Friday, November 29, 2013

Blue and gold

Credit: ESA/Hubble & NASA
Acknowledgement: Luca Limatola

This sprinkling of cosmic glitter makes up the galaxy known as ESO 149-3, located some 20 million light-years away from us. It is an example of an irregular galaxy, characterised by its amorphous, undefined shape — a property that sets it apart from its perhaps more photogenic spiral and elliptical relatives. Around one quarter of all galaxies are thought to be irregular-type galaxies.

In this image taken with the NASA/ESA Hubble Space Telescope ESO 149-3 can be seen as a smattering of golden and blue stars, with no apparent central nucleus or arm structure. The surrounding sky is rich in other more distant galaxies, visible as small, colourful streaks and dashes.

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


Thursday, November 28, 2013

ESA's new vision to study the invisible Universe

 
Artist's impression of an active galaxy
Copyright: ESA/AOES Medialab

The hot and energetic Universe and the search for elusive gravitational waves will be the focus of ESA’s next two large science missions, it was announced today. 

Both topics will bridge fundamental astrophysics and cosmology themes by studying in detail the processes that are crucial to the large-scale evolution of the Universe and its underlying physics. 

The science theme “the hot and energetic Universe” was selected for L2 – the second Large-class mission in ESA’s Cosmic Vision science programme – and is expected to be pursued with an advanced X-ray observatory. 

This mission, with a launch date foreseen for 2028, will address two key questions. How and why does ordinary matter assemble into the galaxies and galactic clusters that we see today, and how do black holes grow and influence their surroundings? 

Black holes, which lurk unseen at the centres of almost all galaxies, are regarded as one of the keys to understanding galaxy formation and evolution. 

The L3 mission will study the gravitational Universe, searching for ripples in the very fabric of space–time created by celestial objects with very strong gravity, such as pairs of merging black holes. 

Predicted by Einstein’s theory of general relativity but yet to be detected directly, gravitational waves promise to open a completely new window on the Universe. 

Planned for launch in 2034, it will require the development of a spaceborne gravitational wave observatory, or extreme precision ‘gravitometer’, an ambitious enterprise that will push the boundaries of current technology. 

“ESA has an outstanding record for developing state-of-the art space observatories that have revolutionised our knowledge of how stars and galaxies were born and evolved,” says Alvaro Gimenez, ESA’s Director of Science and Robotic Exploration. 

“By pursuing these two new themes, we will continue to push back the scientific boundaries and unveil the mysteries of the invisible Universe.” 

The selection process for L2 and L3 began in March 2013, when ESA issued a call to the European science community to suggest the next scientific themes that should be pursued by the Cosmic Vision programme’s Large missions. 

Thirty-two proposals were received and assessed by a Senior Survey Committee, and following an extensive interaction with the scientific community two major themes were recommended to the Director of Science and Robotic Exploration. 

“We had a difficult task in deciding which scientific themes to choose from all of the excellent candidates, but we believe that missions to study the hot, energetic Universe and gravitational waves will result in discoveries of the greatest importance to cosmology, astrophysics, and physics in general,” says Catherine Cesarsky, chair of the Senior Survey Committee. 

Although the launch dates for the L2 and L3 missions are more than a decade away, activities to prepare the missions will start very soon. Early in 2014, a call for L2 mission concepts will be announced to solicit proposals for a next-generation X-ray observatory. A similar procedure will be followed at a later date for the L3 mission. 

“We have opened up a new scientific roadmap for Europe today that will establish our leadership in this field for the next two decades while we develop and implement new technologies for these exciting missions,” adds Prof. Gimenez. 

Source: ESA

Do Black Holes Come in Size Medium?

The magenta spots in this image show two black holes in the spiral galaxy called NGC 1313, or the Topsy Turvy galaxy. Both black holes belong to a class called ultraluminous X-ray sources, or ULXs. The magenta X-ray data come from NASA's Nuclear Spectroscopic Telescopic Array, and are overlaid on a visible image from the Digitized Sky Survey. Image credit: NASA/JPL-Caltech/IRAP.  › Full image and caption

The magenta spots in this image show two black holes in the Circinus galaxy: the supermassive black hole at its heart, and a smaller one closer to the edge that belongs to a class called ultraluminous X-ray sources, or ULXs. The magenta X-ray data come from NASA's Nuclear Spectroscopic Telescopic Array, and are overlaid on a visible/infrared image from the Digitized Sky Survey. Image credit: NASA/JPL-Caltech.  › Full image and caption -  enlarge image
  
Black holes can be petite, with masses only about 10 times that of our sun -- or monstrous, boasting the equivalent in mass up to 10 billion suns. Do black holes also come in size medium? NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, is busy scrutinizing a class of black holes that may fall into the proposed medium-sized category.

"Exactly how intermediate-sized black holes would form remains an open issue," said Dominic Walton of the California Institute of Technology, Pasadena. "Some theories suggest they could form in rich, dense clusters of stars through repeated mergers, but there are a lot of questions left to be answered."

The largest black holes, referred to as supermassive, dominate the hearts of galaxies. The immense gravity of these black holes drags material toward them, forcing the material to heat up and release powerful X-rays. Small black holes dot the rest of the galactic landscape. They form under the crush of collapsing, dying stars bigger than our sun.

Evidence for medium-sized black holes lying somewhere between these two extremes might come from objects called ultraluminous X-ray sources, or ULXs. These are pairs of objects in which a black hole ravenously feeds off a normal star. The feeding process is somewhat similar to what happens around supermassive black holes, but isn't as big and messy. In addition, ULXs are located throughout galaxies, not at the cores.

The bright glow of X-rays coming from ULXs is too great to be the product of typical small black holes. This and other evidence indicates the objects may be intermediate in mass, with 100 to 10,000 times the mass of our sun. Alternatively, an explanation may lie in some kind of exotic phenomenon involving extreme accretion, or "feeding," of a black hole.

NuSTAR is joining with other telescopes to take a closer look at ULXs. It's providing the first look at these objects in focused, high-energy X-rays, helping to get better estimates of their masses and other characteristics.

