Wednesday, April 10, 2019

First Image of a Black Hole Captured Here: Galaxy Messier 87

First Image of a Black Hole Captured Here
Galaxy Messier 87 | ESO’s Very Large Telescope
Messier 87 (M87) is an enormous elliptical galaxy located about 55 million light years from Earth, visible in the constellation Virgo. It was discovered by Charles Messier in 1781, but not identified as a galaxy until the 20th Century. At double the mass of our own galaxy, the Milky Way, and containing as many as ten times more stars, it is amongst the largest galaxies in the local universe. Besides its raw size, M87 has some very unique characteristics. For example, it contains an unusually high number of globular clusters: while our Milky Way contains under 200, M87 has about 12,000, which some scientists theorize it collected from its smaller neighbors.

Just as with all other large galaxies, M87 has a supermassive black hole at its center. The mass of the black hole at the center of a galaxy is related to the mass of the galaxy overall, so it shouldn’t be surprising that M87’s black hole is one of the most massive known. The black hole also may explain one of the galaxy’s most energetic features: a relativistic jet of matter being ejected at nearly the speed of light.

The black hole was the object of paradigm-shifting observations by the Event Horizon Telescope. The EHT chose the object as the target of its observations for two reasons. While the EHT’s resolution is incredible, even it has its limits. As more massive black holes are also larger in diameter, M87's central black hole presented an unusually large target—meaning that it could be imaged more easily than smaller black holes closer by. The other reason for choosing it, however, was decidedly more Earthly. M87 appears fairly close to the celestial equator when viewed from our planet, making it visible in most of the Northern and Southern Hemispheres. This maximized the number of telescopes in the EHT that could observe it, increasing the resolution of the final image.

This image was captured by FORS2 on ESO’s Very Large Telescope as part of the Cosmic Gems program, an outreach initiative that uses ESO telescopes to produce images of interesting, intriguing or visually attractive objects for the purposes of education and public outreach. The program makes use of telescope time that cannot be used for science observations, and  produces breathtaking images of some of the most striking objects in the night sky. In case the data collected could be useful for future scientific purposes, these observations are saved and made available to astronomers through the ESO Science Archive.

Credit: European Southern Observatory (ESO)
Release Date: April 10, 2019

#NASA #ESO #Astronomy #Space #Science #BlackHoles #VLT #EventHorizon #RealBlackHole #EHTBlackHole #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #Europe #International #STEM #Education

In the Shadow of the Black Hole

In the Shadow of the Black Hole
April 10, 2019: The Event Horizon Telescope (EHT)—a planet-scale array of eight ground-based radio telescopes forged through international collaboration—was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

This 17-minute film explores the efforts that led to this historic image, from the science of Einstein and Schwarzschild to the struggles and successes of the EHT collaboration.

Credit: EHT Collaboration/European Southern Observatory (ESO)
Duration: 17 minutes
Release Date: April 10, 2019


#NASA #ESO #Astronomy #Space #Science #BlackHoles #EventHorizon #RealBlackHole #EHTBlackHole #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #Europe #International #STEM #Education

Astronomers Capture First Image of a Black Hole: ESOcast 199 Light

Astronomers Capture First Image of a Black Hole: ESOcast 199 Light
April 10, 2019: The Event Horizon Telescope (EHT)a planet-scale array of eight ground-based radio telescopes forged through international collaborationwas designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

This video is available in 4K UHD.

The ESOcast Light is a series of short videos bringing you the wonders of the Universe in bite-sized pieces.

Credit: European Southern Observatory (ESO)
Duration: 1 minute, 42 seconds
Release Date: April 10, 2019


#NASA #ESO #Astronomy #Space #Science #BlackHoles #EventHorizon #RealBlackHole #EHTBlackHole #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #Europe #International #STEM #Education

Capturing the First image of a Black Hole Event Horizon: A Quick Look

Capturing the First image of a Black Hole Event Horizon: 
A Quick Look
April 10, 2019: The Event Horizon Telescope, a network of radio antennae around the globe, has captured the first image of a black hole event horizon.

This black hole is located in Messier 87, or M87, which is about 55 million light years from Earth.

The event horizon is the boundary between what can and cannot escape a black hole's gravitational grasp.

Astronomers were also using other telescopes while the Event Horizon Telescope was getting its data including NASA's Chandra X-ray Observatory.

