Our Giant Universe: Hubble Spots Massive Galaxy Cluster With a Wealth of Exciting Possibilities

This detailed image features Abell 3827, a galaxy cluster that offers a wealth of exciting possibilities for study. It was observed by Hubble in order to study dark matter, which is one of the greatest puzzles cosmologists face today. The science team used Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) to complete their observations. The two cameras have different specifications and can observe different parts of the electromagnetic spectrum, so using them both allowed the astronomers to collect more complete information. Abell 3827 has also been observed previously by Hubble, because of the interesting gravitational lens at its core. Looking at this cluster of hundreds of galaxies, it is amazing to recall that until less than 100 years ago, many astronomers believed that the Milky Way was the only galaxy in the Universe. The possibility of other galaxies had been debated previously, but the matter was not truly settled until Edwin Hubble confirmed that the Great Andromeda Nebula was in fact far too distant to be part of the Milky Way. The Great Andromeda Nebula became the Andromeda Galaxy, and astronomers recognized that our Universe was much, much bigger than humanity had imagined. We can only imagine how Edwin Hubble — after whom the Hubble Space Telescope was named — would have felt if he’d seen this spectacular image of Abell 3827.

Hubble Team Releases Reprocessed Image of Veil Nebula

A small portion of the Veil Nebula, which is part of a supernova remnant called the Cygnus Loop, was featured in previous Hubble photos, but now new processing techniques have been applied, bringing out fine details of the Veil Nebula’s delicate threads and filaments of ionized gas. The Cygnus Loop is a large donut-shaped nebula located approximately 2,400 light-years away from Earth. Also known as W78 and Sharpless 103, it is actually an expanding blast wave from a supernova explosion that occurred about 15,000 years ago. Its name comes from its position in the northern constellation of Cygnus, where it covers an area 36 times larger than the full Moon. The visual portion of the supernova remnant is known as the Veil Nebula, also called the Cirrus Nebula or the Filamentary Nebula. “The nebula’s progenitor star — which was 20 times the mass of the Sun — lived fast and died young, ending its life in a cataclysmic release of energy,” Hubble astronomers said. “Despite this stellar violence, the shockwaves and debris from the supernova sculpted the nebula’s delicate tracery of ionized gas — creating a scene of surprising astronomical beauty.”

This Hubble image shows a small portion of the Veil Nebula, which is located 2,400 light-years away in the constellation of Cygnus. Image credit: NASA / ESA / Hubble / Z. Levay.

To create this colorful image, of the Veil Nebula observations taken by Hubble’s Wide Field Camera 3 (WFC3) instrument through five different filters were used.

The new post-processing methods have further enhanced details of emissions from doubly ionized oxygen (blue), ionized hydrogen and ionized nitrogen (red).

Astronomers Puzzled After Hubble View of Torrential Outflows From Infant Stars Blows Hole in Current Theories

Study Finds That Cavities Sculpted by Stellar Outflows Did Not Expand Over Time. Stars aren’t shy about announcing their births. As they are born from the collapse of giant clouds of hydrogen gas and begin to grow, they launch hurricane-like winds and spinning, lawn-sprinkler-style jets shooting off in opposite directions. This action carves out huge cavities in the giant gas clouds. Astronomers thought these stellar temper tantrums would eventually clear out the surrounding gas cloud, halting the star’s growth. But in a comprehensive analysis of 304 fledgling stars in the Orion Complex, the nearest major star-forming region to Earth, researchers discovered that gas-clearing by a star’s outflow may not be as important in determining its final mass as conventional theories suggest. Their study was based on previously collected data from NASA’s Hubble and Spitzer space telescopes and the European Space Agency’s Herschel Space Telescope. The study leaves astronomers still wondering why star formation is so inefficient. Only 30% of a hydrogen gas cloud’s initial mass winds up as a newborn star.

These four images taken by NASA’s Hubble Space Telescope reveal the chaotic birth of stars in the Orion complex, the nearest major star-forming region to Earth. The protostars were photographed in near-infrared light by Hubble’s Wide Field Camera 3. The images were taken November 14, 2009, and January 25, February 11, and August 11, 2010. Credit: NASA, ESA, STScI, N. Habel and S. T. Megeath (University of Toledo)

Though our galaxy is an immense city of at least 200 billion stars, the details of how they formed remain largely cloaked in mystery.

Scientists know that stars form from the collapse of huge hydrogen clouds that are squeezed under gravity to the point where nuclear fusion ignites. But only about 30 percent of the cloud’s initial mass winds up as a newborn star. Where does the rest of the hydrogen go during such a terribly inefficient process?