In a new paper from Walton and colleagues accepted for publication in the Astrophysical Journal, the astronomers report serendipitously finding a ULX that had gone largely unnoticed before. They studied the object, which lies in the Circinus spiral galaxy 13 million light-years away, not only with NuSTAR but also with the European Space Agency's XMM-Newton satellite. Archival data from NASA's Chandra, Swift and Spitzer space telescopes as well as Japan's Suzaku satellite, were also used for further studies. "We went to town on this object, looking at a range of epochs and wavelengths," said Walton.

The results indicate the black hole in question is about 100 times the mass of the sun, putting it right at the border between small and medium black holes.

In another accepted Astrophysical Journal paper, Matteo Bachetti of the Institut de Recherche en Astrophysique et Planétologie and colleagues looked at two ULXs in NGC 1313, a spiral galaxy known as the "Topsy Turvy galaxy," also about 13 million light-years way.

These are among the best-studied ULXs known. A single viewing with NuSTAR showed that the black holes didn't fit with models of medium-size black holes. As a result, the researchers now think both ULXs harbor small, stellar-mass black holes. One of the objects is estimated to be big for its size category, at 70 to 100 solar masses.

"It's possible that these objects are ultraluminous because they are accreting material at a high rate and not because of their size," said Bachetti. "If intermediate-mass black holes are out there, they are doing a good job of hiding from us."

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

NuSTAR's mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

Wednesday, November 27, 2013

MAST Discovery Portal Goes Live

The Mikulski Archive for Space Telescopes (MAST) Discovery Portal is now available online. MAST is home to more than 15 missions, including Hubble, Kepler, Swift, and XMM-Newton, and many of these have had their own separate search interfaces from which to access their data. No longer! The MAST Discovery Portal allows users with a single search to locate all data MAST has on a particular target or in a particular field. Not only does this simplify searching for known data, but it also allows for discovery of data on your targets that you may not have been aware of, subsequently enabling new research capabilities. For example, a quick search on "M60" results in data from six different missions, ranging from the 1980s to the present, including both images and spectra, and all of which are available for previewing or downloading.

In addition to data at MAST, users can search for data available through the Virtual Observatory, either by providing a resolvable target name or coordinates or by using the "Search The VO" button in the More Information window for a given MAST data product. The VO gives Portal users access to data spanning the electromagnetic spectrum, from radio to high energy, including images, spectra, catalogs, and even NASA Astrophysics Data System (ADS) records. You can browse contents and download the data from within the Portal without having to leave to visit other sites. Basic plotting tools allow you to visualize metadata from your search results. You can also upload your own tables of targets (IDs and coordinates) for use within the Portal. Cross-matching can be done with all MAST data or any data available through the Strasbourg Astronomical Data Center (CDS).

Learn more about the MAST Discovery Portal by watching our introductory videos (short, 2-minute videos explaining the basics of how to use the Portal) or by visiting the Portal's help page. Note that the tutorial videos currently do not have voiceover. Watch for more improvements in the future, as we continue to add new functionality and data into the Portal. Among the best ways are to read the MAST Newsletter, like us on Facebook, or follow us on Twitter. If you have questions or comments, please email them to MAST.

A Fiery Drama of Star Birth and Death

The star formation region NGC 2035 imaged by the ESO Very Large Telescope

The star formation region NGC 2035 in the constellation of Dorado

Wide-field view of part of the Large Magellanic Cloud

Videos

Zooming in on the star formation region NGC 2035
Zooming in on the star formation region NGC 2035

The Large Magellanic Cloud is one of the closest galaxies to our own. Astronomers have now used the power of ESO’s Very Large Telescope to explore one of its lesser known regions. This new image shows clouds of gas and dust where hot new stars are being born and are sculpting their surroundings into odd shapes. But the image also shows the effects of stellar death — filaments created by a supernova explosion.

Located only about 160 000 light-years from us (eso1311) in the constellation of Dorado (The Swordfish), the Large Magellanic Cloud is one of our closest galactic neighbours. It is actively forming new stars in regions that are so bright that some can even be seen from Earth with the naked eye, such as the Tarantula Nebula (eso1033). This new image, taken by ESO’s Very Large Telescope at the Paranal Observatory in Chile, explores an area called NGC 2035 (right), sometimes nicknamed the Dragon’s Head Nebula.

NGC 2035 is an HII region, or emission nebula, consisting of clouds of gas that glow due to the energetic radiation given off by young stars. This radiation strips electrons from atoms within the gas, which eventually recombine with other atoms and release light. Mixed in with the gas are dark clumps of dust that absorb rather than emit light, creating weaving lanes and dark shapes across the nebula.

The filamentary shapes to the left in the image are the not the results of starbirth, but rather stellar death. It was created by one of the most violent events that can happen in the Universe — a supernova explosion [1]. These explosions are so bright that they often briefly outshine their entire host galaxy, before fading from view over several weeks or months (also see eso1315 and potw1323a).

From looking at this image, it may be difficult to grasp the sheer size of these clouds — they are several hundred light-years across. And they are not in our galaxy, but far beyond. The Large Magellanic Cloud is enormous, but when compared to our own galaxy it is very modest in extent, spanning just 14 000 light-years — about ten times smaller than the Milky Way.

This image was acquired using the FOcal Reducer and low dispersion Spectrograph instrument attached to ESO’s Very Large Telescope, which is located at the Paranal Observatory in Chile, as part of the ESO Cosmic Gems programme [2].

Notes

[1] The remnant left over by the supernova explosion that can be seen in this image is called SNR 0536-67.6.

[2] The ESO Cosmic Gems programme is an initiative to produce images of interesting, intriguing or visually attractive objects using ESO telescopes, for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations. All data collected may also be suitable for scientific purposes, and are made available to astronomers through ESO’s science archive.

