What’s in a name?

 2XMM J143450.5+033843

Credit: ESA/Hubble & NASA

Not all galaxies have the luxury of possessing a simple moniker or quirky nickname. The subject of this NASA/ESA Hubble Space Telescope image was one of the unlucky ones, and goes by the rather unpoetic name of 2XMM J143450.5+033843.

Such a name may seem like a random jumble of numbers and letters, but like all galactic epithets it has a distinct meaning. This galaxy, for example, was detected and observed as part of the second X-ray sky survey performed by ESA’s XMM-Newton Observatory. Its celestial coordinates form the rest of the bulky name, following the “J”: a right ascension value of 14h 34m 50.5s (this can be likened to terrestrial longitude), and a declination of +03d 38m 43s (this can be likened to terrestrial latitude). The other fuzzy object in the frame was named in the same way — it is a bright galaxy named 2XMM J143448.3+033749.

2XMM J143450.5+033843 lies nearly 400 million light-years away from Earth. It is a Seyfert galaxy that is dominated by something known as an Active Galactic Nucleus — its core is thought to contain a supermassive black hole that is emitting huge amounts of radiation, pouring energetic X-rays out into the Universe.

Source: ESA/Hubble/Potw

Korean Astronomers Dissect a Fragmented Asteroid

Figure 1. Rotational light curve of the largest fragment of P/2010 A2. Time-series g’-band photometry over two nights (upper panel) and phase based on the best-fit double-peaked period of 11.36 hr (lower panel). A sine curve with a period of 11.36 hr was plotted in the upper panel (gray line). 

Figure 2. Composite image of asteroid P/2010 A2 constructed from data from the Gemini Multi-Object Spectrograph on Gemini North. The team used this data to compare against models of the object’s structure and dynamics.

A team of Korean astronomers uses imaging from the Gemini Multi-Object Spectrograph (GMOS) on Gemini North to characterize the rotation of active asteroid P/2010 A2’s largest fragment. The observations show that this faint and tiny (about the size of an American football field) asteroid, which underwent a mass ejection episode, is slowly rotating, indicative of an impact fragmentation rather a rotational breakup.

In January 2017, the active and fragmented main belt asteroid P/2010 A2 (hereafter A2) made its closest approach to the Earth after its 2010 discovery, when it exhibited a mysterious comet-like dust trail. Prior to this year’s passage, the fragments had not yet been characterized, due to the extremely small size (~120 meters in diameter) and faintness of this object. A Korean team, led by Yoonyoung Kim of Seoul National University, received time on Gemini North to observe the object’s 2017 close passage when the fragments and associated debris swarm were just over one astronomical unit away. 

According to Kim, a variety of hypotheses have been suggested to explain the history of this body, including rotational breakup, impact cratering, or shattering. The team determined a rotation period ~11.36 hours for the largest fragment. If the fragment’s spin period has been constant after the mass ejection, which Kim says is reasonable to believe, then it fails to meet the critical spin rate for rotational breakup. The observations also reveal that the largest fragment has a highly-elongated shape with about a 2:1 ratio. Looking at the size distributions of the ejecta and other fragments, the team concludes that the body likely underwent impact shattering in order to produce the observed morphology. 

The study’s light curve is shown in Figure 1 and presents the largest fragment’s double-peaked period of 11.36 +/- 0.02 hours. Figure 2 presents a composite from the imaging data revealing the array of fragments and debris used to determine the mass of the largest fragment is about 80% of the system’s mass with the other fragments and ejecta making up the remaining 20%. All figures are from the accepted paper scheduled for publication in The Astrophysical Journal Letters. A preprint is available here. 

Paper Abstract:
 

We report new observations of the active asteroid P/2010 A2 taken when it made its closest approach to the Earth (1.06 au in 2017 January) after its first discovery in 2010. Despite a crucial role of the rotational period in clarifying its ejection mechanism, the rotational property of P/2010 A2 has not yet been studied due to the extreme faintness of this tiny object (∼120 m in diameter). Taking advantage of the best observing geometry since the discovery, we succeed in obtaining the rotational light curve of the largest fragment with Gemini/GMOS-N. We find that (1) the largest fragment has a double-peaked period of 11.36±0.02 hr spinning much slower than its critical spin period; (2) the largest fragment is a highly elongated object (a/b⩾1.94) with an effective radius of 61.9^+16.8_−9.2 m; (3) the size distribution of the ejecta follows a broken power law (the power indices of the cumulative size distributions of the dust and fragments are 2.5±0.1 and 5.2±0.1, respectively); (4) the mass ratio of the largest fragment to the total ejecta is around 0.8; and (5) the dust cloud morphology is in agreement with the anisotropic ejection model in Kim et al. These new characteristics of the ejecta obtained in this work are favorable to the impact shattering hypothesis. 

Source: Gemini Observatory

Astronomers Detect Orbital Motion in Pair of Supermassive Black Holes

Artist's conception of the pair of supermassive black holes at the center of the galaxy 0402+379, 750 million light-years from Earth.Credit: Josh Valenzuela/University of New Mexico. Released image

VLBA image of the central region of the galaxy 0402+379, showing the two cores, labeled C1 and C2, identified as a pair of supermassive black holes in orbit around each other.Credit: Bansal et al., NRAO/AUI/NSF. Released image

---

VLBA reveals first-ever black-hole "visual binary" 

Using the supersharp radio “vision” of the National Science Foundation’s Very Long Baseline Array (VLBA), astronomers have made the first detection of orbital motion in a pair of supermassive black holes in a galaxy some 750 million light-years from Earth.