It has been assumed that a newly forming star blows off a lot of hot gas through light-saber-shaped outflowing jets and hurricane-like winds launched from the encircling disk by powerful magnetic fields. These fireworks should squelch further growth of the central star. But a new, comprehensive Hubble survey shows that this most common explanation doesn’t seem to work, leaving astronomers puzzled.

Researchers used data previously collected from NASA’s Hubble and Spitzer space telescopes and the European Space Agency’s Herschel Space Telescope to analyze 304 developing stars, called protostars, in the Orion Complex, the nearest major star-forming region to Earth. (Spitzer and Herschel are no longer operational.)

This ground-based image offers a wide view of the entire Orion cloud complex, the closest major star-forming region to Earth.
The red material is hydrogen gas ionized and heated by ultraviolet radiation from massive stars in Orion. The stars are forming in clouds of cold hydrogen gas that are either invisible or appear as dark regions in this image. The crescent shape is called Barnard’s Loop and partly wraps around the winter constellation figure of Orion the Hunter. The hunter’s belt is the diagonal chain of three stars at image center. His feet are the bright stars Saiph (bottom left) and Rigel (bottom right).
This landscape encompasses tens of thousands of newly forming stars bursting to life. Many are still encased in their natal cocoons of gas and dust and only seen in infrared light.
The undulating line of yellow dots, beginning at lower left, is a superimposed image of 304 nascent stars taken by NASA’s Hubble Space Telescope.
Researchers used NASA’s Hubble and Spitzer space telescopes and the European Space Agency’s Herschel Space Telescope to analyze how young stars’ powerful outflows carve out cavities in the vast gas clouds. The study is the largest-ever survey of developing stars.
Credit: Image courtesy of R. B. Andreo, DeepSkyColors.com; Data Overlay: NASA, ESA, STScI, N. Habel and S. T. Megeath (University of Toledo)

In this largest-ever survey of nascent stars to date, researchers are finding that gas — clearing by a star’s outflow may not be as important in determining its final mass as conventional theories suggest. The researchers’ goal was to determine whether stellar outflows halt the infall of gas onto a star and stop it from growing.

Instead, they found that the cavities in the surrounding gas cloud sculpted by a forming star’s outflow did not grow regularly as they matured, as theories propose.

“In one stellar formation model, if you start out with a small cavity, as the protostar rapidly becomes more evolved, its outflow creates an ever-larger cavity until the surrounding gas is eventually blown away, leaving an isolated star,” explained lead researcher Nolan Habel of the University of Toledo in Ohio.

“Our observations indicate there is no progressive growth that we can find, so the cavities are not growing until they push out all of the mass in the cloud. So, there must be some other process going on that gets rid of the gas that doesn’t end up in the star.”

The team’s results will appear in an upcoming issue of The Astrophysical Journal.

A Star is Born

During a star’s relatively brief birthing stage, lasting only about 500,000 years, the star quickly bulks up on mass. What gets messy is that, as the star grows, it launches a wind, as well as a pair of spinning, lawn-sprinkler-style jets shooting off in opposite directions. These outflows begin to eat away at the surrounding cloud, creating cavities in the gas.

Popular theories predict that as the young star evolves and the outflows continue, the cavities grow wider until the entire gas cloud around the star is completely pushed away. With its gas tank empty, the star stops accreting mass – in other words, it stops growing.

These four images taken by NASA’s Hubble Space Telescope reveal the chaotic birth of stars in the Orion complex, the nearest major star-forming region to Earth. The protostars were photographed in near-infrared light by Hubble’s Wide Field Camera 3. Credit: NASA, ESA, STScI, N. Habel and S. T. Megeath (University of Toledo)

To look for cavity growth, the researchers first sorted the protostars by age by analyzing Herschel and Spitzer data of each star’s light output. The protostars in the Hubble observations were also observed as part of the Herschel telescope’s Herschel Orion Protostar Survey.

Then the astronomers observed the cavities in near-infrared light with Hubble’s Near-infrared Camera and Multi-object Spectrometer and Wide Field Camera 3. The observations were taken between 2008 and 2017. Although the stars themselves are shrouded in dust, they emit powerful radiation which strikes the cavity walls and scatters off dust grains, illuminating the gaps in the gaseous envelopes in infrared light.

The Hubble images reveal the details of the cavities produced by protostars at various stages of evolution. Habel’s team used the images to measure the structures’ shapes and estimate the volumes of gas cleared out to form the cavities. From this analysis, they could estimate the amount of mass that had been cleared out by the stars’ outbursts.

