Overfed Black Holes Shut Down Galactic Star-Making

J.D. Harrington

Headquarters, Washington

202-358-5241

j.d.harrington@nasa.gov

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

818-354-4673

whitney.clavin@jpl.nasa.gov

WASHINGTON -- The Herschel Space Observatory has shown galaxies with the most powerful, active black holes at their cores produce fewer stars than galaxies with less active black holes. The results are the first to demonstrate black holes suppressed galactic star formation when the universe was less than half its current age.

Herschel is a European Space Agency-led mission with important NASA contributions.

"We want to know how star formation and black hole activity are linked," said Mathew Page of University College London's Mullard Space Science Laboratory in the United Kingdom and lead author of the Nature paper describing these findings. "The two processes increase together up to a point, but the most energetic black holes appear to turn off star formation."

Supermassive black holes, weighing as much as millions of suns, are believed to reside in the hearts of all large galaxies. When gas falls upon these monsters, the material is accelerated and heated around the black hole, releasing great torrents of energy. Earlier in the history of the universe, these giant, luminous black holes, called active galactic nuclei, were often much brighter and more energetic. Star formation was also livelier back then.

Studies of nearby galaxies suggest active black holes can squash star formation. The revved-up, central black holes likely heat up and disperse the galactic reservoirs of cold gas needed to create new stars. These studies have only provided "snapshots" in time, however, leaving the overall relationship of active galactic nuclei and star formation unclear, especially over the cosmic history of galaxy formation.

"To understand how active galactic nuclei affect star formation over the history of the universe, we investigated a time when star formation was most vigorous, between eight and 12 billion years ago," said co-author James Bock, a senior research scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., and co-coordinator of the Herschel Multi-tiered Extragalactic Survey. "At that epoch, galaxies were forming stars 10 times more rapidly than they are today on average. Many of these galaxies are incredibly luminous, more than 1,000 times brighter than our Milky Way."

For the new study, Page and colleagues used Herschel data that probed 65 galaxies at wavelengths equivalent to the thickness of several sheets of office paper, a region of the light spectrum known as the far-infrared. These wavelengths reveal the rate of star formation, because most of the energy released by developing stars heats surrounding dust, which then re-radiates starlight out in far-infrared wavelengths.

The researchers compared their infrared readings with X-rays streaming from the active central black holes in the survey's galaxies, measured by NASA’s Chandra X-ray Observatory. At lower intensities, the black holes' brightness and star formation increased in sync. However, star formation dropped off in galaxies with the most energetic central black holes. Astronomers think inflows of gas fuel new stars and supermassive black holes. Feed a black hole too much, however, and it starts spewing radiation into the galaxy that prevents raw material from coalescing into new stars.

"Now that we see the relationship between active supermassive black holes and star formation, we want to know more about how this process works," said Bill Danchi, Herschel program scientist at NASA Headquarters in Washington. "Does star formation get disrupted from the beginning with the formation of the brightest galaxies of this type, or do all active black holes eventually shut off star formation, and energetic ones do this more quickly than less active ones?"

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and important participation by NASA. NASA's Herschel Project Office is based at JPL. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at Caltech, supports the United States astronomical community. Caltech manages JPL for NASA.

For NASA'S Herschel website, visit http://www.nasa.gov/herschel.

For ESA'S Herschel website, visit http://www.esa.int/SPECIALS/Herschel/index.html.

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The Swan Glowing in Flight

Best known as a swan winging its way across the night, the constellation Cygnus is easily seen in the northern hemisphere's summertime sky. This new view of the Cygnus-X star-forming region by the Herschel Telescope highlights chaotic networks of dust and gas that point to sites of massive star formation. This image combines far-infrared data acquired at 70 micron (corresponding to the blue channel); 160 micron (corresponding to the green channel); and 250 micron (corresponding to the red channel). The observations were made on May 24, 2010, and Dec. 18, 2010.

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA.

Image Credit: ESA/PACS/SPIRE/Martin Hennemann & Frederique Motte, Laboratoire AIM Paris-Saclay, CEA/Irfu -- CNRS/INSU -- Univ. Paris Diderot, France

Active Black Hole Squashes Star Formation

New data from the Herschel Space Observatory shows that galaxies with the most powerful, active, supermassive black holes at their cores produce fewer stars than galaxies with less ones.

Supermassive black holes are believed to reside in the hearts of all large galaxies. When gas falls upon these monsters, the materials are accelerated and heated around the black hole, releasing great torrents of energy. In the process, active black holes often generate colossal jets that blast out twin streams of heated matter.

Inflows of gas into a galaxy also fuel the formation of new stars. In a new study of distant galaxies, Herschel helped show that star formation and black hole activity increase together, but only up to a point. Astronomers think that if an active black hole flares up too much, it starts spewing radiation that prevents raw material from coalescing into new stars.