Chandra has studied M87 many times over its 20-year mission and sees a much wider field-of-view that the EHT.

By combining Chandra data with the EHT image, scientists can learn more about the giant black hole and its behavior.

For example, was material actively falling onto the black hole while the EHT was getting its revolutionary image? 

What was happening to energetic particles near and far from the event horizon during this time?

Scientists will use these data to learn as much as they can about the exotic and fascinating objects known as black holes.

For additional information and resources, please visit: NSF Exploring Black Holes: https://www.nsf.gov/news/special_reports/blackholes/

Credit: NASA/CXC/SAO
Duration: 1 minute, 8 seconds
Release Date: April 10, 2019

#NASA #Astronomy #Space #Science #BlackHoles #EventHorizon #RealBlackHole #EHTBlackHole #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #UnitedStates #International #STEM #Education

First Ever Picture of a Black Hole: Animation Explained

First Ever Picture of a Black Hole: Animation Explained
If you could fly next to the supermassive black hole M87*, this is what you would see. 

April 10, 2019: The Event Horizon Telescope (EHT)—a planet-scale array of eight ground-based radio telescopes forged through international collaboration—was designed to capture images of a black hole.

Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

This breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun.


For additional information and resources, please visit: NSF Exploring Black Holes: https://www.nsf.gov/news/special_reports/blackholes/

Credit: National Science Foundation (NSF)
Release Date: April 10, 2019

#NASA #Astronomy #Space #Science #BlackHoles #EventHorizon #RealBlackHole #EHTBlackHole #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #UnitedStates #International #STEM #Education

Astronomers capture first image of a black hole

Astronomers capture first image of a black hole
National Science Foundation and Event Horizon Telescope contribute to paradigm-shifting observations of the gargantuan black hole at the heart of distant galaxy Messier 87

Using the Event Horizon Telescope, scientists obtain the first image of a black hole.

April 10, 2019: The Event Horizon Telescope (EHT)—a planet-scale array of eight ground-based radio telescopes forged through international collaboration—was designed to capture images of a black hole.

Today, in coordinated press conferences across the globe, EHT researchers reveal that they have succeeded, unveiling the first direct visual evidence of a supermassive black hole and its shadow.

This breakthrough was announced in a series of six papers published in a special issue of The Astrophysical Journal Letters. The image reveals the black hole at the center of Messier 87, a massive galaxy in the nearby Virgo galaxy cluster. This black hole resides 55 million light-years from Earth and has a mass 6.5-billion times that of the Sun.

"This is a huge day in astrophysics," said NSF Director France Córdova. "We're seeing the unseeable. Black holes have sparked imaginations for decades. They have exotic properties and are mysterious to us. Yet with more observations like this one they are yielding their secrets. This is why NSF exists. We enable scientists and engineers to illuminate the unknown, to reveal the subtle and complex majesty of our universe."

The EHT links telescopes around the globe to form an Earth-sized virtual telescope with unprecedented sensitivity and resolution. The EHT is the result of years of international collaboration and offers scientists a new way to study the most extreme objects in the Universe predicted by Einstein's general relativity during the centennial year of the historic experiment that first confirmed the theory.

"We have taken the first picture of a black hole," said EHT project director Sheperd S. Doeleman of the Center for Astrophysics | Harvard & Smithsonian. "This is an extraordinary scientific feat accomplished by a team of more than 200 researchers."

The National Science Foundation (NSF) played a pivotal role in this discovery by funding individual investigators, interdisciplinary scientific teams and radio astronomy research facilities since the inception of EHT. Over the last two decades, NSF has directly funded more than $28 million in EHT research, the largest commitment of resources for the project.

Black holes are extraordinary cosmic objects with enormous masses but extremely compact sizes. The presence of these objects affects their environment in extreme ways, warping spacetime and super-heating any surrounding material.

"If immersed in a bright region, like a disc of glowing gas, we expect a black hole to create a dark region similar to a shadow -- something predicted by Einstein's general relativity that we've never seen before," explained chair of the EHT Science Council Heino Falcke of Radboud University, the Netherlands. "This shadow, caused by the gravitational bending and capture of light by the event horizon, reveals a lot about the nature of these fascinating objects and allowed us to measure the enormous mass of M87's black hole."

Multiple calibration and imaging methods have revealed a ring-like structure with a dark central region—the black hole's shadow—that persisted over multiple independent EHT observations.

