ALMA finds best evidence for galactic merger in distant protocluster AzTEC-3

An artist's impression of the protocluster observed by ALMA. 

It shows the central starburst galaxy AzTEC-3 along with its labeled cohorts of smaller, less active galaxies. 

New ALMA observations suggest that AzTEC-3 recently merged with another young galaxy and that the whole system represents the first steps toward forming a galaxy cluster. 

Credit: B. Saxton (NRAO/AUI/NSF)

Nestled among a triplet of young galaxies more than 12.5 billion light-years away is a cosmic powerhouse: a galaxy that is producing stars nearly 1,000 times faster than our own Milky Way.

This energetic starburst galaxy, known as AzTEC-3, together with its gang of calmer galaxies may represent the best evidence yet that large galaxies grow from the merger of smaller ones in the early Universe, a process known as hierarchical merging.

An international team of astronomers observed these remarkable objects with the Atacama Large Millimeter/submillimeter Array (ALMA).

"The ALMA data reveal that AzTEC-3 is a very compact, highly disturbed galaxy that is bursting with new stars at close to its theoretically predicted maximum limit and is surrounded by a population of more normal, but also actively star-forming galaxies," said Dominik Riechers, an astronomer and assistant professor at Cornell University in Ithaca, New York, and lead author on a paper published today (Nov. 10) in the Astrophysical Journal.

"This particular grouping of galaxies represents an important milestone in the evolution of our Universe: the formation of a galaxy cluster and the early assemblage of large, mature galaxies."

Combined data from Japan's Subaru telescope and ALMA of the AzTEC-3 region; the circled regions are members of this protocluster, which were previously highlighted by Subaru. 

The ALMA data are highlighted with arrows. 

Credit: Subaru/NASA/JPL, P. Capak (SSC/Caltech); ALMA (NRAO/ESO/NAOJ); B. Saxton (NRAO/AUI/NSF)

In the early Universe, starburst galaxies like AzTEC-3 were forming new stars at a monstrous pace fueled by the enormous quantities of star-forming material they devoured and by merging with other adolescent galaxies.

Over billions of years, these mergers continued, eventually producing the large galaxies and clusters of galaxies we see in the Universe today.

Evidence for this hierarchical model of galaxy evolution has been mounting, but these latest ALMA data show a strikingly clear picture of the all-important first steps along this process when the Universe was only 8 percent of its current age.

"One of the primary science goals of ALMA is the detection and detailed study of galaxies throughout cosmic time," said Chris Carilli, an astronomer with the National Radio Astronomy Observatory in Socorro, New Mexico.

"These new observations help us put the pieces together by showing the first steps of a galaxy merger in the early Universe."

AzTEC-3, which is located in the direction of the constellation Sextans, is what astronomers refer to as a submillimeter galaxy, since it shines brightly in that portion of the spectrum, but is remarkably dim at optical and infrared wavelengths.

This is due to light from its stars being absorbed by dust in the star-forming environments of the galaxy and then re-emitted by the dust at far-infrared wavelengths.

As this light travels across the cosmos, it becomes stretched due to the expansion of the Universe, so by the time it arrives at Earth, the far-infrared light has shifted to the submillimeter/millimeter portion of the spectrum.

More information: Dominik A. Riechers et al. 2014 ApJ 796 84: iopscience.iop.org/0004-637X/796/2/84/article

ALMA and ATCA Astronomers dissect the remnants of a supernova

Simulated still showing components of Supernova Remnant 1987A. 

Credit: The International Centre for Radio Astronomy Research (ICRAR)

In research published today in the Astrophysical Journal, an Australian led team of astronomers has used radio telescopes in Australia and Chile to see inside the remains of a supernova.

The supernova, known as SN1987A, was first seen by observers in the Southern Hemisphere in 1987 when a giant star suddenly exploded at the edge of a nearby dwarf galaxy called the Large Magellanic Cloud.

In the two and a half decades since then the remnant of Supernova 1987A has continued to be a focus for researchers the world over, providing a wealth of information about one of the Universe's most extreme events.

PhD Candidate Giovanna Zanardo at The University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR) led the team that used the Atacama Large Millimetre/submillimeter Array (ALMA) in Chile's Atacama Desert and the Australia Telescope Compact Array (ATCA) in New South Wales to observe the remnant at wavelengths spanning the radio to the far infrared.

"By combining observations from the two telescopes we've been able to distinguish radiation being emitted by the supernova's expanding shock wave from the radiation caused by dust forming in the inner regions of the remnant," said Zanardo.

A panel of images showing different views of Supernova 1987A. 

Left Panel: SNR1987A as seen by the Hubble Space Telescope in 2010. 

Middle Panel: SNR1987A as seen by the ATCA in New South Wales and the ALMA in Chile. 

Right Panel: A computer generated visualisation of the remnant showing the possible location of a Pulsar. 

