ALMA Takes Close Look at Drama of Starbirth

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Stunning ALMA and NTT image of Newborn Star

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ALMA’s view of the outflow associated with the Herbig-Haro object HH 46/47

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The Herbig-Haro object HH 46/47 seen with ESO’s New Technology Telescope

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Wide-field view of the star-forming region around the Herbig-Haro object HH 46/47 

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The Herbig-Haro object HH 46/47 in the constellation of Vela

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Zooming in on the Herbig-Haro object HH 46/47

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have obtained a vivid close-up view of material streaming away from a newborn star. By looking at the glow coming from carbon monoxide molecules in an object called Herbig-Haro 46/47 they have discovered that its jets are even more energetic than previously thought. The very detailed new images have also revealed a previously unknown jet pointing in a totally different direction.

Young stars are violent objects that eject material at speeds as high as one million kilometres per hour. When this material crashes into the surrounding gas it glows, creating a Herbig-Haro object [1]. A spectacular example is named Herbig-Haro 46/47 and is situated about 1400 light-years from Earth in the southern constellation of Vela (The Sails). This object was the target of a study using ALMA during the Early Science phase, whilst the telescope was still under construction and well before the array was completed.

The new images reveal fine detail in two jets, one coming towards Earth and one moving away. The receding jet was almost invisible in earlier pictures made in visible light, due to obscuration by the dust clouds surrounding the new-born star. ALMA has not only provided much sharper images than earlier facilities but also allowed astronomers to measure how fast the glowing material is moving through space.

These new observations of Herbig-Haro 46/47 revealed that some of the ejected material had velocities much higher than had been measured before. This means the outflowing gas carries much more energy and momentum than previously thought.

The team leader and first author of the new study, Héctor Arce (Yale University, USA) explains that "ALMA's exquisite sensitivity allows the detection of previously unseen features in this source, like this very fast outflow. It also seems to be a textbook example of a simple model where the molecular outflow is generated by a wide-angle wind from the young star."

The observations were obtained in just five hours of ALMA observation time – even though ALMA was still under construction at the time – similar quality observations with other telescopes would have taken ten times longer.

"The detail in the Herbig-Haro 46/47 images is stunning. Perhaps more stunning is the fact that, for these types of observations, we really are still in the early days. In the future ALMA will provide even better images than this in a fraction of the time," adds Stuartt Corder (Joint ALMA Observatory, Chile), a co-author on the new paper.

Diego Mardones (Universidad de Chile), another co-author, emphasises that "this system is similar to most isolated low mass stars during their formation and birth. But it is also unusual because the outflow impacts the cloud directly on one side of the young star and escapes out of the cloud on the other. This makes it an excellent system for studying the impact of the stellar winds on the parent cloud from which the young star is formed."

The sharpness and sensitivity achieved by these ALMA observations also allowed the team to discover an unsuspected outflow component that seems to be coming from a lower mass companion to the young star. This secondary outflow is seen almost at right angles to the principal object and is apparently carving its own hole out of the surrounding cloud.

Arce concludes that "ALMA has made it possible to detect features in the observed outflow much more clearly than previous studies. This shows that there will certainly be many surprises and fascinating discoveries to be made with the full array. ALMA will certainly revolutionise the field of star formation!"

Notes

[1] The astronomers George Herbig and Guillermo Haro were not the first to see one of the objects that now bear their names, but they were the first to study the spectra of these strange objects in detail. They realised that they were not just clumps of gas and dust that reflected light, or glowed under the influence of the ultraviolet light from young stars, but were a new class of objects associated with shocks created by material ejected at high speeds in star formation regions.

More information

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Southern Observatory (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

This research was presented in a paper entitled "ALMA Observations of the HH 46/47 Molecular Outflow" by Héctor Arce et al, to appear in the Astrophysical Journal.

The team is composed of Héctor G. Arce (Yale University, New Haven, USA), Diego Mardones (Universidad de Chile, Santiago, Chile), Stuartt A. Corder (Joint ALMA Observatory, Santiago, Chile), Guido Garay (Universidad de Chile), Alberto Noriega-Crespo (Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, USA) and Alejandro C. Raga (Instituto de Ciencias Nucleares, Mexico).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It is supported by 15 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world's most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world's largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is the European partner of a revolutionary astronomical telescope ALMA, the largest astronomical project in existence. ESO is currently planning the 39-metre European Extremely Large optical/near-infrared Telescope, the E-ELT, which will become "the world's biggest eye on the sky".

Links

• Research paper
• More about ALMA
• Photos of ALMA

Contacts

Héctor Arce
Yale University
New Haven, USA
Tel: +1 203 432 3018
Email: hector.arce@yale.edu

Diego Mardones
Universidad de Chile
Santiago, Chile
Tel: + 56 2 977 1143
Email: dmardone@das.uchile.cl

Stuartt Corder
Joint ALMA Observatory
Santiago, Chile
Email: scorder@alma.cl

Lars Lindberg Christensen
Head, ESO education and Public Outreach Department
Garching bei München, Germany
Cell: +49 173 38 72 621
Email: lars@eso.org

The Strange Attraction of Hot Jupiters

A new ScienceCast video explores the unexpected and exotic characteristics of hot Jupiters
Play it

When the Space Age began, astronomers knew of exactly zero planets outside the solar system.  What a difference 50 years makes. 

Modern, ground-based telescopes and NASA's Kepler spacecraft have now confirmed more than 850 exoplanets, while thousands more await confirmation.   The pace of discovery suggests "there are at least 100 billion planets in our galaxy," says John Johnson of Caltech, who works with data from the Kepler mission. "That's mind-boggling." 

When the hunt for exoplanets began, the focus was on Earth-like worlds, planets like our own that might support alien life in distant solar systems. Yet planets as small as Earth are difficult to detect when they circle stars hundreds of light years away.  Indeed, only a handful have been found so far.

The real haul has been in gas giants, especially “hot Jupiters.”  These are behemoth worlds that orbit close to their parent stars, blocking a fraction of the star’s light when it transits in front. Observations of hot Jupiter “mini-eclipses” have yielded hundreds of discoveries. 

At first considered to be the "chaff" researchers would have to wade through to get to the fainter Earth-like worlds, hot Jupiters are now attracting their own attention.  

Consider the case of "HD189733b," discovered in 2005 by a team working at the Haute-Provence Observatory in France.  Because it is nearby, only 63 light years away, and because it blocks a whopping 3% of the light from its orange-dwarf parent star, astronomers are rapidly learning a great deal.

