radboud University, the Netherlands

Thanks to the NASA/ESA Hubble Space Telescope, some of the most mysterious cosmic residents have just become even more puzzling.

New observations of globular clusters in a small galaxy show they are very similar to those found in the Milky Way, and so must have formed in a similar way.

One of the leading theories on how these clusters form predicts that globular clusters should only be found nestled in among large quantities of old stars, but these old stars, though rife in the Milky Way, are not present in this small galaxy, and so, the mystery deepens.

Globular clusters, large balls of stars that orbit the centres of galaxies, but can lie very far from the, remain one of the biggest cosmic mysteries. They were once thought to consist of a single population of stars that all formed together.

However, research has since shown that many of the Milky Way's globular clusters had far more complex formation histories and are made up of at least two distinct populations of stars.

Of these populations, around half the stars are a single generation of normal stars that were thought to form first, and the other half form a second generation of stars, which are polluted with different chemical elements.

In particular, the polluted stars contain up to 50-100 times more nitrogen than the first generation of stars.

The proportion of polluted stars found in the Milky Way's globular clusters is much higher than astronomers expected, suggesting that a large chunk of the first generation star population is missing.

A leading explanation for this is that the clusters once contained many more stars but a large fraction of the first generation stars were ejected from the cluster at some time in its past.

This explanation makes sense for globular clusters in the Milky Way, where the ejected stars could easily hide among the many similar, old stars in the vast halo, but the new observations, which look at this type of cluster in a much smaller galaxy, call this theory into question.

Astronomers used Hubble's Wide Field Camera 3 (WFC3) to observe four globular clusters in a small nearby galaxy known as the Fornax Dwarf Spheroidal galaxy.

"We knew that the Milky Way's clusters were more complex than was originally thought, and there are theories to explain why, but to really test our theories about how these clusters form we needed to know what happened in other environments," says Søren Larsen of Radboud University in Nijmegen, the Netherlands, lead author of the new paper.

"Before now we didn't know whether globular clusters in smaller galaxies had multiple generations or not, but our observations show clearly that they do!"

"If these kicked-out stars were there, we would see them but we don't!" explains Frank Grundahl of Aarhus University in Denmark, co-author on the paper.

"Our leading formation theory just can't be right. There's nowhere that Fornax could have hidden these ejected stars, so it appears that the clusters couldn't have been so much larger in the past."

The new work is detailed in a paper published today, 20 November 2014, in The Astrophysical Journal. "Nitrogen abundances and multiple stellar populations in the globular clusters of the Fornax dSph" arxiv.org/abs/1409.0541

Hubble maps temperature, water vapour on wild exoplanet

An artist's conception of exoplanet WASP-43b orbiting an orange dwarf star roughly 260 light-years from Earth. 

About twice as massive as Jupiter, WASP-43b heats up to about 3,000 degrees Fahrenheit during its closest passes by its star, a temperature hot enough to melt steel. 

Credit: NASA, ESA

A team of scientists including a University of Colorado Boulder professor used NASA's Hubble Space Telescope to make the most detailed global map yet of the glow from a giant, oddball planet orbiting another star, an object twice as massive as Jupiter and hot enough to melt steel.

The Hubble observations show that the planet, called WASP-43b, is no place to call home.

It's a world of extremes, where winds howl at the speed of sound from a 3,000-degree-Fahrenheit dayside to a pitch-black nightside when temperatures plunge to a relatively cool 1,000 degrees Fahrenheit, still hot enough to melt silver.

The map provides information about temperatures at different layers of the planet's atmosphere and traces the amount and distribution of water present.

The findings have ramifications for understanding the atmospheric dynamics and the formation of giant planets like Jupiter, said team leader Jacob Bean of the University of Chicago.

"These measurements have opened the door for a new kind of comparative planetology."

A paper on the subject was published online Oct. 9 in Science Express.

As a ball of predominately hot hydrogen gas, there are no surface features on WASP-43b like oceans or continents that can be used to track its rotation, said CU-Boulder Assistant Professor Jean-Michel Désert, second author on the new study.

Only the drastic temperature difference between the dayside and nightside can be used by remote observers to mark the passage of a day on the strange, gaseous planet, he said.

