Releases from NASA, NASA Galex, NASA's Goddard Space Flight Center, HubbleSite, Hinode, Spitzer, Cassini, ESO, ESA, Chandra, HiRISE, Royal Astronomical Society, NRAO, Astronomy Picture of the Day, Harvard-Smithsonian Center For Astrophysics, Max Planck Institute for Astrophysics, Gemini Observatory, Subaru Telescope, W. M. Keck Observatory, Fermi Gamma-ray Space Telescope, JPL-Caltech, etc
A new ScienceCast video explores the strange quantum realm of NASA's new Cold Atom Lab.Play it
Everyone knows that space is cold. In the vast gulf between stars and
galaxies, the temperature of gaseous matter routinely drops to 3
degrees K, or 454 degrees below zero Fahrenheit.
It’s about to get even colder.
NASA researchers are planning to create the coldest spot in the known universe inside the International Space Station.
“We’re going to study matter at temperatures far colder than are
found naturally,” says Rob Thompson of JPL. He’s the Project Scientist
for NASA’s Cold Atom Lab, an atomic ‘refrigerator’ slated for launch to
the ISS in 2016. "We aim to push effective temperatures down to 100
100 pico-Kelvin is just one ten billionth of a degree
above absolute zero, where all the thermal activity of atoms
theoretically stops. At such low temperatures, ordinary concepts of
solid, liquid and gas are no longer relevant. Atoms interacting just
above the threshold of zero energy create new forms of matter that are
essentially ... quantum.
Quantum mechanics is a branch of physics that describes the
bizarre rules of light and matter on atomic scales. In that realm,
matter can be in two places at once; objects behave as both particles and waves; and nothing is certain: the quantum world runs on probability.
It is into this strange realm that researchers using the Cold Atom Lab will plunge.
In 1995, researchers discovered that if you took a few million
rubidium atoms and cooled them near absolute zero, they would merge into
a single wave of matter. The trick worked with sodium, too. In 2001,
Eric Cornell of the National Institute of Standards & Technology and
Carl Wieman of University of Colorado shared the Nobel Prize with
Wolfgang Ketterle of MIT for their independent discovery of these
condensates, which Albert Einstein and Satyendra Bose had predicted in
the early 20th century.
If you create two BECs and put them together, they don't mix like
an ordinary gas. Instead, they can "interfere" like waves: thin,
parallel layers of matter are separated by thin layers of empty space.
An atom in one BEC can add itself to an atom in another BEC and produce –
no atom at all.
“The Cold Atom Lab will allow us to study these objects at perhaps the lowest temperatures ever,” says Thompson.
The lab is also a place where researchers can mix super-cool
atomic gasses and see what happens.
“Mixtures of different types of
atoms can float together almost completely free of perturbations,”
explains Thompson, “allowing us to make sensitive measurements of very
weak interactions. This could lead to the discovery of interesting and
novel quantum phenomena.”
The space station is the best place to do this research.
Microgravity allows researchers to cool materials to temperatures much
colder than are possible on the ground.
Thompson explains why:
“It’s a basic principle of thermodynamics that when a gas expands,
it cools. Most of us have hands-on experience with this. If you spray a
can of aerosols, the can gets cold.”
Quantum gases are cooled in much the same way. In place of an aerosol can, however, we have a ‘magnetic trap.’
“On the ISS, these traps can be made very weak because they do not
have to support the atoms against the pull of gravity. Weak traps
allow gases to expand and cool to lower temperatures than are possible
on the ground.”
No one knows where this fundamental research will lead. Even the
“practical” applications listed by Thompson—quantum sensors, matter wave
interferometers, and atomic lasers, just to name a few—sound like
science fiction. “We’re entering the unknown,” he says.
Researchers like Thompson think of the Cold Atom Lab as a doorway
into the quantum world. Could the door swing both ways? If the
temperature drops low enough, “we’ll be able to assemble atomic wave
packets as wide as a human hair--that is, big enough for the human eye
to see.” A creature of quantum physics will have entered the
Radiation and winds from massive stars have
blown a cavity into the surrounding dust and gas, creating the Trifid
nebula, as seen here in infrared light by NASA's Wide-field Infrared
Survey Explorer, or WISE. Image credit: NASA/JPL-Caltech/UCLA.Larger image
A storm of stars is brewing in the Trifid nebula, as seen in this
view from NASA's Wide-field Infrared Survey Explorer, or WISE. The
stellar nursery, where baby stars are bursting into being, is the
yellow-and-orange object dominating the picture. Yellow bars in the
nebula appear to cut a cavity into three sections, hence the name Trifid
Colors in this image represent different wavelengths of infrared
light detected by WISE. The main green cloud is made up of hydrogen gas.
Within this cloud is the Trifid nebula, where radiation and winds from
massive stars have blown a cavity into the surrounding dust and gas, and
presumably triggered the birth of new generations of stars. Dust glows
in infrared light, so the three lines that make up the Trifid, while
appearing dark in visible-light views, are bright when seen by WISE.
The blue stars scattered around the picture are older, and they lie
between Earth and the Trifid nebula. The baby stars in the Trifid will
eventually look similar to those foreground stars. The red cloud at
upper right is gas heated by a group of very young stars.
The Trifid nebula is located 5,400 light-years away in the constellation Sagittarius.
Blue represents light emitted at 3.4-micron wavelengths, and cyan
(blue-green) represents 4.6 microns, both of which come mainly from hot
stars. Relatively cooler objects, such as the dust of the nebula, appear
green and red. Green represents 12-micron light and red, 22-micron
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and
operates the recently activated NEOWISE asteroid-hunting mission for
NASA's Science Mission Directorate. The results presented here are from
the WISE all-sky survey mission, which operated before NEOWISE, using
the same spacecraft, in 2010 and 2011. WISE was selected competitively
under NASA's Explorers Program managed by the agency's Goddard Space
Flight Center in Greenbelt, Md. The science instrument was built by the
Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by
Ball Aerospace & Technologies Corp. in Boulder, Colo. Science
operations and data processing take place at the Infrared Processing and
Analysis Center at the California Institute of Technology, Pasadena.
Caltech manages JPL for NASA.