Credit: ATCA & ALMA Observations & data - G. Zanardo et al. / HST Image: NASA, ESA, K. France (University of Colorado, Boulder), P. Challis and R. Kirshner (Harvard-Smithsonian Center for Astrophysics)

"This is important because it means we're able to separate out the different types of emission we're seeing and look for signs of a new object which may have formed when the star's core collapsed. It's like doing a forensic investigation into the death of a star."

"Our observations with the ATCA and ALMA radio telescopes have shown signs of something never seen before, located at the centre or the remnant. It could be a pulsar wind nebula, driven by the spinning neutron star, or pulsar, which astronomers have been searching for since 1987."

"It's amazing that only now, with large telescopes like ALMA and the upgraded ATCA, we can peek through the bulk of debris ejected when the star exploded and see what's hiding underneath."

More research published recently in the Astrophysical Journal also attempts to shine a light on another long-standing mystery surrounding the supernova remnant.

Since 1992 the radio emission from one side of the remnant has appeared 'brighter' than the other.

More information: 'Spectral and Morphological Analysis of the Remnant of Supernova 1987a with ALMA & ATCA' G. Zanardo, L. Staveley-Smith, R. Indebetouw et al. Astrophysical Journal November 10th, 2014: arxiv.org/abs/1409.7811 and iopscience.iop.org/0004-637X/796/2/82

'Multi-dimensional simulations of the expanding supernova remnant SN 1987a' T.M Potter, L Staveley-Smith, B. Reville et al. Astrophysical Journal October 20th, 20144: arxiv.org/abs/1409.4068 and iopscience.iop.org/0004-637X/794/2/174

Animation of Star's Protoplanetary Disc - Video

Artists from the European Southern Observatory (ESO) and the National Science Foundation have created impressions of a planet forming disc around a stars.

Best-Ever View of Alien Planet Birth Caught by Giant Radio Telescope

Hubble observes Jets, bubbles, and bursts of light in Taurus

The NASA/ESA Hubble Space Telescope has snapped a striking view of a multiple star system called XZ Tauri, its neighbour HL Tauri and several nearby young stellar objects. 

XZ Tauri is blowing a hot bubble of gas into the surrounding space, which is filled with bright and beautiful clumps that are emitting strong winds and jets. 

These objects illuminate the region, creating a truly dramatic scene. 

Credit: ESA/Hubble/ NASA

The NASA/ESA Hubble Space Telescope has snapped a striking view of a multiple star system called XZ Tauri, its neighbour HL Tauri, and several nearby young stellar objects.

XZ Tauri is blowing a hot bubble of gas into the surrounding space, which is filled with bright and beautiful clumps that are emitting strong winds and jets.

These objects illuminate the region, creating a truly dramatic scene.

This dark and ominous landscape is located some 450 light-years away in the constellation of Taurus (The Bull).

It lies in the north-eastern part of a large, dark cloud known as LDN 1551.

Just to the left of centre in this image, embedded within a rust-coloured cloud, lies XZ Tauri. While it appears to be a single star, this bright spot actually consists of several stars.

It has long been known to be a binary, but one of these two stars is thought also to be a binary, making a total of three stars within a single system.

This is not the first time that Hubble has observed XZ Tauri, between the years of 1995 and 2000, a hot bubble of gas was spotted expanding outwards from the system.

This bubble can be seen as the small orange lobe very close to the top left of XZ Tauri. This gas is speeding out from the star system, leaving a trail spanning tens of billions of kilometres.

As the bubble travels it hits slower moving material, triggering pulses of light and rippling shockwaves.

Above and to the right of XZ Tauri, an equally epic scene is unfolding. Wisps of deep red seem to be streaking away from the blue-tinged clumps on the right.

This bright blue patch contains a star known as HL Tauri, which is associated with Herbig-Haro object HH 150.

Herbig-Haro objects are streaks of hot gas blasted into space by newborn and newly forming stars and LDN 1551 is particularly rich in these dramatic objects.

In the bottom right of this Hubble image is another Herbig-Haro object known as HH 30, associated with the variable star V1213 Tauri.

The star itself is hidden within a flat, bright disc of dust that is split in half by a dark lane. This dust blocks direct light from V1213 Tauri, but the star is visible via its reflected light and the prominent, knotty jets it is blasting out into space.

Hubble previously viewed HH 30, alongside XZ Tauri, with its Wide Field Planetary Camera 2 between the years of 1995 and 2000.

The observations were used to image and study the changes in disc brightness and jet strength over the five-year period.

V1213 Tauri's strong magnetic field forms the jets by funnelling and shepherding gas from the disc, accelerating it along the star's magnetic poles to form two narrow beams.

ALMA image of the young star HL Tau and its protoplanetary disk. 

This best image ever of planet formation reveals multiple rings and gaps that herald the presence of emerging planets as they sweep their orbits clear of dust and gas 

Credit: ALMA (NRAO /ESO /NAOJ); C. Brogan, B. Saxton (NRAO /AUI /NSF)

In the above image released by the European Southern Observatory today, observations from the Atacama Large Millimeter /submillimeter Array (ALMA) reveal extraordinarily fine and never-before-seen detail in the planet-forming disc around HL Tauri.