"Once we were sure we had imaged the shadow, we could compare our observations to extensive computer models that include the physics of warped space, superheated matter and strong magnetic fields. Many of the features of the observed image match our theoretical understanding surprisingly well," remarks Paul T.P. Ho, EHT Board member and Director of the East Asian Observatory. "This makes us confident about the interpretation of our observations, including our estimation of the black hole's mass."

Creating the EHT was a formidable challenge that required upgrading and connecting a worldwide network of eight pre-existing telescopes deployed at a variety of challenging high-altitude sites. These locations included volcanoes in Hawai`i and Mexico, mountains in Arizona and the Spanish Sierra Nevada, the Chilean Atacama Desert, and Antarctica.

The EHT observations use a technique called very-long-baseline interferometry (VLBI). which synchronizes telescope facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope observing at a wavelength of 1.3mm. VLBI allows the EHT to achieve an angular resolution of 20 micro-arcseconds -- enough to read a newspaper in New York from a sidewalk café in Paris.

The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope Alfonso Serrano, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope. Petabytes of raw data from the telescopes were combined by highly specialized supercomputers hosted by the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory.

The construction of the EHT and the observations announced today represent the culmination of decades of observational, technical, and theoretical work. This example of global teamwork required close collaboration by researchers from around the world. Thirteen partner institutions worked together to create the EHT, using both pre-existing infrastructure and support from a variety of agencies. Key funding was provided by the US National Science Foundation, the EU's European Research Council (ERC), and funding agencies in East Asia.

"We have achieved something presumed to be impossible just a generation ago," concluded Doeleman. "Breakthroughs in technology, connections between the world's best radio observatories, and innovative algorithms all came together to open an entirely new window on black holes and the event horizon."

For additional information and resources, please visit: NSF Exploring Black Holes: https://www.nsf.gov/news/special_reports/blackholes/

Credit: National Science Foundation (NSF)
Release Date: April 10, 2019

#NASA #Astronomy #Space #Science #BlackHoles #EventHorizon #Discovery #Exploration #History #EHT #Telescope #Galaxy #Messier87 #NSF #Earth #UnitedStates #International #STEM #Education

Friday, November 16, 2018

Russia Launches Cargo Ship to International Space Station

Roscosmos Progress 71 Launch in Kazakhstan | NASA TV
Nov. 16, 2018: The unpiloted Russian ISS Progress 71 cargo ship launched from the Baikonur Cosmodrome in Kazakhstan atop a Soyuz booster rocket Nov. 16 (Nov. 17, Kazakhstan time), carrying almost three tons of food, fuel and supplies for the residents of the International Space Station. The Progress is scheduled to execute an automated docking to the aft port of the Zvezda Service Module Nov. 18 to begin a four-month stay at the complex.

Inside NASA's Kennedy Space Center! | Week of Nov. 16, 2018


This week in space news, the recently arrived European Service Module—the powerhouse for the Orion spacecraft—was unpacked and moved into the high bay in Kennedy Space Center's Neil Armstrong Operations and Checkout Building to begin processing for Exploration Mission-1. Also, launch teams from Boeing, United Launch Alliance and NASA successfully completed an integrated simulation for the first flight of the CST-100 Starliner spacecraft aboard an Atlas V rocket.

Credit: NASA's Kennedy Space Center (KSC)
Duration: 2 minutes, 5 seconds
Release Date: November 16, 2018


#NASA #Space #Orion #ESM #ESA #SLS #EM1 #Moon #CST100 #Starliner #Spacecraft #AtlasV #Astronauts #Earth #Mars #JourneyToMars #DeepSpace #SolarSystem #Exploration #Kennedy #KSC #Spaceport #Florida #USA #UnitedStates #STEM #Education #HD #Video

Astronomers Find Possible Elusive Star Behind Supernova

Artist's Illustration of Supernova SN 2017ein
Astronomers may have finally uncovered the long-sought progenitor to a specific type of exploding star by sifting through NASA Hubble Space Telescope archival data. The supernova, called a Type Ic, is thought to detonate after its massive star has shed or been stripped of its outer layers of hydrogen and helium.

These stars could be among the most massive known—at least 30 times heftier than our Sun. Even after shedding some of their material late in life, they are expected to be big and bright. So it was a mystery why astronomers had not been able to nab one of these stars in pre-explosion images.