Herbig-Haro 30 is the prototype of a
gas-rich "young stellar object" disk around a star. The dark disk spans
40 billion miles (64 billion kilometers) in this image from NASA's
Hubble Space Telescope, cutting the bright nebula in two and blocking
the central star from direct view. Image credit NASA/Hubble/STScI.Full image and caption
NASA is inviting the public to help astronomers discover embryonic
planetary systems hidden among data from the agency's Wide-field
Infrared Survey Explorer (WISE) mission through a new website,
Disk Detective is NASA's largest crowdsourcing project whose primary
goal is to produce publishable scientific results. It exemplifies a new
commitment to crowdsourcing and open data by the United States
"Through Disk Detective, volunteers will help the astronomical community
discover new planetary nurseries that will become future targets for
NASA's Hubble Space Telescope and its successor, the James Webb Space
Telescope," said James Garvin, the chief scientist for NASA Goddard's
Sciences and Exploration Directorate.
WISE was designed to survey the entire sky at infrared wavelengths. From
a perch in Earth orbit, the spacecraft completed two scans of the
entire sky between 2010 and 2011. It took detailed measurements on more
than 745 million objects, representing the most comprehensive survey of
the sky at mid-infrared wavelengths currently available.
Astronomers have used computers to search this haystack of data for
planet-forming environments and narrowed the field to about a
half-million sources that shine brightly in infrared, indicating they
may be "needles": dust-rich disks that are absorbing their star's light
and reradiating it as heat.
"Planets form and grow within disks of gas, dust and icy grains that
surround young stars, but many details about the process still elude
us," said Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight
Center in Greenbelt, Md. "We need more examples of planet-forming
habitats to better understand how planets grow and mature."
But galaxies, interstellar dust clouds and asteroids also glow in
infrared, which stymies automated efforts to identify planetary
habitats. There may be thousands of nascent solar systems in the WISE
data, but the only way to know for sure is to inspect each source by
eye, which poses a monumental challenge.
Public participation in scientific research is a type of crowdsourcing
known as citizen science. It allows the public to make critical
contributions to the fields of science, technology, engineering and
mathematics by collecting, analyzing and sharing a wide range of data.
NASA uses citizen science to engage the public in problem-solving.
Kuchner recognized that spotting planetary nurseries is a perfect
opportunity for crowdsourcing. He arranged for NASA to team up with the
Zooniverse, a collaboration of scientists, software developers and
educators who collectively develop and manage citizen science projects
on the Internet. The result of their combined effort is Disk Detective.
Disk Detective incorporates images from WISE and other sky surveys in
brief animations the website calls flip books. Volunteers view a flip
book and classify the object based on simple criteria, such as whether
the image is round or includes multiple objects. By collecting this
information, astronomers will be able to assess which sources should be
explored in greater detail, for example, to search for planets outside
our solar system.
"Disk Detective's simple and engaging interface allows volunteers from
all over the world to participate in cutting-edge astronomy research
that wouldn't even be possible without their efforts," said Laura Whyte,
director of citizen science at Adler Planetarium in Chicago, Ill., a
founding partner of the Zooniverse collaboration.
The project aims to find two types of developing planetary environments.
The first, known as a young stellar object disk, typically is less than
5 million years old, contains large quantities of gas, and often is
found in or near young star clusters. For comparison, our own solar
system is 4.6 billion years old. The second planetary environment, known
as a debris disk, tends to be older than 5 million years, possesses
little or no gas, and contains belts of rocky or icy debris that
resemble the asteroid and Kuiper belts found in our own solar system.
Vega and Fomalhaut, two of the brightest stars in the sky, host debris
WISE was shut down in 2011 after its primary mission was completed. But
in September 2013, it was reactivated, renamed Near-Earth Object
Wide-field Infrared Survey Explorer (NEOWISE), and given a new mission,
which is to assist NASA's efforts to identify the population of
potentially hazardous near-Earth objects (NEOs). NEOWISE also can assist
in characterizing previously detected asteroids that could be
considered potential targets for future exploration missions.
NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages and
operates WISE for NASA's Science Mission Directorate. The WISE mission
was selected competitively under NASA's Explorers Program managed by the
agency's Goddard Space Flight Center. The science instrument was built
by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was
built by Ball Aerospace & Technologies Corp. in Boulder, Colo.
Science operations and data processing take place at the Infrared
Processing and Analysis Center at the California Institute of
Technology, which manages JPL for NASA.
A rainbow of lunar transitsas seen by NASA's Solar Dynamics Observatory.
The observatory watches the sun in many different wavelengths of
light, which are each colorized in a different color. Image Credit: NASA/SDO
On Jan 30, 2014, beginning at 8:31 a.m EST, the moon moved between
NASA’s Solar Dynamics Observatory, or SDO, and the sun, giving the
observatory a view of a partial solar eclipse from space. Such a lunar
transit happens two to three times each year. This one lasted two and
one half hours, which is the longest ever recorded. When the next one
will occur is as of yet unknown due to planned adjustments in SDO's
Note in the picture how crisp the horizon is on the moon, a
reflection of the fact that the moon has no atmosphere around it to
distort the light from the sun.
Solar Dynamics Observatory capturedthis imageof the moon crossing in
front of its view of the sun on Jan. 30, 2014, at 9:00 a.m. EST. Image Credit: NASA/SDO
movie of the moon crossing in front of the sun as seen by NASA’s Solar
Dynamics Observatory on Jan 30, 2014. The sun appears to move because
SDO’s fine guidance systems rely on seeing the whole sun to keep the
images centered from exposure to exposure. Image Credit: NASA/SDO/Goddard Space Flight Center
Flying among the closest stars to the Solar System
ESO’s VLT charts surface of nearest brown dwarf
ESO's Very Large Telescope has been used
to create the first ever map of the weather on the surface of the
nearest brown dwarf to Earth. An international team has made a chart of
the dark and light features on WISE J104915.57-531906.1B, which is
informally known as Luhman 16B and is one of two recently discovered
brown dwarfs forming a pair only six light-years from the Sun. The new
results are being published in the 30 January 2014 issue of the journal
Brown dwarfs fill the gap between giant gas planets, such as Jupiter
and Saturn, and faint cool stars. They do not contain enough mass to
initiate nuclear fusion in their cores and can only glow feebly at
infrared wavelengths of light. The first confirmed brown dwarf was only
found twenty years ago and only a few hundred of these elusive objects
The closest brown dwarfs to the Solar System form a pair called Luhman 16AB 
that lies just six light-years from Earth in the southern constellation
of Vela (The Sail). This pair is the third closest system to the Earth,
after Alpha Centauri and Barnard's Star, but it was only discovered in
early 2013. The fainter component, Luhman 16B, had already been found to
be changing slightly in brightness every few hours as it rotated — a
clue that it might have marked surface features.