The new observations are an enormous step forward in the observation of how protoplanetary discs develop and how planets form.

ESO ALMA: Planet-forming Lifeline Discovered in a Binary Star System

This artist's impression shows the dust and gas around the double star system GG Tauri-A. 

Researchers using ALMA have detected gas in the region between two discs in this binary system. 

This may allow planets to form in the gravitationally perturbed environment of the binary. 

Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets. 

Image courtesy ESO/L. Calcada

For the first time, researchers using ALMA have detected a streamer of gas flowing from a massive outer disc toward the inner reaches of a binary star system.

This never-before-seen feature may be responsible for sustaining a second, smaller disc of planet-forming material that otherwise would have disappeared long ago.

Half of Sun-like stars are born in binary systems, meaning that these findings will have major consequences for the hunt for exoplanets.

The results are published in the journal Nature on 30 October 2014.

Anne Dutrey

A research group led by Anne Dutrey from the Laboratory of Astrophysics of Bordeaux, France and CNRS used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the distribution of dust and gas in a multiple-star system called GG Tau-A.

This object is only a few million years old and lies about 450 light-years from Earth in the constellation of Taurus (The Bull).

Like a wheel in a wheel, GG Tau-A contains a large, outer disc encircling the entire system as well as an inner disc around the main central star.

This second inner disc has a mass roughly equivalent to that of Jupiter.

Its presence has been an intriguing mystery for astronomers since it is losing material to its central star at a rate that should have depleted it long ago.

While observing these structures with ALMA, the team made the exciting discovery of gas clumps in the region between the two discs.

The new observations suggest that material is being transferred from the outer to the inner disc, creating a sustaining lifeline between the two.

"Material flowing through the cavity was predicted by computer simulations but has not been imaged before. Detecting these clumps indicates that material is moving between the discs, allowing one to feed off the other," explains Dutrey.

"These observations demonstrate that material from the outer disc can sustain the inner disc for a long time. This has major consequences for potential planet formation."

Planets are born from the material left over from star birth. This is a slow process, meaning that an enduring disc is a prerequisite for planet formation.

If the feeding process into the inner disc now seen with ALMA occurs in other multiple-star systems the findings introduce a vast number of new potential locations to find exoplanets in the future.

The first phase of exoplanet searches was directed at single-host stars like the Sun. More recently it has been shown that a large fraction of giant planets orbit binary-star systems.

Now, researchers have begun to take an even closer look and investigate the possibility of planets orbiting the individual stars of multiple-star systems.

The new discovery supports the possible existence of such planets, giving exoplanet discoverers new happy hunting grounds.

Emmanuel Di Folco, co-author of the paper, concludes: "Almost half the Sun-like stars were born in binary systems. This means that we have found a mechanism to sustain planet formation that applies to a significant number of stars in the Milky Way. Our observations are a big step forward in truly understanding planet formation."

Organic molecules in Titan's atmosphere are intriguingly skewed

An ALMA image of the distribution of the organic molecule HNC in the upper atmosphere of Saturn's moon Titan. 

The denser, brighter concentrations are shown near the moon's north and south poles. 

Their shifted, off-axis locations were unexpected and could help researchers better understand Titan's complex atmospheric processes. 

The globe outline represents Titan's orientation at the time of the observations. 

Credit: NRAO/AUI/NSF; M. Cordiner et al./NASA

While studying the atmosphere on Saturn's moon Titan, scientists discovered intriguing zones of organic molecules unexpectedly shifted away from its north and south poles.

These misaligned features seem to defy conventional thinking about Titan's windy atmosphere, which should quickly smear out such off-axis concentrations.

"This is an unexpected and potentially groundbreaking discovery," said Martin Cordiner, an astrochemist working at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of a study published online today in the Astrophysical Journal Letters.

"These kinds of east-to-west variations have never been seen before in Titan's atmospheric gases. Explaining their origin presents us with a fascinating new problem."

This discovery, made during a remarkably brief three-minute "snapshot" observation with the Atacama Large Millimeter/submillimeter Array (ALMA), may help astronomers better understand the processes that shape this world's complex chemistry.

Titan's atmosphere has long been of interest because it acts as a chemical factory, using energy from the Sun and Saturn's magnetic field to produce a wide range of organic molecules.

Studying this complex chemistry may provide insights into the properties of Earth's very early atmosphere, which may have shared many chemical characteristics with present-day Titan.

An ALMA image of the distribution of the organic molecule HC3N in the upper atmosphere of Saturn's moon Titan. 

The denser, brighter concentrations are shown near the moon's north and south poles. 

Their shifted, off-axis locations were unexpected and could help researchers better understand Titan's complex atmospheric processes. 

The globe outline represents Titan's orientation at the time of the observations. 

Credit: NRAO/AUI/NSF; M. Cordiner et al./NASA

The researchers used ALMA's extreme sensitivity and resolution to track the atmospheric distributions of hydrogen isocyanide (HNC) and cyanoacetylene (HC3N), which initially appeared to be concentrated evenly over Titan's north and south poles.