For one thing, it's blue.  Data obtained by the Hubble Space Telescope suggest that, seen from a distance, the azure disk of HD 189733b would look to the human eye much like Earth.  Indeed, some members of the media have taken to calling it "the other blue planet." 

It is, however, anything but Earthlike.  

In 2007, Heather Knutson of Caltech made a global temperature map of HD189733b using NASA’s infrared Spitzer Space Telescope. She knew it would be hot because HD189733b orbits its star 13 times closer than Mercury.  “Even so, we were impressed by the readings,” she recalls. Temperatures ranged from 1200 F on the nightside to 1700 F on the dayside.  Thermal gradients drive winds as fast as 6000 mph, carrying suffocating heat around the globe. 

The blue color may be caused by silicate particles in the planet’s atmosphere, which scatter blue wavelengths of light from the parent star.  The same physics plays out in Earth’s atmosphere, although the chemicals are different. Silicates are a component of glass, so some researchers have speculated that it is actually raining molten glass on HD189733b. 

The newest observations come from a pair of X-ray observatories. NASA’s Chandra and the ESA’s XMM Newton watched HD189733b transit its star and detected a drop in X-rays three times deeper than the corresponding decrease in optical light. This means the outer atmosphere is larger than anyone expected.

In fact, it is probably boiling away. Authors of the study estimate HD189733b is losing 100 million to 600 million kilograms of mass per second. 

"The extended atmosphere of this planet makes it a bigger target for high-energy radiation from its star, so more evaporation occurs," notes Scott Wolk of the Center for Astrophysics. 

Blasts of stellar radiation hitting the planet at point-blank range could have another effect: auroras that wrap around the planet from pole to pole, orders of magnitude brighter than any Northern Lights in our own solar system. This is speculative, though. 

While the search for Earth-like planets proceeds, hot Jupiters are a welcome albeit unexpected diversion. It makes you wonder, what will we be looking for 50 years from now…? 

Credits:

 Author: Dr. Tony Phillips  | Production editor: Dr. Tony Phillips | Credit: Science@NASA

More information:   Big Weather on Hot Jupiters  - ScienceCast video

Stars fleeing a cosmic crash

ESO 489-056

Credit: ESA/Hubble & NASA
Acknowledgement: Luca Limatola

Astronomical pictures sometimes deceive us with tricks of perspective. Right in the centre of this image, two spiral galaxies appear to be suffering a spectacular collision, with a host of stars appearing to flee the scene of the crash in a chaotic stampede.

However, this is just a trick of perspective. It is true that two spiral galaxies are colliding, but they are millions of light-years away, far beyond the cloud of blue and red stars near the merging spiral. This sprinkling of stars is actually an isolated, irregular dwarf galaxy named ESO 489-056. The dwarf galaxy is actually much more distant than many bright stars in the foreground of the image, which are located much closer to us, in the Milky Way.

ESO 489-056 is located 16 million light-years from Earth in the constellation of Canis Major (The Greater Dog), in our local Universe. It is composed of a few billion red and blue stars — a very small number when compared to galaxies like the Milky Way, which is estimated to contain around 200 to 400 billion stars, or the Andromeda Galaxy, which contains a mind-boggling one trillion.

A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Luca Limatola.

Source: ESA/Hubble - Space Telescope

Hubble explores the origins of modern galaxies

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The Hubble Sequence throughout the Universe's history

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The present day Universe 

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The Universe 4 billion years ago 

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The Universe 11 billion years ago

 

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The Hubble Tuning Fork - Classification of Galaxies

Astronomers see true shapes of galaxies 11 billion years back in time

Astronomers have used observations from Hubble’s CANDELS survey to explore the sizes, shapes, and colours of distant galaxies over the last 80% of the Universe’s history. In the Universe today galaxies come in a variety of different forms, and are classified via a system known as the Hubble Sequence — and it turns out that this sequence was already in place as early as 11 billion years ago.

The Hubble Sequence classifies galaxies according to their morphology and star-forming activity, organising them into a cosmic zoo of spiral, elliptical, and irregular shapes with whirling arms, fuzzy haloes and bright central bulges. Two main types of galaxy are identified in this sequence: elliptical and spiral, with a third type, lenticular, settling somewhere between the two.

This accurately describes what we see in the region of space around us, but how does galaxy morphology change as we look further back in time, to when the Universe was very young?

"This is a key question: when and over what timescale did the Hubble Sequence form?" says BoMee Lee of the University of Massachusetts, USA, lead author of a new paper exploring the sequence. "To do this you need to peer at distant galaxies and compare them to their closer relatives, to see if they too can be described in the same way."

The astronomers used Hubble to look 11 billion years back in time to when the Universe was very young, exploring the anatomy of distant galaxies.

While it was known that the Hubble Sequence holds true as far back as around 8 billion years ago [1], these new observations push a further 2.5 billion years back in cosmic time, covering a huge 80% of the past history of the Universe. Previous studies had also reached into this epoch of the cosmos to study lower-mass galaxies, but none had conclusively also looked at large, mature galaxies like the Milky Way. The new CANDELS observations confirm that all galaxies this far back — big and small alike — fit into the different classifications of the sequence.

"This is the only comprehensive study to date of the visual appearance of the large, massive galaxies that existed so far back in time," says co-author Arjen van der Wel of the Max Planck Institute for Astronomy in Heidelberg, Germany. "The galaxies look remarkably mature, which is not predicted by galaxy formation models to be the case that early on in the history of the Universe."

The galaxies at these earlier times appear to be split between blue star-forming galaxies with a complex structure — including discs, bulges, and messy clumps — and massive red galaxies that are no longer forming stars, as seen in the nearby Universe [2].

Galaxies as massive as the Milky Way or more are rather rare in the young Universe. This scarcity has prevented previous studies from being able to gather a large enough sample of mature galaxies to properly describe their characteristics.

What was needed was a systematic set of observations such as those from Hubble's CANDELS survey, which was large enough to allow the astronomers to analyse a larger number of these galaxies consistently, and in detail [3]. With Hubble's Wide Field Camera 3 (WFC3), the astronomers were able to observe in the infrared part of the spectrum to see how the galaxies appeared in their visible rest-frame [4], which is easier to compare with galaxies in our neighbourhood.

"The huge CANDELS dataset was a great resource for us to use in order to consistently study ancient galaxies in the early Universe," concludes Lee. "And the resolution and sensitivity of Hubble's WFC3 is second to none in the infrared wavelengths needed to carry out this study. The Hubble Sequence underpins a lot of what we know about how galaxies form and evolve — finding it to be in place this far back is a significant discovery."

