Supermassive black hole wind can stop new stars from forming

An artist’s rendition of the galaxies Akira (right) and Tetsuo (left) in action. Akira’s gravity pulls Tetsuo’s gas into its central supermassive black hole, fueling winds that have the power to heat Akira’s gas. Because of the action of the black hole winds, Tetsuo’s donated gas is rendered inert, preventing a new cycle of star formation in Akira. (Credit: Kavli IPMU)  

Edmond Cheung (left) and Kevin Bundy (right) 

Credit: Kavli IPMU, Kevin Bundy

Scientists have uncovered a new class of galaxies with supermassive black hole winds that are energetic enough to suppress future star formation.

Devoid of fresh young stars, red and dead galaxies make up a large fraction of galaxies in our nearby universe, but a mystery that has plagued astronomers for years has been how these systems remain inactive despite having all of the ingredients needed to form stars. Now, an international team of researchers have used optical imaging spectroscopy from the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV MaNGA) to catch a supermassive black hole in the act of heating gas within its host galaxy, leading to the prevention of star formation.

“Stars are created by the cooling and collapse of gas, but in these galaxies there are no new stars despite an abundance of gas. It’s like we have rain clouds hanging over a desert, but none of the rainwater is reaching the ground,” said Edmond Cheung, Project Researcher at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), and lead author of a new study published in Nature on May 26.

The team studied a galaxy nicknamed Akira, the prototypical example of the newly discovered class of galaxies called "red geysers” - red referring to the color of galaxies that lack young blue stars, and geyser referring to the episodic wind outbursts from the supermassive black hole. Akira showed intriguing and complex patterns of warm gas, implying the presence of an outflowing wind from the supermassive black hole in its center. The researchers say the fuel for Akira’s supermassive black hole likely came from the interaction with a smaller galaxy, nicknamed Tetsuo. The outflowing wind had enough energy to heat the surrounding gas through shocks and turbulence and could ultimately prevent any future star formation.

These are some of the early results from the Kavli IPMU-led SDSS-IV MaNGA survey, which began observations in 2014. The technology involved in the new survey allows scientists to map galaxies ten to one hundred times faster than before, making it possible to build large enough samples required to catch galaxies undergoing rapidly changing phenomena.

“The critical power of MaNGA is the ability to observe thousands of galaxies in three dimensions, by mapping not only how they appear on the sky, but also how their stars and gas move inside them,” said Kevin Bundy, MaNGA’s Principal Investigator and Kavli IPMU Project Assistant Professor.

The team will continue to analyze the survey’s data and plans a number of follow-up studies to further reveal the role of red geysers on the evolution of galaxies.

Paper details

Journal: Nature
Title: Suppressing star formation in quiescent galaxies with supermassive black hole winds

Authors: Edmond Cheung (1), Kevin Bundy (1), Michele Cappellari (2), Sébastien Peirani (1,3), Wiphu Rujopakarn (1,4), Kyle Westfall (5), Renbin Yan (6), Matthew Bershady (7), Jenny E. Greene (8), Timothy M. Heckman (9), Niv Drory (10), David R. Law (11), Karen L. Masters (4), Daniel Thomas (4), David A. Wake (7,12), AnneMarie Weijmans (13), Kate Rubin (14), Francesco Belfiore (15,16), Benedetta Vulcani (1), Yan-mei Chen (17), Kai Zhang (6), Joseph D. Gelfand (18,19), Dmitry Bizyaev (20,21), A. Roman-Lopes (22), Donald P. Schneider (23,24)

Author affiliations:

1. Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277­8583, Japan

2. Sub­department of Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK

3. Institut d’Astrophysique de Paris (UMR 7095: CNRS and UPMC), 98 bis Bd Arago F­75014 Paris, France

4. Department of Physics, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok 10330, Thailand

5. Institute for Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX

6. Department of Physics and Astronomy, University of Kentucky, 505 Rose Street, Lexington, KY 40506­0055, USA

7. Department of Astronomy, University of Wisconsin­Madison, 475 North Charter Street, Madison, WI 53706, USA

8. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA

9. Center for Astrophysical Sciences, Department of Physics & Astronomy, The Johns Hopkins University, Baltimore, Maryland 21218

10. McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712­0259, USA

11. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA

12. Department of Physical Sciences, The Open University, Milton Keynes, MK7 6AA, UK

13. School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK

14. Harvard­Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

15. Cavendish Laboratory, University of Cambridge, 19 J.J. Thomson Ave, CB3 0HE Cambridge, UK

16. University of Cambridge, Kavli Institute for Cosmology, CB3 0HE Cambridge, UK

17. Department of Astronomy, Nanjing University, Nanjing 210093, China

18. NYU Abu Dhabi, P.O. Box 129188, Abu Dhabi, UAE

19. Center for Cosmology and Particle Physics, New York University, Meyer Hall of Physics, 4 Washington Place, New York, NY 10003, USA

20. Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349­0059, USA

21.Sternberg Astronomical Institute, Moscow State University, Moscow

22. Departamento de Física y Astronomía, Facultad de Ciencias, Universidad de La Serena, Cisternas 1200, La Serena, Chile

23. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802

24. Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802

DOI: 10.1038/nature18006 (Published May 26, 2016)

Paper abstract (Nature): http://nature.com/articles/doi:10.1038/nature18006

Media contact:
 
Motoko Kakubayashi
Press Officer
Kavli Institute for the Physics and Mathematics of the Universe
The University of Tokyo Institutes for Advanced Study,
The University of Tokyo
TEL: +81-04-7136-5980
E-mail: pres@ipmu.jp


Research contact:
 
Edmond Cheung
Project Researcher
Kavli Institute for the Physics and Mathematics of the Universe
The University of Tokyo Institutes for Advanced Study,
The University of Tokyo
TEL: +81-04-7136-6553
E-mail: edmond.cheung@ipmu.jp


Kevin Bundy
Project Assistant Professor
Kavli Institute for the Physics and Mathematics of the Universe
The University of Tokyo Institutes for Advanced Study,
The University of Tokyo
TEL: +81-04-7136-6513
E-mail: kevin.bundy@ipmu.jp

Useful links

 
All images can be downloaded from this page: http://web.ipmu.jp/press/201605-Akira/

Source:  Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)

NASA Scientist Suggests Possible Link Between Primordial Black Holes and Dark Matter

Left: This image from NASA's Spitzer Space Telescope shows an infrared view of a sky area in the constellation Ursa Major. Right: After masking out all known stars, galaxies and artifacts and enhancing what's left, an irregular background glow appears. This is the cosmic infrared background (CIB); lighter colors indicate brighter areas. The CIB glow is more irregular than can be explained by distant unresolved galaxies, and this excess structure is thought to be light emitted when the universe was less than a billion years old. Scientists say it likely originated from the first luminous objects to form in the universe, which includes both the first stars and black holes. Credits: NASA/JPL-Caltech/A. Kashlinsky (Goddard)

Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe's existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

"This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good," said Alexander Kashlinsky, an astrophysicist at NASA Goddard. "If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun's mass."  

