Starving Black Hole Returns Brilliant Galaxy to the Shadows

ESO - European Southern Observatory logo.

15 September 2016

The active galaxy Markarian 1018

The mystery of a rare change in the behaviour of a supermassive black hole at the centre of a distant galaxy has been solved by an international team of astronomers using ESO’s Very Large Telescope along with the NASA/ESA Hubble Space Telescope and NASA’s Chandra X-ray Observatory. It seems that the black hole has fallen on hard times and is no longer being fed enough fuel to make its surroundings shine.

Many galaxies are found to have an extremely bright core powered by a supermassive black hole. These cores make “active galaxies” some of the brightest objects in the Universe. They are thought to shine so brightly because hot material is glowing fiercely as it falls into the black hole, a process known as accretion. This brilliant light can vary hugely between different active galaxies, so astronomers classify them into several types based on the properties of the light they emit [1].

The sky around the active galaxy Markarian 1018

Some of these galaxies have been observed to change dramatically over the course of only 10 years; a blink of an eye in astronomical terms. However, the active galaxy in this new study, Markarian 1018 stands out by having changed type a second time, reverting back to its initial classification within the last five years. A handful of galaxies have been observed to make this full-cycle change, but never before has one been studied in such detail.

The discovery of Markarian 1018’s fickle nature was a chance by-product of the Close AGN Reference Survey (CARS), a collaborative project between ESO and other organisations to gather information on 40 nearby galaxies with active cores. Routine observations of Markarian 1018 with the Multi-Unit Spectroscopic Explorer (MUSE) installed on ESO’s Very Large Telescope revealed the surprising change in the light output of the galaxy.

“We were stunned to see such a rare and dramatic change in Markarian 1018”, said Rebecca McElroy, lead author of the discovery paper and a PhD student at the University of Sydney and the ARC Centre of Excellence for All Sky Astrophysics (CAASTRO).

The location of the galaxy Markarian 1018 in the constellation of Cetus

The chance observation of the galaxy so soon after it began to fade was an unexpected opportunity to learn what makes these galaxies tick, as Bernd Husemann, CARS project leader and lead author of one of two papers associated with the discovery, explained: “We were lucky that we detected the event just 3-4 years after the decline started so we could begin monitoring campaigns to study details of the accretion physics of active galaxies that cannot be studied otherwise.”

The research team made the most of this opportunity, making it their first priority to pinpoint the process causing Markarian 1018’s brightness to change so wildly. This could have been caused by any one of a number of astrophysical events, but they could rule out the black hole pulling in and consuming a single star [2] and cast doubt on the possibility of obscuration by intervening gas [3]. But the true mechanism responsible for Markarian 1018’s surprising variation remained a mystery after the first round of observations.

However, the team were able to gather extra data after they were awarded observing time to use the NASA/ESA Hubble Space Telescope, and NASA’s Chandra X-ray Observatory. With the new data from this suite of instruments they were able to solve the mystery — the black hole was slowly fading because it was being starved of accretion material.

Zooming in on the unusual active galaxy Markarian 1018

“It’s possible that this starvation is because the inflow of fuel is being disrupted”, said Rebecca McElroy. “An intriguing possibility is that this could be due to interactions with a second supermassive black hole”. Such a black hole binary system is a distinct possibility in Markarian 1018, as the galaxy is the product of a major merger of two galaxies — each of which likely contained a supermassive black hole in its centre.

Research continues into the mechanisms at work in active galaxies such as Markarian 1018 that change their appearance. “The team had to work fast to determine what was causing Markarian 1018’s return to the shadows,” comments Bernd Husemann. “Ongoing monitoring campaigns with ESO telescopes and other facilities will allow us to explore the exciting world of starving black holes and changing active galaxies in more detail.”

Notes:

[1] The brightest of the active galaxies are quasars, where the brilliant nucleus outshines the rest of the galaxy. Another, less extreme, class are known as Seyfert galaxies. Originally a method was developed that used brightness and the emission spectrum — the plot of the strength of radiation emitted at different wavelength — to distinguish between just two types of Seyfert galaxies, Type 1 and Type 2, but extra classifications such as Type 1.9 Seyferts have since been introduced.

[2] Such a tidal disruption event occurs when a star strays too close to a supermassive black hole and is torn apart by the extreme gravitational tidal force. This results in a sharp rise in the brightness of the central region that slowly declines over a period of years. The observed brightness variations of Markarian 1018 were found not to match the profile of such an event.

[3] Gas obscuration can affect the classification of an active galaxy by blocking the line of sight, drifting in front of the galaxy’s bright core like fog in front of a car’s headlights, and dimming the light passing through. This also affects the spectrum of galaxy, perhaps changing its classification.

More information:

This research was presented in two papers entitled “Mrk 1018 returns to the shadows after 30 years as a Seyfert 1”, and “What is causing Mrk 1018’s return to the shadows after 30 years?”, both to appear as Letters in the journal Astronomy & Astrophysics.