"WASP-43b is extreme in many ways," said Désert. "It's the size of Jupiter with twice its mass. Its orbit around its host star, called an orange dwarf, takes only about 19 hours – the blink of an eye compared to the 365 days it takes Earth to orbit the sun."

Désert said the study is compelling to those trying to understand planetary formation. "Basically it is like taking a planet like Jupiter into a giant laboratory, then warming it at such a high temperature that all of the atoms and molecules comprising its atmosphere are in a gas phase."

Another bizarre thing about WASP-43b is its orbit. It orbits so close to its host star it always "shows" the same hemisphere, a phenomena similar to the orbit of the moon around Earth that is known as known as "tidal locking."

Discovered in 2011, WASP-43b is 260 light-years away, too distant to be photographed, but because its orbit is observed "edge-on" to Earth, astronomers detected it by observing regular dips in the light of its parent star as the planet passed in front of it, said Désert of CU-Boulder's Department of Astrophysical and Planetary Sciences.

More information: "Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy," by K.B. Stevenson et al. Science, 2014. www.sciencemag.org/lookup/doi/… 1126/science.1256758

Hubble finds jets and explosions in NGC 7793

Credit: ESA /Hubble & NASA, Acknowledgement: D. Calzetti (University of Massachusetts) and the LEGUS Team

This new image from the NASA/ESA Hubble Space Telescope shows NGC 7793, a spiral galaxy in the constellation of Sculptor some 13 million light-years away from Earth.

NGC 7793 is one of the brightest galaxies in the Sculptor Group, one of the closest groups of galaxies to the Local Group, the group of galaxies containing our galaxy, the Milky Way and the Magellanic Clouds.

The image shows NGC 7793's spiral arms and small central bulge.

Unlike some other spirals, NGC 7793 doesn't have a very pronounced spiral structure, and its shape is further muddled by the mottled pattern of dark dust that stretches across the frame.

The occasional burst of bright pink can be seen in the galaxy, highlighting stellar nurseries containing newly-forming baby stars.

Although it may look serene and beautiful from our perspective, this galaxy is actually a very dramatic and violent place.

Astronomers have discovered a powerful micro-quasar within NGC 7793, a system containing a black hole actively feeding on material from a companion star.

A micro-quasar is an object that has some of the properties of quasars in miniature. While many full-sized quasars are known at the cores of other galaxies, it is unusual to find a quasar in a galaxy's disk rather than at its center.

Micro-quasars are almost like scale models, they allow astronomers to study quasars in detail. As material falls inwards towards this black hole, it creates a swirling disk around it.

Some of the infalling gas is propelled violently outwards at extremely high speeds, creating jets streaking out into space in opposite directions.

In the case of NGC 7793, these jets are incredibly powerful, and are in the process of creating an expanding bubble of hot gas some 1,000 light-years across.

Hubble Image: NGC 6872 in the constellation of Pavo

Credit: ESA /Hubble & NASA / Acknowledgement: Judy Schmidt

This picture, taken by the NASA/ESA Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2), shows a galaxy known as NGC 6872 in the constellation of Pavo (The Peacock).

Its unusual shape is caused by its interactions with the smaller galaxy that can be seen just above NGC 6872, called IC 4970. They both lie roughly 300 million light-years away from Earth.

From tip to tip, NGC 6872 measures over 500,000 light-years across, making it the second largest spiral galaxy discovered to date.

In terms of size it is beaten only by NGC 262, a galaxy that measures a mind-boggling 1.3 million light-years in diameter!

To put that into perspective, our own galaxy, the Milky Way, measures between 100,000 and 120,000 light-years across, making NGC 6872 about five times its size.

The upper left spiral arm of NGC 6872 is visibly distorted and is populated by star-forming regions, which appear blue on this image.

This may have been be caused by IC 4970 recently passing through this arm, although here, recent means 130 million years ago!

Astronomers have noted that NGC 6872 seems to be relatively sparse in terms of free hydrogen, which is the basis material for new stars, meaning that if it weren't for its interactions with IC 4970, NGC 6872 might not have been able to produce new bursts of star formation.

Nasa Hubble Image: NGC 6872 lying in the constellation of Pavo (The Peacock)

This Hubble Space Telescope photo shows galaxy NGC 6872 lying in the constellation of Pavo (The Peacock). 

The galaxy’s odd shape stems from interactions with galaxy IC 4970, above. 