These findings were consistent with observations made by NASA's Cassini spacecraft, which found high concentrations of some gases over whichever pole is experiencing winter on Titan.


Recent observations of comet Lemmon provided a 3-D view of the inner coma, including detailed mapping of the molecule HCN (made of one hydrogen, one carbon and one nitrogen), shown here, as well as HNC and formaldehyde.

Visualization by Brian R. Kent/NRAOThe surprise came when the research

ers compared the gas concentrations at different levels in the atmosphere. At the highest altitudes, the pockets of organic molecules were shifted away from the poles.

These off-pole concentrations are unexpected because the fast-moving, east-west winds in Titan's middle atmosphere should thoroughly mix the molecules formed there.

The researchers do not have an obvious explanation for these findings yet.

"It seems incredible that chemical mechanisms could be operating on rapid enough timescales to cause enhanced 'pockets' in the observed molecules," said Conor Nixon, a planetary scientist at Goddard and a coauthor of the paper.

"We would expect the molecules to be quickly mixed around the globe by Titan's winds."

An ALMA image of the distribution of the organic molecule HC3N at intermediate-to-lower elevations in the atmosphere of Saturn's moon Titan. 

The denser, brighter concentrations are oriented more evenly about the poles than is observed for HC3N at higher elevations. 

The globe outline represents Titan's orientation at the time of the observations. 

Credit: NRAO/AUI/NSF; M. Cordiner (NASA) et al.

At the moment, the scientists are considering thermal or other effects tied to interaction with Saturn's powerful magnetic field, which extends far enough to engulf Titan, as potential sources of this skewed molecular concentration.

"Alternatively, I don't think we could rule out some kind of peculiar atmospheric circulation pattern," speculates Cordiner.

This marks ALMA's first foray into atmospheric studies of a major body in our Solar System.

Further observations are expected to improve our understanding of the atmosphere and ongoing processes on Titan and other objects throughout our Solar System.

Titan is in some ways the most Earthlike body in the Solar System, with a thick atmosphere and prominent lakes, rivers, and seas.

In place of water, however, Titan's frigid surface flows with liquid organic molecules, including methane (CH4) and ethane (C2H6).

"These ALMA observations give us new insights into how organic molecules, the building blocks of life, form and evolve in a planet-like environment," said Anthony Remijan, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Va., and coauthor on the paper.

"It is exciting to imagine the new discoveries ALMA will enable as we look more deeply at other interesting objects in our Solar System."

ESO ALMA: Detection of organic molecule iso-propyl cyanide in interstellar clouds

The image shows dust and molecules in the central region of our galaxy. 

The background image shows the dust emission in a combination of data obtained with the APEX telescope and the Planck space observatory at a wavelength around 860 micrometers. 

The organic molecule iso-propyl cyanide with a branched carbon backbone (i-C3H7CN, left) as well as its straight-chain isomer normal-propyl cyanide (n-C3H7CN, right) were both detected with the Atacama large millimeter/submillimeter array in the star-forming region Sgr B2, about 300 light years away from the Galactic center Sgr A*. 

Credit: MPIfR/A. Weiss (background image), University of Cologne/M. Koerber (molecular models), MPIfR/A. Belloche (montage)

Scientists from the Max Planck Institute for Radio Astronomy, Cornell University, and the University of Cologne have for the first time detected a carbon-bearing molecule with a "branched" structure in interstellar space.

The molecule, iso-propyl cyanide (i-C3H7CN), was discovered in a giant gas cloud called Sagittarius B2, a region of ongoing star formation close to the center of our galaxy that is a hot-spot for molecule-hunting astronomers.

The branched structure of the carbon atoms within the iso-propyl cyanide molecule is unlike the straight-chain carbon backbone of other molecules that have been detected so far, including its sister molecule normal-propyl cyanide.

The discovery of iso-propyl cyanide opens a new frontier in the complexity of molecules found in regions of star formation, and bodes well for the presence of amino acids, for which this branched structure is a key characteristic.

The results are published in this week's issue of Science.

While various types of molecules have been detected in space, the kind of hydrogen-rich, carbon-bearing (organic) molecules that are most closely related to the ones necessary for life on Earth appear to be most plentiful in the gas clouds from which new stars are being formed.

"Understanding the production of organic material at the early stages of star formation is critical to piecing together the gradual progression from simple molecules to potentially life-bearing chemistry," says Arnaud Belloche from the Max Planck Institute for Radio Astronomy, the lead author of the paper.

The search for molecules in interstellar space began in the 1960's, and around 180 different molecular species have been discovered so far.

Each type of molecule emits light at particular wavelengths, in its own characteristic pattern, or spectrum, acting like a fingerprint that allows it to be detected in space using radio telescopes.

Until now, the organic molecules discovered in star-forming regions have shared one major structural characteristic: they each consist of a "backbone" of carbon atoms that are arranged in a single and more or less straight chain.

The new molecule discovered by the team, iso-propyl cyanide, is unique in that its underlying carbon structure branches off in a separate strand.