Notes

[1] Previous studies have looked at the proportions of the different galaxy types back in time (heic1002). The mix of spiral, elliptical, lenticular and peculiar galaxies is different from today, with a great many more peculiars in the distant Universe than we see nearby.

[2] In a related recent paper, Alice Mortlock and collaborators took a different but complementary approach by classifying these distant galaxies by visual inspection. They found that the types of galaxies we see in the Hubble Sequence are well defined in terms of colour, structure, and star formation rates at very large distances from us, but that their morphology is still developing. While the morphology of a galaxy may be the final property to settle, the fundamentals of the Hubble Sequence are set much earlier on.

[3] CANDELS, the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, is the largest project in the history of Hubble, with 902 assigned orbits of observing time. It is being carried out with two cameras on board Hubble – WFC3 and ACS – and aims to explore galactic evolution in the early Universe, and the very first seeds of cosmic structure at less than one billion years after the Big Bang.

[4] Previous studies of this period of cosmic history were inconclusive as they were limited to visible light, showing only the redshifted ultraviolet emission of the galaxies, which highlights star formation. As this star formation dominated the observations, the galaxies appeared to be clumpy and messy, with no resemblance to the galaxy shapes we see around us today. By pushing into the infrared part of the spectrum the astronomers could observe how these distant galaxies appear in their visible rest frame (which is now redshifted).

Notes for editors

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

These results are described in a paper entitled "CANDELS: The correlation between galaxy morphology and star formation activity as Z~2", to appear in The Astrophysical Journal.

[1] The international team of astronomers in this study consists of B. Lee (University of Massachusetts, USA), M. Giavalisco (University of Massachusetts, USA), C. C. Williams (University of Massachusetts, USA), Y. Guo (University of California, USA), J. Lotz (Space Telescope Science Institute, Baltimore, USA), A. van der Wel (Max Planck Institute for Astronomy, Heidelberg, Germany), H. C. Ferguson (Space Telescope Science Institute, Baltimore, USA), S. M Faber (University of California, USA), A. Koekemoer (Space Telescope Science Institute, Baltimore, USA), N. Grogin (Space Telescope Science Institute, Baltimore, USA), D. Kocevski (University of Kentucky, USA), C. J. Conselice (University of Nottingham, UK), S. Wuyts (Max Planck Institute for Extraterrestrial Physics, Garching, Germany), A. Dekel (The Hebrew University, Israel), J. Kartaltepe (NOAO-Tuscon, Arizona, USA), E. F. Bell (University of Michigan, USA).

More information

Image credit: NASA, ESA

Links

• Research Paper
• Images of Hubble

Contacts

BoMee Lee
University of Massachusetts
Massachusetts, USA
Tel: +1-413-545-0731
Email: bomee@astro.umass.edu

Arjen van der Wel
Max Planck Institute for Astronomy
Heidelberg, Germany
Tel: +49-6221-528-461
Email: vdwel@mpia.de

Mauro Giavalisco
University of Massachusetts
Massachusetts, USA
Tel: +1-413-545-4767
Email: mauro@astro.umass.edu

Nicky Guttridge
Hubble/ESA
Garching, Germany
Tel: +49-89-3200-6855
Email: nguttrid@partner.eso.org

The calm before the storm

NGC 799 and NGC 800

Credit:  ESO

This beautiful image portrays the galaxies NGC 799 (below) and NGC 800 (above) located in the constellation of Cetus (The Whale). This pair of galaxies was first observed by the American astronomer Lewis Swift back in 1885.

Located at a distance of about 300 million light-years, our face-on view allows us to clearly appreciate their shapes. Like the Milky Way — our galaxy — these objects are both spiral galaxies, with characteristic long arms winding towards a bright bulge at the centre. In the prominent spiral arms, a large number of hot, young, blue stars are forming in clusters (tiny blue dots seen in the image) whereas in the central bulge a large group of cooler, redder, old stars are packed into a compact, almost spherical region.

At first glance, these galaxies look rather similar, but the devil is in the detail. Apart from the obvious difference in size, only NGC 799 has a bar structure, extending from its central bulge, and the spiral arms wind out from the ends of the bar. Galactic bars are thought to act as a mechanism that channels gas from the spiral arms to the centre, intensifying star formation. A supernova was also observed in NGC 799 in 2004, and was given the name SN2004dt.

Another interesting differentiating feature is the number of spiral arms. The small NGC 800 has three bright, knotty spiral arms, whilst NGC 799 only has two relatively dim, but broad spiral arms. These start at the end of the bar and wrap nearly completely around the galaxy forming a structure that looks almost like a ring.

While it might seem that this image depicts two impressive close spiral galaxies coexisting in an everlasting peace, nothing can be further than the truth. We could be just witnessing the calm before the storm. We don’t know exactly what the future will bring, but typically, when two galaxies are close enough, they interact over hundreds of millions of years by means of gravitational disturbances. In some cases, only minor interactions occur, causing shape distortions, but sometimes galaxies collide, merging to form a single, new and larger galaxy.

The image was obtained using the FORS1 instrument on the 8.2-metre ESO Very Large Telescope (VLT) atop Cerro Paranal, Chile. It combines exposures taken through three filters (B, V, R).

Five asteroids can also be seen — can you find them all? The asteroids moved between the different exposures leaving colourful streaks in the image.

Source:   ESO

Mysterious magnetar boasts one of strongest magnetic fields in Universe

Magnetic loop on magnetar SGR 0418

Artist impression of a magnetar with a ‘magnetic loop'. This is the interpretation of data collected by ESA’s XMM-Newton space telescope of the magnetar known as SGR 0418, which boasts one of the strongest magnetic fields in the Universe. In order to maintain such a strong magnetic field, the magnetar must have a twisted internal magnetic field, which manifests itself as a small region on the star’s surface, somewhat similar to the localised magnetic fields anchored in sunspots on the Sun. Copyright: ESA/ATG Medialab

 

Scientists using ESA’s XMM-Newton space telescope have discovered that a curious dead star has been hiding one of the strongest magnetic fields in the Universe all along, despite earlier suggestions of an unusually low magnetic field. 

The object, known as SGR 0418+5729 (or SGR 0418 for short), is a magnetar, a particular kind of neutron star. 

A neutron star is the dead core of a once massive star that collapsed in on itself after burning up all its fuel and exploding in a dramatic supernova event. They are extraordinarily dense objects, packing more than the mass of our Sun into a sphere only some 20 km across – about the size of a city. 