Finally, in 2017, astronomers got lucky. A nearby star ended its life as a Type Ic supernova. Two teams of astronomers pored through the archive of Hubble images to uncover the putative precursor star in pre-explosion photos taken in 2007. The supernova, cataloged as SN 2017ein, appeared near the center of the nearby spiral galaxy NGC 3938, located roughly 65 million light-years away.

This potential discovery could yield insight into stellar evolution, including how the masses of stars are distributed when they are born in batches.

"Finding a bona fide progenitor of a supernova Ic is a big prize of progenitor searching," said Schuyler Van Dyk of the California Institute of Technology (Caltech) in Pasadena, lead researcher of one of the teams. "We now have for the first time a clearly detected candidate object." His team's paper was published in June in The Astrophysical Journal.

A paper by a second team, which appeared in the Oct. 21, 2018, issue of the Monthly Notices of the Royal Astronomical Society, is consistent with the earlier team's conclusions: https://academic.oup.com/mnras

"We were fortunate that the supernova was nearby and very bright, about 5 to 10 times brighter than other Type Ic supernovas, which may have made the progenitor easier to find," said Charles Kilpatrick of the University of California, Santa Cruz, leader of the second team. "Astronomers have observed many Type Ic supernovas, but they are all too far away for Hubble to resolve. You need one of these massive, bright stars in a nearby galaxy to go off. It looks like most Type Ic supernovas are less massive and therefore less bright, and that's the reason we haven't been able to find them."

An analysis of the object's colors shows that it is blue and extremely hot. Based on that assessment, both teams suggest two possibilities for the source's identity. The progenitor could be a single hefty star between 45 and 55 times more massive than our Sun. Another idea is that it could have been a massive binary-star system in which one of the stars weighs between 60 and 80 solar masses and the other roughly 48 suns. In this latter scenario, the stars are orbiting closely and interact with each other. The more massive star is stripped of its hydrogen and helium layers by the close companion, and eventually explodes as a supernova.

The possibility of a massive double-star system is a surprise. "This is not what we would expect from current models, which call for lower-mass interacting binary progenitor systems," Van Dyk said.

Expectations on the identity of the progenitors of Type Ic supernovas have been a puzzle. Astronomers have known that the supernovas were deficient in hydrogen and helium, and initially proposed that some hefty stars shed this material in a strong wind (a stream of charged particles) before they exploded. When they didn't find the progenitors stars, which should have been extremely massive and bright, they suggested a second method to produce the exploding stars that involves a pair of close-orbiting, lower-mass binary stars. In this scenario, the heftier star is stripped of its hydrogen and helium by its companion. But the "stripped" star is still massive enough to eventually explode as a Type Ic supernova.

"Disentangling these two scenarios for producing Type Ic supernovas impacts our understanding of stellar evolution and star formation, including how the masses of stars are distributed when they are born, and how many stars form in interacting binary systems," explained Ori Fox of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, a member of Van Dyk's team. "And those are questions that not just astronomers studying supernovas want to know, but all astronomers are after."

Type Ic supernovas are just one class of exploding star. They account for about 20 percent of massive stars that explode from the collapse of their cores.

The teams caution that they won't be able to confirm the source's identity until the supernova fades in about two years. The astronomers hope to use either Hubble or the upcoming NASA James Webb Space Telescope to see whether the candidate progenitor star has disappeared or has significantly dimmed. They also will be able to separate the supernova's light from that of stars in its environment to calculate a more accurate measurement of the object's brightness and mass.

SN 2017ein was discovered in May 2017 by Tenagra Observatories in Arizona. But it took the sharp resolution of Hubble to pinpoint the exact location of the possible source. Van Dyk's team imaged the young supernova in June 2017 with Hubble's Wide Field Camera 3. The astronomers used that image to pinpoint the candidate progenitor star nestled in one of the host galaxy's spiral arms in archival Hubble photos taken in December 2007 by the Wide Field Planetary Camera 2.

Kilpatrick's group also observed the supernova in June 2017 in infrared images from one of the 10-meter telescopes at the W. M. Keck Observatory in Hawaii. The team then analyzed the same archival Hubble photos as Van Dyk's team to uncover the possible source.