The team is composed of B. Husemann (ESO, Garching, Germany), T. Urrutia (Leibniz-Institut für Astrophysik Potsdam, Potsdam, Germany), G. R. Tremblay (Yale Center for Astronomy and Astrophysics, New Haven, USA), M. Krumpe (Leibniz-Institut für Astrophysik Potsdam, Potsdam, Germany), J. Dexter (Max-Planck-Institut für extraterrestrische Physik, Garching, Germany), V. N. Bennert (Physics Department, California Polytechnic State University, USA), G. Busch (I. Physikalisches Institut, Universität zu Köln, Germany), F. Combes (LERMA, Observatoire de Paris, France), S. M. Croom (Sydney Institute for Astronomy, Sydney, Australia & ARC Centre of Excellence for All-sky Astrophysics), T. A. Davis (School of Physics & Astronomy, Cardiff University, UK), A. Eckart (I. Physikalisches Institut Universität zu Köln, Germany; Max-Planck-Institut für Radioastronomie, Bonn, Germany), R. E. McElroy (Sydney Institute for Astronomy, Sydney, Australia & ARC Centre of Excellence for All-sky Astrophysics), M. Pérez-Torres (Instituto de Astrofísica de Andalucía, Granada, Spain), M. Powell (Yale Center for Astronomy and Astrophysics, New Haven, USA) and J. Scharwächter (Gemini Observatory, Northern Operations Center, Hawaii, USA).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Research paper 1: http://www.eso.org/public/archives/releases/sciencepapers/eso1631/eso1631a.pdf

Research paper 2: http://www.eso.org/public/archives/releases/sciencepapers/eso1631/eso1631b.pdf

Photos of the VLT: http://www.eso.org/public/images/archive/category/paranal/

CARS Survey: http://cars-survey.org/

Multi-Unit Spectroscopic Explorer (MUSE): http://www.eso.org/public/teles-instr/vlt/vlt-instr/muse/

ESO’s Very Large Telescope (VLT): http://www.eso.org/public/teles-instr/paranal/

ARC Centre of Excellence for All Sky Astrophysics (CAASTRO): http://www.caastro.org/

NASA/ESA Hubble Space Telescope: http://www.spacetelescope.org/

NASA’s Chandra X-ray Observatory: https://www.nasa.gov/mission_pages/chandra/main/index.html

Images, Text, Credits: ESO/CARS survey/Digitized Sky Survey 2. Acknowledgement: Davide De Martin//IAU and Sky & Telescope/Video: ESO/A. Fujii/Digitized Sky Survey 2/CARS survey.

Best regards, Orbiter.ch

NASA Sees Tropical Storm Meranti Make Landfall in China

NASA - CloudSat & Calipso Satellites Mission patch / NASA & NOAA - Suomi NPP Satellite Mission logo.

Sept. 15, 2016

Meranti (was 16W - Northwestern Pacific Ocean)

Once a Super Typhoon, Meranti made landfall in southeastern China late on Sept. 14 as NASA-NOAA's Suomi NPP satellite passed overhead from space. Previously, NASA's CloudSat satellite provided a sideways look at the storm when it was near its peak.

Image above: CloudSat analyzed Typhoon Meranti on Sept. 13 at 1:12 a.m. EDT (0512 UTC) as the storm was approaching Taiwan. CloudSat found cloud top heights averaging around 16 km with heavy rainfall (deep red and pink colors). Areas of green and blue denote smaller ice and water particle sizes typically located at top of the system (in the anvil area). Image Credits: Natalie Tourville/Colorado State University.

NASA's CloudSat satellite passed over Typhoon Meranti on Sept.13 at 1:12 a.m. EDT (512 UTC) as the storm was approaching Taiwan. The system contained sustained winds of 160 knots with a minimum pressure of 898 millibars designating this system as a ’Super Typhoon.’

CloudSat found cloud top heights averaging around 16 km with heavy rainfall. CloudSat also saw areas of smaller ice and water particle sizes typically located at top of the system in the anvil area.

On Sept. 15 at 12:35 a.m. EDT (04:35 UTC) NASA-NOAA's Suomi NPP satellite flew over Tropical Storm Meranti as it was making landfall in southeastern China. The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard NASA-NOAA's Suomi NPP satellite captured a visible image of the storm that showed most of the storm had already blanketed southeastern China with clouds and rain.

Image above: On Sept. 15 at 12:35 a.m. EDT (04:35 UTC) NASA-NOAA's Suomi NPP satellite captured an image of Tropical Storm Meranti as it was making landfall in southeastern China. Image Credits: NASA Goddard MODIS Rapid Response/NOAA.

The final warning on the storm was issued on Sept. 14 at 5 p.m. EDT (2100 UTC) from the Joint Typhoon Warning Center (JTWC). At that time, Meranti was making landfall in southeastern China near Xiamen in Fujian Province. At the time of landfall, Meranti's maximum sustained winds were near 145 mph (126 knots/233 kph), making it a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale.

JTWC expects Meranti's winds to drop to 40 mph (35 knots/64.2 kph) during the day on Sept. 15 and weaken to 23 mph (20 knots/37 kph)3by Sept. 16 as it curves to the north over land.