“We find that at the end of the protostellar phase, where most of the gas has fallen from the surrounding cloud onto the star, a number of young stars still have fairly narrow cavities,” said team member Tom Megeath of the University of Toledo. “So, this picture that is still commonly held of what determines the mass of a star and what halts the infall of gas is that this growing outflow cavity scoops up all of the gas. This has been pretty fundamental to our idea of how star formation proceeds, but it just doesn’t seem to fit the data here.”

Future telescopes such as NASA’s upcoming James Webb Space Telescope will probe deeper into a protostar’s formation process. Webb spectroscopic observations will observe the inner regions of disks surrounding protostars in infrared light, looking for jets in the youngest sources. Webb also will help astronomers measure the accretion rate of material from the disk onto the star, and study how the inner disk is interacting with the outflow.

Reference: “An HST Survey of Protostellar Outflow Cavities: Does Feedback Clear Envelopes?” by Nolan M. Habel, S. Thomas Megeath, Joseph Jon Booker, William J. Fischer, Marina Kounkel, Charles Poteet, Elise Furlan, Amelia Stutz, P. Manoj, John J. Tobin, Zsofia Nagy, Riwaj Pokhrel and Dan Watson, Accepted, The Astrophysical Journal.

JADES will go deeper than the Hubble Deep Fields

Astronomers announced this month that a new deep-field survey called JADES will be carried out with the James Webb Space Telescope, Hubble’s much-anticipated successor. The Webb is due to launch later this year. Astronomers announced a new deeper-than-ever sky survey this month (January 15, 2021), to be conducted with the James Webb Space Telescope, the Hubble telescope’s successor, scheduled for launch in October of this year. The new survey is abbreviated JADES, which is short for James Webb Space Telescope Advanced Deep Extragalactic Survey. The survey will be like the Hubble Deep Fields, but deeper still. Its main goal is to see far away in space – and thus far back into the very young universe – and image it just at the end of the so-called Cosmic Dark Ages, that is, at the time when gas in the universe went from being opaque to transparent. This is also the time when the very first stars were forming – very large, massive and bright stars – in a veritable firestorm of star birth when the young universe was less than 5% of its current age. The Webb telescope will be located near the second Lagrange point – a relatively stable region of space, gravitationally speaking, known as L2 – some 930,000 miles (1.5 million km) from Earth. To conduct the new survey, the Webb telescope will be staring at a small point of space for nearly 800 hours (approximately 33 days) to be able to see fainter objects than those ever seen before and thus to find the first generation of galaxies. Astronomers want to know, among other things, how fast did these galaxies form, and how fast did their stars form? They also want to look for the very first supermassive black holes, which are thought to lie at the hearts of nearly all large galaxies, including our Milky Way.

The Hubble Ultra Deep Field (in its eXtreme version) is the deepest view of the universe yet obtained … and will be, until JADES takes over. It stretches approximately 13 billion light-years and includes approximately 10,000 galaxies. It took 11.3 days for the Hubble Space Telescope to collect these ancient photons. Try downloading the largest version and zoom in on different sections. We’re seeing these galaxies as they were billions of years ago. How might they look today? Image via NASA/ ESA/ S. Beckwith (STSci)/ HUDF team.

The long-anticipated launch of the James Webb Space Telescope has been postponed a number of times for a variety of reasons, most recently because of effects of the Covid-19 pandemic. It is the formal successor to the Hubble Space Telescope, but is equipped with instrumentation able to image further into the infrared part of the electromagnetic spectrum than Hubble could.

This capability also makes it a worthy successor to the infrared Spitzer Space Telescope which recently went into retirement.

What makes the infrared part of the spectrum so important for surveys like JADES? If you look really deep, you will also look back in time, and the farther back in time you look, the more redshifted the galaxies are (the farther away they are, the faster they move away from us, and the more their light has been shifted towards the red part of the spectrum). This means that the light we want to observe, originally in the optical (visible) part of the electromagnetic spectrum, might not even show much in the optical part anymore. Instead, it’s been shifted to longer wavelengths, into the infrared regime.

In other words, the use of infrared cameras is necessary to be able to see the light from the first generation of galaxies. Daniel Eisenstein, a professor of astronomy at Harvard University, said:

Galaxies, we think, begin building up in the first billion years after the Big Bang, and sort of reach adolescence at 1 to 2 billion years. We’re trying to investigate those early periods. We must do this with an infrared-optimized telescope because the expansion of the universe causes light to increase in wavelength as it traverses the vast distance to reach us. So even though the stars are emitting light primarily in optical and ultraviolet wavelengths, that light is shifted quite relentlessly out into the infrared. Only Webb can get to the depth and sensitivity that’s needed to study these early galaxies.