"This is the first ever interstellar detection of a molecule with a branched carbon backbone," says Holger Müller, a spectroscopist at the University of Cologne and co-author on the paper, who measured the spectral fingerprint of the molecule in the laboratory, allowing it to be detected in space.

But it is not just the structure of the molecule that surprised the team, it is also plentiful, at almost half the abundance of its straight-chain sister molecule, normal-propyl cyanide (n-C3H7CN), which the team had already detected using the single-dish radio telescope of the Institut de Radioastronomie Millimétrique (IRAM) a few years ago.

"The enormous abundance of iso-propyl cyanide suggests that branched molecules may in fact be the rule, rather than the exception, in the interstellar medium," says Robin Garrod, an astrochemist at Cornell University and a co-author of the paper.

The central region of the Milky Way above the antennas of the ALMA observatory. 

The direction to the Galactic center is halfway between Antares, the brightest star visible in the picture and the tip of an ALMA antenna in the foreground (second from right). 

Credit: Y. Beletsky (LCO)/ESO

The team used the Atacama Large Millimeter/submillimeter Array (ALMA), in Chile, to probe the molecular content of the star-forming region Sagittarius B2 (Sgr B2).

This region is located close to the Galactic Center, at a distance of about 27,000 light years from the Sun, and is uniquely rich in emission from complex interstellar organic molecules.

"Thanks to the new capabilities offered by ALMA, we were able to perform a full spectral survey toward Sgr B2 at wavelengths between 2.7 and 3.6 mm, with sensitivity and spatial resolution ten times greater than our previous survey," explains Belloche.

"But this took only a tenth of the time." The team used this spectral survey to search systematically for the fingerprints of new interstellar molecules.

"By employing predictions from the Cologne Database for Molecular Spectroscopy (CDMS), we could identify emission features from both varieties of propyl cyanide," says Müller.

As many as 50 individual features for i-propyl cyanide and even 120 for n-propyl cyanide were unambiguously identified in the ALMA spectrum of Sgr B2.

The two molecules, each consisting of 12 atoms, are also the joint-largest molecules yet detected in any star-forming region.

Journal Reference:
Arnaud Belloche, Robin T. Garrod, Holger S. P. Müller, and Karl M. Menten. "Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide." Science, 26 September 2014: 1584-1587 DOI: 10.1126/science.1256678

ESO ALMA: Violent origins of disc galaxies probed

Each of the colourful objects in this image illustrates one of 30 merging galaxies. 

The contours in the individual galaxies indicate the dispersion of carbon monoxide while the color represents the motion of gas. 

Gas that is moving away from us appears red while the blue colour shows gas that is approaching. 

The contours together with the transition from red to blue indicate a gaseous disc that is rotating about the center of the galaxy. Credit: ALMA (ESO /NAOJ /NRAO) /SMA /CARMA /IRAM /J. Ueda et al.

For decades scientists have believed that galaxy mergers usually result in the formation of elliptical galaxies.

Now, for the the first time, researchers using the Atacama Large Millimeter/sub-millimeter Array (ALMA) and a host of other radio telescopes have found direct evidence that merging galaxies can instead form disc galaxies, and that this outcome is in fact quite common.

This surprising result could explain why there are so many spiral galaxies like the Milky Way in the Universe.

An international research group led by Junko Ueda, a Japan Society for the Promotion of Science postdoctoral fellow, has made surprising observations that most galaxy collisions in the nearby Universe, within 40 million light-years from Earth, result in so-called disc galaxies.

Disc galaxies, including spiral galaxies like the Milky Way and lenticular galaxies, are defined by pancake-shaped regions of dust and gas, and are distinct from the category of elliptical galaxies.

It has, for some time, been widely accepted that merging disc galaxies would eventually form an elliptically shaped galaxy.

During these violent interactions the galaxies do not only gain mass as they merge or cannibalise each-other, but they are also changing their shape throughout cosmic time, and therefore changing type along the way.

Computer simulations from the 1970s predicted that mergers between two comparable disc galaxies would result in an elliptical galaxy.

The simulations predict that most galaxies today are elliptical, clashing with observations that over 70% of galaxies are in fact disc galaxies.

However, more recent simulations have suggested that collisions could also form disc galaxies.


This artist’s impression shows the merger between two galaxies leading to the formation of a disc galaxy. 

Upon merging, the shape of the galaxies is disturbed by their mutual gravitational interaction and results in a galaxy with a disc structure.

Gas that is moving away from us appears red while the blue colour shows gas that is approaching. 

The contours together with the transition from red to blue indicate a gaseous disc that is rotating about the centre of the galaxy.

The movie shows the collision of two disc galaxies, but the actual shape of galaxies prior to the collision in this study is not known. Credit: NAOJ

To identify the final shapes of galaxies after mergers observationally, the group studied the distribution of gas in 37 galaxies that are in their final stages of merging.

The Atacama Large Millimeter/sub-millimeter Array (ALMA) and several other radio telescopes were used to observe emission from carbon monoxide (CO), an indicator of molecular gas.