A small proportion of neutron stars form and live briefly as magnetars, named for their extremely intense magnetic fields, billions to trillions of times greater than those generated in hospital MRI machines, for example. These fields cause magnetars to erupt sporadically with bursts of high-energy radiation. 

SGR 0418 lies in our galaxy, about 6500 light years from Earth. It was first detected in June 2009 by space telescopes including NASA’s Fermi and Roscosmos’ Koronas-Photon when it suddenly lit up in X-rays and soft gamma rays. It has been studied subsequently by a fleet of observatories, including ESA’s XMM-Newton. 

“Until very recently, all indications were that this magnetar had one of the weakest surface magnetic fields known; at 6 x 10¹² Gauss, it was roughly a 100 times lower than for typical magnetars,” said Andrea Tiengo of the Istituto Universitario di Studi Superiori, Pavia, Italy, and lead author of the paper published inNature.

“Understanding these results was a challenge. However, we suspected that SGR 0418 was in fact hiding a much stronger magnetic field, out of reach of our usual analytical techniques.” 

Magnetars spin more slowly than neutron stars, but still complete a rotation within a few seconds. The normal way of determining the magnetic field of a magnetar is to measure the rate at which the spin is declining. Three years of observations of SGR 0418 had led astronomers to infer a weak magnetic field. 

The new technique developed by Dr Tiengo and his collaborators involves searching for variations in the X-ray spectrum of the magnetar over extremely short time intervals as it rotates. This method allows astronomers to analyse the magnetic field in much more detail and has revealed SGR 0418 as a true magnetic monster. 

“To explain our observations, this magnetar must have a super-strong, twisted magnetic field reaching 10¹⁵ Gauss across small regions on the surface, spanning only a few hundred metres across,” said Dr Tiengo. 

“On average, the field can appear fairly weak, as earlier results have suggested. But we are now able to probe sub-structure on the surface and see that the field is very strong locally.” 

A simple analogy can be made with localised magnetic fields anchored in sunspots on the Sun, where a change in configuration can suddenly lead to their collapse and the production of a flare or, in the case of SGR 0418, a burst of X-rays. 

“The spectral data provided by XMM-Newton, combined with a new way of analysing the data, allowed us to finally make the first detailed measurements of the magnetic field of a magnetar, confirming it as one of the largest values ever measured in the Universe,” adds Norbert Schartel, ESA’s XMM-Newton Project Scientist. 

“We now have a new tool to probe the magnetic fields of other magnetars, which will help constrain models of these exotic objects.” 

Notes for Editors

To read this news article in depth, see Weakling magnetar reveals hidden strength on ESA’s Science & Technology pages. 

 “A variable absorption feature in the X-ray spectrum of a magnetar,” by A. Tiengo et al is published in Nature, 15 August 2013. 


For further information, please contact:
 
Markus Bauer
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954
Email: markus.bauer@esa.int

Andrea Tiengo
Istituto Universitario di Studi Superiori and Istituto Nazionale di Fisica Nucleare Pavia, Italy and Istituto di Astrofisica Spaziale e Fisica Cosmica/INAF Milan, Italy
Phone: +39-0382-375865 or +39-02-23699-468
Email: andrea.tiengo@iusspavia.it

Norbert Schartel
XMM-Newton Project Scientist
Tel: +34 91 8131 184
Email: Norbert.Schartel@sciops.esa.int

Poised for Discovery: Gemini’s Much-anticipated Infrared Instrument Goes On-sky

This FLAMINGOS-2 near-infrared image details part of the magnificent Swan Nebula (M17), where ultraviolet radiation streaming from young hot stars sculpts a dense region of dust and gas into myriad fanciful forms. M17 lies some 5,200 light-years distant in the constellation Sagittarius and is one of the most massive and luminous star-forming region's in our Galaxy. It is also one of the most studied. Field of view: 5.5 x 4.0 arcmin. Credit: Gemini Observatory/AURA.  Full Resolution TIF (4MB) | Full Resolution JPG (2MB) | Med Resolution JPG (280KB) 

NGC 6300 is an intriguing barred spiral galaxy in the constellation of Ara. This near-infrared image with FLAMINGOS-2 shows the galaxy’s complex arm structure forming a spectacular ring of star formation. The galaxy’s bar also has a strong vein of dust that almost obscures its bright active nucleus –– whose prodigious energy is the result of matter accreting onto a black hole with an estimated mass of 280,000 Suns. Field of view: 3.1 x 2.9 arcmin. Credit: Gemini Observatory/AURA. Full Resolution TIF (2.3MB) | Full Resolution JPG (1.2MB) | Med Resolution JPG (153KB) 

In this near-infrared image, FLAMINGOS-2 peered deep into the heart of spiral galaxy NGC 253, which lies about 11.5 million light-years nearby in the constellation of Sculptor. The new instrument captured an intricate whirlpool of dust spiraling in to a diffuse nuclear region, where violent star formation may be occurring around a supermassive black hole. The instrument also imaged a dusting of star forming sites in its spiral arms. Field of view: 4.8 x 4.1 arcmin. Credit: Gemini Observatory/AURA.   Full Resolution TIF (4MB) | Full Resolution JPG (2MB) | Med Resolution JPG (141KB) 

 

Spiral galaxy NGC 7582 is the brightest member of the Grus Quartet of galaxies, some 60 million light-years distant traveling together through space. In this near-infrared image, FLAMINGOS-2 resolved its high quantity of dust that line NGC 7582’s arms as well as regions rich in star formation. Field of view: 2.5 x 1.7 arcmin. Credit: Gemini Observatory/AURA.  Full Resolution TIF (836KB) | Med Resolution JPG (425KB)

Gemini Observatory’s latest instrument, a powerful infrared camera and spectrograph at Gemini South, reveals its potential in a series of striking on-sky commissioning images released today. 

 

Gemini Observatory’s latest tool for astronomers, a second-generation infrared instrument called FLAMINGOS-2, has “traveled a long road” to begin science observations for the Gemini scientific community. Recent images taken by FLAMINGOS-2 during its last commissioning phase dramatically illustrate that the instrument was worth the wait for astronomers around the world who are anxious to begin using it. 

“It’s already one of our most requested instruments at the Gemini telescopes,” remarks Nancy Levenson, Gemini’s Deputy Director and Head of Science. “We see a long and productive life ahead for FLAMINGOS-2 once astronomers really start using it later this year.” 