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

Credits:
Artwork: NASA, ESA, and J. Olmsted (STScI)
Science: NASA, ESA, S. Van Dyk (Caltech), and C. Kilpatrick (University of California, Santa Cruz)
Release date: November 15, 2018


#NASA #Hubble #Astronomy #Space #Science #Star #Supernova #TypeIc #Galaxy #NGC3938 #Spiral #Astrophysics #Cosmos #Universe #Telescope #ESA #Goddard #GSFC #STScI #Art #Illustration #STEM #Education

NASA's Space to Ground: Honoring a Legend | Week of Nov. 16, 2018

NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. 

Credit: NASA's Johnson Space Center (JSC)
Duration: 2 minutes, 14 seconds
Release Date: November 16, 2018

#NASA #Space #Earth #ISS #Science #NorthropGrumman #Cygnus #Russia #Progress #Progress71 #Soyuz #Союз #Роскосмос #Россия #Cargo #Resupply #Research #Microgravity #Astronauts #JohnYoung #ESA #AlexanderGerst #Germany #Deutschland #DLR #SerenaAuñónChancellor #Cosmonaut #SergeyProkopyev #Russia #Россия #Human #Spaceflight #Spacecraft #JSC #Houston #Texas #UnitedStates #STEM #Education #HD #Video

We Are NASA

We’ve taken giant leaps and left our mark in the heavens. Now we’re building the next chapter, returning to the Moon to stay, and preparing to go beyond. We are NASA—and after 60 years, we’re just getting started.

Special thanks to Mike Rowe for the voiceover work.

Credit: National Aeronautics and Space Administration
Duration: 2 minutes, 23 seconds
Release Date: November 16, 2018


#NASA #Space #Earth #Science #Mars #JourneyToMars #Moon #SolarSystem #Exploration #Human #Spaceflight #Future #STEM #Education #HD #Video

Monday, November 12, 2018

"Of Bent Time and Jellyfish" | Hubble

At first glance, a bright blue crescent immediately jumps out of this NASA/ESA Hubble Space Telescope image: is it a bird? A plane? Evidence of extraterrestrial life? No—it is a galaxy.

The shape of this galaxy admittedly appears to be somewhat bizarre, so confusion would be forgiven. This is due to a cosmic phenomenon called gravitational lensing. In this image, the gravitational influence of a massive galaxy cluster (called SDSS J1110+6459) is causing its surroundings spacetime to bend and warp, affecting the passage of any nearby light. This cluster to the lower left of the blue streak; a few more signs of lensing (streaks, blobs, curved lines, distorted shapes) can be seen dotted around this area.

This image also features a rare and interesting type of galaxy called a jellyfish galaxy, visible just right next to the cluster and apparently dripping bright blue material. These are galaxies that lose gas via a process called galactic ram pressure stripping, where the drag caused by the galaxy moving through space causes gas to be stripped away.

Credit: ESA/Hubble & NASA
Acknowledgement: Judy Schmidt
Release Date: November 12, 2018


#NASA #Hubble #Astronomy #Space #Science #Galaxy #Jellyfish #GravitationalLensing #Cluster #SDSSJ11106459 #Astrophysics #Cosmos #Universe #Telescope #ESA #Goddard #GSFC #STScI #STEM #Education

Friday, November 09, 2018

NASA's Space to Ground: Surviving the Plunge | Week of Nov. 9, 2018

NASA's Space to Ground: Surviving the Plunge | Week of Nov. 9, 2018
NASA's Space to Ground is your weekly update on what's happening aboard the International Space Station. The Expedition 57 crew said farewell to a Japanese resupply ship Wednesday, Nov. 7, 2018, and is getting ready to welcome U.S. and Russian space freighters in less than two weeks. The trio practiced International Space Station emergency procedures this week then went on to space research and robotics training.

The U.S. company Northrop Grumman is getting its 10th Cygnus cargo craft packed and ready for launch atop an Antares rocket Nov. 15 at 4:49 a.m. EST. Russia will launch its 71st station resupply mission aboard a Progress spaceship the next day at 1:14 p.m.

Both resupply ships are due to arrive at the station Sunday Nov. 18 just 10 hours apart. The Cygnus will get there first following its head start. Commander Alexander Gerst assisted by Flight Engineer Serena Auñón-Chancellor will capture the American vessel with the Canadarm2 robotic arm at 4:35 a.m. A few hours later, cosmonaut Sergey Prokopyev will monitor the approach and automated docking of the Russian Progress 71 cargo craft to the Zvezda service module at 2:30 p.m.