The team's research is the largest study of molecular gas in galaxies to date and provides unique insight into how the Milky Way might have formed.

Their study revealed that almost all of the mergers show pancake-shaped areas of molecular gas, and hence are disc galaxies in the making.

Ueda explains: "For the first time there is observational evidence for merging galaxies that could result in disc galaxies. This is a large and unexpected step towards understanding the mystery of the birth of disc galaxies."

Nonetheless, there is a lot more to discover. Ueda added: "We have to start focusing on the formation of stars in these gas discs."

"Furthermore, we need to look farther out in the more distant Universe. We know that the majority of galaxies in the more distant Universe also have discs."

"We however do not yet know whether galaxy mergers are also responsible for these, or whether they are formed by cold gas gradually falling into the galaxy."

"Maybe we have found a general mechanism that applies throughout the history of the Universe."

More information: Research paper on Astro-Ph: arxiv.org/abs/1407.6873

NASA's 3-D Study of Comets Reveals Chemical Factory at Work

This rotating 3-D map shows how HNC molecules (made of hydrogen, carbon and nitrogen) are released from the nucleus of comet Lemmon and then spread evenly throughout the atmosphere, or coma. 

Similar maps revealed that HNC and formaldehyde are produced in the coma, rather than the comet's nucleus. 

Image courtesy Brian Kent /NRAO /AUI /NSF.

A NASA-led team of scientists has created detailed 3-D maps of the atmospheres surrounding comets, identifying several gases and mapping their spread at the highest resolution ever achieved.

"We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets," said Martin Cordiner, a researcher working in the Goddard Center for Astrobiology at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Cordiner led the international team of researchers.

Almost unheard of for comet studies, the 3-D perspective provides deeper insight into which materials are shed from the nucleus of the comet and which are produced within the atmosphere, or coma.

This helped the team nail down the sources of two key organic, or carbon-containing, molecules.

The observations were conducted in 2013 on comets Lemmon and ISON using the Atacama Large Millimeter/submillimeter Array (ALMA), a network of high-precision antennas in Chile. These comets are the first to be studied with ALMA.

The ALMA observations combine a high-resolution 2-D image of a comet's gases with a detailed spectrum at each point.

From these spectra, researchers can identify the molecules present at every point and determine their velocities (speed plus direction) along the line-of-sight; this information provides the third dimension - the depth of the coma.

"So, not only does ALMA let us identify individual molecular species in the coma, it also gives us the ability to map their locations with great sensitivity," said Anthony Remijan, a scientist with the National Radio Astronomy Observatory, one of the organizations that operates ALMA, and a co-author of the study.

The researchers reported results for three molecular species, focusing primarily on two whose sources have been difficult to discern (except in comet Halley).

The 3-D maps indicated whether each molecule was flowing outward evenly in all directions or coming off in jets or in clumps.

In each comet, the team found that two species - formaldehyde and HNC (made of one hydrogen, one nitrogen and one carbon) - were produced in the coma.

For formaldehyde, this confirmed what researchers already suspected, but the new maps contained enough detail to resolve clumps of the material moving into different regions of the coma day-by-day and even hour-by-hour.

For HNC, the maps settled a long-standing question about the material's source. Initially, HNC was thought to be pristine interstellar material coming from the nucleus of a comet, whereas later work suggested other possible sources.

The new study provided the first proof that HNC is produced during the breakdown of large molecules or organic dust in the coma.

"Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to early Earth, thereby fueling the emergence of life," said Michael Mumma, Director of the Goddard Center for Astrobiology, and a co-author on the study.

"These observations open a new window on this poorly known component of cometary organics."

ALMA pinpoints Pluto to help guide NASA's New Horizons spacecraft

The cold surface of Pluto and its largest moon Charon as seen with ALMA on July 15, 2014. 

Credit: NRAO/AUI/NSF

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) are making high-precision measurements of Pluto's location and orbit around the Sun to help NASA's New Horizons spacecraft accurately home in on its target when it nears Pluto and its five known moons in July 2015.

Though observed for decades with ever-larger optical telescopes on Earth and in space, astronomers are still working out Pluto's exact position and path around our Solar System.

ALMA - The Atacama Array

This lingering uncertainty is due to Pluto's extreme distance from the Sun (approximately 40 times farther out than the Earth) and the fact that we have been studying it for only about one-third of its orbit.

Pluto was discovered in 1930 and takes 248 years to complete one revolution around the Sun.

"With these limited observational data, our knowledge of Pluto's position could be wrong by several thousand kilometers, which compromises our ability to calculate efficient targeting maneuvers for the New Horizons spacecraft," said New Horizons Project Scientist Hal Weaver, from the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

NASA's New Horizons spacecraft

The New Horizons team made use of the ALMA positioning data, together with newly analyzed visible light measurements stretching back to Pluto's discovery, to determine how to perform the first such scheduled course correction for targeting, known as a Trajectory Correction Maneuver (TCM), in July.