“It has not been an easy journey,” says Percy Gomez Gemini’s FLAMINGOS-2 Instrument Scientist, “but thanks to the dedicated work of Gemini engineers and scientists very soon astronomers will be able to use a reliable and robust instrument.” After significant redesign and rebuilds for optimal performance on the Gemini South telescope, FLAMINGOS-2 has proven that it will provide astronomers with a powerful mix of capabilities. These include extreme sensitivity to infrared (heat) radiation from the universe, high-resolution wide-field imaging, and a combination of spectroscopic capabilities that will allow cutting-edge research in topics spanning from the exploration of our Solar System, to the most distant and energetic explosions in our universe. 

While work still remains on some of its spectroscopic features, as well as refining imaging at the edge of its large field of view, Gemini’s team of engineers and scientists has mitigated its most severe risk – potential damage to a large collimator lens that catastrophically cracked during a planned final commissioning in early 2012 (it was later replaced). The thermal environment surrounding this lens – located where the temperature changes periodically for routine switching of masks for multi-object spectroscopy - creates special challenges. It was these temperature changes that initially caused the crack, but a year later procedures and design modifications are now in place to significantly reduce risks to the lens’s integrity and functionality. 

“The Gemini team has done a remarkable job in optimizing this instrument for Gemini and it will soon be everything, and more, that we had envisioned years ago when the project began,” says Steve Eikenberry, who led the team who built FLAMINGOS-2 at the University of Florida. “Like a lot of scientists, I’m anxious to use FLAMINGOS-2 to collect data – specifically, I want to look toward the center of our Galaxy and study binary black holes as well as the mass evolution of the super-massive black hole that lurks at the heart of our Galaxy.” Eikenberry and collaborators are eager to make the most of FLAMINGOS-2’s power as soon as the instrument’s multi-object spectroscopy capability is fully functional. “With most of the challenges behind us, now the fun begins!” Eikenberry said. 

Kevin Stevenson of the University of Chicago already has plans to use FLAMINGOS-2 later this year to study the intriguing exoplanet WASP-18b. This well-known exoplanet is being strongly heated by its ultra-nearby host star and according to Stevenson, “It's even hotter than some of the coolest, low-mass stars known.” Stevenson and his team hope to determine the abundances of water vapor and methane when the planet is eclipsed by its host star. “Our plan is to compare the system's light immediately before and during an eclipse to measure the contribution from the planet. When we do this over several parts of the infrared part of the light spectrum, we can piece together the planet's spectrum and learn about its temperature and composition.” 

The quality and usefulness of FLAMINGOS-2 for these and future projects is reflected in the images released today. They cover a wide range of targets which are representative of the types of science in which FLAMINGOS-2 is expected to excel. In addition, the instrument may later accept an adaptive optics (AO) feed for extremely high-resolution imaging from GeMS (Gemini Multi-conjugate adaptive optics System). 

It is expected that most of these systems, including multi-object spectroscopy, will be fully integrated in 2014 with imaging and long-slit spectroscopy available now. The next round of observations with FLAMINGOS-2 are slated to begin on September 1st.

Contacts:

• Percy Gomez
  Gemini Observatory, La Serena, Chile
  Phone (Desk): 56-51-2-205696
  Email: pgomez@gemini.edu


• Peter Michaud
  Gemini Observatory, Hilo, Hawai‘i
  Office: +1 (808) 974-2510
  Cell: +1 (808) 936-6643
  pmichaud@gemini.edu


• Antonieta Garcia
  Gemini Observatory, La Serena, Chile
  Phone (Desk): 56-51-2-205628
  Cell: 09-69198294
  Email: agarcia@gemini.edu

First Hundred Thousand Years of Our Universe

The microwave sky as seen by Planck

Mottled structure of the CMB, the oldest light in the universe, is displayed in the high-latitude regions of the map. The central band is the plane of our galaxy, the Milky Way. (Courtesy of European Space Agency)

Eric Linder is a theoretical physicist with Berkeley Lab’s Physics Division and member of the Supernova Cosmology Project. (Photo by Roy Kaltschmidt)

Mystery fans know that the best way to solve a mystery is to revisit the scene where it began and look for clues. To understand the mysteries of our universe, scientists are trying to go back as far they can to the Big Bang. A new analysis of cosmic microwave background (CMB) radiation data by researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) has taken the furthest look back through time yet – 100 years to 300,000 years after the Big Bang – and provided tantalizing new hints of clues as to what might have happened.

“We found that the standard picture of an early universe, in which radiation domination was followed by matter domination, holds to the level we can test it with the new data, but there are hints that radiation didn’t give way to matter exactly as expected,” says Eric Linder, a theoretical physicist with Berkeley Lab’s Physics Division and member of the Supernova Cosmology Project. “There appears to be an excess dash of radiation that is not due to CMB photons.”

Our knowledge of the Big Bang and the early formation of the universe stems almost entirely from measurements of the CMB, primordial photons set free when the universe cooled enough for particles of radiation and particles of matter to separate. These measurements reveal the CMB’s influence on the growth and development of the large-scale structure we see in the universe today.

Linder, working with Alireza Hojjati and Johan Samsing, who were then visiting scientists at Berkeley Lab, analyzed the latest satellite data from the European Space Agency’s Planck mission and NASA’s Wilkinson Microwave Anisotropy Probe (WMAP), which pushed CMB measurements to higher resolution, lower noise, and more sky coverage than ever before.

“With the Planck and WMAP data we’re really pushing back the frontier and looking further back in the history of the universe, to regions of high energy physics we previously could not access,” Linder says. “While our analysis shows the CMB photon relic afterglow of the Big Bang being followed mainly by dark matter as expected, there was also a deviation from the standard that hints at relativistic particles beyond CMB light.”

Linder says the prime suspects behind these relativistic particles are “wild” versions of neutrinos, the phantomlike subatomic particles that are the second most populous residents (after photons) of today’s universe. The term “wild” is used to distinguish these primordial neutrinos from those expected within particle physics and being observed today. Another suspect is dark energy, the anti-gravitational force that accelerates our universe’s expansion. Again, however, this would be from the dark energy we observe today.

“Early dark energy is a class of explanations for the origin of cosmic acceleration that arises in some high energy physics models,” Linder says. “While conventional dark energy, such as the cosmological constant, are diluted to one part in a billion of total energy density around the time of the CMB’s last scattering, early dark energy theories can have 1-to-10 million times more energy density.”

Linder says early dark energy could have been the driver that seven billion years later caused the present cosmic acceleration. Its actual discovery would not only provide new insight into the origin of cosmic acceleration, but perhaps also provide new evidence for string theory and other concepts in high energy physics.

“New experiments for measuring CMB polarization that are already underway, such as the POLARBEAR and SPTpol telescopes, will enable us to further explore primeval physics, Linder says.