The two black holes, with a combined mass 15 billion times that of the Sun, are likely separated by only about 24 light-years, extremely close for such a system.

“This is the first pair of black holes to be seen as separate objects that are moving with respect to each other, and thus makes this the first black-hole ‘visual binary,'” said Greg Taylor, of the University of New Mexico (UNM).

Supermassive black holes, with millions or billions of times the mass of the Sun, reside at the cores of most galaxies. The presence of two such monsters at the center of a single galaxy means that the galaxy merged with another some time in the past. In such cases, the two black holes themselves may eventually merge in an event that would produce gravitational waves that ripple across the universe.

“We believe that the two supermassive black holes in this galaxy will merge,” said Karishma Bansal, a graduate student at UNM, adding that the merger will come at least millions of years in the future.

The galaxy, an elliptical galaxy called 0402+379, after its location in the sky, was first observed in 1995. It was studied in 2003 and 2005 with the VLBA. Based on finding two cores in the galaxy, instead of one, Taylor and his collaborators concluded in 2006 that it contained a pair of supermassive black holes.

The latest research, which Taylor and his colleagues are reporting in the Astrophysical Journal, incorporates new VLBA observations from 2009 and 2015, along with re-analysis of the earlier VLBA data. This work revealed motion of the two cores, confirming that the two black holes are orbiting each other. The scientists’ initial calculations indicate that they complete a single orbit in about 30,000 years.

“We need to continue observing this galaxy to improve our understanding of the orbit, and of the masses of the black holes,” Taylor said. “This pair of black holes offers us our first chance to study how such systems interact,” he added.

The astronomers also hope to discover other such systems. The galaxy mergers that bring two supermassive black holes close together are considered to be a common process in the universe, so astronomers expect that such binary pairs should be common.

“Now that we’ve been able to measure orbital motion in one such pair, we’re encouraged to seek other, similar pairs. We may find others that are easier to study,” Bansal said.

The VLBA, part of the Long Baseline Observatory, is a continent-wide radio telescope system using ten, 240-ton dish antennas distributed from Hawaii to St. Croix in the Caribbean. All ten antennas work together as a single telescope with the greatest resolving power available to astronomy. That extraordinary resolving power allows scientists to make extremely fine measurements of objects and motions in the sky, such as those done for the research on 0402+379.

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

---

Media Contact:

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

Source: National Radio Astronomy Observatory (NRAO)

Arp 299: Galactic Goulash

Arp 299 (composite)

Credit: X-ray: NASA/CXC/Univ of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; 

Optical: NASA/STScI

JPEG (696 kb) - Large JPEG (12.3 MB) - Tiff (26.4 MB) - More Images

 A Tour of Arp 299

More Animations

---

What would happen if you took two galaxies and mixed them together over millions of years? A new image including data from NASA's Chandra X-ray Observatory reveals the cosmic culinary outcome.

Arp 299 is a system located about 140 million light years from Earth. It contains two galaxies that are merging, creating a partially blended mix of stars from each galaxy in the process.

However, this stellar mix is not the only ingredient. New data from Chandra reveals 25 bright X-ray sources sprinkled throughout the Arp 299 concoction. Fourteen of these sources are such strong emitters of X-rays that astronomers categorize them as "ultra-luminous X-ray sources," or ULXs.

These ULXs are found embedded in regions where stars are currently forming at a rapid rate. Most likely, the ULXs are binary systems where a neutron star or black hole is pulling matter away from a companion star that is much more massive than the Sun. These double star systems are called high-mass X-ray binaries.

Such a loaded buffet of high-mass X-ray binaries is rare, but Arp 299 is one of the most powerful star-forming galaxies in the nearby Universe. This is due at least in part to the merger of the two galaxies, which has triggered waves of star formation. The formation of high-mass X-ray binaries is a natural consequence of such blossoming star birth as some of the young massive stars, which often form in pairs, evolve into these systems.

This new composite image of Arp 299 contains X-ray data from Chandra (pink), higher-energy X-ray data from NuSTAR (purple), and optical data from the Hubble Space Telescope (white and faint brown). Arp 299 also emits copious amounts of infrared light that has been detected by observatories such as NASA's Spitzer Space Telescope, but those data are not included in this composite.

The infrared and X-ray emission of the galaxy is remarkably similar to that of galaxies found in the very distant Universe, offering an opportunity to study a relatively nearby analog of these distant objects. A higher rate of galaxy collisions occurred when the universe was young, but these objects are difficult to study directly because they are located at colossal distances.

The Chandra data also reveal diffuse X-ray emission from hot gas distributed throughout Arp 299. Scientists think the high rate of supernovas, another common trait of star-forming galaxies, has expelled much of this hot gas out of the center of the system.

A paper describing these results appeared in the August 21st, 2016 issue of the Monthly Notices of the Royal Astronomical Society and is available online. The lead author of the paper is Konstantina Anastasopoulou from the University of Crete in Greece. 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.