Related links:

NASA's CloudSat satellite: http://cloudsat.atmos.colostate.edu/

NASA-NOAA's Suomi NPP satellite: http://www.nasa.gov/mission_pages/NPP/main/index.html

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Rob Gutro.

Greetings, Orbiter.ch

Pluto ‘Paints’ its Largest Moon Red

NASA - New Horizons Mission logo.

Sept. 14, 2016

Image above: NASA's New Horizons spacecraft captured this high-resolution, enhanced color view of Pluto’s largest moon, Charon, just before closest approach on July 14, 2015. The image combines blue, red and infrared images taken by the spacecraft's Ralph/Multispectral Visual Imaging Camera (MVIC); the colors are processed to best highlight the variation of surface properties across Charon. Scientists have learned that reddish material in the north (top) polar region – informally named Mordor Macula – is chemically processed methane that escaped from Pluto’s atmosphere onto Charon. Charon is 754 miles (1,214 kilometers) across; this image resolves details as small as 1.8 miles (2.9 kilometers). Image Credits: NASA/JHUAPL/SwRI.

In June 2015, when the cameras on NASA’s approaching New Horizons spacecraft first spotted the large reddish polar region on Pluto’s largest moon, Charon, mission scientists knew two things: they’d never seen anything like it elsewhere in our solar system, and they couldn’t wait to get the story behind it.

Over the past year, after analyzing the images and other data that New Horizons has sent back from its historic July 2015 flight through the Pluto system, the scientists think they’ve solved the mystery. As they detail this week in the international scientific journal Nature, Charon’s polar coloring comes from Pluto itself – as methane gas that escapes from Pluto’s atmosphere and becomes “trapped” by the moon’s gravity and freezes to the cold, icy surface at Charon’s pole. This is followed by chemical processing by ultraviolet light from the sun that transforms the methane into heavier hydrocarbons and eventually into reddish organic materials called tholins.

Who would have thought that Pluto is a graffiti artist, spray-painting its companion with a reddish stain that covers an area the size of New Mexico?

--Will Grundy, New Horizons co-investigator, Lowell Observatory, Flagstaff, Arizona.

"Who would have thought that Pluto is a graffiti artist, spray-painting its companion with a reddish stain that covers an area the size of New Mexico?" asked Will Grundy, a New Horizons co-investigator from Lowell Observatory in Flagstaff, Arizona, and lead author of the paper. "Every time we explore, we find surprises. Nature is amazingly inventive in using the basic laws of physics and chemistry to create spectacular landscapes."

The team combined analyses from detailed Charon images obtained by New Horizons with computer models of how ice evolves on Charon’s poles. Mission scientists had previously speculated that methane from Pluto’s atmosphere was trapped in Charon’s north pole and slowly converted into the reddish material, but had no models to support that theory.

The New Horizons team dug into the data to determine whether conditions on the Texas-sized moon (with a diameter of 753 miles or 1,212 kilometers) could allow the capture and processing of methane gas. The models using Pluto and Charon’s 248-year orbit around the sun show some extreme weather at Charon’s poles, where 100 years of continuous sunlight alternate with another century of continuous darkness. Surface temperatures during these long winters dip to -430 Fahrenheit (-257 Celsius), cold enough to freeze methane gas into a solid.

“The methane molecules bounce around on Charon's surface until they either escape back into space or land on the cold pole, where they freeze solid, forming a thin coating of methane ice that lasts until sunlight comes back in the spring,” Grundy said. But while the methane ice quickly sublimates away, the heavier hydrocarbons created from it remain on the surface.

The models also suggested that in Charon’s springtime the returning sunlight triggers conversion of the frozen methane back into gas. But while the methane ice quickly sublimates away, the heavier hydrocarbons created from this evaporative process remain on the surface.

Sunlight further irradiates those leftovers into reddish material – called tholins – that has slowly accumulated on Charon’s poles over millions of years. New Horizons’ observations of Charon’s other pole, currently in winter darkness – and seen by New Horizons only by light reflecting from Pluto, or “Pluto-shine” – confirmed that the same activity was occurring at both poles.

“This study solves one of the greatest mysteries we found on Charon, Pluto’s giant moon,” said Alan Stern, New Horizons principal investigator from the Southwest Research Institute, and a study co-author. “And it opens up the possibility that other small planets in the Kuiper Belt with moons may create similar, or even more extensive ‘atmospheric transfer’ features on their moons.”

For more information about New Horizons, visit: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Image (mentioned), Text, Credits: NASA/Bill Keeter.

Greetings, Orbiter.ch

X-ray Detection Sheds New Light on Pluto

NASA - Chandra X-ray Observatory logo.

Sept. 14, 2016

Scientists using NASA’s Chandra X-ray Observatory have made the first detections of X-rays from Pluto. These observations offer new insight into the space environment surrounding the largest and best-known object in the solar system’s outermost regions.

While NASA’s New Horizons spacecraft was speeding toward and beyond Pluto, Chandra was aimed several times on the dwarf planet and its moons, gathering data on Pluto that the missions could compare after the flyby. Each time Chandra pointed at Pluto – four times in all, from February 2014 through August 2015 – it detected low-energy X-rays from the small planet.