More information

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

Contacts

Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email:
rhook@eso.org


Scientists Seek Other Scientists for Cosmology Problem

Can you match each galaxy in the top row with its warped counterpart in the bottom row? For example, is the warped version of galaxy A in box D, E, or F? › Click for full-size quiz image  |  › See answers

How do you measure something that is invisible? It's a challenging task, but astronomers have made progress on one front: the study of dark matter and dark energy, two of the most mysterious substances in our cosmos. Dark matter is intermixed with normal matter, but it gives off no light, making it impossible to see. Dark energy is even more slippery, yet scientists think it works against gravity to pull our universe apart at the seams.

Now for the third time, an innovative competition has begun again with the goal of finding better tools for probing dark matter and dark energy. Called GREAT3, which stands for GRavitational lEnsing Accuracy Testing 3, the event is sponsored by NASA's Jet Propulsion Laboratory, Pasadena, Calif., and a European Union Network of Excellence called Pattern Analysis, Statistical Modeling and Computation Learning 2 (PASCAL2).

The idea behind the challenge is to spur scientists, including those from fields outside astronomy, to come up with new insight into the problems of measuring dark matter and dark energy. Contestants are asked to solve galaxy puzzles involving millions of images from NASA's Hubble Space Telescope. A better understanding of the "dark side of the cosmos" may reveal new information about the very fabric and fate of our universe.

The first two challenges were a big success, attracting new brainpower to the field, including scientists from machine learning and particle physics. Machine learning involves programming computers to learn on their own using actual data from the real world. It has several applications, such as facial-recognition software, medical diagnostics and spam filtering, to name a few.

"Other data scientists have been thinking about the same type of algorithms we need for our cosmology tools for a long time," said Jason Rhodes of JPL. "We want to acquire that knowledge and see this field grow."

One of the most powerful tools for studying dark matter and dark energy is gravitational lensing. When dark matter lies between us and a distant galaxy, the light of the galaxy can be warped by the gravity from the dark matter. By measuring this warping, scientists can map dark matter, despite it being invisible. What's more, by looking at the distribution of dark and normal matter in our universe, scientists can get a better handle on dark energy and how it battles gravity to slow the growth of galactic structures.

In some cases of gravitational lensing, galaxies look wacky, as if seen in a funhouse mirror, or they appear multiple times. This is referred to as strong lensing. But in most cases, called weak lensing, the warping effects are tiny and impossible to see by eye.

The GREAT3 challenge is designed to improve methods for measuring weak lensing in preparation for future dark matter/dark energy missions, such as the European Space Agency's Euclid, in which NASA plays an important role, and the National Academy of Science's highest priority for NASA, WFIRST -- also known as the WFIRST-AFTA mission, which stands for Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets.

The millions of images given to GREAT3 contestants show galaxies that have been artificially warped via weak lensing. The puzzle is to figure out precisely how the galaxy images were warped, a complex task that involves looking for patterns and sifting out artificial warping effects caused by telescope optics and the atmosphere.

The winner will be announced in May 2014 and will receive $3,000 worth of computing equipment, the perfect gift for programmers hoping to crack more cosmic codes.

"With these contests, we have seen new ideas seeping into our field," said Rachel Mandelbaum of Carnegie Mellon University, Pittsburgh, who is working with Rhodes and Barnaby Rowe of UCL (University College London), England, to organize the challenge, along with a special committee. "It's a fun problem to work on and it's a problem that needs to be solved."

A visual quiz involving strongly lensed, or warped, galaxies is at: http://www.nasa.gov/jpl/news/galaxy20131126.html .

More information about the competition is online at: http://great3challenge.info/ .

The California Institute of Technology, Pasadena, manages JPL for NASA.

Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

Tuesday, November 26, 2013

A Sunny Outlook for NASA Kepler's Second Light

 
NASA Kepler's Second Light. This image by NASA's Kepler spacecraft shows the telescope's full field of view taken in a new demonstration mode in late October. A new mission concept, dubbed K2, would continue Kepler's search for other worlds, and introduce new science observation opportunities. Image Credit: NASA Ames

This conception illustration depicts how solar pressure can be used to balance NASA's Kepler spacecraft, keeping the telescope stable enough to continue searching for transiting planets around distant stars.Image Credit:  NASA Ames/W Stenzel

You may have thought that NASA's Kepler spacecraft was finished. Well, think again. A repurposed Kepler Space telescope may soon start searching the sky again.

A new mission concept, dubbed K2, would continue Kepler's search for other worlds, and introduce new opportunities to observe star clusters, young and old stars, active galaxies and supernovae.

In May, the Kepler spacecraft lost the second of four gyroscope-like reaction wheels, which are used to precisely point the spacecraft, ending new data collection for the original mission. The spacecraft required three functioning wheels to maintain the precision pointing necessary to detect the signal of small Earth-sized exoplanets, which are planets outside our solar system, orbiting stars like our sun in what's known as the habitable zone -- the range of distances from a star where the surface temperature of a planet might be suitable for liquid water.

With the failure of a second reaction wheel, the spacecraft can no longer precisely point at the mission's original field of view. The culprit is none other than our own sun.

The very body that provides Kepler with its energy needs also pushes the spacecraft around by the pressure exerted when the photons of sunlight strike the spacecraft. Without a third wheel to help counteract the solar pressure, the spacecraft's ultra-precise pointing capability cannot be controlled in all directions.

However, Kepler mission and Ball Aerospace engineers have developed an innovative way of recovering pointing stability by maneuvering the spacecraft so that the solar pressure is evenly distributed across the surfaces of the spacecraft.

To achieve this level of stability, the orientation of the spacecraft must be nearly parallel to its orbital path around the sun, which is slightly offset from the ecliptic, the orbital plane of Earth. The ecliptic plane defines the band of sky in which lie the constellations of the zodiac.

This technique of using the sun as the 'third wheel' to control pointing is currently being tested on the spacecraft and early results are already coming in. During a pointing performance test in late October, a full frame image of the space telescope's full field of view was captured showing part of the constellation Sagittarius.