Now astronomers have used the power of ESO's Very Large Telescope
(VLT) not just to image these brown dwarfs, but to map out dark and
light features on the surface of Luhman 16B.
Ian Crossfield (Max Planck Institute for Astronomy, Heidelberg,
Germany), the lead author of the new paper, sums up the results: “Previous
observations suggested that brown dwarfs might have mottled surfaces,
but now we can actually map them. Soon, we will be able to watch cloud
patterns form, evolve, and dissipate on this brown dwarf — eventually,
exometeorologists may be able to predict whether a visitor to Luhman 16B
could expect clear or cloudy skies.”
To map the surface the astronomers used a clever technique. They observed the brown dwarfs using the CRIRES instrument on the VLT.
This allowed them not just to see the changing brightness as Luhman 16B
rotated, but also to see whether dark and light features were moving
away from, or towards the observer. By combining all this information
they could recreate a map of the dark and light patches of the surface.
The atmospheres of brown dwarfs are very similar to those of hot gas
giant exoplanets, so by studying comparatively easy-to-observe brown
astronomers can also learn more about the atmospheres of young, giant
planets — many of which will be found in the near future with the new SPHERE instrument that will be installed on the VLT in 2014.
Crossfield ends on a personal note: “Our brown dwarf map helps
bring us one step closer to the goal of understanding weather patterns
in other solar systems. From an early age I was brought up to appreciate
the beauty and utility of maps. It's exciting that we're starting to
map objects out beyond the Solar System!”
 This pair was discovered by the
American astronomer Kevin Luhman on images from the WISE infrared survey
satellite. It is formally known as WISE J104915.57-531906.1, but a
shorter form was suggested as being much more convenient. As Luhman had
already discovered fifteen double stars the name Luhman 16 was adopted.
Following the usual conventions for naming double stars, Luhman 16A is
the brighter of the two components, the secondary is named Luhman 16B
and the pair is referred to as Luhman 16AB.
 Hot Jupiter exoplanets lie very close to their
parent stars, which are much brighter. This makes it almost impossible
to observe the faint glow from the planet, which is swamped by
starlight. But in the case of brown dwarfs there is nothing to overwhelm
the dim glow from the object itself, so it is much easier to make
This research was presented in a paper, “A
Global Cloud Map of the Nearest Known Brown Dwarf”, by Ian Crossfield et
al. to appear in the journal Nature.
The team is composed of I. J. M. Crossfield (Max Planck Institute for
Astronomy [MPIA], Heidelberg, Germany), B. Biller (MPIA; Institute for
Astronomy, University of Edinburgh, United Kingdom), J. Schlieder
(MPIA), N. R. Deacon (MPIA), M. Bonnefoy (MPIA; IPAG, Grenoble, France),
D. Homeier (CRAL-ENS, Lyon, France), F. Allard (CRAL-ENS), E. Buenzli
(MPIA), Th. Henning (MPIA), W. Brandner (MPIA), B. Goldman (MPIA) and T.
Kopytova (MPIA; International Max-Planck Research School for Astronomy
and Cosmic Physics at the University of Heidelberg, Germany).
ESO is the foremost intergovernmental astronomy organisation in
Europe and the world's most productive ground-based astronomical
observatory by far. It is supported by 15 countries: Austria, Belgium,
Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy,
the Netherlands, Portugal, Spain, Sweden, Switzerland and the United
Kingdom. ESO carries out an ambitious programme focused on the design,
construction and operation of powerful ground-based observing facilities
enabling astronomers to make important scientific discoveries. ESO also
plays a leading role in promoting and organising cooperation in
astronomical research. ESO operates three unique world-class observing
sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO
operates the Very Large Telescope, the world's most advanced
visible-light astronomical observatory and two survey telescopes. VISTA
works in the infrared and is the world's largest survey telescope and
the VLT Survey Telescope is the largest telescope designed to
exclusively survey the skies in visible light. ESO is the European
partner of a revolutionary astronomical telescope ALMA, the largest
astronomical project in existence. ESO is currently planning the
39-metre European Extremely Large optical/near-infrared Telescope, the
E-ELT, which will become “the world's biggest eye on the sky”.
This graphic shows the evolutionary sequence in the growth of massive
elliptical galaxies over 13 billion years, as gleaned from space-based
and ground-based telescopic observations. The growth of this class of
galaxies is quickly driven by rapid star formation and mergers with
other galaxies. Credit:NASA,ESA, S. Toft (Niels Bohr Institute), and A. Feild (STScI)
Astronomers combining the power of the Hubble Space Telescope,
Spitzer and Herschel infrared space telescopes, and ground-based
telescopes have assembled a coherent picture of the formation history
of the most massive galaxies in the universe, from their initial burst
of violent star formation through their appearance as high
stellar-density galaxy cores and to their ultimate destiny as giant
This solves a decade-long mystery as to how compact elliptical-shaped
galaxies that existed when the universe was only 3 billion years old,
or one-quarter of its current age of 13.8 billion years, already had
completed star formation. These compact ellipticals have now been
definitively linked directly to an earlier population of dusty
starburst galaxies that voraciously used up available gas for star
formation very quickly. Then they grew slowly through merging as the
star formation in them was quenched, and they eventually became giant
"This is the first time anybody has put together a representative
spectroscopic sample of ultra-compact, burned-out galaxies with the
high quality of infrared imaging of Hubble," said Sune Toft of the Dark
Cosmology Center at the Niels Bohr Institute in Copenhagen.