The first detection of Pluto in X-rays has been made using NASA’s Chandra X-ray Observatory.

Image above: The first detection of Pluto in X-rays has been made using NASA’s Chandra X-ray Observatory in conjunction with observations from NASA’s New Horizon spacecraft.
Image Credits: X-ray: NASA/CXC/JHUAPL/R.McNutt et al; Optical: NASA/JHUAPL.

Pluto is the largest object in the Kuiper Belt, a ring or belt containing a vast population of small bodies orbiting the Sun beyond Neptune.  The Kuiper belt extends from the orbit of Neptune, at 30 times the distance of Earth from the Sun, to about 50 times the Earth-Sun distance.  Pluto’s orbit ranges over the same span as the overall Kupier Belt.

"We've just detected, for the first time, X-rays coming from an object in our Kuiper Belt, and learned that Pluto is interacting with the solar wind in an unexpected and energetic fashion,” said Carey Lisse, an astrophysicist at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, who led the Chandra observation team with APL colleague and New Horizons Co-Investigator Ralph McNutt. “We can expect other large Kuiper Belt objects to be doing the same."

The team recently published its findings online in the journal Icarus. The report details what Lisse says was a somewhat surprising detection given that Pluto – being cold, rocky and without a magnetic field – has no natural mechanism for emitting X-rays. But Lisse, having also led the team that made the first X-ray detections from a comet two decades ago, knew the interaction between the gases surrounding such planetary bodies and the solar wind – the constant streams of charged particles from the sun that speed throughout the solar system ­– can create X-rays.

New Horizons scientists were particularly interested in learning more about the interaction between the gases in Pluto’s atmosphere and the solar wind. The spacecraft itself carries an instrument designed to measure that activity up-close – the aptly named Solar Wind Around Pluto (SWAP) – and scientists are using that data to craft a picture of Pluto that contains a very mild, close-in bowshock, where the solar wind first “meets” Pluto (similar to a shock wave that forms ahead of a supersonic aircraft) and a small wake or tail behind the planet.

The immediate mystery is that Chandra’s readings on the brightness of the X-rays are much higher than expected from the solar wind interacting with Pluto’s atmosphere.

“Before our observations, scientists thought it was highly unlikely that we’d detect X-rays from Pluto, causing a strong debate as to whether Chandra should observe it at all,” said co-author Scott Wolk, of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “Prior to Pluto, the most distant solar system body with detected X-ray emission was Saturn's rings and disk."

The Chandra detection is especially surprising since New Horizons discovered Pluto’s atmosphere was much more stable than the rapidly escaping, “comet-like” atmosphere that many scientists expected before the spacecraft flew past in July 2015. In fact, New Horizons found that Pluto’s interaction with the solar wind is much more like the interaction of the solar wind with Mars, than with a comet. However, although Pluto is releasing enough gas from its atmosphere to make the observed X-rays, in simple models for the intensity of the solar wind at the distance of Pluto, there isn't enough solar wind flowing directly at Pluto to make them.

Lisse and his colleagues – who also include SWAP co-investigators David McComas from Princeton University and Heather Elliott from Southwest Research Institute – suggest several possibilities for the enhanced X-ray emission from Pluto.  These include a much wider and longer tail of gases trailing Pluto than New Horizons detected using its SWAP instrument. Other possibilities are that interplanetary magnetic fields are focusing more particles than expected from the solar wind into the region around Pluto, or the low density of the solar wind in the outer solar system at the distance of Pluto could allow for the formation of a doughnut, or torus, of neutral gas centered around Pluto's orbit.

That the Chandra measurements don’t quite match up with New Horizons up-close observations is the benefit – and beauty – of an opportunity like the New Horizons flyby. “When you have a chance at a once in a lifetime flyby like New Horizons at Pluto, you want to point every piece of glass – every telescope on and around Earth – at the target,” McNutt says. “The measurements come together and give you a much more complete picture you couldn’t get at any other time, from anywhere else.”

New Horizons has an opportunity to test these findings and shed even more light on this distant region – billions of miles from Earth – as part of its recently approved extended mission to survey the Kuiper Belt and encounter another smaller Kuiper Belt object, 2014 MU69, on Jan. 1, 2019. It is unlikely to be feasible to detect X-rays from MU69, but Chandra might detect X-rays from other larger and closer objects that New Horizons will observe as it flies through the Kuiper Belt towards MU69.

The Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft and manages the mission for NASA’s Science Mission Directorate. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.si.edu/press/16_releases/press_091416.html

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Image (mentioned), Text, Credits: NASA/Marshall Space Flight Center/Molly Porter/Chandra X-ray Center/Megan Watzke/Lee Mohon.

Greetings, Orbiter.ch

Know Thy Star, Know Thy Planet

NASA - Kepler Mission patch.

Sept. 14, 2016

When it comes to exoplanets, astronomers have realized that they only know the properties of the planets they discover as well as they know the properties of the stars being orbited. For a planet's size, precisely characterizing the host star can mean the difference in our understanding of whether a distant world is small like Earth or huge like Jupiter.