In 2005, Kashlinsky led a team of astronomers using NASA's Spitzer Space Telescope to explore the background glow of infrared light in one part of the sky. The researchers reported excessive patchiness in the glow and concluded it was likely caused by the aggregate light of the first sources to illuminate the universe more than 13 billion years ago. Follow-up studies confirmed that this cosmic infrared background (CIB) showed similar unexpected structure in other parts of the sky.

In 2013, another study compared how the cosmic X-ray background (CXB) detected by NASA's Chandra X-ray Observatory compared to the CIB in the same area of the sky. The first stars emitted mainly optical and ultraviolet light, which today is stretched into the infrared by the expansion of space, so they should not contribute significantly to the CXB.

Yet the irregular glow of low-energy X-rays in the CXB matched the patchiness of the CIB quite well. The only object we know of that can be sufficiently luminous across this wide an energy range is a black hole. The research team concluded that primordial black holes must have been abundant among the earliest stars, making up at least about one out of every five of the sources contributing to the CIB.

The nature of dark matter remains one of the most important unresolved issues in astrophysics. Scientists currently favor theoretical models that explain dark matter as an exotic massive particle, but so far searches have failed to turn up evidence these hypothetical particles actually exist. NASA is currently investigating this issue as part of its Alpha Magnetic Spectrometer and Fermi Gamma-ray Space Telescope missions.

"These studies are providing increasingly sensitive results, slowly shrinking the box of parameters where dark matter particles can hide," Kashlinsky said. "The failure to find them has led to renewed interest in studying how well primordial black holes -- black holes formed in the universe's first fraction of a second -- could work as dark matter."

Physicists have outlined several ways in which the hot, rapidly expanding universe could produce primordial black holes in the first thousandths of a second after the Big Bang. The older the universe is when these mechanisms take hold, the larger the black holes can be. And because the window for creating them lasts only a tiny fraction of the first second, scientists expect primordial black holes would exhibit a narrow range of masses.

On Sept. 14, gravitational waves produced by a pair of merging black holes 1.3 billion light-years away were captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana. This event marked the first-ever detection of gravitational waves as well as the first direct detection of black holes. The signal provided LIGO scientists with information about the masses of the individual black holes, which were 29 and 36 times the sun's mass, plus or minus about four solar masses. These values were both unexpectedly large and surprisingly similar.

"Depending on the mechanism at work, primordial black holes could have properties very similar to what LIGO detected," Kashlinsky explained. "If we assume this is the case, that LIGO caught a merger of black holes formed in the early universe, we can look at the consequences this has on our understanding of how the cosmos ultimately evolved."

Primordial black holes, if they exist, could be similar to the merging black holes detected by the LIGO team in 2014. This computer simulation shows in slow motion what this merger would have looked like up close. The ring around the black holes, called an Einstein ring, arises from all the stars in a small region directly behind the holes whose light is distorted by gravitational lensing. The gravitational waves detected by LIGO are not shown in this video, although their effects can be seen in the Einstein ring. Gravitational waves traveling out behind the black holes disturb stellar images comprising the Einstein ring, causing them to slosh around in the ring even long after the merger is complete. Gravitational waves traveling in other directions cause weaker, shorter-lived sloshing everywhere outside the Einstein ring. If played back in real time, the movie would last about a third of a second.Credits: SXS Lensing. Youtube

In his new paper, published May 24 in The Astrophysical Journal Letters, Kashlinsky analyzes what might have happened if dark matter consisted of a population of black holes similar to those detected by LIGO. 

The black holes distort the distribution of mass in the early universe, adding a small fluctuation that has consequences hundreds of millions of years later, when the first stars begin to form.

For much of the universe's first 500 million years, normal matter remained too hot to coalesce into the first stars. Dark matter was unaffected by the high temperature because, whatever its nature, it primarily interacts through gravity. Aggregating by mutual attraction, dark matter first collapsed into clumps called minihaloes, which provided a gravitational seed enabling normal matter to accumulate. Hot gas collapsed toward the minihaloes, resulting in pockets of gas dense enough to further collapse on their own into the first stars. 

Kashlinsky shows that if black holes play the part of dark matter, this process occurs more rapidly and easily produces the lumpiness of the CIB detected in Spitzer data even if only a small fraction of minihaloes manage to produce stars.

As cosmic gas fell into the minihaloes, their constituent black holes would naturally capture some of it too. Matter falling toward a black hole heats up and ultimately produces X-rays. Together, infrared light from the first stars and X-rays from gas falling into dark matter black holes can account for the observed agreement between the patchiness of the CIB and the CXB.

Occasionally, some primordial black holes will pass close enough to be gravitationally captured into binary systems. The black holes in each of these binaries will, over eons,  emit gravitational radiation, lose orbital energy and spiral inward, ultimately merging into a larger black hole like the event LIGO observed. 

"Future LIGO observing runs will tell us much more about the universe's population of black holes, and it won't be long before we'll know if the scenario I outline is either supported or ruled out," Kashlinsky said.

Kashlinsky leads science team centered at Goddard that is participating in the European Space Agency's Euclid mission, which is currently scheduled to launch in 2020. The project, named LIBRAE, will enable the observatory to probe source populations in the CIB with high precision and determine what portion was produced by black holes.

By Francis Reddy
NASA's Goddard Space Flight Center, Greenbelt, Maryland

Source: NASA/Dark Energy/Matter

New Insights into Debris Discs

HD 181327

Credit: ESO/Marino et al.