"We at last show how these compact galaxies can form, how it
happened, and when it happened," Toft added. "This basically is the
missing piece in the understanding of how the most massive galaxies
formed, and how they evolved into the giant ellipticals of today. This
had been a great mystery for many years because just 3 billion years
after the big bang we see that half of the most massive galaxies have
already completed their star formation."
Even more surprising, said Toft, is that these massive, burned-out
galaxies were once extremely compact, compared to similar elliptical
galaxies seen today in the nearby universe. This means that stars had
to be crammed together 10 to 100 times more densely than seen in
galaxies today. "It's comparable to the densities of stars in globular
clusters, but on the larger scale of a galaxy," said Toft.
In tying together an evolutionary sequence for these compact massive
galaxies, Toft identified their progenitors as highly dust-obscured
galaxies undergoing rapid star formation at rates that are thousands of
times faster than in our Milky Way galaxy. Starbursts in these
galaxies are likely ignited when two gas-rich galaxies collided. These
galaxies are so dusty that they are almost invisible at optical
wavelengths, but are bright at submillimeter wavelengths, where they
were first identified nearly two decades ago by the SCUBA
(Submillimeter Common-User Bolometer Array) camera on the James Clerk
Maxwell Telescope in Hawaii.
Toft's team assembled, for the first time, representative samples of
the two galaxy populations using the rich dataset in Hubble's COSMOS
(Cosmic Evolution Survey) program.
They constructed the first representative sample of compact quiescent
galaxies with accurate sizes and distances (spectroscopic redshifts)
measured from the Hubble Space Telescope's CANDELS (Cosmic Assembly
Near-Infrared Deep Extragalactic Legacy Survey) and 3D-HST programs.
3D-HST is a near-infrared Hubble spectroscopic survey to study the
physical processes that shape galaxies in the distant universe. The
astronomers combined these data with observations from the Subaru
telescope in Hawaii and NASA's Spitzer Space Telescope. This allowed
for accurate stellar age estimates, from which they concluded that
galaxies formed in intense starbursts 1 billion to 2 billion years
earlier, in the very early universe.
The team then made the first representative sample of the most
distant submillimeter galaxies using the rich COSMOS data from the
Hubble, Spitzer, and Herschel space telescopes, and ground-based
telescopes such as Subaru, the James Clerk Maxwell Telescope, and the
Submillimeter Array. This multi-spectral information, stretching from
optical light through submillimeter wavelengths, yielded a full suite of
information about the sizes, stellar masses, star-formation rates,
dust content, and precise distances of the dust-enshrouded galaxies
present early on in the universe.
When Toft's team compared the samples of these two galaxy
populations, they discovered a link between the compact elliptical
galaxies and the submillimeter galaxies observed 1 billion to 2 billion
years earlier. The observations show that the violent starburst
activity in the earlier galaxies had the same characteristics that would
have been predicted for progenitors to the compact elliptical
galaxies. The team also calculated that the intense starburst activity
only lasted about 40 million years before the interstellar gas supply
A team of astronomers has conducted infrared observations of luminous,
gas-rich, merging galaxies with the Subaru Telescope to study active,
mass-accreting supermassive black holes (SMBHs). They found that at
least one SMBH almost always becomes active and luminous by accreting a
large amount of material (Figure 1).
However, only a small fraction of the observed merging galaxies show
multiple, active SMBHs. These results suggest that local physical
conditions near SMBHs rather than general properties of galaxies
primarily determine the activation of SMBHs.
Figure 1:Artist's rendition of an active, mass-accreting black hole in a luminous, gas-rich merging galaxy. (Credit: NAOJ)
In this Universe, dark matter has a much higher mass
than luminous matter, and it dominates the formation of galaxies and
their large-scale structures. The widely accepted, cold-dark-matter
based galaxy formation scenario posits that collisions and mergers of
small gas-rich galaxies result in the formation of massive galaxies seen
in the current Universe. Recent observations show that SMBHs with more
than one-million solar masses ubiquitously exist in the center of
galaxies. The merger of gas-rich galaxies with SMBHs in their centers
not only causes active star formation but also stimulates mass accretion
onto the existing SMBHs. When material accretes onto a supermassive
black hole (SMBH), the accretion disk surrounding the black hole becomes
very hot from the release of gravitational energy, and it becomes very
luminous. This process is referred to as active galactic nucleus (AGN)
activity; it is different from the energy generation activity by nuclear
fusion reactions within stars. Understanding the difference between
these kinds of activities is crucial for clarifying the physical
processes of galaxy formation. However, observation of these processes
is challenging, because dust and gas shroud both star-formation and AGN
activities in merging galaxies. Infrared observations are indispensable
for this type of research, because they substantially reduce the effects
of dust extinction.
To better understand these activities, a team of
astronomers at the National Astronomical Observatory of Japan (NAOJ),
led by Dr. Masatoshi Imanishi, used Subaru Telescope’s Infrared Camera
and Spectrograph (IRCS) and its adaptive optics system to observe
infrared luminous merging galaxies at the infrared K-band (a wavelength
of 2.2 micrometers) and L’-band (a wavelength of 3.8 micrometers). They
used imaging data at these wavelengths to establish a method to
differentiate the activities of deeply buried, active SMBHs from those
of star formation. The radiative energy-generation efficiency from
active, mass-accreting SMBHs is much higher than that of the nuclear
fusion reactions inside stars. An active SMBH generates a large amount
of hot dust (several 100 Kelvins), which produces strong infrared
L’-band radiation; the relative strengths of the infrared K- and L’-band
emission distinguish the active SMBH from star-forming activity. Since
dust extinction effects are small at these infrared wavelengths, the
method can detect even deeply buried, active SMBHs, which are elusive in
optical wavelengths. Subaru Telescope’s adaptive optics system enabled
the team to obtain high spatial resolution images that allowed them to
effectively investigate emission that originates in active SMBHs in the
nuclear regions of galaxies by minimizing emission contamination from
galaxy-wide, star-forming activity.
The team observed 29 infrared luminous gas-rich
merging galaxies. Based on the relative strength of the infrared K- and
L’-band emission at galaxy nuclei, they confirmed that at least one
active SMBH occurs in every galaxy but one (Figure 2).