This artist concept of the local galaxy Arp 220, captured by the Hubble Space Telescope, helps illustrate the Herschel results. The bright core of the galaxy, paired with an overlaid artist's impression of jets emanating from it, indicate that the central black hole's activity is intensifying. As the active black hole continues to rev up, the rate of star formation will, in turn, be suppressed in the galaxy. Astronomers want to further study how star formation and black hole activity are intertwined.

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes, with important participation by NASA.

Image Credit: NASA/JPL-Caltech

The Eagle Nebula

Combining almost opposite ends of the electromagnetic spectrum, this composite of the Herschel in far-infrared and XMM-Newton’s X-ray images shows how the hot young stars detected by the X-ray observations are sculpting and interacting with the surrounding ultra-cool gas and dust, which, at only a few degrees above absolute zero, is the critical material for star formation itself. Both wavelengths would be blocked by Earth’s atmosphere, so are critical to our understanding of the lifecycle of stars
 
Image Credit: ESA/Herschel/PACS/SPIRE/Hill, Motte, HOBYS Key Programme Consortium

Herschel Space Observatory Finds Oceans of Water in Planet-Forming Disk Around Nearby Star

Trent J. Perrotto

Headquarters, Washington

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- Using data from the Herschel Space Observatory, astronomers have detected for the first time cold water vapor enveloping a dusty disk around a young star. The findings suggest that this disk, which is poised to develop into a solar system, contains great quantities of water, suggesting that water-covered planets like Earth may be common in the universe. Herschel is a European Space Agency mission with important NASA contributions.

Scientists previously found warm water vapor in planet-forming disks close to a central star. Evidence for vast quantities of water extending out into the cooler, far reaches of disks where comets take shape had not been seen until now. The more water available in disks for icy comets to form, the greater the chances that large amounts eventually will reach new planets through impacts.

"Our observations of this cold vapor indicate enough water exists in the disk to fill thousands of Earth oceans," said astronomer Michiel Hogerheijde of Leiden Observatory in The Netherlands. Hogerheijde is the lead author of a paper describing these findings in the Oct. 21 issue of the journal Science.

The star with this water-logged disk, called TW Hydrae, is 10 million years old and located about 175 light-years away from Earth, in the constellation Hydra. The frigid watery haze detected by Hogerheijde and his team is thought to originate from ice-coated grains of dust near the disk's surface. Ultraviolet light from the star causes some water molecules to break free of this ice, creating a thin layer of gas with a light signature detected by Herschel's Heterodyne Instrument for the Far-Infrared, or HIFI.

"These are the most sensitive HIFI observations to-date," said Paul Goldsmith, NASA project scientist for the Herschel Space Observatory at the agency's Jet Propulsion Laboratory in Pasadena, Calif. "It is a testament to the instrument-builders that such weak signals can be detected."

TW Hydrae is an orange dwarf star, somewhat smaller and cooler than our yellow-white sun. The giant disk of material that encircles the star has a size nearly 200 times the distance between Earth and the sun. Over the next few million years, astronomers believe matter within the disk will collide and grow into planets, asteroids and other cosmic bodies. Dust and ice particles will assemble as comets.

As the new solar system evolves, icy comets are likely to deposit much of the water they contain on freshly created worlds through impacts, giving rise to oceans. Astronomers believe TW Hydrae and its icy disk may be representative of many other young star systems, providing new insights on how planets with abundant water could form throughout the universe.

Herschel is a European Space Agency cornerstone mission launched in 2009, carrying science instruments provided by consortia of European institutes. NASA's Herschel Project Office based at JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.

For NASA's Herschel website, visit http://www.nasa.gov/herschel.

For ESA's Herschel website, visit http://www.esa.int/SPECIALS/Herschel/index.html.

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Herschel Telescope Detects Oxygen Molecules In Space

Trent J. Perrotto

Headquarters, Washington

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- The Herschel Space Observatory's large telescope and state-of-the-art infrared detectors have provided the first confirmed finding of oxygen molecules in space. The molecules were discovered in the Orion star-forming complex.

Individual atoms of oxygen are common in space, particularly around massive stars. But, molecular oxygen, which makes up about 20 percent of the air we breathe, has eluded astronomers until now.

"Oxygen gas was discovered in the 1770s, but it's taken us more than 230 years to finally say with certainty that this very simple molecule exists in space," said Paul Goldsmith, NASA's Herschel project scientist at the agency's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Goldsmith is lead author of a recent paper describing the findings in the Astrophysical Journal. Herschel is a European Space Agency-led mission with important NASA contributions.

Astronomers searched for the elusive molecules in space for decades using balloons, as well as ground- and space-based telescopes. The Swedish Odin telescope spotted the molecule in 2007, but the sighting could not be confirmed.