Photons of light from a distant star field were collected over a 30-minute period and produced an image quality within five percent of the primary mission image quality, which used four reaction wheels to control pointing stability. Additional testing is underway to demonstrate the ability to maintain this level of pointing control for days and weeks.

To capture the telltale signature of a distant planet as it crosses the face of its host star and temporarily blocks the amount of starlight collected by Kepler, the spacecraft must maintain pointing stability over these longer periods.

"This 'second light' image provides a successful first step in a process that may yet result in new observations and continued discoveries from the Kepler space telescope," said Charlie Sobeck, Kepler deputy project manager at NASA Ames Research Center in Moffett Field, CA.

The K2 mission concept has been presented to NASA Headquarters. A decision to proceed to the 2014 Senior Review – a biannual assessment of operating missions – and propose for budget to fly K2 is expected by the end of 2013.

Kepler's original mission, which is still in progress to fully process the wealth of data collected, is to determine what percentage of stars like the sun harbor small planets the approximate size and surface temperature of Earth. For four years, the space telescope simultaneously and continuously monitored the brightness of more than 150,000 stars, recording a measurement every 30 minutes.

More than a year of the data collected by Kepler remains to be fully reviewed and analyzed.

Michele Johnson, 650-604-6982
Ames Research Center, Moffett Field, Calif.

michele.johnson@nasa.gov


Hyper Suprime-Cam Captures a Clear Image of Comet ISON's Long Tails

During an intensive commissioning run, Hyper Suprime-Cam (HSC), mounted at prime focus on the Subaru Telescope, has successfully imaged the Comet ISON (C/2012 S1) as it journeys toward the Sun. Especially striking in the HSC image are the comet's long tails, which span a distance more than twice the diameter of the full moon. (Figure 1)

Figure 1: Comet ISON (C/2012 S1) imaged by HSC, taken during the early morning of November 5, 2013 in Hawaii in i band (760 nm wavelength). The top of the image is to the north, and the left part is to the east. The diameter of the frame is 1.5 degrees. Click here for a high-resolution image. (Credit: HSC Project/NAOJ).
The observation took place in the early morning of November 5, 2013 in Hawaii during a test of non-sidereal tracking, which follows an object that moves at a different rate than the stars. Since Solar System objects such as comets and asteroids appear to move faster than more distant stars and galaxies, they require this special mode of telescope tracking, which allows observers to keep the target in view. An additional challenge for tracking Comet ISON was its low altitude of less than 30 degrees. Nevertheless, the commissioning team was able to capture a clear image of the comet and its tails, including their faint parts, which extend more than one degree away from the Sun. At the time of the observation, Comet ISON was 170 million kilometers from the Earth and 130 million kilometers from the Sun.

This image demonstrates some of HSC's exceptional qualities: use of the large, light-collecting power of the Subaru Telescope's 8.2-m primary mirror, a wide field-of-view, and sharp imaging capability. HSC's wide field of view captures objects in an area equivalent to the size of 9 full moons in one frame and does so with high sensitivity. This extraordinary instrument, first installed on August 16-17, 2012 (Hyper Suprime-Cam Ushers in a New Era of Observational Astronomy), was the product of international collaboration among major research partners -- the National Astronomical Observatory of Japan (NAOJ Japan), Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, Japan), the School of Science at the University of Tokyo (Japan), KEK (High Energy Accelerator Research Organization, Japan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), Princeton University (U.S.A) -- and with outstanding companies from industry -- Hamamatsu Photonics K.K., Canon Inc., and Mitsubishi Electric Corporation.

Dr. Satoshi Miyazaki, an associate professor at NAOJ and the director of the HSC Project, conducted this commissioning run and summarized some of the process: "In order to verify the performance of this camera with a Solar System object as a target, we decided to observe Comet ISON. This kind of object is tricky to track. Despite the challenges of tracking this comet, we were very happy to see the tails clearly shown in the image. We are delighted that we can share this image, which proves that HSC is capable of capturing images of Solar System objects."

Dr. Jun-ichi Watanabe, the Deputy Director General of NAOJ and an expert on cometary research, praised this recent achievement of the HSC team by commenting, "This image clearly shows the power of HSC on the Subaru Telescope. The two distinct streaks of the tails might be from their dust and the gas, respectively. I am excited that this comet and its tail might be seen with binoculars or even with the naked eye."

References:


 Source: Subaru Telescope


Monday, November 25, 2013

Infant Galaxies Merging Near 'Cosmic Dawn'

Himiko

Credit: NASA, ESA, ESO, NRAO, NAOJ, JAO, M. Ouchi (University of Tokyo), R. Ellis (California Institute of Technology), Y. Ono (University of Tokyo), K. Nakanishi (The Graduate University for Advanced Studies (SOKENDAI) and Joint ALMA Observatory), K. Kohno and R. Momose (University of Tokyo), Y. Kurono (Joint ALMA Observatory), M. Ashby (Harvard-Smithsonian Center for Astrophysics), K. Shimasaku (University of Tokyo), S. Willner and G. Fazio (Harvard-Smithsonian Center for Astrophysics), Y. Tamura (University of Tokyo), and D. Iono (National Astronomical Observatory of Japan).    Release Images

Astronomers using the combined power of NASA's Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA) telescope have discovered a far-flung trio of primitive galaxies nestled inside an enormous blob of primordial gas. The rare triple system existed when the universe was only 800 million years old. The trio may eventually merge into a single massive galaxy, researchers predict. The researchers state that the system provides key insights into the earliest stages of galaxy formation. 

This composite color image of a giant primordial bubble of gas, dubbed Himiko (after the queen of ancient Japan), is assembled from Hubble, Subaru, and Spitzer data. The left panel shows the field around Himiko, as viewed by Hubble. The position of Himiko is marked with a square.

The right panels show close-up views of the Hubble image (top) and a combination of Hubble, Subaru, and Spitzer images (bottom). In the Hubble image, infrared wavelengths captured by Hubble's Wide Field Camera 3 at 0.98, 1.25, and 1.6 microns are represented by blue, green, and red, respectively. In the Hubble/Subaru/Spitzer image, the combination of three Hubble infrared bands is green, while Lyman-alpha emission captured by Subaru Suprime-Cam and infrared 3.6 micron taken by the Spitzer Infrared Array Camera are presented with blue and red, respectively.