For astronomers to determine the size of an exoplanet—planets outside the solar system—depends critically on knowing not only the radius of its host star but also whether that star is single or has a close companion. Consider that about half of the stars in the sky are not one but two stars orbiting around each other, this makes knowing the binary property of a star paramount.

Artist's view of TRAPPIST-1. Image Credit: NASA

One particularly interesting and relatively nearby star, named TRAPPIST-1, recently caught the attention of a team of researchers. They wanted to determine if TRAPPIST-1, which is home to three small, potentially rocky planets—one of which orbits in the temperate habitable zone where liquid water might pool on the surface—was a single star like the sun, or if it had a companion star. If TRAPPIST-1 did have a companion star, the discovered planets will have larger sizes, possibly large enough to be ice giants similar to Neptune.

If an exoplanet orbits a star in a binary system but astronomers believe the starlight captured by the telescope is from a single star, the real radius of the planet will be larger than measured. The difference in the measured size of the exoplanet can be small ranging from 10 percent to more than a factor of two in size, depending on the brightness of the companion star in the system.

To confirm or deny the single star nature of TRAPPIST-1, Steve Howell, senior research scientist at NASA's Ames Research Center at Moffett Field, California, led an investigation of the star. Using a specially designed camera, called the Differential Speckle Survey Instrument or DSSI, Howell and his team measured the rapid disturbances in the light emitted by the star caused by the Earth’s atmosphere and corrected for them. The resultant high-resolution image revealed that the light coming from the TRAPPIST-1 system is from a single star.

With the confirmation that no other companion star resides in the vicinity of TRAPPIST-1, the research team's result validates not only that transiting planets are responsible for the periodic dips seen in the star’s brightness but that they are indeed Earth-size and may likely to be rocky worlds.

"Knowing that a terrestrial-size potentially rocky planet orbits in the habitable zone of a star only 40 light-years from the Earth is an awesome finding," said Howell. “The TRAPPIST-1 system will continue to be studied in great detail as these transiting exoplanets offer one of the best chances to characterize the atmosphere of an alien world."

Mounted on the 8-meter Gemini Observatory South telescope in Chile, the DSSI provided astronomers with the highest resolution images available today from a single ground-based telescope. The nearness of TRAPPIST-1 allowed astronomers to peer deep into the system, looking closer than Mercury's orbit to our sun.

The paper the result is based on is published in the September 13th issue of The Astrophysical Journal Letters.

Interest in the recently-discovered TRAPPIST-1 with its three Earth-size planets is high. Astronomically speaking, at 40 light-years from Earth, the system is a hop, skip and a jump away. The star itself is a dim M-type star, which, relative to most stars, is very small and cool, but making transit detection of small planets easier.

Further detailed measurement of the planetary transits seen in TRAPPIST-1 will begin later this year when NASA's Kepler space telescope in its K2 mission will precisely monitor minute changes in the light emitted from the star for a period of about 75 days.

The space-based observations from the Kepler spacecraft will provide extremely precise measurements of the planet transit shapes allowing for more refined radius and orbital period determination. Noting variations in the mid-time of the transit events can also help astronomers determine the planet masses. Additionally, the new observations will be searched for more transiting planets in the TRAPPIST-1 system.

Speckle interferometry, the imaging technique used by the DSSI, is a powerful asset in the astronomer's toolkit as it provides a unique capability to characterize the environment around distant stars. The technique provides ultra high-resolution images by taking multiple extremely short (40-60 millisecond) exposures of a star to capture fine detail in the received light and “freeze” the turbulence caused by Earth’s atmosphere.

By combining the many thousands of exposures and using mathematical techniques to remove the momentary distortions caused by Earth’s atmosphere, the final result provides a resolution equal to the theoretical limit of what the 8-meter Gemini telescope would produce if no atmosphere were present.

Image above: The four-panel graphic illustrates the difference of measured starlight when seen through a ground-based telescope with (top left corner) and without the blurring effects caused by Earth's atmosphere. The technique to neutralize Earth's atmospheric blur is called speckle interferometry. All four images are shown at the same scale. Image Credits: Gemini Observatory/AURA and NASA/Ames/W. Stenzel.

Howell and his team at NASA Ames are currently undertaking the construction of two new speckle interferometric instruments. One of the new instruments will be delivered this fall to the 3.5-meter WIYN telescope located at Kitt Peak National Observatory outside of Tucson, Arizona, where it will be used by the NN_EXPLORE guest observer research program. The other is being developed for the Gemini Observatory North telescope located on Mauna Kea in Hawaii.

NASA Ames manages the Kepler and K2 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 at Boulder.

Related link:

NN_EXPLORE guest observer research program: https://exoplanets.nasa.gov/exep/NNExplore/GuestObserver/

To learn more about the result from the Gemini Observatory, visit: http://www.gemini.edu/node/12567.

For more information on the Kepler and the K2 mission, visit: http://www.nasa.gov/kepler.

Images (mentioned), Text, Credits: NASA/Ames Research Center/Michele Johnson.

Greetings, Orbiter.ch

Fighting Cancer with Space Research

JPL - Jet Propulsion Laboratory logo.