Credit: NASA's Johnson Space Center
Duration: 2 minutes, 19 seconds
Release Date: November 9, 2018


#NASA #Space #ISS #Science #HTV #Cargo #Supply #JAXA #日本 #Japan #Research #Microgravity #Astronauts #ESA #AlexanderGerst #Germany #Deutschland #DLR #SerenaAuñónChancellor #Cosmonaut #SergeyProkopyev #Russia #Россия #Boeing #CST100 #Starliner #LaunchAmerica #Human #Spaceflight #Spacecraft #JSC #Houston #Texas #UnitedStates #STEM #Education #HD #Video

Thursday, November 08, 2018

Astronomers Unveil Growing Black Holes in Colliding Galaxies

Nov. 7, 2018: Peering through thick walls of gas and dust surrounding the messy cores of merging galaxies, astronomers are getting their best view yet of close pairs of supermassive black holes as they march toward coalescence into mega black holes.

A team of researchers led by Michael Koss of Eureka Scientific Inc., in Kirkland, Washington, performed the largest survey of the cores of nearby galaxies in near-infrared light, using high-resolution images taken by NASA's Hubble Space Telescope and the W. M. Keck Observatory in Hawaii. The Hubble observations represent over 20 years' worth of snapshots from its vast archive.

"Seeing the pairs of merging galaxy nuclei associated with these huge black holes so close together was pretty amazing," Koss said. "In our study, we see two galaxy nuclei right when the images were taken. You can't argue with it; it's a very 'clean' result, which doesn't rely on interpretation."

The images also provide a close-up preview of a phenomenon that must have been more common in the early universe, when galaxy mergers were more frequent. When galaxies collide, their monster black holes can unleash powerful energy in the form of gravitational waves, the kind of ripples in space-time that were just recently detected by ground-breaking experiments.

The new study also offers a preview of what will likely happen in our own cosmic backyard, in several billion years, when our Milky Way combines with the neighboring Andromeda galaxy and their respective central black holes smash together.

"Computer simulations of galaxy smashups show us that black holes grow fastest during the final stages of mergers, near the time when the black holes interact, and that's what we have found in our survey," said study team member Laura Blecha of the University of Florida, in Gainesville. "The fact that black holes grow faster and faster as mergers progress tells us galaxy encounters are really important for our understanding of how these objects got to be so monstrously big."

A galaxy merger is a slow process lasting more than a billion years as two galaxies, under the inexorable pull of gravity, dance toward each other before finally joining together. Simulations reveal that galaxies kick up plenty of gas and dust as they undergo this slow-motion train wreck.

The ejected material often forms a thick curtain around the centers of the coalescing galaxies, shielding them from view in visible light. Some of the material also falls onto the black holes at the cores of the merging galaxies. The black holes grow at a fast clip as they engorge themselves with their cosmic food, and, being messy eaters, they cause the infalling gas to blaze brightly. This speedy growth occurs during the last 10 million to 20 million years of the union. The Hubble and Keck Observatory images captured close-up views of this final stage, when the bulked-up black holes are only about 3,000 light-years apart—a near-embrace in cosmic terms.

It's not easy to find galaxy nuclei so close together. Most prior observations of colliding galaxies have caught the coalescing black holes at earlier stages when they were about 10 times farther away. The late stage of the merger process is so elusive because the interacting galaxies are encased in dense dust and gas and require high-resolution observations in infrared light that can see through the clouds and pinpoint the locations of the two merging nuclei.

The team first searched for visually obscured, active black holes by sifting through 10 years' worth of X-ray data from the Burst Alert Telescope (BAT) aboard NASA's Neil Gehrels Swift Telescope, a high-energy space observatory. "Gas falling onto the black holes emits X-rays, and the brightness of the X-rays tells you how quickly the black hole is growing," Koss explained. "I didn't know if we would find hidden mergers, but we suspected, based on computer simulations, that they would be in heavily shrouded galaxies.Therefore we tried to peer through the dust with the sharpest images possible, in hopes of finding coalescing black holes."

The researchers combed through the Hubble archive, identifying those merging galaxies they spotted in the X-ray data. They then used the Keck Observatory's super-sharp, near-infrared vision to observe a larger sample of the X-ray-producing black holes not found in the Hubble archive.