Both galaxies lie about 300 million light-years from Earth. 

NGC 6872 stretches over 500,000 light-years across, making it the second largest known spiral galaxy. 

Credit: NASA ESA Hubble

Hubble Image: Cauldron of Star Birth

This space wallpaper reveals the celestial fireworks deep inside the core of a developing galaxy in the young Universe, as seen from a hypothetical planetary system.

The sky is depicted as ablaze with the glow from nebulae, fledgling star clusters, and stars exploding as supernovae. 

The rapidly forming core may eventually become the heart of a mammoth galaxy similar to one of the giant elliptical galaxies seen today.

Credit: NASA, ESA, Z. Levay and G. Bacon (Space Telescope Science Institute)

Hubble Image: Galaxy IC559 in constellation of Leo

Credit: ESA/Hubble, NASA, D. Calzetti (UMass) and the LEGUS Team

Far beyond the stars in the constellation of Leo (The Lion) is irregular galaxy IC 559.

IC 559 is not your everyday galaxy. With its irregular shape and bright blue spattering of stars, it is a fascinating galactic anomaly.

It may look like sparse cloud, but it is in fact full of gas and dust which is spawning new stars.

Discovered in 1893, IC 559 lacks the symmetrical spiral appearance of some of its galactic peers and not does not conform to a regular shape.

It is actually classified as a Megallanic spiral or "type Sm" galaxy, an irregular galaxy with some evidence of a spiral structure.

Irregular galaxies make up about a quarter of all known galaxies and do not fall into any of the regular classes of the Hubble sequence.

Most of these uniquely shaped galaxies were not always so, IC 559 may have once been a conventional spiral galaxy that was then distorted and twisted by the gravity of a nearby cosmic companion.

This image, captured by the NASA/ESA Hubble Space Telescope's Wide Field Camera 3 (WFC3), combines a wide range of wavelengths spanning the ultraviolet, optical, and infrared parts of the spectrum.

ESA NASA Hubble Image: Spiral galaxy in Serpens

This new NASA/ESA Hubble Space Telescope image shows a beautiful spiral galaxy known as PGC 54493, located in the constellation of Serpens (The Serpent). 

This galaxy is part of a galaxy cluster that has been studied by astronomers exploring an intriguing phenomenon known as weak gravitational lensing.

This effect, caused by the uneven distribution of matter (including dark matter) throughout the Universe, has been explored via surveys such as the Hubble Medium Deep Survey.

Dark matter is one of the great mysteries in cosmology. It behaves very differently from ordinary matter as it does not emit or absorb light or other forms of electromagnetic energy, hence the term "dark."

Even though we cannot observe dark matter directly, we know it exists. One prominent piece of evidence for the existence of this mysterious matter is known as the "galaxy rotation problem."

Galaxies rotate at such speeds and in such a way that ordinary matter alone, the stuff we see, would not be able to hold them together.

The amount of mass that is "missing" visibly is dark matter, which is thought to make up some 27 percent of the total contents of the Universe, with dark energy and normal matter making up the rest.

PGC 55493 has been studied in connection with an effect known as cosmic shearing. This is a weak gravitational lensing effect that creates tiny distortions in images of distant galaxies.

Credit: European Space Agency

Hubble Image: Spiral galaxies engaged in a cosmic tug-of-war

Credit: ESA/Hubble & NASA, Acknowledgement: Luca Limatola

From objects as small as Newton's apple to those as large as a galaxy, no physical body is free from the stern bonds of gravity, as evidenced in this stunning picture captured by the Wide Field Camera 3 and Advanced Camera for Surveys onboard the NASA/ESA Hubble Space Telescope.

Here we see two spiral galaxies engaged in a cosmic tug-of-war but in this contest, there will be no winner.

The structures of both objects are slowly distorted to resemble new forms, and in some cases, merge together to form new, super galaxies.

This particular fate is similar to that of the Milky Way Galaxy, when it will ultimately merge with our closest galactic partner, the Andromeda Galaxy.

There is no need to panic however, as this process takes several hundreds of millions of years.

Not all interacting galaxies result in mergers though. The merger is dependent on the mass of each galaxy, as well as the relative velocities of each body.