September 14, 2016

JPL and National Cancer Institute Renew Big Data Partnership

Every day, NASA spacecraft beam down hundreds of petabytes of data, all of which has to be codified, stored and distributed to scientists across the globe. Increasingly, artificial intelligence is helping to "read" this data as well, highlighting similarities between datasets that scientists might miss.

For the past 15 years, the big data techniques pioneered by NASA's Jet Propulsion Laboratory in Pasadena, California, have been revolutionizing biomedical research. On Sept. 6, 2016, JPL and the National Cancer Institute (NCI), part of the National Institutes of Health, renewed a research partnership through 2021, extending the development of data science that originated in space exploration and is now supporting new cancer discoveries.

The NCI-supported Early Detection Research Network (EDRN) is a consortium of biomedical investigators who share anonymized data on cancer biomarkers, chemical or genetic signatures related to specific cancers. Their goal is to pool all their research data into a single, searchable network, with the goal of translating their collective work into techniques for early diagnosis of cancer or cancer risk.

Image above: NGC 3718, NGC 3729 and other galaxies have been analyzed using machine learning algorithms that can be "taught" to recognize astrophysical similarities. The same technology is now being applied to cancer images, as well. Image Credits: Catalina Sky Survey, U of Arizona, and Catalina Realtime Transient Survey, Caltech.

In the time they've worked together, JPL and EDRN's efforts have led to the discovery of six new Food and Drug Administration-approved cancer biomarkers and nine biomarkers approved for use in Clinical Laboratory Improvement Amendments labs. The FDA has approved each of these biomarkers for use in cancer research and diagnosis. These agency-approved biomarkers have been used in more than 1 million patient diagnostic tests worldwide.

"After the founding of EDRN in 2000, the network needed expertise to take data from multiple studies on cancer biomarkers and create a single, searchable network of research findings for scientists," said Sudhir Srivastava, chief of NCI's Cancer Biomarkers Research Group and head of EDRN. JPL had decades of experience doing similar work for NASA, where spacecraft transmit hundreds of petabytes of data to be coded, stored and distributed to scientists across the globe.

Dan Crichton, the head of JPL's Center for Data Science and Technology, a joint initiative with Caltech in Pasadena, California, helped establish a JPL-based informatics center dedicated to supporting EDRN's big data efforts. In the renewed partnership, JPL is expanding its data science efforts to research and applying technologies for additional NCI-funded programs. Those programs include EDRN, the Consortium for Molecular and Cellular Characterization of Screen-Detected Lesions, and the Informatics Technology for Cancer Research initiative.

"From a NASA standpoint, there are significant opportunities to develop new data science capabilities that can support both the mission of exploring space and cancer research using common methodological approaches," Crichton said. "We have a great opportunity to perfect those techniques and grow JPL's data science technologies, while serving our nation.

Crichton said JPL has led the way when it comes to taking data from raw observations to scientific conclusions. One example: JPL often deals with measurements from a variety of sensors -- say, cameras and mass spectrometers. Both can be used to study a star, planet or similar target object. But it takes special software to recognize that readings from very different instruments relate to one another.

There's a similar problem in cancer research, where readings from different biomedical tests or instruments require correlation with one another. For that to happen, data have to be standardized, and algorithms must be "taught" to know what they're looking for.

Image above: A lung specimen that was analyzed using the same machine learning algorithms that were originally developed for space research. Image Credits: Early Research Detection Network/University of Colorado.

Since the time of its founding, EDRN's major challenge has been access. Research centers all over the United States had large numbers of biomarker specimens, but each had its own way of labeling, storing and sharing their datasets. Ten sites may have high-quality specimens for study, but if their common data elements -- age of patient, cancer type and other characteristics - aren't listed uniformly, they can't be studied as a whole.

"We didn't know if they were early-stage or late-stage specimens, or if any level of treatment had been tried," Srivastava said. "And JPL told us, 'We do this type of thing all the time! That's how we manage our Planetary Data System.'"

As the network has developed, it has added members from dozens of institutions, including Dartmouth College's Geisel School of Medicine; Harvard Medical School's Massachusetts General Hospital; Stanford's NIST Genome-Scale Measurements Group; University of Texas' MD Anderson Cancer Center; and numerous others.

Christos Patriotis, program director at NCI's Cancer Biomarkers Research Group, said the network's members now include international researchers from the U.K., China, Japan, Australia, Israel and Chile.

"The more we expand, the more data we integrate," Patriotis said. "Instead of being silos, now our partners can integrate their findings. Each system can speak to the others."

As JPL and NCI's collaboration advances, next steps include image recognition technology, such as helping EDRN archive images of cancer specimens. Those images could be analyzed by computer vision, which is currently used to spot similarities in star clusters and other astrophysics research.

In the near future, Crichton said, machine learning algorithms could compare a CT scan with an archive of similar images, searching for early signs of cancer based on a patient's age, ethnic background and other demographics.

"As we develop more automated methods for detecting and classifying features in images, we see great opportunities for enhancing data discovery," Crichton said. "We have examples where algorithms for detection of features in astronomy images have been transferred to biology and vice-versa."