For more information and graphics for Himiko, visit: https://public.nrao.edu/news/pressreleases/infant-galaxies-merge-near-cosmic-dawn .

Source:  Hubble Site


Saturday, November 23, 2013

NASA Sees 'Watershed' Cosmic Blast in Unique Detail

On April 27, a blast of light from a dying star in a distant galaxy became the focus of astronomers around the world. The explosion, known as a gamma-ray burst and designated GRB 130427A, tops the charts as one of the brightest ever seen.

A trio of NASA satellites, working in concert with ground-based robotic telescopes, captured never-before-seen details that challenge current theoretical understandings of how gamma-ray bursts work.


This animation shows the most common type of gamma-ray burst, thought to occur when a massive star collapses, forms a black hole, and blasts particle jets outward at nearly the speed of light. Viewing into a jet greatly boosts its apparent brightness. A Fermi image of GRB 130427A ends the sequence.Image Credit: NASA's Goddard Space Flight Center. Download this video in HD formats from NASA Goddard's Scientific Visualization Studio
 
"We expect to see an event like this only once or twice a century, so we're fortunate it happened when we had the appropriate collection of sensitive space telescopes with complementary capabilities available to see it," said Paul Hertz, director of NASA's Astrophysics Division in Washington.

Gamma-ray bursts are the most luminous explosions in the cosmos, thought to be triggered when the core of a massive star runs out of nuclear fuel, collapses under its own weight, and forms a black hole. The black hole then drives jets of particles that drill all the way through the collapsing star and erupt into space at nearly the speed of light.

Gamma-rays are the most energetic form of light. Hot matter surrounding a new black hole and internal shock waves produced by collisions within the jet are thought to emit gamma-rays with energies in the million-electron-volt (MeV) range, or roughly 500,000 times the energy of visible light. The most energetic emission, with billion-electron-volt (GeV) gamma rays, is thought to arise when the jet slams into its surroundings, forming an external shock wave.

The Gamma-ray Burst Monitor (GBM) aboard NASA's Fermi Gamma-ray Space Telescope captured the initial wave of gamma rays from GRB 130427A shortly after 3:47 a.m. EDT April 27. In its first three seconds alone, the "monster burst" proved brighter than almost any burst previously observed.

In the most common type of gamma-ray burst, illustrated here, a dying massive star forms a black hole (left), which drives a particle jet into space. Light across the spectrum arises from hot gas near the black hole, collisions within the jet, and from the jet's interaction with its surroundings.Image Credit: NASA's Goddard Space Flight Center

"The spectacular results from Fermi GBM show that our widely accepted picture of MeV gamma rays from internal shock waves is woefully inadequate," said Rob Preece, a Fermi team member at the University of Alabama in Huntsville who led the GBM study.

NASA's Swift Gamma-ray Burst Mission detected the burst almost simultaneously with the GBM and quickly relayed its position to ground-based observatories.

Telescopes operated by Los Alamos National Laboratory in New Mexico as part of the Rapid Telescopes for Optical Response (RAPTOR) Project quickly turned to the spot. They detected an optical flash that peaked at magnitude 7 on the astronomical brightness scale, easily visible through binoculars. It is the second-brightest flash ever seen from a gamma-ray burst.

Just as the optical flash peaked, Fermi's Large Area Telescope (LAT) detected a spike in GeV gamma-rays reaching 95 GeV, the most energetic light ever seen from a burst. This relationship between a burst's optical light and its high-energy gamma-rays defied expectations.

"We thought the visible light for these flashes came from internal shocks, but this burst shows that it must come from the external shock, which produces the most energetic gamma-rays," said Sylvia Zhu, a Fermi team member at the University of Maryland in College Park.

The LAT detected GRB 130427A for about 20 hours, far longer than any previous burst. For a gamma-ray burst, it was relatively nearby. Its light traveled 3.8 billion years before arriving at Earth, about one-third the travel time for light from typical bursts.

"Detailed observations by Swift and ground-based telescopes clearly show that GRB 130427A has properties more similar to typical distant bursts than to nearby ones," said Gianpiero Tagliaferri, a Swift team member at Brera Observatory in Merate, Italy.
These maps show the sky at energies above 100 MeV as seen by Fermi's LAT instrument. Left: The sky during a 3-hour interval before GRB 130427A. Right: A 3-hour map ending 30 minutes after the burst. GRB 130427A was located in the constellation Leo, near its border with Ursa Major.Image Credit: NASA/DOE/Fermi LAT Collaboration
Swift's X-Ray Telescope took this 0.1-second exposure of GRB 130427A at 3:50 a.m. EDT on April 27, just moments after Fermi and Swift detected the outburst. The image is 6.5 arcminutes across.Image Credit: NASA/Swift/Stefan Immler

This extraordinary event enabled NASA's newest X-ray observatory, the Nuclear Spectroscopic Telescope Array (NuSTAR), to make a first-time detection of a burst afterglow in high-energy, or "hard," X-rays after more than a day. Taken together with Fermi LAT data, these observations challenge long-standing predictions.

GRB 130427A is the subject of five papers published online Nov. 21. Four of these, published by Science Express, highlight contributions by Fermi, Swift and RAPTOR. The NuSTAR study is published in The Astrophysical Journal Letters.

NASA's Fermi Gamma-ray Space Telescope is an international and multi-agency astrophysics and particle physics partnership managed by NASA's Goddard Space Flight Center in Greenbelt, Md., and supported by the U.S. Department of Energy's Office of Science. Goddard also manages NASA's Swift mission, which is operated in collaboration with Pennsylvania State University in University Park, Pa., and international partners. NASA's NuSTAR mission is led by the California Institute of Technology and managed by NASA's Jet Propulsion Laboratory, both in Pasadena, with contributions from international partners.