It is quite possible that the event pictured here, romantically named 2MASX J06094582-2140234, will avoid a merger event altogether, and will merely distort the arms of each spiral without colliding—the cosmic equivalent of a hair ruffling!

These galactic interactions also trigger new regions of star formation in the galaxies involved, causing them to be extremely luminous in the infrared part of the spectrum.

For this reason, these types of galaxies are referred to as Luminous Infrared Galaxies (LIRGs).

This image was taken as part of as part of a Hubble survey of the central regions of LIRGs in the local Universe, which also used the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) instrument.

The Universe Is Missing Some Light

New data from the Hubble Space Telescope and computer simulations have revealed that the universe has much less ultraviolet light than previously thought.

Credit: Ben Oppenheimer and Juna Kollmeier

An extraordinary amount of ultraviolet light appears to be missing from the universe, scientists have found.

One potential source of this missing light might be the mysterious dark matter that makes up most of the mass in the cosmos but a simpler explanation could be that ultra violet light escapes from galaxies more easily than is currently thought, according to the new research.

This puzzle begins with hydrogen, the most common element in the universe, which makes up about 75 percent of known matter. High-energy ultraviolet light can convert electrically neutral hydrogen atoms into electrically charged ions.

The two known sources for such ionizing rays are hot young stars and quasars, which are supermassive black holes more than a million times the mass of the sun that release extraordinarily large amounts of light as they rip apart stars and gobble matter.

Astronomers previously found that ionizing rays from hot young stars are nearly always absorbed by gas in their home galaxies. As such, they virtually never escape to affect intergalactic hydrogen.

Space Telescope Imaging Spectrograph

However, when scientists performed supercomputer simulations of the amount of intergalactic hydrogen that should exist and compared their results with observations from the Hubble Space Telescope's Cosmic Origins Spectrograph, they found the amount of light from known quasars is five times lower than what is needed to explain the amount of electrically neutral intergalactic hydrogen observed.

"It's as if you're in a big, brightly-lit room, but you look around and see only a few 40-watt lightbulbs," lead study author Juna Kollmeier, a theoretical astrophysicist at the Observatories of the Carnegie Institution of Washington in Pasadena, Calif., said in a statement.

"Where is all that light coming from? It's missing."

The researchers are calling this giant deficit of ultraviolet light "the photon underproduction crisis."

"In modern astrophysics, you very rarely find large mismatches like the one we are talking about here," Kollmeier told reporters.

"When you see one, you know that there is an opportunity to learn something new about the universe, and that's amazing."

"The great thing about a 400 percent discrepancy is that you know something is really wrong," study co-author David Weinberg at Ohio State University said in a statement.

"We still don't know for sure what it is, but at least one thing we thought we knew about the present day universe isn't true."

Strangely, this missing light only appears in the nearby, relatively well-studied cosmos.

When telescopes focus on light from galaxies billions of light years away, and therefore from billions of years in the past, no problem is seen.

In other words, the amount of ultraviolet light in the early universe makes sense, but the amount of ultraviolet light in the nearby universe does not.

"The authors have performed a careful and thorough analysis of the problem," said theoretical astrophysicist Abraham Loeb, chairman of the astronomy department at Harvard University, who did not take part in this research.

The most exciting possibility these findings raise is that the missing photons are coming from some exotic new source, not galaxies or quasars at all, Kollmeier said.

For example, dark matter, the invisible and intangible substance thought to make up five-sixths of all matter in the universe, might be capable of decay and generating this extra light.

"You know it's a crisis when you start seriously talking about decaying dark matter," study co-author Neal Katz at the University of Massachusetts at Amherst said in a statement.

NASA Hubble: New precise mass map of a distant galaxy cluster

This image from the NASA/ESA Hubble Space Telescope shows the galaxy cluster MCS J0416.1-2403. 

This is one of six being studied by the Hubble Frontier Fields programme. 

This programme seeks to analyse the mass distribution in these huge clusters and to use the gravitational lensing effect of these clusters, to peer even deeper into the distant Universe. 

Credit: ESA/Hubble, NASA, HST Frontier Fields

Astronomers using the NASA/ESA Hubble Space Telescope have mapped the mass within a galaxy cluster more precisely than ever before.

Created using observations from Hubble Frontier Fields observing programme, the map shows the amount and distribution of mass within MCS J0416.1-2403, a massive galaxy cluster found to be 160 trillion times the mass of the Sun.