This indicates that in gas-rich, merging galaxies, a large amount of
material can accrete onto SMBHs, and many such SMBHs can show AGN
Figure 2:Examples of infrared K-band images of
luminous, gas-rich, merging galaxies. The image size is 10 arc seconds.
North is up, and east is to the left. The individual images clearly show
aspects of the merging process, such as interacting double galaxy
nuclei and extended/bridging faint emission structure. (Credit: NAOJ)
However, only four merging galaxies display multiple, active SMBHs (Figure 3).
If both of the original merged galaxies had SMBHs, then we would expect
that multiple SMBHs would occur in many merging galaxies. To observe
these SMBHs as luminous AGN activity, the SMBHs must actively accrete
material. The team’s results mean that not all SMBHs in gas-rich merging
galaxies are actively mass accreting, and that multiple SMBHs may have
considerably different mass accretion rates onto SMBHs. Quantitative
measurement of the degree of mass accretion rates of SMBHs is usually
based on the brightness of AGNs per unit SMBH mass (Figure 4).
Comparison of SMBH-mass-normalized AGN luminosity (=AGN luminosity
divided by SMBH mass) among multiple nuclei confirms the scenario of
different mass accretion rates onto multiple SMBHs in infrared-luminous,
gas-rich merging galaxies.
Figure 3:Infrared K-band and L’-band images of four
luminous, gas-rich, merging galaxies that display multiple, active
SMBHs. The image size is 10 arc seconds. North is up, and east is to
the left. They show emission from multiple galaxy nuclei. The infrared
K-band to L’-band emission strength ratios characterize emission of
AGN-heated hot dust, not a star-formation-related one. (Credit: NAOJ)
Figure 4:The vertical axis is the comparison of
SMBH-mass-normalized AGN luminosity (= AGN luminosity divided by SMBH
mass) between multiple nuclei. The horizontal axis is the apparent
separation of galaxy nuclei. 1 kilo-parsec corresponds to 30000 trillion
kilometers (19000 trillion miles). The supermassive black-hole (SMBH)
masses are derived from stellar emission luminosity at individual galaxy
nuclei, because SMBH mass and galaxy stellar emission luminosity are
found to correlate in nearby galaxies. If both SMBHs have the same mass
accretion rate, when normalized to the SMBH mass, then such objects are
distributed around the horizontal solid line, at the value of unity in
the vertical axis. Objects above the horizontal solid line are SMBHs
with larger mass and show more active mass accretion, while those below
have a smaller mass and show less active mass accretion.(Credit: NAOJ)
The findings demonstrate that local conditions around
SMBHs rather than general properties of galaxies dominate the mass
accretion process onto SMBHs. Since the size scale of mass accretion
onto SMBHs is very small compared to the galaxy scale, such phenomena
are difficult to predict based on computer simulations of galaxy
mergers. Actual observations are crucially important for best
understanding the mass accretion process onto SMBHs that occurs during
Imanishi, M. & Saito, Y. 2014 “Subaru
Adaptive-optics High-spatial-resolution Infrared K- and L’-band Imaging
Search for Deeply Buried Dual AGNs in Merging Galaxies”, Astrophysical
Journal, Volume 780, article id. 106.
Thiscomposite image contains three distinct features: the bright star-filled central region of galaxy NGC 6946 in optical light (blue), the dense hydrogen tracing out the galaxy’s sweeping spiral arms and galactic halo (orange), and the extremely diffuse and extended field of hydrogen engulfing NGC 6946 and its companions (red). The new GBT data show the faintly glowing hydrogen bridging the gulf between the larger galaxy and its smaller companions. This faint structure is precisely what astronomers expect to appear as hydrogen flows from the intergalactic medium into galaxies or from a past encounter between galaxies.
Credit: D.J. Pisano (WVU); B. Saxton (NRAO/AUI/NSF); Palomar Observatory – Space Telescope Science Institute 2nd Digital Sky Survey (Caltech); Westerbork Synthesis Radio Telescope
Using the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT),
astronomer D.J. Pisano from West Virginia University has discovered
what could be a never-before-seen river of hydrogen flowing through
space. This very faint, very tenuous filament of gas is streaming into
the nearby galaxy NGC 6946 and may help explain how certain spiral
galaxies keep up their steady pace of star formation.
that the fuel for star formation had to come from somewhere. So far,
however, we’ve detected only about 10 percent of what would be necessary
to explain what we observe in many galaxies,” said Pisano. “A leading
theory is that rivers of hydrogen – known as cold flows – may be
ferrying hydrogen through intergalactic space, clandestinely fueling
star formation. But this tenuous hydrogen has been simply too diffuse to
detect, until now.”
Spiral galaxies, like our own Milky Way, typically maintain a rather
tranquil but steady pace of star formation.
Others, like NGC 6946, which
is located approximately 22 million light-years from Earth on the
border of the constellations Cepheus and Cygnus, are much more active,
though less-so than more extreme starburst galaxies. This raises the
question of what is fueling the sustained star formation in this and
similar spiral galaxies.
Earlier studies of the galactic
neighborhood around NGC 6946 with the Westerbork Synthesis Radio
Telescope (WSRT) in the Netherlands have revealed an extended halo of
hydrogen (a feature commonly seen in spiral galaxies, which may be
formed by hydrogen ejected from the disk of the galaxy by intense star
formation and supernova explosions). A cold flow, however, would be
hydrogen from a completely different source: gas from intergalactic
space that has never been heated to extreme temperatures by a galaxy’s
star birth or supernova processes.
Using the GBT, Pisano was able to detect the glow emitted by neutral
hydrogen gas connecting NGC 6946 with its cosmic neighbors. This signal
was simply below the detection threshold of other telescopes. The GBT’s
unique capabilities, including its immense single dish, unblocked
aperture, and location in the National Radio Quiet Zone, enabled it to
detect this tenuous radio light.
Astronomers have long
theorized that larger galaxies could receive a constant influx of cold
hydrogen by syphoning it off other less-massive companions.
looking at NGC 6946, the GBT detected just the sort of filamentary
structure that would be present in a cold flow, though there is another
probable explanation for what has been observed. It’s also possible that
sometime in the past this galaxy had a close encounter and passed by
its neighbors, leaving a ribbon of neutral atomic hydrogen in its wake.