Related Links

Francis Reddy


Friday, November 22, 2013

Sagittarius A*: New Evidence For A Jet From Milky Way's Black Hole

Sagittarius A*
Credit: X-ray: NASA/CXC/UCLA/Z.Li et al; Radio: NRAO/VLA


New evidence has been uncovered for the presence of a jet of high-energy particles blasting out of the Milky Way's supermassive black hole. As outlined in the press release, astronomers have made the best case yet that such a jet exists by combining X-ray data from NASA's Chandra X-ray Observatory with radio emission from the NSF's Very Large Array (VLA).

This composite image features both X-rays from Chandra (purple) and radio data from the VLA (blue). A labeled version of this image - seen by mousing over the image - reveals the position of Sagittarius A* (Sgr A* for short) and the suspected jet.

The location of a shock front is also marked. As the jet fires away from Sgr A*, it travels through space until it hits gas several light years away. (The region around the Milky Way's black hole has many clumps of gas and dust.) Once the jet hits, it triggers the formation of a shock front. This interaction also accelerates electrons, generating X-rays as the electrons stream down the path of the jet, past the shock front.

The shock front is also of interest because it is unusually wide in the radio emission compared to the more narrow profile of the jet in X-rays. This suggests that there may be a secondary, weaker outflow, which might be like a sheath or cocoon surrounding the jet with an opening angle of around 25 degrees.

Sgr A* is about 4 million times the mass of the Sun and lies about 26,000 light years from Earth in the center of the Galaxy. Astronomers have been looking for a jet from Sgr A* for years since it is now common to find jets tied to a range of cosmic objects on both big and small scales. Prior to this latest study, there have been reports of possible evidence of a jet associated with Sgr A*. However, these have contradicted one another and have thus not been considered definitive.

A paper describing these results is available online and will appear in an upcoming issue of The Astrophysical Journal.

Fast Facts for Sagittarius A*:

Scale: Image is 1.2 arcmin across (about 9 light years) 
Category: Black Holes, Milky Way Galaxy 
Coordinates (J2000): RA 17h 45m 40s | Dec -29° 00' 28.00" 
Constellation: Sagittarius 
Observation Date: 54 pointings between Sep 1999 and Mar 2011 
Observation Time: 477 hours 21 min (19 days 21 hours 21 min) 
Obs. ID: 242, 945, 1561, 2273, 2276, 2282, 2284, 2943, 2951-2954, 3392, 3393, 3549, 3663, 3665, 4500, 4683, 4684, 5360, 5950-5954, 6113, 6363, 6639-6646, 7048, 7554-7559, 9169-9174, 10556, 11843, 12949, 13438, 13508 I
Instrument: ACIS
Also Known As: Galactic Center References: Li, Z. et al, 2013, ApJ (accepted); arXiv:1310.0146 
Color Code: X-ray (Pink); Radio (Blue) Radio 
Distance Estimate: About 26,000 light years 

Best image of bright quasar 3C 273

Credit: ESA/Hubble & NASA

This image from Hubble’s Wide Field and Planetary Camera 2 (WFPC2) is likely the best of ancient and brilliant quasar 3C 273, which resides in a giant elliptical galaxy in the constellation of Virgo (The Virgin). Its light has taken some 2.5 billion years to reach us. Despite this great distance, it is still one of the closest quasars to our home. It was the first quasar ever to be identified, and was discovered in the early 1960s by astronomer Allan Sandage.

The term quasar is an abbreviation of the phrase “quasi-stellar radio source”, as they appear to be star-like on the sky. In fact, quasars are the intensely powerful centres of distant, active galaxies, powered by a huge disc of particles surrounding a supermassive black hole. As material from this disc falls inwards, some quasars — including 3C 273  — have been observed to fire off super-fast jets into the surrounding space. In this picture, one of these jets appears as a cloudy streak, measuring some 200 000 light-years in length.

Quasars are capable of emitting hundreds or even thousands of times the entire energy output of our galaxy, making them some of the most luminous and energetic objects in the entire Universe. Of these very bright objects, 3C 273 is the brightest in our skies. If it was located 30 light-years from our own planet — roughly seven times the distance between Earth and Proxima Centauri, the nearest star to us after the Sun — it would still appear as bright as the Sun in the sky.  

WFPC2 was installed on Hubble during shuttle mission STS-125. It is the size of a small piano and was capable of seeing images in the visible, near-ultraviolet, and near-infrared parts of the spectrum.




Thursday, November 21, 2013

The Galaxy's ancient brown dwarf population revealed

A brown dwarf from the thick-disk or halo is shown. Although astronomers observe these objects as they pass near to the solar system, they spend much of their time away from the busiest part of the Galaxy, and the Milky Way's disk can be seen in the background. Credit: John Pinfield.  An image is available from http://star-www.herts.ac.uk/~dpi/thickdisk_halo_BD.pnga and https://www.ras.org.uk/images/stories/press/thickdisk_halo_bd_jpg.jpg

A team of astronomers led by Dr David Pinfield at the University of Hertfordshire have discovered two of the oldest brown dwarfs in the Galaxy. These ancient objects are moving at speeds of 100-200 kilometres per second, much faster than normal stars and other brown dwarfs and are thought to have formed when the Galaxy was very young, more than 10 billion years ago. Intriguingly the scientists believe they could be part of a vast and previously unseen population of objects. The researchers publish their results in the Oxford University Press journal Monthly Notices of the Royal Astronomical Society.

Brown dwarfs are star-like objects but are much less massive (with less than 7% of the Sun’s mass), and do not generate internal heat through nuclear fusion like stars. Because of this brown dwarfs simply cool and fade with time and very old brown dwarfs become very cool indeed - the new discoveries have temperatures of 250-600 degrees Celsius, much cooler than stars (in comparison the Sun has a surface temperature of 5600 degrees Celsius).