The detail in this mass map was made possible thanks to the unprecedented depth of data provided by new Hubble observations, and the cosmic phenomenon known as strong gravitational lensing.

Measuring the amount and distribution of mass within distant objects in the Universe can be very difficult.

A trick often used by astronomers is to explore the contents of large clusters of galaxies by studying the gravitational effects they have on the light from very distant objects beyond them.

This is one of the main goals of Hubble Frontier Fields, an ambitious observing programme scanning six different galaxy clusters, including MCS J0416.1-2403, the cluster shown in this stunning new image.

Large clumps of mass in the Universe warp and distort the space-time around them. Acting like lenses, they appear to magnify and bend light that travels through them from more distant objects.

Despite their large masses, the effect of galaxy clusters on their surroundings is usually quite minimal.

For the most part they cause what is known as weak lensing, making even more distant sources appear as only slightly more elliptical or smeared across the sky.

However, when the cluster is large and dense enough and the alignment of cluster and distant object is just right, the effects can be more dramatic.

The images of normal galaxies can be transformed into rings and sweeping arcs of light, even appearing several times within the same image.

This effect is known as strong lensing, and it is this phenomenon, seen around the six galaxy clusters targeted by the Hubble Frontier Fields programme, that has been used to map the mass distribution of MCS J0416.1-2403, using the new Hubble data.

"The depth of the data lets us see very faint objects and has allowed us to identify more strongly lensed galaxies than ever before," explains Mathilde Jauzac of Durham University, UK, and Astrophysics & Cosmology Research Unit, South Africa, lead author of the new Frontier Fields paper.

"Even though strong lensing magnifies the background galaxies they are still very far away and very faint. The depth of these data means that we can identify incredibly distant background galaxies."

"We now know of more than four times as many strongly lensed galaxies in the cluster than we did before."

Using Hubble's Advanced Camera for Surveys, the astronomers identified 51 new multiply imaged galaxies around the cluster, quadrupling the number found in previous surveys and bringing the grand total of lensed galaxies to 68.

Because these galaxies are seen several times this equates to almost 200 individual strongly lensed images which can be seen across the frame.

This effect has allowed Jauzac and her colleagues to calculate the distribution of visible and dark matter in the cluster and produce a highly constrained map of its mass.

Hubble Captures a Dwarf Galaxy Shaped by a Grand Design

Image Credit: ESA/NASA

The subject of this Hubble image is NGC 5474, a dwarf galaxy located 21 million light-years away in the constellation of Ursa Major (The Great Bear).

This beautiful image was taken with Hubble's Advanced Camera for Surveys (ACS).

The term "dwarf galaxy" may sound diminutive, but don't let that fool you, NGC 5474 contains several billion stars!

However, when compared to the Milky Way with its hundreds of billions of stars, NGC 5474 does indeed seem relatively small.

NGC 5474 itself is part of the Messier 101 Group. The brightest galaxy within this group is the well-known spiral Pinwheel Galaxy (also known as Messier 101).

This galaxy's prominent, well-defined arms classify it as a "grand design galaxy," along with other spirals Messier 81 and Messier 74.

Also within this group are Messier 101's galactic neighbors. It is possible that gravitational interactions with these companion galaxies have had some influence on providing Messier 101 with its striking shape.

Similar interactions with Messier 101 may have caused the distortions visible in NGC 5474.

Both the Messier 101 Group and our own Local Group reside within the Virgo Supercluster, making NGC 5474 something of a neighbour in galactic terms.

Hubble Begins Search Beyond Pluto For Potential Flyby Targets

This is an artist's rendering of the New Horizons spacecraft encountering a Kuiper Belt object - a city-sized icy relic left over from the birth of our solar system. 

The sun, more than 4.1 billion miles (6.7 billion kilometers) away, shines as a bright star embedded in the glow of the zodiacal dust cloud. 

Jupiter and Neptune are visible as orange and blue "stars" to the right of the sun. 

Image courtesy JHUAPL /SwRI.

After careful consideration and analysis, the Hubble Space Telescope Time Allocation Committee has recommended using Hubble to search for an object the Pluto-bound NASA New Horizons mission could visit after its flyby of Pluto in July 2015.