If that were the case, however, there should be a small but observable
population of stars in the filaments. Further studies will help to
confirm the nature of this observation and could shine light on the
possible role that cold flows play in the evolution of galaxies.
These results are published in the Astronomical Journal.
The 100-meter GBT is operated by the National Radio Astronomy Observatory (NRAO)
and located in the National Radio Quiet Zone and the West Virginia
Radio Astronomy Zone, which protect the incredibly sensitive telescope
from unwanted radio interference.
Contact: Charles E. Blue, Public Information Officer 434-296-0314 email@example.com
Copyright: ESA / Herschel / XMM-Newton. Acknowledgements:
"Physical Processes in the Interstellar Medium of Very Nearby Galaxies"
Key Programme, Christine Wilson
The Whirlpool Galaxy, also known as M51 or NGC 5194, is one of the
most spectacular examples of a spiral galaxy. With two spiral arms
curling into one another in a billowing swirl, this galaxy hosts over a
hundred billion stars and is currently merging with its companion, the
smaller galaxy NGC 5195.
Around 30 million light-years away, the
Whirlpool Galaxy is close enough to be easily spotted even with
binoculars. Using the best telescopes available both on the ground and
in space, astronomers can scrutinise its population of stars in
In this image, observations performed at
three different wavelengths with ESA’s Herschel and XMM-Newton space
telescopes are combined to reveal how three generations of stars coexist
in the Whirlpool Galaxy.
The infrared light collected by Herschel
– shown in red and yellow – reveals the glow of cosmic dust, which is a
minor but crucial ingredient in the interstellar material in the
galaxy’s spiral arms. This mixture of gas and dust provides the raw
material from which the Whirlpool Galaxy’s future generations of stars
will take shape.
Observing in visible and ultraviolet light,
astronomers can see the current population of stars in the Whirlpool
Galaxy, since stars in their prime shine most brightly at shorter
wavelengths than infrared. Seen at ultraviolet wavelengths with
XMM-Newton and portrayed in green in this composite image are the
galaxy’s fiercest stellar inhabitants: young and massive stars pouring
powerful winds and radiation into their surroundings.
also shows the remains of previous stellar generations, which shine
brightly in X-rays and were detected by XMM-Newton. Shown in blue, these
sources of X-rays are either the sites where massive stars exploded as
supernovae in the past several thousand years, or binary systems that
host neutron stars or black holes, the compact objects left behind by
ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration,
Evans (University of Virginia, Charlottesville/NRAO/Stony Brook
Not all galaxies are neatly shaped, as this new NASA/ESA Hubble Space
Telescope image of NGC 6240 clearly demonstrates. Hubble previously
released an image of this galaxy
back in 2008, but the knotted region, shown here in a pinky-red hue at
the centre of the galaxies, was only revealed in these new observations
from Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys.
6240 lies 400 million light-years away in the constellation of
Ophiuchus (The Serpent Holder). This galaxy has an elongated shape with
branching wisps, loops and tails. This mess of gas, dust and stars bears
more than a passing resemblance to a butterfly and, though perhaps less
conventionally beautiful, a lobster.
This bizarrely-shaped galaxy
did not begin its life looking like this; its distorted appearance is a
result of a galactic merger that occurred when two galaxies drifted too
close to one another. This merger sparked bursts of new star formation
and triggered many hot young stars to explode as supernovae. A new
supernova was discovered in this galaxy in 2013, named SN 2013dc. It is not visible in this image, but its location is indicated here.
the centre of NGC 6240 an even more interesting phenomenon is taking
place. When the two galaxies came together, their central black holes
did so too. There are two supermassive black holes within this jumble,
spiralling closer and closer to one another. They are currently only
some 3000 light-years apart, incredibly close given that the galaxy
itself spans 300 000 light-years. This proximity secures their fate as
they are now too close to escape each other and will soon form a single
immense black hole.
Chandra X-ray and HST optical images of the galaxy cluster RX
J1532.9+3021, located about 3.9 billion light years from Earth. A
labeled version of the combined X-ray/optical image is also given. The
labels show the location of two enormous X-ray cavities, created by jets
from a central supermassive black hole that have pushed aside hot gas.
Astronomers have used NASA's Chandra X-ray Observatory and a suite of
other telescopes to reveal one of the most powerful black holes known.
The black hole has created enormous structures in the hot gas surrounding it and prevented trillions of stars from forming.
The black hole is in a galaxy cluster named RX J1532.9+3021 (RX J1532 for short), located about 3.9 billion light years from Earth. The image here is a composite of X-ray data
from Chandra revealing hot gas in the cluster in purple and optical
data from the Hubble Space Telescope showing galaxies in yellow. The
cluster is very bright in X-rays implying that it is extremely massive,
with a mass about a quadrillion - a thousand trillion - times that of
the sun. At the center of the cluster is a large elliptical galaxy
containing the supermassive black hole.
The large amount of hot gas near the center of the cluster presents a
puzzle. Hot gas glowing with X-rays should cool, and the dense gas in
the center of the cluster should cool the fastest. The pressure in this
cool central gas is then expected to drop, causing gas further out to
sink in towards the galaxy, forming trillions of stars along the way.
However, astronomers have found no such evidence for this burst of stars
forming at the center of this cluster.
This problem has been noted in many galaxy clusters but RX J1532 is
an extreme case, where the cooling of gas should be especially dramatic
because of the high density of gas near the center. Out of the thousands
of clusters known to date, less than a dozen are as extreme as RX
J1532. The Phoenix Cluster is the most extreme, where, conversely, large numbers of stars have been observed to be forming.
What is stopping large numbers of stars from forming in RX J1532?
Images from the Chandra X-ray Observatory and the NSF's Karl G. Jansky
Very Large Array (VLA) have provided an answer to this question. The
X-ray image shows two large cavities in the hot gas on either side of
the central galaxy (mouse over the image for a labeled version).