Pinfield’s team identified the new objects in the survey made by the Wide-field Infrared Survey Explorer (WISE), a NASA observatory that scanned the mid-infrared sky from orbit in 2010 and 2011. The object names are WISE 0013+0634 and WISE 0833+0052, and they lie in the Pisces and Hydra constellations respectively. Additional measurements confirming the nature of the objects came from large ground-based telescopes (Magellan, Gemini, VISTA and UKIRT). The infrared sky is full of faint red sources, including reddened stars, faint background galaxies (large distances from our own Milky Way) and nebulous gas and dust. Identifying cool brown dwarfs in amongst this messy mixture is akin to finding needles in a haystack. But Pinfield's team developed a new method that takes advantage of the way in which WISE scans the sky multiple times. This allowed them to identify cool brown dwarfs that were fainter than other searches had revealed.

The team of scientists then studied the infrared light emitted from these objects, which are unusual compared to typical slower moving brown dwarfs. The spectral signatures of their light reflects their ancient atmospheres, which are almost entirely made up of hydrogen rather than having the more abundant heavier elements seen in younger stars. Pinfield comments on their venerable ages and high speeds, “Unlike in other walks of life, the Galaxy’s oldest members move much faster than its younger population”.

Stars near to the Sun (in the so-called local volume) are made up of 3 overlapping populations - the thin disk, the thick disk and the halo. The thick disk is much older than the thin disk, and its stars move up and down at a higher velocity. Both these disk components sit within the halo that contains the remnants of the first stars that formed in the Galaxy.

Thin disk objects dominate the local volume, with thick disk and halo objects being much rarer. About 97% of local stars are thin disk members, while just 3% are from the thick-disk or halo. Brown dwarfs population numbers probably follow those of stars, which explains why these fast-moving thick-disk/halo objects are only now being discovered.

There are thought to be as many as 70 billion brown dwarfs in the Galaxy’s thin disk, and the thick disk and halo occupy much larger Galactic volumes. So even a small (3%) local population signifies a huge number of ancient brown dwarfs in the Galaxy. "These two brown dwarfs may be the tip of an iceberg and are an intriguing piece of astronomical archaeology", said Pinfield. "We have only been able to find these objects by searching for the faintest and coolest things possible with WISE. And by finding more of them we will gain insight into the earliest epoch of the history of the Galaxy."




Media contact

Dr Robert Massey
Royal Astronomical Society
Tel: +44 (0)20 7734 3307 x214
Mob: +44 (0)794 124 8035

rm@ras.org.uk




Science contacts

Prof David Pinfield
University of Hertfordshire
Tel: +44 (0)1707 284171

davidpinfield@googlemail.com

Dr Joana Gomes
University of Hertfordshire

j.gomes@herts.ac.uk

Dr Avril Day-Jones
University of Hertfordshire

avril_day_jones@hotmail.com

Dr Mariusz Gromadski
University of Val Paraiso
Val Paraiso, Chile

mariusz.gromadzki@uv.cl




Further information

The results are published in the paper “A deep WISE search for very late type objects and the discovery of two halo/thick-disk T dwarfs: WISE 0013+0634 and WISE 0833+0052”, D. J. Pinfield et al, Monthly Notices of the Royal Astronomical Society, in press.

A pre-publication version of the paper is available on arXiv: http://arxiv.org/abs/1308.0495




Useful links

University of Hertfordshire Centre for Astrophysics Research
http://www.herts.ac.uk/research/stri/research-areas/car

WISE homepage at NASA
http://www.nasa.gov/mission_pages/WISE/main/index.html

The Gemini Telescopes
http://www.gemini.edu/

The Magellan Telescope
http://obs.carnegiescience.edu/Magellan

VISTA homepage
http://www.vista.ac.uk/index.html

The UKIRT Infrared Deep Sky Survey homepage
http://www.ukidss.org/index.html




Notes for editors

The Royal Astronomical Society (RAS, www.ras.org.uk), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organizes scientific meetings, publishes international research and review journals, recognizes outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 3500 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

Follow the RAS on Twitter via @royalastrosoc

 

Debris from stellar explosions in the Galaxy's fast lane

Credit: ESA - C. Carreau
 
Astronomers looking at the radioactive afterglow of supernovae with ESA's INTEGRAL mission have revealed that the remains of stellar explosions move through the Milky Way much faster, on average, than stars and most of the Galaxy's gas. This stellar debris is most likely ejected by winds and supernova explosions in large groups of massive stars located primarily on the leading edges of the Galaxy's spiral arms.

While the night sky delivers a peaceful and almost immutable cosmic view, the picture belies a Universe alive with ceaseless motion from the smallest to the largest scales. All structures in the Milky Way, both the stars and the diffuse interstellar medium, swirl around the centre of the Galaxy at velocities as high as hundreds of kilometres per second, taking about one hundred million years to complete a revolution.

By studying how these objects move, astronomers can figure out the structure of the Milky Way at large and, in particular, of the spiral arms – a prominent characteristic of our Galaxy. These investigations are key in the challenge of understanding the history of the Milky Way's evolution.

Using data from ESA's INTEGRAL mission, a team of astronomers has mapped out galactic motions, exploiting a new tracer that follows stellar debris both through space and time. With this new method, they revealed that the remains of stellar explosions move, on average, much faster than stars and most of the gas in the Milky Way.

"The stellar winds blown by a massive star, and the supernova explosions at the end of its life, are powerful agents. They release large amounts of matter and energy into interstellar space, and we managed to trace some of this matter during its very long journey," explains Karsten Kretschmer from the Laboratoire APC in Paris, France. Kretschmer is the lead author of the paper reporting on the new results, published in Astronomy & Astrophysics.

The astronomers traced the path of the supernova debris by tracking its velocity relative to us through the Galaxy. They sought the light emitted at a specific gamma-ray wavelength by the radioactive decay of aluminium-26 (26Al), an isotope produced in the supernova explosions. Matter ejected by a supernova is richer in heavy elements than the raw material from which the parent star formed, because many new atomic nuclei are created in the star's interior as well as during the explosion.