Related link:

Early Detection Research Network (EDRN): https://edrn.nci.nih.gov/

JPL-based informatics center: http://cancer.jpl.nasa.gov/

For more information on the research, visit: http://edrn.cancer.gov

Caltech manages JPL for NASA.

Images (mentioned), Text, Credits: NASA/JPL/Andrew Good.

Greetings, Orbiter.ch

Gaia’s billion-star map hints at treasures to come

ESA - Gaia Mission patch.

14 September 2016

The first catalogue of more than a billion stars from ESA’s Gaia satellite was published today – the largest all-sky survey of celestial objects to date.

On its way to assembling the most detailed 3D map ever made of our Milky Way galaxy, Gaia has pinned down the precise position on the sky and the brightness of 1142 million stars.

Gaia’s first sky map

As a taster of the richer catalogue to come in the near future, today’s release also features the distances and the motions across the sky for more than two million stars.

“Gaia is at the forefront of astrometry, charting the sky at precisions that have never been achieved before,” says Alvaro Giménez, ESA’s Director of Science.

“Today’s release gives us a first impression of the extraordinary data that await us and that will revolutionise our understanding of how stars are distributed and move across our Galaxy.”

Gaia mapping the stars of the Milky Way

Launched 1000 days ago, Gaia started its scientific work in July 2014. This first release is based on data collected during its first 14 months of scanning the sky, up to September 2015.

“The beautiful map we are publishing today shows the density of stars measured by Gaia across the entire sky, and confirms that it collected superb data during its first year of operations,” says Timo Prusti, Gaia project scientist at ESA.

The stripes and other artefacts in the image reflect how Gaia scans the sky, and will gradually fade as more scans are made during the five-year mission.

“The satellite is working well and we have demonstrated that it is possible to handle the analysis of a billion stars. Although the current data are preliminary, we wanted to make them available for the astronomical community to use as soon as possible,” adds Dr Prusti.

Transforming the raw information into useful and reliable stellar positions to a level of accuracy never possible before is an extremely complex procedure, entrusted to a pan-European collaboration of about 450 scientists and software engineers: the Gaia Data Processing and Analysis Consortium, or DPAC.

“Today’s release is the result of a painstaking collaborative work over the past decade,” says Anthony Brown from Leiden University in the Netherlands, and consortium chair.

“Together with experts from a variety of disciplines, we had to prepare ourselves even before the start of observations, then treated the data, packaged them into meaningful astronomical products, and validated their scientific content.”

Gaia scanning the sky

In addition to processing the full billion-star catalogue, the scientists looked in detail at the roughly two million stars in common between Gaia’s first year and the earlier Hipparcos and Tycho-2 Catalogues, both derived from ESA’s Hipparcos mission, which charted the sky more than two decades ago.

By combining Gaia data with information from these less precise catalogues, it was possible to start disentangling the effects of ‘parallax’ and ‘proper motion’ even from the first year of observations only. Parallax is a small motion in the apparent position of a star caused by Earth’s yearly revolution around the Sun and depends on a star’s distance from us, while proper motion is due to the physical movement of stars through the Galaxy.

In this way, the scientists were able to estimate distances and motions for the two million stars spread across the sky in the combined Tycho–Gaia Astrometric Solution, or TGAS.

This new catalogue is twice as precise and contains almost 20 times as many stars as the previous definitive reference for astrometry, the Hipparcos Catalogue.

As part of their work in validating the catalogue, DPAC scientists have conducted a study of open stellar clusters – groups of relatively young stars that were born together – that clearly demonstrates the improvement enabled by the new data.

Galaxies, open and globular clusters in Gaia's sky map

“With Hipparcos, we could only analyse the 3D structure and dynamics of stars in the Hyades, the nearest open cluster to the Sun, and measure distances for about 80 clusters up to 1600 light-years from us,” says Antonella Vallenari from the Istituto Nazionale di Astrofisica (INAF) and the Astronomical Observatory of Padua, Italy.

“But with Gaia’s first data, it is now possible to measure the distances and motions of stars in about 400 clusters up to 4800 light-years away.

For the closest 14 open clusters, the new data reveal many stars surprisingly far from the centre of the parent cluster, likely escaping to populate other regions of the Galaxy.”

Many more stellar clusters will be discovered and analysed in even greater detail with the extraordinary data that Gaia continues to collect and that will be released in the coming years.

From the Solar System to the Hyades cluster

The new stellar census also contains 3194 variable stars, stars that rhythmically swell and shrink in size, leading to periodic brightness changes.

Many of the variables seen by Gaia are in the Large Magellanic Cloud, one of our galactic neighbours, a region that was scanned repeatedly during the first month of observations, allowing accurate measurement of their changing brightness.

Details about the brightness variations of these stars, 386 of which are new discoveries, are published as part of today’s release, along with a first study to test the potential of the data.

“Variable stars like Cepheids and RR Lyraes are valuable indicators of cosmic distances,” explains Gisella Clementini from INAF and the Astronomical Observatory of Bologna, Italy.

“While parallax is used to measure distances to large samples of stars in the Milky Way directly, variable stars provide an indirect, but crucial step on our ‘cosmic distance ladder’, allowing us to extend it to faraway galaxies.”