The Chandra image has been specially processed to emphasize the
cavities. Both cavities are aligned with jets seen in radio images from
the VLA. The location of the supermassive black hole between the
cavities is strong evidence that the supersonic jets generated by the
black hole have drilled into the hot gas and pushed it aside, forming
Shock fronts - akin to sonic booms
- caused by the expanding cavities and the release of energy by sound
waves reverberating through the hot gas provide a source of heat that
prevents most of the gas from cooling and forming new stars.
The cavities are each about 100,000 light years across, roughly equal to the width of the Milky Way
galaxy. The power needed to generate them is among the largest known in
galaxy clusters. For example, the power is almost 10 times greater than
required to create the well-known cavities in Perseus.
Although the energy to power the jets must have been generated by
matter falling toward the black hole, no X-ray emission has been
detected from infalling material. This result can be explained if the
black hole is "ultramassive"
rather than supermassive, with a mass more than 10 billion times that
of the sun. Such a black hole should be able to produce powerful jets
without consuming large amounts of mass, resulting in very little
radiation from material falling inwards.
Another possible explanation is that the black hole has a mass only
about a billion times that of the sun but is spinning extremely rapidly.
Such a black hole can produce more powerful jets than a slowly spinning
black hole when consuming the same amount of matter. In both
explanations the black hole is extremely massive.
A more distant cavity is also seen at a different angle with respect
to the jets, along a north-south direction. This cavity is likely to
have been produced by a jet from a much older outburst from the black
hole. This raises the question of why this cavity is no longer aligned
with the jets. There are two possible explanations. Either large-scale
motion of the gas in the cluster has pushed it to the side or the black
hole is precessing, that is, wobbling like a spinning top.
A paper describing this work was published in the November 10th, 2013 issue of The Astrophysical Journal and is available online. The first author is Julie Hlavacek-Larrondo from Stanford University. The Hubble data used in this analysis were from the Cluster Lensing and Supernova survey, led by Marc Postman from Space Telescope Science Institute.
NASA's Marshall Space Flight Center in Huntsville, Ala., manages the
Chandra program for NASA's Science Mission Directorate in Washington.
The Smithsonian Astrophysical Observatory in Cambridge, Mass., controls
Chandra's science and flight operations.
Fast Facts for RX J1532.9+3021:
Scale: Image is 1.6 arcmin on a side (About 1.6 million light years) Category:Groups & Clusters of Galaxies Coordinates (J2000): RA 15h 32m 53.80s | Dec +30° 20' 57.60" Constellation:Corona Borealis Observation Date: 3 pointings between Aug 2001 and Nov 2011 Observation Time: 30 hours 3 min (1 day, 6 hours, 3 min) Obs. ID: 1649, 1665, 14009 Instrument: ACIS References: Hlavacek-Larrondo, J. et al. 2013, ApJ, 777, 163;arXiv:1306.0907 Color Code:
X-ray (Purple); Optical (Yellow) Distance Estimate:
3.9 billion light years (z = 0.361)
In this new Hubble image two objects are clearly visible, shining
brightly. When they were first discovered in 1979, they were thought to
be separate objects — however, astronomers soon realised that these
twins are a little too identical! They are close together, lie at the
same distance from us, and have surprisingly similar properties. The
reason they are so similar is not some bizarre coincidence; they are in
fact the same object.
These cosmic doppelgangers make up a double quasar known as QSO
0957+561, also known as the "Twin Quasar", which lies just under 14
billion light-years from Earth. Quasars are the intensely powerful centres of distant galaxies. So, why are we seeing this quasar twice?
Some 4 billion light-years from Earth — and directly in our line of
sight — is the huge galaxy YGKOW G1. This galaxy was the first ever
observed gravitational lens, an object with a mass so great that it can
bend the light from objects lying behind it. This phenomenon not only
allows us to see objects that would otherwise be too remote, in cases
like this it also allows us to see them twice over.
Along with the cluster of galaxies
in which it resides, YGKOW G1 exerts an enormous gravitational force.
This doesn't just affect the galaxy's shape, the stars that it forms,
and the objects around it — it affects the very space it sits in,
warping and bending the environment and producing bizarre effects, such
as this quasar double image.
This observation of gravitational lensing, the first of its kind,
meant more than just the discovery of an impressive optical illusion
allowing telescopes like Hubble to effectively see behind an intervening
galaxy. It was evidence for Einstein's theory of general relativity.
This theory had identified gravitational lensing as one of its only
observable effects, but until this observation no such lensing had been
observed since the idea was first mooted in 1936.
ESA’s Herschel space observatory has discovered water vapour around
Ceres, the first unambiguous detection of water vapour around an object
in the asteroid belt.
With a diameter of 950 km, Ceres is the largest object in the asteroid
belt, which lies between the orbits of Mars and Jupiter. But unlike most
asteroids, Ceres is almost spherical and belongs to the category of
‘dwarf planets’, which also includes Pluto.
It is thought that Ceres is layered, perhaps with a rocky core and an
icy outer mantle. This is important, because the water-ice content of
the asteroid belt has significant implications for our understanding of
the evolution of the Solar System.
When the Solar System formed 4.6 billion years ago, it was too hot in
its central regions for water to have condensed at the locations of the
innermost planets, Mercury, Venus, Earth and Mars. Instead, it is
thought that water was delivered to these planets later during a
prolonged period of intense asteroid and comet impacts around 3.9
billion years ago.
While comets are well known to contain water ice, what about asteroids?
Water in the asteroid belt has been hinted at through the observation of
comet-like activity around some asteroids – the so-called Main Belt
Comet family – but no definitive detection of water vapour has ever been
Now, using the HIFI instrument on Herschel to study Ceres, scientists
have collected data that point to water vapour being emitted from the
icy world’s surface.
“This is the first time that water has been detected in the asteroid
belt, and provides proof that Ceres has an icy surface and an
atmosphere,” says Michael Küppers of ESA’s European Space Astronomy
Centre in Spain, lead author of the paper published in Nature.
Although Herschel was not able to make a resolved image of Ceres, the
astronomers were able to derive the distribution of water sources on the
surface by observing variations in the water signal during the dwarf
planet’s 9-hour rotation period. Almost all of the water vapour was seen
to be coming from just two spots on the surface.