"People had conducted studies to look for these close interacting black holes before, but what really enabled this particular study were the X-rays that can break through the cocoon of dust," Koss said. "We also looked a bit farther in the universe so that we could survey a larger volume of space, giving us a greater chance of finding more luminous, rapidly growing black holes."

The team targeted galaxies with an average distance of 330 million light-years from Earth. Many of the galaxies are similar in size to the Milky Way and Andromeda galaxies. The team analyzed 96 galaxies from the Keck Observatory and 385 galaxies from the Hubble archive found in 38 different Hubble observation programs. The sample galaxies are representative of what astronomers would find by conducting an all-sky survey.

To verify their results, Koss's team compared the survey galaxies with 176 other galaxies from the Hubble archive that lack actively growing black holes. The comparison confirmed that the luminous cores found in the researchers' census of dusty interacting galaxies are indeed a signature of rapidly growing black-hole pairs headed for a collision.

When the two supermassive black holes in each of these systems finally come together in millions of years, their encounters will produce strong gravitational waves. Gravitational waves produced by the collision of two stellar-mass black holes have already been detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO). Observatories such as the planned NASA/ESA space-based Laser Interferometer Space Antenna (LISA) will be able to detect the lower-frequency gravitational waves from supermassive black-hole mergers, which are a million times more massive than those detected by LIGO.

Future infrared telescopes, such as NASA's planned James Webb Space Telescope and a new generation of giant ground-based telescopes, will provide an even better probe of dusty galaxy collisions by measuring the masses, growth rate, and dynamics of close black-hole pairs. The Webb telescope may also be able to look in mid-infrared light to uncover more galaxy interactions so encased in thick gas and dust that even near-infrared light cannot penetrate them.

The team's results appear online in the Nov. 7, 2018, issue of the journal Nature:
https://www.nature.com/articles/s41586-018-0652-7

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

Credit:
NASA, ESA, and M. Koss (Eureka Scientific, Inc.); Hubble image: NASA, ESA, and M. Koss (Eureka Scientific, Inc.); Keck images: W. M. Keck Observatory and M. Koss (Eureka Scientific, Inc.); Pan-STARRS images: Panoramic Survey Telescope and Rapid Response System and M. Koss (Eureka Scientific, Inc.)
Release Date: November 7, 2018


#NASA #Hubble #Astronomy #Space #Science #Galaxies #Collisions #BlackHoles #Cosmos #Universe #Astrophysics #Telescope #Keck #Observatory #Hawaii #ESA #Goddard #GSFC #STScI #STEM #Education

Monday, November 05, 2018

Jupiter & Io | Hubble

This image represents Jupiter as it appeared on April 3, 2017 at 02:50:19 UTC.

Io (Jupiter I) is the innermost of the four Galilean moons of the planet Jupiter. It is the fourth-largest moon, has the highest density of all the moons, and has the least amount of water of any known astronomical object in the Solar System. It was discovered in 1610 and was named after the mythological character Io, a priestess of Hera who became one of Zeus' lovers. (Source: Wikipedia)

Technical details:
Red: WFC3/UVIS F631N
Green: WFC3/UVIS F502N
Blue: WFC3/UVIS 395N
North is 50.56° clockwise from up.

Data from the following proposal comprises this image:
Hubble 2020: Outer Planet Atmospheres Legacy (OPAL) Program

Credit: NASA/ESA
Processing: Judy Schmidt
Image Date: April 3, 2017
Release Date: November 3, 2018


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Sunday, November 04, 2018

Saturn & Rhea | NASA Cassini Mission

Processed using calibrated red, green, and blue filtered images of Saturn and Rhea taken by the Cassini spacecraft on November 4, 2009.

Rhea is the second-largest moon of Saturn and the ninth-largest moon in the Solar System. It is the second smallest body in the Solar System—after the asteroid and dwarf planet Ceres—for which precise measurements have confirmed a shape consistent with hydrostatic equilibrium. It was discovered in 1672 by Giovanni Domenico Cassini.
(Source: Wikipedia)


The Cassini-Huygens mission was a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.

For more information about Cassini, go to:
https://www.nasa.gov/cassini
https://saturn.jpl.nasa.gov

Credit: NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill
Image Date: November 4, 2009
Release Date: November 4, 2018


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