Using 39 of the 66 antennas of the Atacama Large Millimeter/submillimeter Array (ALMA), located 5000 metres up on the Chajnantor plateau in the Chilean Andes, astronomers have been able to detect carbon monoxide (CO) in the disc of debris around an F-type star. Although carbon monoxide is the second most common molecule in the interstellar medium, after molecular hydrogen, this is the first time that CO has been detected around a star of this type. The star, named HD 181327, is a member of the Beta Pictoris moving group, located almost 170 light-years from Earth.

Until now, the presence of CO has been detected only around a few A-type stars, substantially more massive and luminous than HD 181327. Using the superb spatial resolution and sensitivity offered by the ALMA observatory astronomers were now able to capture this stunning ring of smoke and map the density of the CO within the disc.

The study of debris discs is one way to characterise planetary systems and the results of planet formation. The CO gas is found to be co-located with the dust grains in the ring of debris and to have been produced recently. Destructive collisions of icy planetesimals in the disc are possible sources for the continuous replenishment of the CO gas. Collisions in debris discs typically require the icy bodies to be gravitationally perturbed by larger objects in order to reach sufficient collisional velocities. Moreover, the derived CO composition of the icy planetesimals in the disc is consistent with the comets in our Solar System. This possible secondary origin for the CO gas suggests that icy comets could be common around stars similar to our Sun which has strong implications for life suitability in terrestrial exoplanets.

The results were published in the journal Monthly Notices of the Royal Astronomical Society under the title “Exocometary gas in the HD 181327 debris ring” by S. Marino et al.

Link

• Paper by Marino et al.

Source: ESO/images

A galactic gathering

MACS J1149.5+2223

Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt (Geckzilla)

Nearly as deep as the Hubble Ultra Deep Field, which contains approximately 10 000 galaxies, this incredible image from the NASA/ESA Space Telescope reveals thousands of colourful galaxies in the constellation of Leo (The Lion). This vibrant view of the early Universe was captured as part of the Frontier Fields campaign, which aims to investigate galaxy clusters in more detail than ever before, and to explore some of the most distant galaxies in the Universe.

Galaxy clusters are massive. They can have a tremendous impact on their surroundings, with their immense gravity warping and amplifying the light from more distant objects. This phenomenon, known as gravitational lensing, can help astronomers to see galaxies that would otherwise be too faint, aiding our hunt for residents of the primordial Universe.

MACS J1149.5+2223 is a galaxy cluster located approximately five billion light-years away. In 2012, it helped astronomers uncover one of the most distant galaxies ever discovered. Light from the young galaxy, magnified 15 times by the galaxy cluster, first shone when our 13.7-billion-year-old Universe was a mere 500 million years old — just 3.6 per cent of its current age!

In 2014 and 2015, MACS J1149.5+2223 was observed as part of the Frontier Fields campaign. While one of Hubble’s cameras observed the galaxy cluster itself, another simultaneously captured the spectacular scene pictured above, of an “unremarkable” patch of space. Referred to as a parallel field, this image — when compared to other similar fields — will help astronomers understand how the Universe looks in different directions.

Source: ESA/Hubble - Space Telescope

NASA’s SDO Peers Into Huge Coronal Hole

This imagery of the sun captured by NASA's Solar Dynamics Observatory from May 17-19, 2016, shows a giant dark area on the star's upper half, known as a coronal hole. Coronal holes are low-density regions of the sun’s atmosphere, known as the corona. Because they contain little solar material, they have lower temperatures and thus appear much darker than their surroundings. Coronal holes are visible in certain types of extreme ultraviolet light, which is typically invisible to our eyes, but is colorized here in purple for easy viewing.

These coronal holes are important to understanding the space environment around Earth through which our technology and astronauts travel. Coronal holes are the source of a high-speed wind of solar particles that streams off the sun some three times faster than the slower wind elsewhere. While it’s unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, without looping back down to the surface, as they do elsewhere. Credits: NASA/SDO. Download this video (mp4 format)

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

Source: NASA/SDO Solar Mission

A Young Mammoth Cluster of Galaxies Sighted in the Early Universe

The newly discovered protocluster of galaxies located in the Bootes field of the NOAO Deep Wide-field Survey.. Green circles identify the confirmed cluster members. Density contours (white lines) emphasize the concentration of member galaxies toward the center of the image. The patch of sky shown is roughly 20 arcminutes x 17 arcminutes in size. The cluster galaxies are typically very faint, about 10 million times fainter than the faintest stars visible to the naked eye on a dark night. The inset images highlight two example members that glow in the Ly-alpha line of atomic hydrogen. The protocluster is massive, with its core weighing as much as a quadrillion suns. The protocluster is likely to evolve, over 12 billion years, into a system much like the nearby Coma cluster of galaxies, shown in the image below. Credit: Dr. Rui Xue, Purdue University. Hi-res image

Coma Cluster image from the Sloan Digital Sky Survey
Credit: Dustin Lang and SDSS Collaboration 

Hi-res image

Astronomers have uncovered evidence for a vast collection of young galaxies 12 billion light years away. The newly discovered “proto-cluster” of galaxies, observed when the universe was only 1.7 billion years old (12% of its present age), is one of the most massive structures known at that distance. The discovery, made using telescopes at Kitt Peak National Observatory in Arizona and the W. M. Keck Observatory on Mauna Kea, has been reported in the Astrophysical Journal.

“The protocluster will very likely grow into a massive cluster of galaxies like the Coma cluster, which weighs more than a quadrillion suns,” said Purdue University astrophysicist Dr. Kyoung-Soo Lee, who initially spotted the protocluster and is one of the authors in this study. Clusters this massive are extremely rare: only a handful of candidates are known at such early times. The new system is the first to be confirmed using extensive spectroscopy to establish cluster membership.

The team, led by Dr. Lee (Purdue University) and Dr. Arjun Dey of the National Optical Astronomy Observatory, used the Mayall telescope on Kitt Peak to obtain very deep images of a small patch of sky, about the size of two full moons, in the constellation of Bootes. The team then used the Keck II Telescope on Mauna Kea to measure distances to faint galaxies in this patch, which revealed the large grouping. “Many of the faint galaxies in this patch lie at the same distance,” say Dr. Dey. “They are clumped together due to gravity and the evidence suggests that the cluster is in the process of forming.”