A Quick Look at Arp 299

---

Fast Facts for Arp 299:

Scale: Image is 2.8 arcmin across (about 117,000 light years).
Category: Quasars & Active Galaxies, Black Holes
Coordinates (J2000): RA 11h 28m 31.33s | Dec 58° 33´ 41.80"
Constellation: Ursa Major
Observation Date: 13 Jul 2001, 14 Feb 2005, 12-13 Mar 2013
Observation Time: 34 hours 41 minutes
Obs. ID: 1641, 6227, 15077, 15619
Instrument: ACIS
References: Anastasopoulou, K. et al, 2016, MNRAS, 460, 3570; arXiv:1605.07001; Ptak, A. et al, 2014, ApJ, 800, 104; arXiv:1412.3120
Color Code: X-ray (Chandra: Pink; NuSTAR: Blue), Optical (Red, Green, Blue)
Distance Estimate: About 140 million light years

Source: NASA’s Chandra X-ray Observatory

ALMA Hears Birth Cry of a Massive Baby Star

Figure 1.  Artist’s impression of Orion KL Source I. The massive protostar is surrounded by a disk of gas and dust. The outflow is launched from the surface of the outer disk. Credit: ALMA (ESO/NAOJ/NRAO)

Figure 2.  Orion KL Source I observed with ALMA. The massive protostar is located in the center and surrounded by a gas disk (red). A bipolar gas outflow is ejected from the protostar (blue). Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

Figure 3. The rotation of the outflow from Orion KL Source I imaged with ALMA. The color shows the motion of the gas; red shows gas moving away from us, whereas blue shows gas moving toward us. The disk is shown in white. Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

---

An international research team led by a Japanese astronomer has determined how the enigmatic gas flow from a massive baby star is launched. The team used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the baby star and obtained clear evidence of rotation in the outflow. The motion and the shape of the outflow indicate that the interplay of centrifugal and magnetic forces in a disk surrounding the star plays a crucial role in the star’s birth cry.

Stars form from gas and dust floating in interstellar space. But, astronomers do not yet fully understand how it is possible to form the massive stars seen in space. One key issue is gas rotation. The parent cloud rotates slowly in the initial stage and the rotation becomes faster as the cloud shrinks due to self-gravity. Stars formed in such a process should have very rapid rotation, but this is not the case. The stars observed in the Universe rotate more slowly.

How is the rotational momentum dissipated? One possible scenario involves that the gas emanating from baby stars. If the gas outflow rotates, it can carry rotational momentum away from the system. Astronomers have tried to detect the rotation of the outflow to test this scenario and understand its launching mechanism. In a few cases signatures of rotation have been found, but it has been difficult to resolve clearly, especially around massive baby stars.

The team of astronomers led by Tomoya Hirota, an assistant professor at the National Astronomical Observatory of Japan (NAOJ) and SOKENDAI (the Graduate University for Advanced Studies) observed a massive baby star called Orion KL Source I in the famous Orion Nebula, located 1,400 light-years away from the Earth. The Orion Nebula is the closest massive-star forming region to Earth. Thanks to its close vicinity and ALMA’s advanced capabilities, the team was able to reveal the nature of the outflow from Source I.

“We have clearly imaged the rotation of the outflow,” said Hirota, the lead author of the research paper published in the journal Nature Astronomy. “In addition, the result gives us important insight into the launching mechanism of the outflow.”

The new ALMA observations beautifully illustrate the rotation of the outflow. The outflow rotates in the same direction as the gas disk surrounding the star. This strongly supports the idea that the outflow plays an important role in dissipating the rotational energy.

Furthermore, ALMA clearly shows that the outflow is launched not from the vicinity of the baby star itself, but rather from the outer edge of the disk. This morphology agrees well with the “magnetocentrifugal disk wind model.” In this model, gas in the rotating disk moves outward due to the centrifugal force and then moves upward along the magnetic field lines to form outflows.

Although previous observations with ALMA have found supporting evidence around a low-mass protostar, there was little compelling evidence around massive protostars because most of the massive-star forming regions are rather distant and difficult to investigate in detail.

“In addition to high sensitivity and fidelity, high resolution submillimeter-wave observation is essential to our study, which ALMA made possible for the first time. Submillimeter waves are a unique diagnostic tool for the dense innermost region of the outflow, and at that exact place we detected the rotation,” explained Hirota. “ALMA’s resolution will become even higher in the future. We would like to observe other objects to improve our understanding of the launching mechanism of outflows and the formation scenario of massive stars with the assistance of theoretical research.”

Note. ALMA also clearly imaged the rotation of a gas jet from a low-mass protostar. Please read the press release “Baby Star Spits a “Spinning Jet” As It Munches Down on a “Space Hamburger”.

Source: Alma/NAOJ

---

Paper and research team 

These observation results were published as Hirota et al. “Disk-Driven Rotating Bipolar Outflow in Orion Source I” in Nature Astronomy on June 12, 2017.

The research team members are:

Tomoya Hirota (National Astronomical Observatory of Japan / SOKENDAI), Masahiro Machida (Kyushu University), Yuko Matsushita (Kyushu University), Kazuhito Motogi (Yamaguchi University / NAOJ), Naoko Matsumoto (Yamaguchi University / NAOJ), Mi Kyoung Kim (Korean Astronomy and Space Science Institute), Ross A. Burns (Joint Institute for VLBI ERIC), Mareki Honma (NAOJ/SOKENDAI)

This research was supported by Grants-in-Aid from the Japan Society for the Promotion of Science and the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 21224002、 24684011、25108005、15H03646、15K17613、24540242、25120007).

ALMA

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

ESA to Develop Gravitational Wave Space Mission with NASA Support

Equal-mass black holes have just merged into a single object in this image from a supercomputer simulation. The merged black hole has settled into its "ringdown" phase and is emitting the last gravitational waves (purple) produced by the event. Credit: NASA/Goddard/UMBC/Bernard J. Kelly, NASA/Ames/Chris Henze, CSC Government Solutions LLC/Tim Sandstrom 

This illustration shows ESA's (the European Space Agency's) LISA observatory, a multi-spacecraft mission to study gravitational waves expected to launch in 2034. In the mission concept, LISA consists of three spacecraft in a triangular formation spanning millions of kilometers. Test masses in spacecraft on each arm of the formation will be linked together by lasers to detect passing gravitational waves.Credits: AEI/Milde Marketing/Exozet

ESA (the European Space Agency) has selected the Laser Interferometer Space Antenna (LISA) for its third large-class mission in the agency's Cosmic Vision science program. The three-spacecraft constellation is designed to study gravitational waves in space and is a concept long studied by both ESA and NASA. 