Linder, Hojjati and Samsing are the authors of a paper describing these results in the journal Physical Review Letters titled “New Constraints on the Early Expansion History of the Universe.” Hojjati is now with the Institute for the Early Universe in South Korea, and Samsing is with the DARK Cosmology Centre in Denmark.

This research was primarily supported by the DOE Office of Science.

For more about the Supernova Cosmology Project go here

Source: Lawrence Berkeley National Laboratory 

 

Astronomers Celebrate “Celestial Pollution” from Perseid Meteor Shower

Close up of the Gemini South (GeMS) laser which splits into 5 points to create a 'constellation' of guide stars for improved corrections over a larger patch of sky. The points at the end of the laser "columns" are where the laser light excites sodium atoms about 90 kilometers overhead and produces laser guide stars used for adaptive optics. The visibility of the laser "columns" beneath the laser guide star "constellation" is due to scattering of the laser's light by dust and moisture in the lower atmosphere.

Publication-quality images and HD video available at: http://www.gemini.edu/node/12052.  Credit: Gemini Observatory/AURA

The Gemini South GeMS laser propagates into the night sky as the Milky Way rises during GeMS/GSAOI System Verification observations.

Publication-quality images and HD video available at: http://www.gemini.edu/node/12052. Credit: Gemini Observatory/AURA

This image of the Orion Nebula Bullets regions exemplifies the dramatic clarity (high resolution) that is achieved with the GeMS adaptive optics system at the Gemini South telescope in Chile. In this image, strong winds from violent explosions associated with a region of star birth behind the Orion Nebula expel bullets of gas that created this spectacular system of molecular hydrogen wakes. Researchers and Principal Investigators John Bally and Adam Ginsberg of the University of Colorado used GeMS data to determine the intensity of the blast and the nature of the bullets. “Are they dense fragments of circumstellar disks? Could they be ejected protoplanets? Or are they portions of the prestellar core from which massive stars form?” Bally asks. “The Sub-arcsecond resolution provided by GeMS is needed to resolve these shocks and to search for the compact, high-density knots responsible for these wakes.”

Technical Data: Image, made from FeII, H2, and K-2.2 microns filters, were assigned the colors blue, orange, and white, respectively. The field-of-view is 2.9 x 3.8 arcminutes and is oriented with north up. The total (integrated) exposure time was 30 minutes cumulative for all filters and fields.

Image data from John Bally and Adam Ginsberg, University of Colorado. Color composite image by Travis Rector, University of Alaska Anchorage. Credit: Gemini Observatory/AURA

Full Resolution TIF (66.2MB) | Full Resolution JPG (27.1MB) | Med Resolution JPG (2.6MB) 

“Celestial Pollution” from meteors like this weekend’s Perseid Meteor Shower sprinkle sodium high up in our atmosphere and give astronomers what they need to see the universe in much greater detail. 

 

This weekend, as millions of people gaze up at the stars and wait for Perseid meteors to streak across the sky, one would hardly think that these awe-inspiring “shooting stars” are also a source of atmospheric pollution. 

However, meteors, like those from this month’s Perseid meteor shower, burn up high in the Earth’s atmosphere leaving behind gases. “It’s a form of natural pollution,” says Gemini Observatory’s Chad Trujillo who heads up the facility’s state-of-the-art Adaptive Optics (AO) program. 

This "pollution" doesn't actually pose a threat to humanity, (it's been around for eons and seems to have had no adverse effect), but it's a real boon to astronomers.

“One of the gases left behind by meteors is sodium, which collects in a layer about 60 miles (90 kilometers) above the Earth,” says Trujillo (see animation). “The reason astronomers are so fond of this particular pollution layer is because we can make it glow by using a sodium laser to excite this sodium and produce temporary, artificial stars wherever we like. Believe it or not,” jokes Trujillo, “there aren’t enough stars in the sky for astronomers!”

Astronomers use these artificial stars, called laser-guide-stars, for AO systems such as the latest technology at the Gemini South telescope in Chile. AO allows scientists to see the universe with unprecedented clarity.

The Perseid meteors are byproducts of Comet 109/Swift-Tuttle, which leaves a trail of dust and ice behind when it passes by Earth’s orbit. Each year, however, the Earth passes through the comet’s dust- and ice-filled orbit. As it plows through that “debris,” it’s small particles burn up in our atmosphere. 

“Perhaps one person’s celestial ‘pollution’ is another’s ‘natural resource,’” said Maria Womack, an astronomy program officer at the US National Science Foundation (NSF). “It's this sodium layer, provided courtesy of meteors like the Perseids, that astronomers use to get the clearest views and understand the universe better.” 

To celebrate this “happy marriage” of AO laser-guide-star technology and natural meteor remains in Earth’s atmosphere, Gemini Observatory is releasing a spectacular set of images illustrating laser guide stars, including its newest technology which is part of its GeMS Adaptive Optics system (GeMS stands for Gemini Multi-conjugate adaptive optics System and is featured in a recent press release at: www.gemini.edu/node/12028). The GeMS system uses five separate laser beams to create a “constellation” of laser guide stars, (see top figure) which allows for significantly better corrections than previous generations of AO systems. 

“The next generation of large ground-based telescopes will require advanced AO systems like GeMS to work at their full-potential,” Trujillo explains, “because as telescopes get bigger they must look through a wider column of air. The wider the column of air, the more turbulence in the air will distort the observed light. Using laser guide stars gives us a reference so we can correct for that turbulence and see things with amazing clarity from the ground.” 

In addition to Gemini South, a laser guide star system is used at the Gemini North telescope on Mauna Kea in Hawai‘i (see images) and many major ground-based observatories worldwide. 

Enjoy this year’s Perseid Meteor shower which peaks on the night of August 11-12; astronomers will!

Contacts:

• Chad Trujillo
  Gemini Observatory, Hilo, Hawai‘i
  Phone (Desk): (808) 974-2566
  Email: ctrujillo@gemini.edu


• Peter Michaud
  Gemini Observatory, Hilo, Hawai‘i
  Office: +1 (808) 974-2510
  Cell: +1 (808) 936-6643
  Email: pmichaud@gemini.edu


• Antonieta Garcia
  Gemini Observatory, La Serena, Chile
  Phone (Desk): 56-51-2-205628
  Cell: 09-69198294
  Email: agarcia@gemini.edu

Publication-quality images and HD video available at: http://www.gemini.edu/node/12052

Constructing a 3D Map of the Large-Scale Structure of the Universe

An international team led by astronomers from Kyoto University, the University of Tokyo and the University of Oxford has released its first version of a 3D map of the Universe from its FastSound project (Note 1), which is surveying galaxies in the Universe over nine billion light years away. Using the Subaru Telescope's new Fiber Multi-Object Spectrograph (FMOS, Note 2), the team's 3D map includes 1,100 galaxies and shows the large-scale structure of the Universe nine billion years ago (Figure 1).