The planned search will involve targeting a small area of sky in search of a Kuiper Belt object (KBO) for the outbound spacecraft to visit.

The Kuiper Belt is a vast debris field of icy bodies left over from the solar system's formation 4.6 billion years ago.

A KBO has never been seen up close because the belt is so far from the sun, stretching out to a distance of 5 billion miles into a never-before-visited frontier of the solar system.

"I am pleased that our science peer-review process arrived at a consensus as to how to effectively use Hubble's unique capabilities to support the science goals of the New Horizons mission," said Matt Mountain, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

Fully carrying out the KBO search is contingent on the results from a pilot observation using Hubble data.

The space telescope will scan an area of sky in the direction of the constellation Sagittarius to try and identify any objects orbiting within the Kuiper Belt.

To discriminate between a foreground KBO and the clutter of background stars in Sagittarius, the telescope will turn at the predicted rate that KBOs are moving against the background stars.

In the resulting images, the stars will be streaked, but any KBOs should appear as pinpoint objects.

If the test observation identifies at least two KBOs of a specified brightness it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit.

At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full moon.

Astronomers around the world apply for observing time on the Hubble Space Telescope. Competition for time on the telescope is extremely intense and the requested observing time significantly exceeds the observing time available in a given year.

Proposals must address significant astronomical questions that can only be addressed with Hubble's unique capabilities, and are beyond the capabilities of ground-based telescopes.

The proposals are peer reviewed annually by an expert committee, which looks for the best possible science that can be conducted by Hubble and recommends to the Space Telescope Science Institute director a balanced program of small, medium, and large investigations.

Though Hubble is powerful enough to see galaxies near the horizon of the universe, finding a KBO is a challenging needle-in-haystack search.

A typical KBO along the New Horizons trajectory may be no larger than Manhattan Island and as black as charcoal.

NASA Chandra Captures Whirlpool Galaxy Sparkling in X-rays

Image courtesy X-ray: NASA/CXC/Wesleyan Univ./R.Kilgard, et al; Optical: NASA/STScI.

Nearly a million seconds of observing time with NASA's Chandra X-ray Observatory has revealed a spiral galaxy similar to the Milky Way glittering with hundreds of X-ray points of light.

The galaxy is officially named Messier 51 (M51) or NGC 5194, but often goes by its nickname of the "Whirlpool Galaxy."

Like the Milky Way, the Whirlpool is a spiral galaxy with spectacular arms of stars and dust.

M51 is located 30 million light years from Earth, and its face-on orientation to Earth gives us a perspective that we can never get of our own spiral galactic home.

By using Chandra, astronomers can peer into the Whirlpool to uncover things that can only be detected in X-rays.

In this new composite image, Chandra data are shown in purple. Optical data from the Hubble Space Telescope are red, green and blue.

Most of the X-ray sources are X-ray binaries (XRBs). These systems consist of pairs of objects where a compact star, either a neutron star or, more rarely, a black hole, is capturing material from an orbiting companion star.

The infalling material is accelerated by the intense gravitational field of the compact star and heated to millions of degrees, producing a luminous X-ray source.

The Chandra observations reveal that at least ten of the XRBs in M51 are bright enough to contain black holes. In eight of these systems the black holes are likely capturing material from companion stars that are much more massive than the sun.

Because astronomers have been observing M51 for about a decade with Chandra, they have critical information about how X-ray sources containing black holes behave over time.

The black holes with massive stellar companions are consistently bright over the ten years of Chandra observations.

These results suggest that the high-mass stars in these X-ray sources also have strong winds that allow for a steady stream of material to flow onto the black hole.

A difference between the Milky Way and the Whirlpool galaxy is that M51 is in the midst of merging with a smaller companion galaxy seen in the upper left of the image. Scientists think this galactic interaction is triggering waves of star formation.

The most massive of the newly formed stars will race through their evolution in a few million years and collapse to form neutron stars or black holes.

Most of the XRBs containing black holes in M51 are located close to regions where stars are forming, showing their connection to the oncoming galactic collision.

Previous studies of the Whirlpool Galaxy with Chandra revealed just over 100 X-ray sources. The new dataset, equivalent to about 900,000 seconds of Chandra observing time, reveals nearly 500 X-ray sources.

About 400 of these sources are thought to be within M51, with the remaining either being in front of or behind the galaxy itself.