ESA’s Science Program Committee announced the selection at a meeting on June 20. The mission will now be designed, budgeted and proposed for adoption before construction begins. LISA is expected to launch in 2034. NASA will be a partner with ESA in the design, development, operations and data analysis of the mission.

Gravitational radiation was predicted a century ago by Albert Einstein's general theory of relativity. Massive accelerating objects such as merging black holes produce waves of energy that ripple through the fabric of space and time. Indirect proof of the existence of these waves came in 1978, when subtle changes observed in the motion of a pair of orbiting neutron stars showed energy was leaving the system in an amount matching predictions of energy carried away by gravitational waves.

In September 2015, these waves were first directly detected by the National Science Foundation’s ground-based Laser Interferometer Gravitational-Wave Observatory (LIGO). The signal arose from the merger of two stellar-mass black holes located some 1.3 billion light-years away. Similar signals from other black hole mergers have since been detected.

Seismic, thermal and other noise sources limit LIGO to higher-frequency gravitational waves around 100 cycles per second (hertz). But finding signals from more powerful events, such as mergers of supermassive black holes in colliding galaxies, requires the ability to detect frequencies much lower than 1 hertz, a sensitivity level only possible from space.

LISA consists of three spacecraft separated by 1.6 million miles (2.5 million kilometers) in a triangular formation that follows Earth in its orbit around the sun. Each spacecraft carries test masses that are shielded in such a way that the only force they respond to is gravity. Lasers measure the distances to test masses in all three spacecraft. Tiny changes in the lengths of each two-spacecraft arm signals the passage of gravitational waves through the formation.

For example, LISA will be sensitive to gravitational waves produced by mergers of supermassive black holes, each with millions or more times the mass of the sun. It will also be able to detect gravitational waves emanating from binary systems containing neutron stars or black holes, causing their orbits to shrink. And LISA may detect a background of gravitational waves produced during the universe's earliest moments.

For decades, NASA has worked to develop many technologies needed for LISA, including measurement, micropropulsion and control systems, as well as support for the development of data analysis techniques.

For instance, the GRACE Follow-On mission, a U.S. and German collaboration to replace the aging GRACE satellites scheduled for launch late this year, will carry a laser measuring system that inherits some of the technologies originally developed for LISA. The mission's Laser Ranging Interferometer will track distance changes between the two satellites with unprecedented precision, providing the first demonstration of the technology in space.

In 2016, ESA's LISA Pathfinder successfully demonstrated key technologies needed to build LISA. Each of LISA's three spacecraft must gently fly around its test masses without disturbing them, a process called drag-free flight. In its first two months of operations, LISA Pathfinder demonstrated this process with a precision some five times better than its mission requirements and later reached the sensitivity needed for the full multi-spacecraft observatory. U.S. researchers collaborated on aspects of LISA Pathfinder for years, and the mission carries a NASA-supplied experiment called the ST7 Disturbance Reduction System, which is managed by NASA’s Jet Propulsion Laboratory in Pasadena, California.

For more information about the LISA project, visit:  https://lisa.nasa.gov

---

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

 

Editor: Rob Garner

Source: ESA/Solar System and Beyond

A stormy stellar nursery

A stormy stellar nursery

Copyright: ESA/Hubble & NASA; CC BY 4.0

Hi-res image

This shot from the NASA/ESA Hubble Space Telescope shows a maelstrom of glowing gas and dark dust within one of the Milky Way’s satellite galaxies, the Large Magellanic Cloud.

The stormy scene shows a stellar nursery known as N159, measuring over 150 light-years across. It is known as a HII region, meaning it is rich in ionised hydrogen. Indeed, it contains many hot young stars that are emitting intense ultraviolet light, which causes nearby hydrogen gas to glow. Torrential stellar winds are also carving out ridges, arcs and filaments from the surrounding material.

At the heart of this cosmic cloud lies the Papillon Nebula, a butterfly-shaped region of nebulosity dominating the left of the scene. This compact nebula likely contains massive stars in the very early stages of formation. Its shape earned it the name (papillon being French for butterfly) and was first resolved by Hubble in 1999.

N159 is located over 160 000 light-years away. It resides just south of the Tarantula Nebula, another massive star-forming complex within the Large Magellanic Cloud.

This image was first released as a Hubble picture of the week on 5 September 2016.

Source: ESA/Space in Images

Surveying the cosmos

ESO 486-21

Credit:  ESA/Hubble & NASA

The object in the middle of this image, sitting alone within a star-studded cosmos, is a galaxy known as ESO 486-21. ESO 486-21 is a spiral galaxy — albeit with a somewhat irregular and ill-defined structure — located some 30 million light-years from Earth.

The NASA/ESA Hubble Space Telescope observed this object while performing a survey — the Legacy ExtraGalactic UV Survey (LEGUS) — of 50 nearby star-forming galaxies. The LEGUS sample was selected to cover a diverse range of galactic morphologies, star formation rates, galaxy masses, and more. Astronomers use such data to understand how stars form and evolve within clusters, and how these processes affect both their home galaxy and the wider Universe. ESO 486-21 is an ideal candidate for inclusion in such a survey as it is known to be in the process of forming new stars, which are created when large clouds of gas and dust (seen here in pink) within the galaxy crumple inwards upon themselves.