Figure 1: The FastSound project's 3D map of the large-scale structure of a region in the Universe about 4.7 billion years after the Big Bang. This area covers 2.5 times 3 degrees of the sky, with a radial distance spanning 12-14.5 billion light years in comoving distance or 8-9.6 billion light years in light travel distance (Note 3). The colors of the galaxies indicate their star formation rate, i.e., the total mass of stars produced in a galaxy every year. The gradation in background color represents the number density of galaxies; the underlying mass distribution (which is dominated by invisible so-called "dark matter" that accounts for about 30% of the total energy in the Universe) would look like this if we could see it. The lower part of the figure shows the relative locations of the FastSound and the Sloan Digital Sky Survey (SDSS) regions, indicating that the FastSound project is mapping a more distant Universe than SDSS's 3D map of the nearby Universe. (Credit: NAOJ, SDSS, CFHT)

The FastSound project, one of Subaru Telescope's Strategic Programs, began its observations in March 2012 and will continue them into the spring of 2014. Although surveys with 3D maps of the Universe have been conducted on the nearby Universe (e.g., the Sloan Digital Sky Survey with coverage up to five billion light years away), the FastSound project distinguishes itself by developing a 3D map of the far-distant Universe, covering the largest volume of the Universe farther than ten billion light years away (in comoving distance, Note 3). Subaru Telescope's FMOS facilitates the project's goal of surveying a large portion of the sky. FMOS is a powerful wide-field spectroscopy system that enables near-infrared spectroscopy of over 100 objects at a time; the spectrograph's location at prime focus allows an exceptionally wide field of view when combined with the light colleting power of the 8.2 m primary mirror of the telescope.

The current 3D map of 1,100 galaxies shows the large-scale structure of the Universe nine billion years ago, spanning 600 million light years along the angular direction and two billion light years in the radial direction. The team will eventually survey a region totaling about 30 square degrees in the sky and then measure precise distances to about 5000 galaxies that are more than ten billion light years away. Although the clustering of galaxies is not as strong as that of the present-day Universe, gravitational interaction will eventually result in clustering that grows to the current level.

The final 3D map of the distant Universe will serve a primary scientific goal of the project: to precisely measure the motion of galaxies and then measure the rate of growth of the large-scale structure as a test of Einstein's general theory of relativity. Although scientists know that the expansion of the Universe is accelerating, they do not know why; it is one of the biggest questions in contemporary physics and astronomy. An unknown form of energy, so-called "dark energy", appears to uniformly fill the Universe, accounting for about 70% of its mass-energy content and apparently causing its acceleration. Alternatively, a fundamental theory of gravity on cosmological scales may differ from that of general relativity, which reigns as the dominant theory of gravitation and spacetime. A comparison of the 3D map of the young Universe with the predictions of general relativity could eventually reveal the mechanism for the mysterious acceleration of the Universe.

Notes:

1. The name FastSound stands for two important aspects of the project. Fast is short for FMOS Acceleration Sampling Test, which refers to the 3D map from the survey. Sound abbreviates Subaru Observation Understanding Nature of Dark energy, which relates more closely to the scientific purpose of the project, i.e., studying dark energy and its implications for the theory of general relativity. The scientific goal of the project is to test the theory of gravity on a cosmological scale for the first time. By examining the large-scale structure of the young Universe when it was about five billion years old, the project aims to shed light on the problem of dark energy and the accelerating Universe.
2. FMOS was constructed as a collaboration between the National Astronomical Observatory of Japan (NAOJ), Kyoto University, and the UK Science and Technology Facilities Council (STFC).
3. The meaning of distance. The expansion of the Universe gives rise to different definitions of what distance means. The 3D map shown in this release uses a measure of comoving distance rather than light travel distance. Light travel distance refers to the time that has elapsed from the epoch of the observed distant galaxy to the present, multiplied by the speed of light. Since the speed of light is always constant for any observer, it describes the distance of the path that a photon has traveled. However, the expansion of the Universe increases the length of the path that the photon traveled in the past. Comoving distance, the geometrical distance in the current Universe, takes this effect into account. Therefore, comoving distance is always larger than the corresponding light travel distance.

Source: Subaru Telescope

Hubble Finds Source of Magellanic Stream

The Magellanic Stream  

Credit for the radio/visible-light image: David L. Nidever et al., NRAO/AUI/NSF and A. Mellinger, LAB Survey, Parkes Observatory, Westerbork Observatory, and Arecibo Observatory. Credit for the radio image: LAB Surve. More Images

Astronomers using NASA's Hubble Space Telescope have solved a 40-year mystery on the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around our Milky Way galaxy.

The Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way, are at the head of the gaseous stream. Since the stream's discovery by radio telescopes in the early 1970s, astronomers have wondered whether the gas comes from one or both of the satellite galaxies. Now, new Hubble observations reveal that most of the gas was stripped from the Small Magellanic Cloud about 2 billion years ago, and a second region of the stream originated more recently from the Large Magellanic Cloud.

A team of astronomers, led by Andrew J. Fox of the Space Telescope Science Institute in Baltimore, Md., and the European Space Agency, determined the source of the gas filament by using Hubble's Cosmic Origins Spectrograph (COS) to measure the amount of heavy elements, such as oxygen and sulfur, at six locations along the Magellanic Stream. COS observed faraway quasars whose emitted light passes through the stream and detected these elements from the way they absorb ultraviolet light. Quasars are the brilliant cores of active galaxies.

Fox's team found a low amount of oxygen and sulfur along most of the stream, matching the levels in the Small Magellanic Cloud about 2 billion years ago, when the gaseous ribbon was thought to have been formed.

In a surprising twist, the team discovered a much higher level of sulfur in a region closer to the Magellanic Clouds. "We're finding a consistent amount of heavy elements in the stream until we get very close to the Magellanic Clouds, and then the heavy element levels go up," said Fox. "This inner region is very similar in composition to the Large Magellanic Cloud, suggesting it was ripped out of that galaxy more recently."

This discovery was a wrinkle Fox's team didn't expect, because computer models of the stream predicted that the gas came entirely out of the Small Magellanic Cloud, which has less gravity than its more massive cousin.