This maneuver helped ensure that New Horizons uses the minimum fuel to reach Pluto, saving as much as possible for a potential extended mission to explore Kuiper Belt objects after the Pluto system flyby is complete.

Animated image of ALMA data showing the motion of the moon Charon around the icy dwarf planet Pluto. 

Credit: B. Saxton (NRAO/AUI/NSF)

To prepare for this first TCM, astronomers needed to pinpoint Pluto's position using the most distant and most stable reference points possible.

Finding such a reference point to accurately calculate trajectories of such small objects at such vast distances is incredibly challenging.

Normally, stars at great distances are used by optical telescopes for astrometry (the positioning of things on the sky) since they change position only slightly over many years.

For New Horizons, however, even more precise measurements were necessary to ensure its encounter with Pluto would be as on-target as possible.

The most distant and most apparently stable objects in the Universe are quasars, galaxies more than 10 billion light-years away.

Though quasars appear very dim to optical telescopes, they are incredibly bright at radio wavelengths, particularly the millimeter wavelengths that ALMA can see.

Ed Fomalont

"The ALMA astrometry used a bright quasar named J1911-2006 with the goal to cut in half the uncertainty of Pluto's position," said Ed Fomalont, an astronomer with the National Radio Astronomy Observatory in Charlottesville, Virginia, and currently assigned to ALMA's Operations Support Facility in Chile.

ALMA was able to study Pluto and its largest moon Charon by picking up the radio emission from their cold surfaces, which are about 43 degrees Kelvin (-230 degrees Celsius).

The team first observed these two icy worlds in November 2013, and then three more times in 2014, once in April and twice in July. Additional observations are scheduled for October 2014.

"By taking multiple observations at different dates, we allow Earth to move along its orbit, offering different vantage points in relation to the Sun," said Fomalont.

"Astronomers can then better determine Pluto's distance and orbit." This astronomical technique is called measuring Pluto's parallax.

"We are very excited about the state-of-the-art capabilities that ALMA brings to bear to help us better target our historic exploration of the Pluto system," said New Horizons Principal Investigator Alan Stern of the Southwest Research Institute in Boulder, Colorado.

"We thank the entire ALMA team for their support and for the beautiful data they are gathering for New Horizons."

Atacama Array (ALMA) detects star forming molecular gas

An artist’s conception of the environment around GRB 020819B based on ALMA observations. 

Image Credit: NAOJ

Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of researchers reports the first-ever detection of molecular gas, the fuel for star formation, in two galaxies that were previously rocked by gamma ray bursts (GRBs), the brightest explosions in the Universe.

These new observations revealed that the molecular gas was concentrated toward the centers of the galaxies, while the GRBs occurred in unusual environments that were surprisingly bereft of gas yet rich in dust.

The researchers speculate that the dearth of molecular gas around the GRBs was due to strong ultraviolet (UV) radiation from young, massive stars, which can break apart the molecules of gas while leaving the dust relatively undisturbed.

The GRBs, dubbed GRB 020819B and GRB 051022, are located approximately 4.3 billion and 6.9 billion light-years away from Earth, respectively.

Astronomer Bunyo Hatsukade, assistant professor at the Chile Observatory of the National Astronomical Observatory of Japan (NAOJ), led the research group that studied the GRB host galaxies. The results are published in the journal Nature.

ALMA's unprecedented sensitivity made it possible to make the first detection ever of carbon monoxide (CO) gas in a GRB host galaxy.

ALMA's unparalleled high resolution also revealed GRB 020819B occurred in a galaxy where the molecular gas was concentrated at the nuclear region while dust was concentrated at the site of the GRB.

The ratio of dust to molecular gas at the GRB site is ten or more times higher than in normal environments. It is the first time that the spatial distribution of molecular gas and dust in the GRB host galaxies is revealed.

Currently, GRBs are classified as either long- or short-duration.

• A long-duration GRB, which lasts two seconds or longer, is believed to be generated by the supernova explosion of a star 40 or more times the mass of our Sun. 
• Short GRBs last less than two seconds and are associated with the collision and merger of neutron stars.

ESO ALMA upgrade to supercharge Event Horizon Telescope

ALMA's new hydrogen maser atomic clock arrives and is ready for installation at the ALMA high site. Supplemental oxygen is used due to the thin air at that altitude (5,000 meters, 16,500 feet).

The team includes Jay Blanchard, Univ. Concepcion (left); Christophe Jacques, NRAO (front); Jack Meadows, NRAO (back); and Enrique Garcia, ALMA Correlator Group (right, partly obscured). Credit: Carlos Padilla (NRAO/AUI/NSF)


Scientists recently upgraded the Atacama Large Millimeter/submillimeter Array (ALMA) by installing an ultraprecise atomic clock at ALMA's Array Operations Site, home to the observatory's supercomputing correlator.

This upgrade will eventually allow ALMA to synchronize with a worldwide network of radio astronomy facilities collectively known as the Event Horizon Telescope (EHT).