LEGUS made use of Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). The WFC3 obtained detailed observations of the target objects while the ACS obtained what are known as parallel fields — instead of leaving ACS idle, it was instead trained on a small patch of sky just offset from the target field itself, allowing it to gather additional valuable information while the primary target was being observed by WFC3. Parallel fields played an important role in Hubble’s Frontier Fields programme, which used the magnifying power of large galaxy clusters (via a phenomenon known as gravitational lensing) to explore objects in the distant Universe.

Source: ESA/Hubble/Potw

Hubble Captures Massive Dead Disk Galaxy that Challenges Theories of Galaxy Evolution

Galaxy Cluster MACS J2129-0741 and Lensed Galaxy MACS2129-1

Credits: Science: NASA, ESA, and S. Toft (University of Copenhagen)

Acknowledgment: NASA, ESA, M. Postman (STScI), and the CLASH team

Released images

---

Young, Dead, Compact, Disk Galaxy Surprises Astronomers, Offers New Clues to How Modern-Day Elliptical Galaxies Formed

By combining the power of a "natural lens" in space with the capability of NASA's Hubble Space Telescope, astronomers made a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang.

Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, say researchers.

When Hubble photographed the galaxy, astronomers expected to see a chaotic ball of stars formed through galaxies merging together. Instead, they saw evidence that the stars were born in a pancake-shaped disk.

This is the first direct observational evidence that at least some of the earliest so-called "dead" galaxies — where star formation stopped — somehow evolve from a Milky Way-shaped disk into the giant elliptical galaxies we see today.

This is a surprise because elliptical galaxies contain older stars, while spiral galaxies typically contain younger blue stars. At least some of these early "dead" disk galaxies must have gone through major makeovers. They not only changed their structure, but also the motions of their stars to make a shape of an elliptical galaxy.

"This new insight may force us to rethink the whole cosmological context of how galaxies burn out early on and evolve into local elliptical-shaped galaxies," said study leader Sune Toft of the Dark Cosmology Center at the Niels Bohr Institute, University of Copenhagen, Denmark. "Perhaps we have been blind to the fact that early "dead" galaxies could in fact be disks, simply because we haven't been able to resolve them."

Previous studies of distant dead galaxies have assumed that their structure is similar to the local elliptical galaxies they will evolve into. Confirming this assumption in principle requires more powerful space telescopes than are currently available. However, through the phenomenon known as "gravitational lensing," a massive, foreground cluster of galaxies acts as a natural "zoom lens" in space by magnifying and stretching images of far more distant background galaxies. By joining this natural lens with the resolving power of Hubble, scientists were able to see into the center of the dead galaxy.

The remote galaxy is three times as massive as the Milky Way but only half the size. Rotational velocity measurements made with the European Southern Observatory's Very Large Telescope (VLT) showed that the disk galaxy is spinning more than twice as fast as the Milky Way.

Using archival data from the Cluster Lensing And Supernova survey with Hubble (CLASH), Toft and his team were able to determine the stellar mass, star-formation rate, and the ages of the stars.

Why this galaxy stopped forming stars is still unknown. It may be the result of an active galactic nucleus, where energy is gushing from a supermassive black hole. This energy inhibits star formation by heating the gas or expelling it from the galaxy. Or it may be the result of the cold gas streaming onto the galaxy being rapidly compressed and heated up, preventing it from cooling down into star-forming clouds in the galaxy's center.

But how do these young, massive, compact disks evolve into the elliptical galaxies we see in the present-day universe? "Probably through mergers," Toft said. "If these galaxies grow through merging with minor companions, and these minor companions come in large numbers and from all sorts of different angles onto the galaxy, this would eventually randomize the orbits of stars in the galaxies. You could also imagine major mergers. This would definitely also destroy the ordered motion of the stars."

The findings are published in the June 22 issue of the journal Nature. Toft and his team hope to use NASA's upcoming James Webb Space Telescope to look for a larger sample of such galaxies.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

The Very Large Telescope is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of Northern Chile.

---

Related Links

This site is not responsible for content found on external links

• The science paper by S. Toft et al.
• NASA's Hubble Portal
• CLASH Project Website
• Journal Nature

---

Contacts

Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4488 / 410-338-4514
jenkins@stsci.edu / villard@stsci.edu

Sune Toft
Dark Cosmology Center, Niels Bohr Institute,
University of Copenhagen, Copenhagen, Denmark
sune@dark-cosmology.dk

Source: HubbleSit

Star’s Birth May Have Triggered Another Star Birth, Astronomers Say

Fig 1. Protostar FIR 3 (HOPS 370) with outflow that may have triggered the formation of younger protostar FIR 4 (HOPS 108, location marked with red dot), in the Orion star-forming region. (au = astronomical unit, the distance from the Earth to the Sun, about 93 million miles.) Credit: Osorio et al., NRAO/AUI/NSF.

 

Fig 2. Protostar FIR 3 (HOPS 370) with outflow that may have triggered the formation of younger protostar FIR 4 (HOPS 108), in the Orion star-forming region. Pullouts are individual VLA images of each protostar. (au = astronomical unit, the distance from the Earth to the Sun, about 93 million miles.) Credit: Osorio et al., NRAO/AUI/NSF.

Astronomers using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) have found new evidence suggesting that a jet of fast-moving material ejected from one young star may have triggered the formation of another, younger protostar.

“The orientation of the jet, the speed of its material, and the distance all are right for this scenario,” said Mayra Osorio, of the Astrophysical Institute of Andalucia (IAA-CSIC) in Spain. Osorio is the lead author of a paper reporting the findings in the Astrophysical Journal.