Matter in the universe organizes itself into large structures through the action of gravity. Most stars are in galaxies, which in turn collect in groups and clusters. Galaxy clusters are commonly observed in the present-day universe and contain some of the oldest and most massive galaxies known. The formation and early history of these clusters is not well understood. The discovery of young proto-clusters allows scientists to directly witness and study their formation. The prevalence of massive clusters in the young universe can help constrain the size and expansion history of the universe.

The team is now searching larger areas of sky to uncover more examples of such young and massive protoclusters. “The discovery and confirmation of one distant and very massive protocluster is very exciting,” said Dr. Naveen Reddy, an astrophysicist at the University of California at Riverside and a coauthor of the study, “but it is important to find a large sample of these so we can understand the possibly varied formation history of the population as a whole.”

The other members of the team are Dr. Michael Cooper (University of California, Irvine), Dr. Hanae Inami (Observatoire de Lyon), Dr. Sungryong Hong (University of Texas, Austin), Dr. Anthony Gonzalez (University of Florida), and Dr. Buell Jannuzi (University of Arizona).

Reference: “Spectroscopic Confirmation of a Protocluster at z=3.786,” Arjun Dey, Kyoung-Soo Lee, Naveen Reddy et al., 2016 May 20, Astrophysical Journal

preprint: http://arxiv.org/abs/1604.08627

Kitt Peak National Observatory and the National Optical Astronomy Observatory are operated by the Association of Universities for Research in Astronomy under a Cooperative Agreement with the National Science Foundation. The W. M. Keck Observatory is a scientific partnership between the National Aeronautics and Space Administration, the California Institute of Technology and the University of California, and made possible by the generous financial support of the W. M. Keck Foundation. The research was funded by the National Aeronautics and Space Administration and by NOAO.

Media Contact:

Dr. Joan Najita
National Optical Astronomy Observatory
950 N Cherry Ave
Tucson AZ 85719 USA
+1 520-318-8416
E-mail: najita@noao.edu


Science Contacts

Dr. Kyoung-Soo Lee
Purdue University
Tel: 765-494-3047
email: soolee@purdue.edu

Dr. Arjun Dey
National Optical Astronomy Observatory
Tel: 520-318-8429
email: dey@noao.edu

Source: National Optical Astronomy Observatory (NOAO)

GOODS-S 29323: NASA Telescopes Find Clues For How Giant Black Holes Formed So Quickly

GOODS-S 29323

Credit: X-ray: NASA/CXC/Scuola Normale Superiore/Pacucci, F. et al, Optical: NASA/STScI; 

Illustration: NASA/CXC/M.Weiss.

JPEG (624.5 kb) - Large JPEG (6.9 MB) - Tiff (65.8 MB) - More Images

Using data from NASA's three Great Observatories, scientists have found the best evidence to date of a mechanism that produced supermassive black holes in the early Universe. If confirmed, this result, described in our latest press release, could lead to new insight into how black holes were formed and grew billions of years ago.

This artist's illustration depicts a possible "seed" for the formation of a supermassive black hole, that is an object that contains millions or even billions of times the mass of the Sun. In the artist's illustration, the gas cloud is shown as the wispy blue material, while the orange and red disk is showing material being funneled toward the growing black hole through its gravitational pull.

Researchers found evidence that two objects could have formed in this way, by directly collapsing into a black hole from a large cloud of gas. These two candidates for being "direct collapse black holes" are so distant that they may have formed less than one billion years after the Big Bang. 

The inset boxes show data from the Hubble Space Telescope (right) and Chandra X-ray Observatory (left) of one of the objects described above. The Hubble image shows the faint, distant galaxy at the center of the image and the Chandra image shows X-ray emission from material falling onto the black hole in the same galaxy.

The researchers used computer models of black hole seeds combined with a new method to select candidates for these objects from long-exposure images from Chandra, Hubble, and Spitzer (not shown in this graphic). By analyzing the combined light from the three telescopes, the team was able to search through thousands of objects to look for any that had properties that matched those predicted by their models.

Two candidates emerged that had the expected red color, seen by Hubble and Spitzer, as well as the X-ray profile predicted from Chandra. These objects were found in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey and the Great Observatories Origins Deep Survey-South surveys. The next steps will involve getting more data on these two intriguing objects as well as extending the analysis to other surveys to look for more direct collapse black hole candidates.

These results will appear in the June 21st issue of the Monthly Notices of the Royal Astronomical Society and is available online. The authors of the paper are Fabio Pacucci (SNS, Italy), Andrea Ferrara (SNS), Andrea Grazian (INAF), Fabrizio Fiore (INAF), Emaneule Giallongo (INAF), and Simonetta Puccetti (ASI Science Data Center). NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Fast Facts for GOODS-S 29323:

Scale: Image is about 15 arcsec across. (about 212,000 light years)
Category: Black Holes, Cosmology/Deep Fields/X-ray Background
Observation Date: 54 pointings between Oct 15, 1999 to Jul 22, 2010
Observation Time: 1111 hours 6 min (46 days 7 hours 6 min).

Obs. ID: 441, 581-582, 1431, 1672, 2239, 2312-2313, 2405-2406, 2409, 8591-8597, 9575, 9578, 9593, 9596, 9718, 12043-12055, 12123, 12128-12129, 12135, 12137-12138, 12213, 12218-12220, 12222-12223, 12227, 12230-12234

Instrument: ACIS
References: Pacucci, F. et al, 2016, MNRAS, 459, 1432; arXiv:1603.08522
Color Code: X-ray (Blue), Optical (Gold)
Distance Estimate: About 13.2 billion light years (z=9.73)

Source: NASA’s Chandra X-ray Observatory

Puffy Giant Planet Discovered by KELT-S Transit Survey

The discovery lightcurve of exoplanet KELT-10b is overlaid on an image of the KELT-S Telescope in South Africa. The lightcurve was obtained using 4967 observations over about 4-years. A 30-minute binned lightcurve is shown in red. Image Credit: R. Kuhn & Vanderbilt University/SAAO.