“We estimate that approximately 6 kg of water vapour is being produced
per second, requiring only a tiny fraction of Ceres to be covered by
water ice, which links nicely to the two localised surface features we
have observed,” says Laurence O’Rourke, Principal Investigator for the
Herschel asteroid and comet observation programme called MACH-11, and
second author on the Nature paper.
The most straightforward explanation of the water vapour production is
through sublimation, whereby ice is warmed and transforms directly into
gas, dragging the surface dust with it, and thus exposing fresh ice
underneath to sustain the process. Comets work in this fashion.
The two emitting regions are about 5% darker than the average on Ceres.
Able to absorb more sunlight, they are then likely the warmest regions,
resulting in a more efficient sublimation of small reservoirs of water
An alternative possibility is that geysers or icy volcanoes – cryovolcanism – play a role in the dwarf planet’s activity.
Much more detailed information on Ceres is expected soon, as NASA’s Dawn mission
is currently en route there for an arrival in early 2015. It will
provide close-up mapping of the surface and monitor how the water
activity is generated and varies with time.
“Herschel’s discovery of water vapour outgassing from Ceres gives us new
information on how water is distributed in the Solar System. Since
Ceres constitutes about one fifth of the total mass of asteroid belt,
this finding is important not only for the study of small Solar System
bodies in general, but also for learning more about the origin of water
on Earth,” says Göran Pilbratt, ESA’s Herschel Project Scientist.
“Localised sources of water vapour on dwarf planet (1) Ceres,” by M. Küppers et al. is published in Nature 23 January 2014.
Ceres was observed on four occasions between November 2011 and March
2013 initially as part of the MACH-11 (Measurements of 11 Asteroids and
Comets with Herschel) Guaranteed Time Programme, and complemented by two
additional Director’s Discretionary Time observations that confirmed
the tentative detection and measured the variation in water vapour as a
function of rotation period.
For further information, please contact:
ESA Science and Robotic Exploration Communication Officer
Tel: +31 71 565 6799
Mob: +31 61 594 3 954 Email:firstname.lastname@example.org
Panning across a new image of the Lagoon Nebula from the VST
VST images the Lagoon Nebula
The VLT Survey Telescope (VST) at ESO's
Paranal Observatory in Chile has captured this richly detailed new image
of the Lagoon Nebula. This giant cloud of gas and dust is creating
intensely bright young stars, and is home to young stellar clusters.
This image is a tiny part of just one of eleven public surveys of the
sky now in progress using ESO telescopes. Together these are providing a
vast legacy of publicly available data for the global astronomical
The Lagoon Nebula is an intriguing object located around 5000
light-years from us in the constellation of Sagittarius (The Archer).
Also known as Messier 8, it is a giant cloud 100 light-years across,
where new stars are forming within its plumes of gas and dust . This new 16 000-pixel-wide image is from the VLT Survey Telescope (VST), one of two dedicated survey telescopes at ESO's Paranal Observatory in northern Chile. A zoomable version of the image allows the viewers to explore the many nooks and crannies of this fascinating object.
The VST was not pointed at the Lagoon deliberately, it simply was included as part of a huge imaging survey called VPHAS+
that covered a much larger region of the Milky Way. VPHAS+ is just one
of three imaging surveys using visible light with the VST. These are
complemented by six infrared surveys with the VISTA survey telescope.
The surveys are addressing many important questions in modern
astronomy. These include the nature of dark energy, searching for
brilliant quasars in the early Universe, probing the structure of the
Milky Way and looking for unusual and hidden objects, studying the
neighbouring Magellanic Clouds in great detail, and many other topics.
History shows that surveys often find things that are unexpected and
these surprises are crucial for the progress of astronomical research.
As well as the nine imaging surveys with VISTA and the VST there are
also two additional surveys that are in progress using other ESO
telescopes. One, the Gaia-ESO Survey, is using the Very Large Telescope at Paranal to map the properties of more than 100 000 stars in the Milky Way, and another (PESSTO) is following up on transient objects such as supernovae using the New Technology Telescope at La Silla .
Some of these surveys began back in 2010, and some much more
recently, but data from all of them are now being made public and are
accessible to astronomers around the world through ESO's archive.
Although they are still in progress, the surveys are already allowing
astronomers to make many discoveries. Just a few of these new results
include new star clusters found in the VVV survey (eso1128, eso1141), the best map yet of the central parts of our Milky Way (eso1242, eso1339), a very deep view of the infrared sky (eso1213) and, very recently, some of the most distant quasars discovered so far (from the VISTA VIKING survey).
The ESO Public Surveys will continue for many years, and their
astronomical legacy value will stretch many decades into the future.
 ESO has produced several stunning
views of this object before — most notably a huge 370-megapixel image as
part of the GigaGalaxy Zoom project (eso0936) — and has also provided a completely different view from the VISTA (the Visible and Infrared Survey Telescope for Astronomy) VVV survey, which explored the Lagoon's mysteries in the infrared (eso1101).
 More information about all eleven surveys are available here and a comprehensive description of their current status and results is given in a dedicated section of the latest ESO Messenger.
ESO is the foremost intergovernmental
astronomy organisation in Europe and the world's most productive
ground-based astronomical observatory by far. It is supported by 15
countries: Austria, Belgium, Brazil, the Czech Republic, Denmark,
France, Finland, Germany, Italy, the Netherlands, Portugal, Spain,
Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious
programme focused on the design, construction and operation of powerful
ground-based observing facilities enabling astronomers to make
important scientific discoveries. ESO also plays a leading role in
promoting and organising cooperation in astronomical research. ESO
operates three unique world-class observing sites in Chile: La Silla,
Paranal and Chajnantor. At Paranal, ESO operates the Very Large
Telescope, the world's most advanced visible-light astronomical
observatory and two survey telescopes. VISTA works in the infrared and
is the world's largest survey telescope and the VLT Survey Telescope is
the largest telescope designed to exclusively survey the skies in
visible light. ESO is the European partner of a revolutionary
astronomical telescope ALMA, the largest astronomical project in
existence. ESO is currently planning the 39-metre European Extremely
Large optical/near-infrared Telescope, the E-ELT, which will become “the
world's biggest eye on the sky”.