The scientists studied a giant cloud of gas some 1,400 light-years from Earth in the constellation Orion, where numerous new stars are being formed. The region has been studied before, but Osorio and her colleagues carried out a series of VLA observations at different radio frequencies that revealed new details.

Images of the pair show that the younger protostar, called HOPS (Herschel Orion Protostar Survey) 108, lies in the path of the outflow from the older, called HOPS 370. This alignment led Yoshito Shimajiri and collaborators to suggest in 2008 that the shock of the fast-moving material hitting a clump of gas had triggered the clump’s collapse into a protostar.

“We found knots of material within this outflow and were able to measure their speeds,” said Ana K. Diaz-Rodriguez also of IAA-CSIC.

The new measurements gave important support to the idea that the older star’s outflow had triggered the younger’s star’s formation process.

The scientists suggest that the jet from HOPS 370 (also known as FIR 3) began to hit the clump of gas about 100,000 years ago, starting the process of collapse that eventually led to the formation of HOPS 108 (also known as FIR 4). Four other young stars in the region also could be the result of similar interactions, but the researchers found evidence for shocks only in the case of HOPS 108.

While the evidence for this triggering scenario is strong, one fact appears to contradict it. The younger star seems to be moving rapidly in a way that indicates it should have been formed elsewhere, apart from the region impacted by the older star’s outflow.

“This motion, however, might be an illusion possibly created by an outflow from the newer star itself,” explained Osorio. “We want to continue to observe it over a period of time to resolve this question,” she added.

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

Media Contact:

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

Source: National Radio Astronomy Observatory (NRAO)

NASA Releases Kepler Survey Catalog with Hundreds of New Planet Candidates

NASA’s Kepler space telescope team has identified 219 new planet candidates, 10 of which are near-Earth size and in the habitable zone of their star.Credits: NASA/JPL-Caltech

NASA’s Kepler space telescope team has released a mission catalog of planet candidates that introduces 219 new planet candidates, 10 of which are near-Earth size and orbiting in their star's habitable zone, which is the range of distance from a star where liquid water could pool on the surface of a rocky planet.

This is the most comprehensive and detailed catalog release of candidate exoplanets, which are planets outside our solar system, from Kepler’s first four years of data. It’s also the final catalog from the spacecraft’s view of the patch of sky in the Cygnus constellation.

With the release of this catalog, derived from data publicly available on the NASA Exoplanet Archive, there are now 4,034 planet candidates identified by Kepler. Of which, 2,335 have been verified as exoplanets. Of roughly 50 near-Earth size habitable zone candidates detected by Kepler, more than 30 have been verified.

Additionally, results using Kepler data suggest two distinct size groupings of small planets. Both results have significant implications for the search for life. The final Kepler catalog will serve as the foundation for more study to determine the prevalence and demographics of planets in the galaxy, while the discovery of the two distinct planetary populations shows that about half the planets we know of in the galaxy either have no surface, or lie beneath a deep, crushing atmosphere – an environment unlikely to host life.

The findings were presented at a news conference Monday at NASA's Ames Research Center in California's Silicon Valley.

“The Kepler data set is unique, as it is the only one containing a population of these near Earth-analogs – planets with roughly the same size and orbit as Earth,” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate. “Understanding their frequency in the galaxy will help inform the design of future NASA missions to directly image another Earth.”

The Kepler space telescope hunts for planets by detecting the minuscule drop in a star’s brightness that occurs when a planet crosses in front of it, called a transit.

This is the eighth release of the Kepler candidate catalog, gathered by reprocessing the entire set of data from Kepler’s observations during the first four years of its primary mission. This data will enable scientists to determine what planetary populations – from rocky bodies the size of Earth, to gas giants the size of Jupiter – make up the galaxy’s planetary demographics.

To ensure a lot of planets weren't missed, the team introduced their own simulated planet transit signals into the data set and determined how many were correctly identified as planets. Then, they added data that appear to come from a planet, but were actually false signals, and checked how often the analysis mistook these for planet candidates. This work told them which types of planets were overcounted and which were undercounted by the Kepler team’s data processing methods.

“This carefully-measured catalog is the foundation for directly answering one of astronomy’s most compelling questions – how many planets like our Earth are in the galaxy?” said Susan Thompson, Kepler research scientist for the SETI Institute in Mountain View, California, and lead author of the catalog study.

One research group took advantage of the Kepler data to make precise measurements of thousands of planets, revealing two distinct groups of small planets. The team found a clean division in the sizes of rocky, Earth-size planets and gaseous planets smaller than Neptune. Few planets were found between those groupings.

Using the W. M. Keck Observatory in Hawaii, the group measured the sizes of 1,300 stars in the Kepler field of view to determine the radii of 2,000 Kepler planets with exquisite precision.

“We like to think of this study as classifying planets in the same way that biologists identify new species of animals,” said Benjamin Fulton, doctoral candidate at the University of Hawaii in Manoa, and lead author of the second study. “Finding two distinct groups of exoplanets is like discovering mammals and lizards make up distinct branches of a family tree.”

It seems that nature commonly makes rocky planets up to about 75 percent bigger than Earth. For reasons scientists don't yet understand, about half of those planets take on a small amount of hydrogen and helium that dramatically swells their size, allowing them to "jump the gap" and join the population closer to Neptune’s size.

The Kepler spacecraft continues to make observations in new patches of sky in its extended mission, searching for planets and studying a variety of interesting astronomical objects, from distant star clusters to objects such as the TRAPPIST-1 system of seven Earth-size planets, closer to home.