Goldsmith and his colleagues propose that oxygen is locked up in water ice that coats tiny dust grains. They think the oxygen detected by Herschel in the Orion nebula was formed after starlight warmed the icy grains, releasing water, which was converted into oxygen molecules.

"This explains where some of the oxygen might be hiding," said Goldsmith. "But we didn't find large amounts of it, and still don't understand what is so special about the spots where we find it. The universe still holds many secrets."

The researchers plan to continue their hunt for oxygen molecules in other star-forming regions.

"Oxygen is the third most common element in the universe and its molecular form must be abundant in space," said Bill Danchi, Herschel program scientist at NASA Headquarters in Washington. "Herschel is proving a powerful tool to probe this unsolved mystery. The observatory gives astronomers an innovative tool to look at a whole new set of wavelengths where the tell-tale signature of oxygen may be hiding."

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes. NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments.

The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.

For NASA'S Herschel website, visit http://www.nasa.gov/herschel.

For ESA'S Herschel website, visit http://www.esa.int/SPECIALS/Herschel/index.html.

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Herschel Telescope Detects Oxygen Molecules In Space

Trent J. Perrotto

Headquarters, Washington

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- The Herschel Space Observatory's large telescope and state-of-the-art infrared detectors have provided the first confirmed finding of oxygen molecules in space. The molecules were discovered in the Orion star-forming complex.

Individual atoms of oxygen are common in space, particularly around massive stars. But, molecular oxygen, which makes up about 20 percent of the air we breathe, has eluded astronomers until now.

"Oxygen gas was discovered in the 1770s, but it's taken us more than 230 years to finally say with certainty that this very simple molecule exists in space," said Paul Goldsmith, NASA's Herschel project scientist at the agency's Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

Goldsmith is lead author of a recent paper describing the findings in the Astrophysical Journal. Herschel is a European Space Agency-led mission with important NASA contributions.

Astronomers searched for the elusive molecules in space for decades using balloons, as well as ground- and space-based telescopes. The Swedish Odin telescope spotted the molecule in 2007, but the sighting could not be confirmed.

Goldsmith and his colleagues propose that oxygen is locked up in water ice that coats tiny dust grains. They think the oxygen detected by Herschel in the Orion nebula was formed after starlight warmed the icy grains, releasing water, which was converted into oxygen molecules.

"This explains where some of the oxygen might be hiding," said Goldsmith. "But we didn't find large amounts of it, and still don't understand what is so special about the spots where we find it. The universe still holds many secrets."

The researchers plan to continue their hunt for oxygen molecules in other star-forming regions.

"Oxygen is the third most common element in the universe and its molecular form must be abundant in space," said Bill Danchi, Herschel program scientist at NASA Headquarters in Washington. "Herschel is proving a powerful tool to probe this unsolved mystery. The observatory gives astronomers an innovative tool to look at a whole new set of wavelengths where the tell-tale signature of oxygen may be hiding."

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes. NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments.

The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community. Caltech manages JPL for NASA.

For NASA'S Herschel website, visit http://www.nasa.gov/herschel.

For ESA'S Herschel website, visit http://www.esa.int/SPECIALS/Herschel/index.html.

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Herschel Measures Dark Matter Required for Star-Forming Galaxies

Trent J. Perrotto

Headquarters, Washington                               

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- The Herschel Space Observatory has revealed how much dark matter it takes to form a new galaxy bursting with stars. Herschel is a European Space Agency cornerstone mission supported with important NASA contributions.

The findings are a key step in understanding how dark matter, an invisible substance permeating our universe, contributed to the birth of massive galaxies in the early universe.

"If you start with too little dark matter, then a developing galaxy would peter out," said astronomer Asantha Cooray of the University of California, Irvine. He is the principal investigator of new research appearing in the journal Nature, online on Feb. 16 and in the Feb. 24 print edition. "If you have too much, then gas doesn't cool efficiently to form one large galaxy, and you end up with lots of smaller galaxies. But if you have the just the right amount of dark matter, then a galaxy bursting with stars will pop out."

This right of amount of dark matter turns out to be a mass equivalent to 300 billion of our suns.

Herschel launched into space in May 2009. The mission's large, 3.5-meter telescope detects longer-wavelength infrared light from a host of objects, ranging from asteroids and planets in our own solar system to faraway galaxies.

"This remarkable discovery shows that early galaxies go through periods of star formation much more vigorous than in our present-day Milky Way," said William Danchi, Herschel program scientist at NASA Headquarters in Washington. "It showcases the importance of infrared astronomy, enabling us to peer behind veils of interstellar dust to see stars in their infancy."

Cooray and colleagues used the telescope to measure infrared light from massive, star-forming galaxies located 10 to 11 billion light-years away. Astronomers think these and other galaxies formed inside clumps of dark matter, similar to chicks incubating in eggs.