Much of the diffuse, or fuzzy, X-ray emission in M51 comes from gas that has been superheated by supernova explosions of massive stars.

Hubble Image: NGC 1566 in the constellation of Dorado (The Dolphinfish)

Image Credit: ESA/Hubble & NASA

This new Hubble image shows NGC 1566, a beautiful galaxy located approximately 40 million light-years away in the constellation of Dorado (The Dolphinfish).

NGC 1566 is an intermediate spiral galaxy, meaning that while it does not have a well-defined bar-shaped region of stars at its center, like barred spirals, it is not quite an unbarred spiral either.

The small but extremely bright nucleus of NGC 1566 is clearly visible in this image, a telltale sign of its membership of the Seyfert class of galaxies.

The centers of such galaxies are very active and luminous, emitting strong bursts of radiation and potentially harbouring supermassive black holes that are many millions of times the mass of the sun.

NGC 1566 is not just any Seyfert galaxy; it is the second brightest Seyfert galaxy known.

It is also the brightest and most dominant member of the Dorado Group, a loose concentration of galaxies that together comprise one of the richest galaxy groups of the southern hemisphere.

This image highlights the beauty and awe-inspiring nature of this unique galaxy group, with NGC 1566 glittering and glowing, its bright nucleus framed by swirling and symmetrical lavender arms.

This image was taken by Hubble’s Wide Field Camera 3 (WFC3) in the near-infrared part of the spectrum.

Hubble IRAS 14568-6304: Violent Birth Announcement from an Infant Star

Image courtesy ESA/Hubble and NASA. Acknowledgements: R. Sahai, NASA JPL/ Serge Meunier. 

This Hubble image shows IRAS 14568-6304, a young star that is cloaked in a haze of golden gas and dust.

It appears to be embedded within an intriguing swoosh of dark sky, which curves through the image and obscures the sky behind.

The Wide-Field Infrared Survey Explorer (WISE), has uncovered a striking population of young stellar objects in a complex of dense, dark clouds in the southern constellation of Circinus.

This dark region is known as the Circinus molecular cloud.

This cloud has a mass around 250 000 times that of the sun, and it is filled with gas, dust and young stars.

Within this cloud lie two prominent and enormous regions known colloquially to astronomers as Circinus-West and Circinus-East.

Each of these clumps has a mass of around 5000 times that of the sun, making them the most prominent star-forming sites in the Circinus cloud.

The clumps are associated with a number of young stellar objects, and IRAS 14568-6304, featured here under a blurry fog of gas within Circinus-West, is one of them.

IRAS 14568-6304 is special because it is driving a protostellar jet, which appears here as the "tail" below the star. This jet is the leftover gas and dust that the star took from its parent cloud to help form it.

While most of this material forms the star and its accretion disc, the disc of material surrounding the star, which may one day form planets, at some point in the formation process the star began to eject some of the material at supersonic speeds through space.

This phenomenon is not only beautiful, but can also provide us with valuable clues about the process of star formation.

ESA Hubble Iamge: Starbursts in the galaxy NGC 4485, constellation Canes Venatici

This image from NASA/ESA's Hubble Space Telescope shows galaxy NGC 4485 in the constellation of Canes Venatici (The Hunting Dogs). 

The galaxy is irregular in shape, but it hasn’t always been so. 

Part of NGC 4485 has been dragged towards a second galaxy, named NGC 4490 (The Cocoon Galaxy), which lies out of frame to the bottom right of this image.

Credit: European Space Agency (ESA)

Between them, these two galaxies make up a galaxy pair called Arp 269. Their interactions have warped them both, turning them from spiral galaxies into irregular ones.

Arp 269

NGC 4485 is the smaller galaxy in this pair, which provides a fantastic real-world example for astronomers to compare to their computer models of galactic collisions.

The most intense interaction between these two galaxies is all but over; they have made their closest approach and are now separating.

The trail of bright stars and knotty orange clumps that we see here extending out from NGC 4485 is all that connects them, a trail that spans some 24 000 light-years.

Many of the stars in this connecting trail could never have existed without the galaxies’ fleeting romance.

When galaxies interact hydrogen gas is shared between them, triggering intense bursts of star formation.

The orange knots of light in this image are examples of such regions, clouded with gas and dust.