Transiting planets orbiting bright stars provide a golden opportunity to learn about the nature of exoplanets, their composition and origin. A robotic survey of the southern sky, designed to detect such systems, has discovered its first exoplanet: KELT-10b, a highly inflated giant planet. Although it is only 2/3 the mass of Jupiter, KELT-10b is 40% larger than Jupiter in radius. Because of its large size, when the planet passes in front of its star, it blocks out a whopping 1.4% of the star’s light, generating a transit signal that is relatively easy to detect. As one of only 25 planets known to transit bright stars (V < 11) in the southern hemisphere, KELT-10b is an attractive target for future studies aimed at characterizing planetary atmospheres. 

KELT-10b was discovered by the Kilodegree Extremely LIttle Telescope-South (KELT-S) transit survey. KELT-S is a robotic telescope located at the Sutherland site of the South African Astronomical Observatory. It is operated by Vanderbilt University and the South African Astronomical Observatory. NOAO astronomer David James is a founding member of the project. 

Describing his enthusiasm for the KELT-S project, James explained, “Efforts to detect and characterize extra-solar planets are driven by the deep-rooted desires of humanity to understand the origin of the solar system and their place in it. Although small aperture planet-hunting telescopes like KELT-S are typically are modest in budget, they deliver a strong return in science. They are also a powerful educational experience for students.” 

James is excited by the future of exoplanet research, as it moves from the era of exoplanet detection and taxonomy to the characterization of their atmospheres and searches for bio-signatures. He mused, “When my daughter is my age, perhaps having detected exoplanets of her own, she may well be using a 30-50m class telescope to describe their biology and potential for hosting life.”

Links to resources and press releases:

• SAAO Press Release
• KELT-South Homepage
• Published paper

 Source: National Optical Astronomy Observatory (NOAO)

The Little Fox and the Giant Stars

The Little Fox and the Giant Stars

Copyright ESA/Herschel/PACS, SPIRE/Hi-GAL Project

New stars are the lifeblood of our Galaxy, and there is enough material revealed by this Herschel infrared image to build stars for millions of years to come.

Situated 8000 light-years away in the constellation Vulpecula – latin for little fox – the region in the image is known as Vulpecula OB1. It is a ‘stellar association’ in which a batch of truly giant ‘OB’ stars is being born.

The vast quantities of ultraviolet and other radiation emitted by these stars is compressing the surrounding cloud, causing nearby regions of dust and gas to begin the collapse into more new stars. In time, this process will ‘eat’ its way through the cloud, transforming some of the raw material into shining new stars.

The image was obtained as part of Herschel’s Hi-GAL key-project. This used the infrared space observatory’s instruments to image the entire galactic plane in five different infrared wavelengths.

These wavelengths reveal cold material, most of it between -220ºC and -260ºC. None of it can be seen at ordinary optical wavelengths, but this infrared view shows astronomers a surprising amount of structure in the cloud’s interior.

The surprise is that the Hi-GAL survey has revealed a spider’s web of filaments that stretches across the star-forming regions of our Galaxy. Part of this vast network can be seen in this image as a filigree of red and orange threads.

At visual wavelengths, the OB association is linked to a star cluster catalogued as NGC 6823. It was discovered by William Herschel in 1785 and contains 50–100 stars. A nebula emitting visible light, catalogued as NGC 6820, is also part of this multi-faceted star-forming region.

The giant stars at the heart of Vulpecula OB1 are some of the biggest in the Galaxy. Containing dozens of times the mass of the Sun, they have short lives, astronomically speaking, because they burn their fuel so quickly.

At an estimated age of two million years, they are already well through their lifespans. When their fuel runs out, they will collapse and explode as supernovas. The shock this will send through the surrounding cloud will trigger the birth of even more stars, and the cycle will begin again.

Source: ESA/Space in images

Are mystery Mars plumes caused by space weather

Mars mystery plume

Copyright visual images: D. Parker (large Mars image and bottom inset) & W. Jaeschke (top inset)

All other graphics courtesy D. Andrews

 Hi-res image (JPG)

 Mystery plume on Mars

Observations of a mysterious plume-like feature (marked with yellow arrow) at the limb of the Red Planet on 20 March 2012. The observation was made by astronomer W. Jaeschke. The image is shown with the north pole towards the bottom and the south pole to the top.  Copyright: W. Jaeschke

 Hi-res image (Gif)

Mysterious high-rise clouds seen appearing suddenly in the martian atmosphere on a handful of occasions may be linked to space weather, say Mars Express scientists.

Amateur astronomers using telescopes on Earth were the first to report an unusual cloud-like plume in 2012 that topped-out high above the surface of Mars at an altitude around 250 km. The feature developed in less than 10 hours, covered an area of up to 1000 x 500 km, and remained visible for around 10 days.

The extreme altitude poses something of a problem in explaining the features: it is far higher than where typical clouds of frozen carbon dioxide and water are thought to be able to form in the atmosphere.

Indeed, the high altitude corresponds to the ionosphere, where the atmosphere directly interacts with the incoming solar wind of electrically charged atomic particles.

Speculation as to their cause has included exceptional atmospheric circumstances, auroral emissions, associations with local crustal anomalies, or a meteor impact, but so far it has not been possible to identify the root cause.

Unfortunately, the spacecraft orbiting Mars were not in the right position to see the 2012 plume visually, but scientists have now looked into plasma and solar wind measurements collected by Mars Express at the time.

They have found evidence for a large ‘coronal mass ejection’, or CME, from the Sun striking the martian atmosphere in the right place and at around the right time.

“Our plasma observations tell us that there was a space weather event large enough to impact Mars and increase the escape of plasma from the planet’s atmosphere,” says David Andrews of the Swedish Institute of Space Physics, and lead author of the paper reporting the Mars Express results.

“But we were not able to see any signatures in the ionosphere that we can categorically say were due to the presence of this plume.

“One problem is that the plume was seen at the day–night boundary, over a region of known strong crustal magnetic fields where we know the ionosphere is generally very disturbed, so searching for ‘extra’ signatures is rather challenging.”

To go further, the scientists have looked at the chances of these two relatively rare events – a large and fast CME colliding with Mars, and the mysterious plume – occurring at the same time.

They have been searching back through the archives for similar events, but they are rare.

For example, the Hubble Space Telescope observed a similar high plume in May 1997, and a CME was registered hitting Earth at the same time.