Giant clumps of dark matter act like gravitational wells that collect the gas and dust needed for making galaxies. When a mixture of gas and dust falls into a well, it condenses and cools, allowing new stars to form. Eventually enough stars form, and a galaxy is born.

Herschel was able to uncover more about how this galaxy-making process works by mapping the infrared light from collections of very distant, massive star-forming galaxies. This pattern of light, called the cosmic infrared background, is like a web that spreads across the sky. Because Herschel can survey large areas quickly with high resolution, it was able to create the first detailed maps of the cosmic infrared background.

"It turns out that it's much more effective to look at these patterns rather than the individual galaxies," said Jamie Bock of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Bock is the U.S. principal investigator for Herschel's Spectral and Photometric Imaging Receiver instrument used to make the maps. "This is like looking at a picture in a magazine from a reading distance. You don't notice the individual dots, but you see the big picture. Herschel gives us the big picture of these distant galaxies, showing the influence of dark matter."

The maps showed the galaxies are more clustered into groups than previously believed. The amount of galaxy clustering depends on the amount of dark matter. After a series of complicated numerical simulations, the astronomers were able to determine exactly how much dark matter is needed to form a single star-forming galaxy.

"This measurement is important, because we are homing in on the very basic ingredients in galaxy formation," said Alexandre Amblard, also of UC Irvine, first author of the Nature paper. "In this case, the ingredient, dark matter, happens to be an exotic substance that we still have much to learn about."

NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community.

For more information about Herschel, visit http://www.nasa.gov/herschel and http://www.esa.int/herschel.

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Herschel Measures Dark Matter Required for Star-Forming Galaxies

Trent J. Perrotto

Headquarters, Washington                               

 

Whitney Clavin

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- The Herschel Space Observatory has revealed how much dark matter it takes to form a new galaxy bursting with stars. Herschel is a European Space Agency cornerstone mission supported with important NASA contributions.

The findings are a key step in understanding how dark matter, an invisible substance permeating our universe, contributed to the birth of massive galaxies in the early universe.

"If you start with too little dark matter, then a developing galaxy would peter out," said astronomer Asantha Cooray of the University of California, Irvine. He is the principal investigator of new research appearing in the journal Nature, online on Feb. 16 and in the Feb. 24 print edition. "If you have too much, then gas doesn't cool efficiently to form one large galaxy, and you end up with lots of smaller galaxies. But if you have the just the right amount of dark matter, then a galaxy bursting with stars will pop out."

This right of amount of dark matter turns out to be a mass equivalent to 300 billion of our suns.

Herschel launched into space in May 2009. The mission's large, 3.5-meter telescope detects longer-wavelength infrared light from a host of objects, ranging from asteroids and planets in our own solar system to faraway galaxies.

"This remarkable discovery shows that early galaxies go through periods of star formation much more vigorous than in our present-day Milky Way," said William Danchi, Herschel program scientist at NASA Headquarters in Washington. "It showcases the importance of infrared astronomy, enabling us to peer behind veils of interstellar dust to see stars in their infancy."

Cooray and colleagues used the telescope to measure infrared light from massive, star-forming galaxies located 10 to 11 billion light-years away. Astronomers think these and other galaxies formed inside clumps of dark matter, similar to chicks incubating in eggs.

Giant clumps of dark matter act like gravitational wells that collect the gas and dust needed for making galaxies. When a mixture of gas and dust falls into a well, it condenses and cools, allowing new stars to form. Eventually enough stars form, and a galaxy is born.

Herschel was able to uncover more about how this galaxy-making process works by mapping the infrared light from collections of very distant, massive star-forming galaxies. This pattern of light, called the cosmic infrared background, is like a web that spreads across the sky. Because Herschel can survey large areas quickly with high resolution, it was able to create the first detailed maps of the cosmic infrared background.

"It turns out that it's much more effective to look at these patterns rather than the individual galaxies," said Jamie Bock of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Bock is the U.S. principal investigator for Herschel's Spectral and Photometric Imaging Receiver instrument used to make the maps. "This is like looking at a picture in a magazine from a reading distance. You don't notice the individual dots, but you see the big picture. Herschel gives us the big picture of these distant galaxies, showing the influence of dark matter."

The maps showed the galaxies are more clustered into groups than previously believed. The amount of galaxy clustering depends on the amount of dark matter. After a series of complicated numerical simulations, the astronomers were able to determine exactly how much dark matter is needed to form a single star-forming galaxy.

"This measurement is important, because we are homing in on the very basic ingredients in galaxy formation," said Alexandre Amblard, also of UC Irvine, first author of the Nature paper. "In this case, the ingredient, dark matter, happens to be an exotic substance that we still have much to learn about."

NASA's Herschel Project Office is based at JPL, which contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the U.S. astronomical community.

For more information about Herschel, visit http://www.nasa.gov/herschel and http://www.esa.int/herschel.

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