"Only Hubble can measure these abundances," Fox explained. "You have to go to space because the absorption lines we need to measure these abundances are all in the ultraviolet, and Earth's atmosphere absorbs ultraviolet light."

Astronomers have debated whether the two Magellanic Clouds are on their first pass near our Milky Way or are bound to it.

"What's interesting is that all the other nearby satellite galaxies of the Milky Way have lost their gas," Fox said. "The Magellanic Clouds have been able to retain their gas and are still forming stars because they're more massive than the other satellites. However, as they're now approaching the Milky Way, they're feeling its gravity more and also encountering its halo of hot gas, which puts pressure on them. That process, together with the gravitational tug-of-war between the Magellanic Clouds, leads to the production of the stream. You're seeing material stripped out of the Clouds as they come in toward the Milky Way."

Ultimately, the gaseous stream may rain down onto the Milky Way's disk, fueling the birth of new stars. This infusion of fresh gas is part of one process that triggers star formation in a galaxy. Astronomers want to know the origin of that wayward gas in order to more fully understand how galaxies make new stars.

"We want to understand how galaxies like the Milky Way strip the gas from small galaxies that fall into them and use that to form new stars," Fox explained. "This seems like it's an episodic process. It's not a smooth process where a slow stream of gas comes in continuously. Instead, once in a while a large gas cloud falls in. We've got a way of testing that here, where two galaxies are coming in. We have shown which of them is producing the gas that ultimately will fall into the Milky Way."

The team reported its results in two papers that appeared in the Aug. 1 issue of The Astrophysical Journal. Fox is the lead author of one paper; the other paper's lead author is Philipp Richter of the University of Potsdam in Germany.

CONTACT

Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Md.
410-338-4493/4514
dweaver@stsci.edu / villard@stsci.edu

Andrew Fox
Space Telescope Science Institute, Baltimore, Md.
410-338-5083
afox@stsci.edu

 

Explosion Illuminates Invisible Galaxy in the Dark Ages

This artist's illustration depicts a gamma-ray burst illuminating clouds of interstellar gas in its host galaxy. By analyzing a recent gamma-ray burst, astronomers were able to learn about the chemistry of a galaxy 12.7 billion light-years from Earth. They discovered it contains only one-tenth of the heavy elements (metals) found in our solar system. Credit: Gemini Observatory/AURA, artwork by Lynette Cook.  High Resolution Image (jpg)  - Low Resolution Image (jpg)

Before light from the gamma-ray burst arrives at the Earth for astronomers to study, it passes through interstellar gas in its host galaxy (close-up view, left), and intergalactic gas between the distant galaxy and us (wide view, right). This gas filters the light by absorbing some colors and leaves a signature on the light that can be seen in its spectrum. This "signature" allows scientists to characterize the gamma-ray burst, its environment, and the material between us and the distant galaxy.Credit: Gemini Observatory/AURA, artwork by Lynette Cook. High Resolution Image (jpg)  -  Low Resolution Image (jpg)

Before light from the gamma-ray burst arrives at the Earth for astronomers to study, it passes through interstellar gas in its host galaxy (close-up view, left), and intergalactic gas between the distant galaxy and us (wide view, right). This gas filters the light by absorbing some colors and leaves a signature on the light that can be seen in its spectrum. This "signature" allows scientists to characterize the gamma-ray burst, its environment, and the material between us and the distant galaxy. Credit: Gemini Observatory/AURA, artwork by Lynette Cook. High Resolution Image (jpg) - Low Resolution Image (jpg)
 

Cambridge, MA - More than 12 billion years ago a star exploded, ripping itself apart and blasting its remains outward in twin jets at nearly the speed of light. At its death it glowed so brightly that it outshone its entire galaxy by a million times. This brilliant flash traveled across space for 12.7 billion years to a planet that hadn't even existed at the time of the explosion - our Earth. By analyzing this light, astronomers learned about a galaxy that was otherwise too small, faint and far away for even the Hubble Space Telescope to see.

"This star lived at a very interesting time, the so-called dark ages just a billion years after the Big Bang," says lead author Ryan Chornock of the Harvard-Smithsonian Center for Astrophysics (CfA).

"In a sense, we're forensic scientists investigating the death of a star and the life of a galaxy in the earliest phases of cosmic time," he adds.

The star announced its death with a flash of gamma rays, an event known as a gamma-ray burst (GRB). GRB 130606A was classified as a long GRB since the burst lasted for more than four minutes. It was detected by NASA's Swift spacecraft on June 6th. Chornock and his team quickly organized follow-up observations by the MMT Telescope in Arizona and the Gemini North telescope in Hawaii.

"We were able to get right on target in a matter of hours," Chornock says. "That speed was crucial in detecting and studying the afterglow."

A GRB afterglow occurs when jets from the burst slam into surrounding gas, sweeping that material up like a snowplow, heating it, and causing it to glow. As the afterglow's light travels through the dead star's host galaxy, it passes through clouds of interstellar gas. Chemical elements within those clouds absorb light at certain wavelengths, leaving "fingerprints." By splitting the light into a rainbow spectrum, astronomers can study those fingerprints and learn what gases the distant galaxy contained.

All chemical elements heavier than hydrogen, helium, and lithium had to be created by stars. As a result those heavy elements, which astronomers collectively call "metals," took time to accumulate. Life could not have existed in the early universe because the elements of life, including carbon and oxygen, did not exist.

Chornock and his colleagues found that the GRB galaxy contained only about one-tenth of the metals in our solar system. Theory suggests that although rocky planets might have been able to form, life probably could not thrive yet.

"At the time this star died, the universe was still getting ready for life. It didn't have life yet, but was building the required elements," says Chornock.

At a redshift of 5.9, or a distance of 12.7 billion light-years, GRB 130606A is one of the most distant gamma-ray bursts ever found.

"In the future we will be able to find and exploit even more distant GRBs with the planned Giant Magellan Telescope," says Edo Berger of the CfA, a co-author on the publication.

The team's results will be published in the Sept. 1 issue of The Astrophysical Journal and are available online.

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.  cpulliam@cfa.harvard.edu

For more information, contact:

David A. Aguilar 
Director of Public Affairs 
Harvard-Smithsonian Center for Astrophysics 
617-495-7462 
daguilar@cfa.harvard.edu

Christine Pulliam 
Public Affairs Specialist 
Harvard-Smithsonian Center for Astrophysics 
617-495-7463 
cpulliam@cfa.harvard.edu

Source: Harvard-Smithsonian Center for Astrophysics