Although that CME was widely studied, there is no information from Mars orbiters to judge the scale of its impact at the Red Planet. 

Similarly, CMEs have been detected at Mars without any associated plume being reported, although changes in distance and visibility of Mars from Earth makes it difficult to acquire good ground-based images at all times.

“The jury is still out as to what physics is at play here, but given the altitude of the plume, we think that plasma interactions must be important,” says David.

“One idea is that a fast-travelling CME causes a significant perturbation in the ionosphere resulting in dust and ice grains residing at high altitudes in the upper atmosphere being pushed around by the ionospheric plasma and magnetic fields, and then lofted to even higher altitudes by electrical charging.

“This could lead to a plume effect that is significant enough to be detected from Earth by astronomers.”

“A number of processes could be responsible, but if these plumes are indeed driven by space-weather disturbances, this adds an important angle to our understanding of how Mars may have lost much of its atmosphere in the past, changing from a warm, wet world and becoming the cold, dry, dusty place it is today,” says Dmitri Titov, Mars Express project scientist.

“The plume also emphasises the scientific potential for continuous monitoring of Mars by both orbiters and ground-based observatories. In particular, we are now going to use the webcam on Mars Express for more frequent coverage of the planet.”

Notes for Editors

“Plasma observations during the Mars atmospheric “plume” event of March–April 2012”, by D. Andrews et al has been accepted for publication in the Journal of Geophysical Research.

The measurements were conducted by the Mars Express Analyzer for 
Space Plasmas and Energetic Atoms (ASPERA-3) plasma instrument suite and the Mars Advanced Radar for Sub-Surface and Ionospheric Sounding (MARSIS).

For further information, please contact:

David Andrews
Swedish Institute of Space Physics
Tel: +46 (0) 184715922 
Email: david.andrews@irfu.se

Dmitri Titov
ESA Mars Express project scientist
Email: Dmitri.titov@esa.int

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

Source: ESA

Faintest Early-Universe Galaxy Ever, Detected and Confirmed

Color image of the cluster taken with Hubble Space Telescope (images in three different filters were combined to make an RGB image). In the inset we show three spectra of the multiply imaged systems. They have peaks at the same wavelength, hence showing that they belong to the same source. Credit: Bradac/HST/W. M. Keck Observatory

MAUNAKEA, Hawaii – An international team of scientists has detected and confirmed the faintest early-Universe galaxy ever using the W. M. Keck Observatory on the summit on Maunakea, Hawaii. In addition to using the world’s most powerful telescope, the team relied on gravitational lensing to see the incredibly faint object born just after the Big Bang. The results are being published in The Astrophysical Journal Letters today.

The team detected the galaxy as it was 13 billion years ago, or when the Universe was a toddler on a cosmic time scale.

The detection was made using the DEIMOS instrument fitted on the ten-meter Keck II telescope, and was made possible through a phenomenon predicted by Einstein in which an object is magnified by the gravity of another object that is between it and the viewer. In this case, the detected galaxy was behind the galaxy cluster MACS2129.4-0741, which is massive enough to create three different images of the object.

"Keck Observatory's telescopes are simply the best in the world for this work," said Marusa Bradac, a proefssor at University of California, Davis who led the team. "Their power, paired with the gravitational force of a massive cluster of galaxies, allows us to truly see where no human has seen before."

“Because you see three of them and the characteristics are exactly the same, that means it was lensed,” said Marc Kassis, staff astronomer at Keck Observatory who assists the discovery team at night. “The other thing that is particularly interesting is that it is small. The only way they would have seen it is through lensing. This allowed them to identify it as an ordinary galaxy near the edge of the visible Universe.”

“If the light from this galaxy was not magnified by factors of 11, five and two, we would not have been able to see it,” said Kuang-Han Huang, a team member from UC Davis and the lead author of the paper. “It lies near the end of the reionization epoch, during which most of the hydrogen gas between galaxies transitioned from being mostly neutral to being mostly ionized (and lit up the stars for the first time). That shows how gravitational lensing is important for understanding the faint galaxy population that dominates the reionization photon production.”

The galaxy’s magnified images were originally seen separately in both Keck Observatory and Hubble Space Telescope data. The team collected and combined all the Keck Observatory/DEIMOS spectra from all three images, confirming they were the same and that this is a triply-lensed system.

“We now have good constraints on when the reionization process ends – at redshift around 6 or 12.5 billion years ago – but we don’t yet know a lot of details about how it happened,” Huang said. “The galaxy detected in our work is likely a member of the faint galaxy population that drives the reionization process.”

“This galaxy is exciting because the team infers a very low stellar mass, or only one percent of one percent of the Milky Way galaxy,” Kassis said. “It’s a very, very small galaxy and at such a great distance, it’s a clue in answering one of the fundamental questions astronomy is trying to understand: What is causing the hydrogen gas at the very beginning of the Universe to go from neutral to ionized about 13 billion years ago. That’s when stars turned on and matter became more complex.”

The core of the team consisted of Bradac, Huang, Brian Lemaux, and Austin Hoag of UC Davis who are most directly involved with spectroscopic observation and data reduction of galaxies at redshift above seven.

Keck Observatory astronomers Luca Rizzi and Carlos Alvarez were instrumental in helping the team collect the DEIMOS data. Tommaso Treu from University of California, Los Angeles and Kasper Schmidt of Leibniz Institute for Astrophysics Potsdam were also part of the team. They lead the effort that obtains and analyzes spectroscopic data from the WFC3/IR grism on Hubble.

The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

DEIMOS (the DEep Imaging and Multi-Object Spectrograph) boasts the largest field of view (16.7 arcmin by 5 arcmin) of any of the Keck instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.

Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

By Steve Jefferson

Source:  W.M. Keck Observatory

Busy bees

NGC 5308

 Credit:ESA/Hubble & NASA
Acknowledgement: Judy Schmidt (Geckzilla)

This NASA/ESA Hubble Space Telescope image shows star clusters encircling a galaxy, like bees buzzing around a hive. The hive in question the an edge-on lenticular galaxy NGC 5308, located just under 100 million light-years away in the constellation of Ursa Major (The Great Bear).