This is possible because some kinds of variable stars are special. For example, in the case of Cepheid stars, the brighter they are intrinsically, the slower their brightness variations. The same is true for RR Lyraes when observed in infrared light. The variability pattern is easy to measure and can be combined with the apparent brightness of a star to infer its true brightness.

This is where Gaia steps in: in the future, scientists will be able to determine very accurate distances to a large sample of variable stars via Gaia's measurements of parallaxes. With those, they will calibrate and improve the relation between the period and brightness of these stars, and apply it to measure distances beyond our Galaxy. A preliminary application of data from the TGAS looks very promising.

“This is only the beginning: we measured the distance to the Large Magellanic Cloud to test the quality of the data, and we got a sneak preview of the dramatic improvements that Gaia will soon bring to our understanding of cosmic distances,” adds Dr Clementini.

Pluto occultation

Knowing the positions and motions of stars in the sky to astonishing precision is a fundamental part of studying the properties and past history of the Milky Way and to measure distances to stars and galaxies, but also has a variety of applications closer to home – for example, in the Solar System.

In July, Pluto passed in front of a distant, faint star, offering a rare chance to study the atmosphere of the dwarf planet as the star gradually disappeared and then reappeared behind Pluto.

This stellar occultation was visible only from a narrow strip stretching across Europe, similar to the totality path that a solar eclipse lays down on our planet’s surface. Precise knowledge of the star’s position was crucial to point telescopes on Earth, so the exceptional early release of the Gaia position for this star, which was 10 times more precise than previously available, was instrumental to the successful monitoring of this rare event.

Early results hint at a pause in the puzzling pressure rise of Pluto’s tenuous atmosphere, something that has been recorded since 1988 in spite of the dwarf planet moving away from the Sun, which would suggest a drop in pressure due to cooling of the atmosphere.

“These three examples demonstrate how Gaia’s present and future data will revolutionise all areas of astronomy, allowing us to investigate our place in the Universe, from our local neighbourhood, the Solar System, to Galactic and even grander, cosmological scales,” explains Dr Brown.

This first data release shows that the mission is on track to achieve its ultimate goal: charting the positions, distances, and motions of one billion stars – about 1% of the Milky Way’s stellar content – in three dimensions to unprecedented accuracy.

“The road to today has not been without obstacles: Gaia encountered a number of technical challenges and it has taken an extensive collaborative effort to learn how to deal with them,” says Fred Jansen, Gaia mission manager at ESA.

“But now, 1000 days after launch and thanks to the great work of everyone involved, we are thrilled to present this first dataset and are looking forward to the next release, which will unleash Gaia’s potential to explore our Galaxy as we've never seen it before.”

Notes for Editors:

The data from Gaia’s first release can be accessed at http://archives.esac.esa.int/gaia

The content of this first release was presented today during a media briefing at ESA’s European Space Astronomy Centre (ESAC) in Villanueva de la Cañada, Madrid, Spain.

Fifteen scientific papers describing the data contained in the release and their validation process will appear in a special issue of Astronomy & Astrophysics: http://www.aanda.org/component/toc/?task=topic&id=641

Gaia is an ESA mission to survey one billion stars in our Galaxy and local galactic neighbourhood in order to build the most precise 3D map of the Milky Way and answer questions about its structure, origin and evolution.

A large pan-European team of expert scientists and software developers, the Data Processing and Analysis Consortium, located in and funded by many ESA member states, is responsible for the processing and validation of Gaia’s data, with the final objective of producing the Gaia Catalogue. Scientific exploitation of the data will only take place once they are openly released to the community.

Members of the consortium come from 20 European countries (Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Netherlands, Poland, Portugal, Slovenia, Spain, Switzerland, Sweden and the UK) as well as from further afield (Algeria, Brazil, Israel and the US).

In addition, ESA makes a significant contribution to the consortium in the form of the Data Processing Centre at ESAC, which, among other tasks and responsibilities, acts as the central hub for all Gaia data processing.

Related links:

Gaia: http://www.esa.int/Our_Activities/Space_Science/Gaia

Gaia overview: http://www.esa.int/Our_Activities/Space_Science/Gaia/Gaia_overview

Gaia factsheet: http://www.esa.int/Our_Activities/Space_Science/Gaia/Gaia_factsheet

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Gaia/Frequently_Asked_Questions_about_Gaia

Gaia brochure: http://www.esa.int/About_Us/ESA_Publications/ESA_BR-296_Gaia_ESA_s_galactic_census

Images, Videos, Text, Credits: ESA/Gaia/DPAC/ATG medialab; background: ESO/S. Brunier/B. Sicardy (LESIA, Observatoire de Paris, France), P. Tanga (Observatoire de la Côte d'Azur, Nice, France), A. Carbognani (Osservatorio Astronomico Valle d'Aosta, Italy), Rodrigo Leiva (LESIA, Observatoire de Paris)/Video: ESA/Gaia/DPAC; acknowledgement: S. Jordan & T. Sagristà Sellés (Zentrum für Astronomie der Universität Heidelberg).

Best regards, Orbiter.ch