Once assembled, the EHT, with ALMA as the largest and most sensitive site, will form an Earth-sized telescope with the magnifying power required to see details at the edge of the supermassive black hole at the center of the Milky Way.

Before ALMA can lend its unmatched capabilities to this and similar scientific observations, however, it must first transform into a different kind of instrument known as a phased array.

This new version of ALMA will allow its 66 antennas to function as a single radio dish 85 meters in diameter. It's this unified power coupled with ultraprecise timekeeping that will allow ALMA to link with other observatories.

A major milestone along this path was achieved recently when the science team performed what could be considered a "heart transplant" on the telescope by installing a custom-built atomic clock powered by a hydrogen maser.

This new timepiece uses a process similar to a laser to amplify a single pure tone, cycles of which are counted to produce a highly accurate 'tick'.

ALMA's original time reference, a clock based on rubidium gas, will be retired and used as a spare after the maser is completely integrated with ALMA's electronics.

Shep Doeleman, the principal investigator of the ALMA Phasing Project and assistant director of the Massachusetts Institute of Technology's Haystack Observatory, participated during the maser installation via remote video link.

"Once the phasing is complete, ALMA will use the ultraprecise ticking of this new atomic clock to join the aptly named Event Horizon Telescope as the most sensitive participating site, increasing sensitivity by a factor of 10," he said.


Expanding the Frontiers of Astronomy
Supermassive black holes lurk at the center of all galaxies and contain millions or even billions of times the mass of our Sun. These space-bending behemoths are so massive that nothing, not even light, can escape their gravitational influence.

Understanding how a black hole devours matter, powers jets of particles and energy, and distorts space and time are leading challenges in astronomy and physics.

The black hole at the center of the Milky Way is a 4 million solar mass giant located approximately 26,000 light-years from Earth in the direction of the constellation Sagittarius.

It is shrouded from optical telescopes by dense clouds of dust and gas, which is why observatories like ALMA, which operate at the longer millimeter and submillimeter wavelengths, are essential to study its properties.

Supermassive black holes can be relatively tranquil or they can flare up and drive incredibly powerful jets of subatomic particles deep into intergalactic space; quasars seen in the very early Universe are an extreme example.

The fuel for these jets comes from in-falling material, which becomes superheated as it spirals inward.

Astronomers hope to capture our Galaxy's central black hole in the process of actively feeding to better understand how black holes affect the evolution of our Universe and how they shape the development of stars and galaxies.

ALMA maser installation team in front of a small portion of the ALMA antennas. Left to right: Jay Blanchard, Univ. Concepcion; Jack Meadows, NRAO; Neil Nagar, Univ. Concepcion; and Christophe Jacques, NRAO. Credit: Carlos Padilla (NRAO/AUI/NSF)

A phased ALMA will arrive just in time to observe a highly anticipated cosmic event, the collision of a giant cloud of dust and gas known as G2 with our Galaxy's central supermassive black hole.

It is speculated that this collision may awaken this sleeping giant, generating extreme energy and possibly fueling a jet of subatomic particles, a highly unusual feature in a mature spiral galaxy like the Milky Way. The collision is predicted to begin in 2014 and will likely continue for more than a year.

High resolution imaging of the event horizon also could improve our understanding of how the highly ordered Universe as described by Einstein meshes with the messy and chaotic cosmos of quantum mechanics – two systems for describing the physical world that are woefully incompatible on the smallest of scales.

Other independent research will target molecules in space to determine whether or not the fundamental constants of nature have changed over cosmic time.

ESO ALMA: Chile Earthquake Leaves Astronomy Observatories Unscathed

The epicenter for the 8.2 earthquake that rocked Chile on Tuesday was approximately 310 miles (500 km) from the Very Large Telescope and ALMA.

Credit: ESO

The massive earthquake that struck Chile on Tuesday (April 1) left three main European-built observatories in the region relatively untouched despite causing damage and a tsunami along the country's western coast.

The powerful 8.2-magnitude earthquake struck about 60 miles (95 kilometers) northwest of the coastal city Iquique, causing several landslides and triggering a tsunami that rose some 7 feet (2.1 meters).

The earthquake struck at 8:46 p.m. local time (7:46 EDT).

A powerful 7.6-magnitude aftershock rattled the area late Wednesday night (April 2).

The European Southern Observatory (ESO) operates three major observatories in Chile, each with multiple telescopes: the Paranal Observatory, which is home to Europe's Very Large Telescope; the La Silla Observatory, which hosts various telescopes, such as the 2.2-m Max-Planck telescope, 1.2-m Swiss Leonhard Euler Telescope and the 1.5-m Danish Telescope; and ALMA and APEX, or the Atacama Large Millimeter/submillimeter Array and the Atacama Pathfinder Experiment. (Also in the Chajnantor region is Caltech's Chajnantor Observatory.)

The epicenter was located approximately 310 miles (500 km) from both the ALMA/APEX and Paranal sites.

"The quake was felt at the ALMA camp as a prolonged swaying, which lasted for about 2 minutes," the ALMA Observatory said in a statement.

However, none of the ESO facilities reported any damage.