Members of a galaxy type that lies somewhere between an elliptical and a spiral galaxy, lenticular galaxies such as NGC 5308 are disc galaxies that have used up, or lost, the majority of their gas and dust. As a result, they experience very little ongoing star formation and consist mainly of old and aging stars. On 9 October 1996, one of NGC 5308’s aging stars met a dramatic demise, exploding as a spectacular Type la supernova.

Lenticular galaxies are often orbited by gravitationally bound collections of hundreds of thousands of older stars. Called globular clusters, these dense collections of stars form a delicate halo as they orbit around the main body of NGC 5308, appearing as bright dots on the dark sky.

The dim, irregular galaxy to the right of NGC 5308 is known, rather prosaically, as SDSS J134646.18+605911.9.

Source: ESA/Hubble - Space Telescope

Hubble Takes Mars Portrait Near Close Approach

Mars Near 2016 Oppostion (Annotated)

Credit: NASA, ESA, and L. Frattare (STScI)

Release images

 

Bright, frosty polar caps, and clouds above a vivid, rust-colored landscape reveal Mars as a dynamic seasonal planet in this NASA Hubble Space Telescope view taken on May 12, 2016, when Mars was 50 million miles from Earth. The Hubble image reveals details as small as 20 to 30 miles across.

The large, dark region at far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth century observers. Christiaan Huygens used this feature to measure the rotation rate of Mars. (A Martian day is about 24 hours and 37 minutes.) Today we know that Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view.

A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact.

The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands.

South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeus (to the east) and Sinus Meridiani (to the west). These darker regions are covered by dark bedrock and fine-grained sand deposits ground down from ancient lava flows and other volcanic features. These sand grains are coarser and less reflective than the fine dust that gives the brighter regions of Mars their ruddy appearance. Early Mars watchers first mapped these regions.

An extended blanket of clouds can be seen over the southern polar cap. The icy northern polar cap has receded to a comparatively small size because it is now late summer in the northern hemisphere. Hubble photographed a wispy, afternoon, lateral cloud extending for at least 1,000 miles at mid-northern latitudes. Early morning clouds and haze extend along the western limb.

This hemisphere of Mars contains landing sites for several NASA Mars surface robotic missions, including Viking 1 (1976), Mars Pathfinder (1997), and the still-operating Opportunity Mars rover. The landing sites of the Spirit and Curiosity Mars rovers are on the other side of the planet.

This observation was made just a few days before Mars opposition on May 22, when the sun and Mars will be on exact opposite sides of Earth, and when Mars will be at a distance of 47.4 million miles from Earth. On May 30, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.

The biennial close approaches between Mars and Earth are not all the same. Mars' orbit around the sun is markedly elliptical; the close approaches to Earth can range from 35 million miles to 63 million miles.

They occur because about every two years Earth's orbit catches up to Mars' orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on "opposing" sides of Earth. This phenomenon is a result of the difference in orbital periods between Earth's orbit and Mars' orbit. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.

For additional information, contact:

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

Jim Bell
Arizona State University, Tempe, Arizona
480-965-1044
jim.bell@asu.edu

Michael Wolff
Space Science Institute, Boulder, Colorado
262-352-2910
mjwolff@spacescience.org

Source: HubbleSite

A Beautiful Instance of Stellar Ornamentation

PR Image eso1616a

The glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud

PR Image eso1616b

LHA 120-N55 in the constellation of Dorado

Videos

PR Video eso1616a

Zooming in on the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud

PR Video eso1616b

Close-up view of the glowing gas cloud LHA 120-N55 in the Large Magellanic Cloud

In this image from ESO’s Very Large Telescope (VLT), light from blazing blue stars energises the gas left over from the stars’ recent formation. The result is a strikingly colourful emission nebula, called LHA 120-N55, in which the stars are adorned with a mantle of glowing gas. Astronomers study these beautiful displays to learn about the conditions in places where new stars develop.

LHA 120-N55, or N55 as it is usually known, is a glowing gas cloud in the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way located about 163 000 light-years away. N55 is situated inside a supergiant shell, or superbubble called LMC 4. Superbubbles, often hundreds of light-years across, are formed when the fierce winds from newly formed stars and shockwaves from supernova explosions work in tandem to blow away most of the gas and dust that originally surrounded them and create huge bubble-shaped cavities.

The material that became N55, however, managed to survive as a small remnant pocket of gas and dust. It is now a standalone nebula inside the superbubble and a grouping of brilliant blue and white stars — known as LH 72 — also managed to form hundreds of millions of years after the events that originally blew up the superbubble. The LH 72 stars are only a few million years old, so they did not play a role in emptying the space around N55. The stars instead represent a second round of stellar birth in the region.

The recent rise of a new population of stars also explains the evocative colours surrounding the stars in this image. The intense light from the powerful, blue–white stars is stripping nearby hydrogen atoms in N55 of their electrons, causing the gas to glow in a characteristic pinkish colour in visible light. Astronomers recognise this telltale signature of glowing hydrogen gas throughout galaxies as a hallmark of fresh star birth.

While things seem quiet in the star-forming region of N55 for now, major changes lie ahead. Several million years hence, some of the massive and brilliant stars in the LH 72 association will themselves go supernova, scattering N55’s contents. In effect, a bubble will be blown within a superbubble, and the cycle of starry ends and beginnings will carry on in this close neighbour of our home galaxy.

This new image was acquired using the FOcal Reducer and low dispersion Spectrograph (FORS2) instrument attached to ESO's VLT. It was taken as part of the ESO Cosmic Gems programme, an outreach 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 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. 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 a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links

• Photos of the VLT

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

Source: ESO

NRAO Media Tip Sheet: May 2016

ALMA image of dusty cometary ring around HR 8799, the only star where multiple planets have been imaged. The new data suggest the planets either migrated or another undiscovered planet is present. The zoom-in portion of the image, taken with ESO's Very Large Telescope, shows the location of the known planets in this system in relation to a graphical representation of the central star. Credit: Booth et al., ALMA (NRAO/ESO/NAOJ); A. Zurlo, et al.

VLBA image of Compact Symmetric Object J13262+3152, called "an archetypical example" of such an object.

Credit: Tremblay, et al., NRAO/AUI/NSF

Patent for surface treatment for self-calibrating radiometer awarded to NRAO engineer Galen Watts.