Part of the ejected material is in the form of nuclei of radioactive isotopes, and the majority of them decay over short timescales – ranging between a few days and several years. But not 26Al. With a half-life of about 700 000 years, 26Al nuclei can travel very long distances before they decay. When they do so, astronomers can exploit the gamma rays emitted during the decay to trace the long-term reach of stellar explosions.

"Looking at the radioactive afterglow of supernovae about a million years after the explosions, we followed how their debris has spread across the Galaxy. This is not possible with observations at other wavelengths, which only show the remnants of more recent supernovae," adds Kretschmer.

Kretschmer and his collaborators used the SPectrometer on INTEGRAL (SPI) instrument to search for the emission from the radioactive decay of 26Al. With these data, they could map the distribution and velocity of this isotope across the Milky Way.

"Surprisingly, during the first million years of their journey, the ejecta from supernovae seem to move, on average, twice as fast as stars and the diffuse gas we see at other wavelengths in the Galaxy," comments co-author Roland Diehl from the Max-Planck Institut für Extraterrestrische Physik in Munich, Germany.

"We expected such high velocities in the initial phase after the explosion, but not after a million years. Our measurements are unique as they can detect the motion of the debris on such a long time scale, but still before it is slowed down as it ploughs through the surrounding gas that moves with the general flow."

The astronomers also found that supernovae tend to be more abundant in the inner parts of the Milky Way, where the spiral arms stem from the central regions of the Galaxy, rather than at the periphery.
"We conclude that the ejecta from supernovae are mainly concentrated towards the leading edges of the arms, while most of the gas and dust from which stars take shape are located in the core of the arms," he adds.

This offset in velocity and location between the cradles of star formation and the graveyard of stellar remains suggests the existence of strong asymmetries in the outflows from massive stars and supernovae within the Galaxy.

Stars form deep within the spiral arms, but may migrate outwards during their lifetime. The most massive of them blow intense winds during their lifetime and eventually die as supernovae. The material ejected during these events proceeds faster towards the regions of the Milky Way between the arms, creating gigantic bubbles that expand more easily in those directions where interstellar material is less dense.

"From the images of nearby spiral galaxies at optical and ultraviolet wavelengths, previous studies had already suggested that massive stars and supernovae may be preferentially located on the edges of spiral arms. Now, we have obtained direct proof," says Kretschmer.

The result will help astronomers piece together the turbulent journey of matter across the Galaxy, from one generation of stars to the next. It is also a valuable clue to investigate how the complex structure of arms arises in spiral galaxies.

Many observations were needed in this study to gain optimal control over the spectral resolution of the SPI instrument, which varies over time.

"We had to collect data over almost ten years to achieve the spectral resolution required for this study," notes Diehl.

"This velocity measurement is an unprecedented technical result at these wavelengths: with such a high spectral resolution, SPI is and will remain a unique instrument for years to come."

The motion of 26Al nuclei rotating in the Galaxy was already evident in the results from an earlier study, based on INTEGRAL data and published in 2006. But longer monitoring and improved spectral resolution were crucial to pinpoint the velocity of these nuclei to great precision.

"The goal of this study was very ambitious: looking at stellar aftermaths that only INTEGRAL can see. And we've succeeded, revealing that they move much faster than we could imagine," concludes Erik Kuulkers, ESA's INTEGRAL Project Scientist.

Background information

The results described in this article are reported in "Kinematics of massive star ejecta in the Milky Way as traced by 26Al", by K. Kretschmer et al., published in Astronomy & Astrophysics, 559, A99, 2013; 10.1051/0004-6361/201322563. The study is based on data collected with the SPI (Spectrometer on INTEGRAL) instrument on board ESA's INTEGRAL mission. The data were collected between February 2003 and February 2012.

The International Gamma-ray Astrophysics Laboratory (INTEGRAL) was launched on 17 October 2002. It is an ESA project with the instruments and a science data centre funded by ESA Member States (especially the Principal Investigator countries: Denmark, France, Germany, Italy, Spain, Switzerland) and Poland, and with the participation of Russia and the USA. The mission is dedicated to the fine spectroscopy (E/∆E = 500) and fine imaging (angular resolution: 12 arcmin FWHM) of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent source monitoring in the X-ray (4-35 keV) and optical (V-band, 550 nm) energy ranges.

Contacts

Karsten Kretschmer
Laboratoire APC - AstroParticule et Cosmologie
Université Paris Diderot
Paris, France
Email:
kkretsch@apc.univ-paris7.fr
Phone: +33-1572-79376

Roland Diehl
Max-Planck Institute for Extraterrestrial Physics
Garching, Germany
Email:
rod@mpe.mpg.de
Phone: +49-89-30000-3850


Erik Kuulkers
INTEGRAL Project Scientist
Directorate of Science and Robotic Exploration
European Space Agency
Email:
Erik.Kuulkers@sciops.esa.int
Phone: +34-91-8131-358



Source: ESA


Wednesday, November 20, 2013

X-Class Solar Flare

Adding on to a series of solar flares throughout October and November, the sun emitted another significant solar flare on Nov. 19, 2013, peaking at 5:26 a.m. EST. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
 
An X1-class flare erupts from the right side of the sun in this image captured by NASA's Solar Dynamics Observatory on Nov. 19, 2013. The flare erupted from a region that produced many flares in its two-week journey across the face of the sun, and is shown here just before rotating out of view.Image Credit: NASA/SDO

 To see how this event may impact Earth, please visit NOAA's Space Weather Prediction Center, the U.S. government's official source for space weather forecasts, alerts, watches and warnings.

This flare is classified as an X1.0 class flare. "X-class" denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc.

This flare came from an active region numbered AR 1893 that is just rotating out of sight over the sun's right side. Increased numbers of flares are quite common at the moment, since the sun's normal 11-year activity cycle is ramping up toward solar maximum conditions. Humans have tracked this solar cycle continuously since it was discovered in 1843, and it is normal for there to be many flares a day during the sun's peak activity.

Updates will be provided as needed.

Karen C. Fox
NASA's Goddard Space Flight Center, Greenbelt, Md.