Ames manages the Kepler missions for NASA’s Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

For more information about the Kepler mission, visit:  https://www.nasa.gov/kepler

---

Felicia Chou
Headquarters, Washington
202-358-0257
felicia.chou@nasa.gov

Michele Johnson
Ames Research Center, California’s Silicon Valley
650-604-6882
michele.johnson@nasa.gov

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

Editor: Karen Northon

Source: NASA/Kepler and K2

A most detailed view into distant stellar nurseries

This composition out of six images shows far distant galaxies. Depicted in green are the visually visible and near-infrared regimes. Only at radio wavelengths (red) the hidden activities of the central black holes deep within the galaxies are unveiled via highly energetic emission processes on spatial scales far beyond the host galaxy. The radio waves also map the birth places of stars as the example of a relatively nearby galaxy shows (lower left). A bright reddish ring of radio emission indicates that star formation proceeds over virtually the entire extent oft he host galaxy. [less] Image credit: Dr. Eleni Vardoulaki and Eric Faustino Jimenez-Andrade (Argelander-Institute)/VLA-COSMOS Team

---

Press release of the University of Bonn with participation of MPIA regarding the VLA-COSMOS 3 GHz project

Just like in human civilizations the birth rate in the Universe fluctuated over time. When the Universe had reached 2.5 Billion years of its current age of approximately 13.8 Billion years, galaxies produced the majority of all stars ever formed. An international team of astronomers including reasearcher from the Argelander-Institute for Astronomy at the University of Bonn and the Max-Planck-Institute for Astronomy Heidelberg has now vastly improved on previous estimates. The Karl G. Jansky Very Large Array Telescope in New Mexico (USA) allowed to undertake a survey of distant galaxies that produced unprecendentedly detailed and deep radio views over a very large celestial area. The results will now be published in a special edition of the journal „Astronomy & Astrophysics“.

The international team observed almost 11,000 galaxies over an area equivalent to about nine full moons on the sky. Thanks to these unique data the life cycle of galaxies over the past 13 Billion years could be reconstructed. „The radio light from a galaxy can show us at least two very important things,” said the lead investigator of the project, Associate-Professor Vernesa Smolčić from the University of Zagreb. „Radio light helps us to see straight through dust clouds and so reveals new stars forming within galaxies. It can also show us highly energetic signatures of growing supermassive black holes.“

Contrary to visible light, radio-light is not blocked by the large clouds of interstellar dust that often reside in galaxies. This means that radio waves can be used to detect newborn stars within galaxies in a way usually not possible at other wavelengths.

The VLA-COSMOS project started with Dr. Eva Schinnerer at the Max-Planck Institute for Astronomy Heidelberg as principal investigator already back in 2004 with a first radio survey of a celestial area called „COSMOS“. The tremendous scientific success of this project motivated the team – now led by Prof. Smolčić who at that time was based as a researcher at the Argelander-Institute for Astronomy at the University of Bonn – to apply for a large follow-up survey. This effort only became possible thanks to a major technological upgrade the Karl G. Jansky Very Large Array (VLA) Telescope in New Mexico (USA) had undergone in the meanwhile.

The astronomers combined the new radio data with optical, infrared, and X-ray information from many of the world’s leading telescopes. „The synergy of sensitive, multi-wavelength data allowed us to investigate the properties of galaxies shining at radio wavelengths out to about 13 billion years into the universe’s past,” said Dr. Alexander Karim who is responsible for the VLA-COSMOS survey at the Argelander-Institute for Astronomy at the University of Bonn.

The team found that the rate of production of new stars within galaxies was the highest when the universe was about 2.5 billion years old – a fifth of its current age. During that period, about a quarter of all newborn stars were being created in massive galaxies. They also found that up to 20 percent more star formation was occurring in galaxies in the early universe, compared to what was previously thought.

Moreover, a very distant but vigurously star forming population of galaxies – so called submillimeter-galaxies – were found to be substantially larger than previously expected. The exact reasons for this have not been entirely clarified yet but they could be linked to collisions and gravitational interactions between galaxies.

The new radio survey has also provided a unique insight into galaxies containing actively growing supermassive black holes in their centers. These galaxies are called Active Galactic Nuclei, or AGN for short. Matter orbiting around and falling into the black hole can release huge amounts of energy. Using the new radio data, the astronomers discovered more than 1000 AGN. Only their radio emission signatures betray their hidden black hole activity. They are particularly interesting because of their influence on the fate of their host galaxies but even on their cosmic environment. The astronomers compared the AGN heating process assumed in cosmological simulations to what they detected in the new radio data. They found a strong similarity between the two. „Physical processes associated with emission from these supermassive black holes may heat the gas in and around the galaxy, preventing the formation of new stars and halting the runaway growth of galaxies”, says Dr. Schinnerer from the MPI for Astronomy in Heidelberg. Dr. Karim adds: „The VLA-COSMOS survey marks an important milestone on our way towards the next generation large area sky surveys.”

---

Original press release with additional images, videos and all contact persons:  

http://cosmos.astro.caltech.edu/news/52

German press release of Bonn University at the Informationsdienst Wissenschaft (idw):  

https://idw-online.de/de/news676338

English version of the press release of Bonn University at Informationsdienst Wissenschaft (idw):  

 https://idw-online.de/de/news676339

Scientific publications belonging to the project: The VLA-COSMOS 3 GHz Large Project, Astronomy & Astrophysics -  https://www.aanda.org/component/toc/?task=topic&id=752

---

Project funding:

• ERC Starting Grant project (‘CoSMass’): Constraining Stellar Mass and Supermassive Black Hole Growth through Cosmic Times: Paving the way for the next generation sky surveys (European Union’s Seventh Framework program under grant agreement 337595)
• CIG project (‘AGN feedback’): Constraining AGN feedback through cosmic times: Paving the way for the next generation radio facilities (European Union’s Seventh Framework program under grant agreement 333654)
• Deutsche Foschungsgemeinschaft (DFG): grant BE 1837/13-1 (‘The Cosmic Evolution of Black Hole and Stellar Mass Growth Probed Through Radio Observations’) and Collaborative Research Council 956 (“Conditions and Impact of Star Formation”) sub-project A1.