Credit: NRAO/AUI/NSF

NRAO engineers Tod Boyd and Matt Morgan, recipients of the 2015 IEEE Antenna and Propagation Society Harold A. Wheeler Applications Prize Paper Award. Credit: NRAO/AUI/NSF

1. Cometary Belt around Distant Multi-planet System Hints at Hidden or Wandering Planets

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have made the first high-resolution image of the cometary belt (a region analogous to our own Kuiper belt) around HR 8799, the only star where multiple planets have been imaged directly. The shape of this dusty disk, particularly its inner edge, is surprisingly inconsistent with the orbits of the planets, suggesting that either they changed position over time or there is at least one more planet in the system yet to be discovered. "These data really allow us to see the inner edge of this disk for the first time," explains Mark Booth from Pontificia Universidad Católica de Chile and lead author of the study. "By studying the interactions between the planets and the disk, this new observation shows that either the planets that we see have had different orbits in the past or there is at least one more planet in the system that is too small to have been detected." The disk, which fills a region 150 to 420 times the Sun-Earth distance, is produced by the ongoing collisions of cometary bodies in the outer reaches of this star system. ALMA was able to image the emission from millimeter-size debris in the disk; according to the researchers, the small size of these dust grains suggests that the planets in the system are larger than Jupiter. Previous observations with other telescopes at shorter wavelengths did not detect this discrepancy in the disk. It is not clear if this difference is due to the low resolution of the previous observations or because different wavelengths are sensitive to different grain sizes, which would be distributed slightly differently. HR 8799 is a young star approximately 1.5 times the mass of the Sun located 129 light-years from Earth in the direction of the constellation Pegasus. "This is the very first time that a multi-planet system with orbiting dust is imaged, allowing for direct comparison with the formation and dynamics of our own Solar System," explains Antonio Hales, co-author of the study from the National Radio Astronomy Observatory in Charlottesville, Va. The astronomers are reporting their results in the Monthly Notices of the Royal Astronomical Society.

Reference: "Resolving the Planetesimal Belt of HR 8799 with ALMA," Booth et al.; Monthly Notices of the Royal Astronomical Society [http://dx.doi.org/10.1093/mnrasl/slw040], May 2016. Preprint: http://arxiv.org/abs/1603.04853

2. VLBA Study Doubles Sample of Youngest Radio Galaxies

Astronomers using the National Science Foundation's Very Long Baseline Array (VLBA) have found 15 new examples of a rare type of object that may yield valuable clues about how radio-emitting galaxies and their environments evolve in their early stages of development. The objects, called compact symmetric objects (CSOs), are small, young versions of the supermassive black hole-powered "engines" that propel fast-moving jets of material outward from radio galaxies. Following up on a large-scale VLBA survey done in 2006, the scientists made more-detailed observations of objects they identified as possible CSOs. Of 103 such candidates, they confirmed 24, 15 of which are newly identified as CSOs. Using McDonald Observatory's Hobby-Eberly Telescope, they determined distances to some of the objects, which allowed them to measure the objects' sizes. "This doubles the number of these objects known," said Steven Tremblay, of Curtin University in Australia. Enlarging the sample of known CSOs, the astronomers said, can be a big help to understanding radio galaxies in general. With sizes as small as 5 light-years across, and ages from only 20 to 2,000 years, CSOs represent an important early stage in the development of the much larger and older radio-emitting galaxies. Even at this early stage, the scientists said the CSOs in their sample show a distinction between higher-powered and lower-powered objects that also typifies older radio galaxies. "Understanding these young objects is vital to understanding their larger cousins," said Greg Taylor, of the University of New Mexico. The astronomers are reporting their results in the Monthly Notices of the Royal Astronomical Society.

Reference: "Compact Symmetric Objects and Supermassive Binary Black Holes in the VLBA Imaging and Polarimetry Survey," Tremblay et al.; Monthly Notices of the Royal Astronomical Society, May 2016. Preprint: http://arxiv.org/abs/1603.03094

3. Innovation from NRAO Engineer Yields New Patent

Galen Watts, an engineer at the National Radio Astronomy Observatory's Green Bank Microwave Electronics Group, received a patent (U.S. Patent Number: 9,343,815) for a surface treatment application for radiometers that aids in their self-calibration. Radiometers are devices that measure the actual energy of microwaves and other forms of electromagnetic radiation. Radio astronomers and other researchers use microwave radiometry to discover the molecular and atomic composition as well as the temperature of many objects on Earth and even the most distant celestial objects. They do this by examining the content of these objects’ naturally emitted microwave signals. To make accurate readings, however, a radiometer has to be properly calibrated. The new surface treatment application, developed by Watts, aids in radiometer self-calibration by reflecting an image of the feed horn back onto itself in a manner that doesn't set up standing waves. Similar applications could also be useful for reducing antenna side-lobes (extraneous readings in radio astronomy), reducing radar cross-sections of objects, and eliminating resonances from stray reflections in quasi-optical component assemblies.

4. NRAO Engineers Receive IEEE Antenna and Propagation Society Award

NRAO engineers Mathew A. Morgan and Tod A. Boyd have been awarded jointly the 2015 IEEE Antenna and Propagation Society Harold A. Wheeler Applications Prize Paper Award, which is presented to the authors of the best applications paper published in the IEEE Transactions on Antennas and Propagation during the previous year. Their paper, "A 10-100 GHz Double-Ridged Horn Antenna and Coax Launcher," was published in August 2015 and reports on the development of a novel radio antenna. It is described as an ultra-wideband, double-ridged horn antenna with a bandwidth that covers a ten-fold range in frequencies. This is believed to be the first such decade-bandwidth horn in the millimeter-wave frequency range, covering -- in this case -- 10-100 GHz. Such horns can be used for test and measurement applications, including material characterization. It was originally designed as a scale model for an even higher-frequency horn covering 100 GHz - 1 THz. For this award, they will each receive a certificate and share in the $1,000 honorarium. The award will be presented at the IEEE APS/URSI Symposium Awards Ceremony, June 29, 2016, in Fajardo, Puerto Rico.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of South Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

Contacts:

Charles Blue, Public Information Officer
(434) 296-0314; cblue@nrao.edu

Dave Finley, Public Information Officer
(575) 835-7302; dfinley@nrao.edu

Source: National Radio Astronomy Observatory (NRAO)