---

Contact at MPIA:

Eva Schinnerer
Phone: (+49|0) 6221 528-293
Email: schinnerer@mpia.de
Links: Personal homepage

Media Contact:

Klaus Jäger
Scientific coordinator
Phone: (+49|0) 6221 528-379
Email: jaeger@mpia.de

Source: Max Planck Institute for Astronomy

True shape of the Boomerang

Boomerang Nebula
Credit: ALMA (ESO/NAOJ/NRAO)/R. Sahai

This Picture of Week shows the Boomerang Nebula, a protoplanetary nebula,  as seen by the Atacama Large Millimeter/submillimeter Array (ALMA). The background purple structure, as seen in visible light with the NASA/ESA Hubble Space Telescope, shows a classic double-lobe shape with a very narrow central region. ALMA’s ability to see the cold molecular gas reveals the nebula’s more elongated shape, in orange.

Since 2003 the nebula, located about 5000 light-years from Earth, has held the record for the coldest known object in the Universe. The nebula is thought to have formed from the envelope of a star in its later stages of life which engulfed a smaller, binary companion. It is possible that this is the cause of the ultra-cold outflows, which are illuminated by the light of the central, dying star.

ALMA looked at the nebula’s central dusty disc and the outflows further out, which span a distance of almost four light-years across the sky. These outflows are even colder than the cosmic microwave background, reaching temperatures below –270 °C. The outflows are also expanding at a speed of 590 000 kilometres per hour.

---

Links

• NRAO press release

Source: ESO/Potw

Chaotically Magnetized Cloud Is No Place to Build a Star, or Is It?

Artist impression of chaotic magnetic field lines very near a newly emerging protostar.

Credit: NRAO/AUI/NSF; D. Berry. Low Resolution (jpg)

 

Texture represents the magnetic field orientation in the region surrounding the Ser-emb 8 protostar, as measured by ALMA. 

The gray region is the millimeter wavelength dust emission.

Credit: ALMA (ESO/NAOJ/NRAO); P. Mocz, C. Hull, CfA.  Low Resolution (jpg)

Cambridge, MA - For decades, scientists believed that the magnetic field lines coursing around newly forming stars were both powerful and unyielding, working like jail bars to corral star-forming material. More recently, astronomers have found tantalizing evidence that large-scale turbulence far from a nascent star can drag magnetic fields around at will.

Now, a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has discovered a surprisingly weak and wildly disorganized magnetic field very near a newly emerging protostar. These observations suggest that the impact of a magnetic field on star formation is more complex than previously thought.

The researchers used ALMA to map the magnetic field surrounding the young protostar dubbed Ser-emb 8, which resides about 1,420 light-years away in the Serpens star-forming region. These new observations are the most sensitive ever made of the small-scale magnetic fields surrounding a young protostar. They also provide important insights into the formation of low-mass stars like our own sun.
Previous observations with other telescopes found that magnetic fields surrounding some young protostars form a classic "hourglass" shape – a hallmark of a strong magnetic field – that starts near the protostar and extends many light-years into the surrounding cloud of dust and gas.

"Before now, we didn’t know if all stars formed in regions that were controlled by strong magnetic fields. Using ALMA, we found our answer," said Charles L. H. "Chat" Hull, an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author on a paper appearing in the Astrophysical Journal Letters. "We can now study magnetic fields in star-forming clouds on the broadest of scales all the way down to the forming star itself. This is exciting because it may mean stars can emerge from a wider range of conditions than we once thought."

ALMA is able to study magnetic fields at the small scales inside star-forming clumps by mapping the polarization of light emitted by dust grains that have aligned themselves with magnetic fields.

By comparing the structure of the magnetic field in the observations with cutting-edge supercomputer simulations on multiple scales, the astronomers gained important insights into the earliest stages of magnetized star formation. The simulations – which extend from a relatively nearby 140 astronomical units from the protostar (about four times the distance from the sun to Pluto) to as far out as 15 light-years – were performed by CfA astronomers Philip Mocz and Blakesley Burkhart, who are co-authors on the paper.

In the case of Ser-emb 8, the astronomers believe they have captured the original magnetic field around the star "red handed," before outflowing material from the star could erase the pristine signature of the magnetic field in the surrounding molecular cloud, noted Mocz.

"Our observations show that the importance of the magnetic field in star formation can vary widely from star to star," concluded Hull. "This protostar formed in a weakly magnetized environment dominated by turbulence, while previous observations show sources that clearly formed in strongly magnetized environments. We need further research to understand how common each scenario is."

This research was presented in a paper titled "Unveiling the Role of the Magnetic Field at the Smallest Scales of Star Formation," by C. Hull et al., appearing in the Astrophysical Journal Letters.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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

For more information, contact:

Megan Watzke
Harvard-Smithsonian Center for Astrophysics
+1 617-496-7998
mwatzke@cfa.harvard.edu

Charles Blue
National Radio Astronomy Observatory
434-296-0314
cblue@nrao.edu

Source:  Harvard-Smithsonian Center for Astrophysics (CfA)