In fact, the James Webb Space Telescope was built specifically for this purpose. Up to now, infrared images are much less resolved – less clear – than optical images, because of their longer wavelength. With its much larger collecting area, the Webb will be able to image, in infrared, at the same resolution – detail – that Hubble could obtain in the optical part of the spectrum.

Get ready for a whole new set of mind-blowing images of the universe, this time in the infrared, from Webb!

After having successfully deployed its solar panels – precisely as it’s supposed to do once it’s in space – the Webb telescope is shown here ready for the final tests on December 17, 2020, at NASA’s Goddard Space Flight Center. Then it will be packed up and transported to French Guyana, to be launched on October 31, 2021, via an Ariane V rocket. Image via NASA/ Chris Gunn.

The use of deep field surveys is a young science, for two reasons. First, astronomers didn’t have the right instrumentation before Hubble to do them. Second, it’s also because no one initially knew the result of staring into a piece of empty space for a long time. Such a long stare into the unknown would require valuable observation time, and if this long observation didn’t produce any results, it would be considered a waste.

But in 1995, Robert Williams, then the director of the Space Telescope Science Institute (STSci), which administrates the Hubble telescope, decided to use his “director’s discretionary time” to point the Hubble toward a very small and absolutely empty-looking part of the sky in the direction of the constellation Ursa Major the Great Bear. There were no stars visible from our Milky Way (or extremely few), no nearby galaxies visible in the field, and no visible gas clouds. Hubble collected photons for 10 consecutive days, and the result, the Hubble Deep Field, was a success and a paradigm changer: A patch of sky about as small as the eye of George Washington on an American quarter (25-cent coin) held out at arm’s length, showed a 10 billion-light-years-long tunnel back in time with a plethora of galaxies – around 3,000 of them – at different evolutionary stages along the way. The field of observational cosmology was born.

This was done again in 1998 with the Hubble telescope pointed to the southern sky (Hubble Deep Field South), and the result was the same. Thus we learned that the universe is uniform over large scales.

Next was the installation of a new, powerful camera on Hubble (the Advanced Camera for Surveys) in 2002. The incredible Hubble Ultra Deep Field was acquired in 2004, in a similarly small patch of sky near the constellation Orion, about 1/10 of a full moon diameter (2.4 x 3.4 arc minutes, in contrast to the original Hubble Deep Fields north and south, which were 2.6 x 2.6 arc minutes). And so our reach was extended even deeper into space, and even further back in time, showing light from 10 thousand galaxies along a 13-billion-light-years-long tunnel of space. If you’ll remember that the universe is about 13.77 billion years old, you’ll see this is getting us really close to the beginning!

The Hubble Ultra Deep Field was the most sensitive astronomical image ever made at wavelengths of visible (optical) light until 2012, when an even more refined version was released, called the Hubble eXtreme Deep Field, which reached even farther: 13.2 billion years back in time.

The JADES survey will be observed in two batches, one on the northern sky and one on the southern in two famous fields called GOODS North and South (abbreviated from Great Observatories Origins Deep Survey).

Marcia Rieke, a professor of astronomy at the University of Arizona who co-leads the JADES Team with Pierre Ferruit of the European Space Agency (ESA), explained:

We chose these fields because they have such a great wealth of supporting information. They’ve been studied at many other wavelengths, so they were the logical ones to do.

Look closely. Every single speck of light in this image is a distant galaxy (except for the very few ones with spikes which are foreground stars). This telescopic field of view is part of the GOODS South field. It’s one of the directions in space that’ll be observed in JADES, a new survey that aims to study the very first galaxies to appear in the infancy of the universe. Image via NASA/ Hubble Space Telescope/ James Webb Space Telescope site.

The GOODS fields have been observed with several of the most famous telescopes, covering a great wavelength range from infrared through optical to X-ray. They are not fully as deep (the observations don’t reach as far back) as the Ultra Deep Field, but cover a larger area of the sky (4-5 times larger) and are the most data-rich areas of the sky in terms of depth combined with wavelength coverage. By the way, the first deep field, HDF-N, is located in the GOODS north image, and the Ultra deep field/eXtreme (don’t you love these names?) is located in the GOODS south field.

There are a large number of ambitious science goals for the JADES program pertaining to the composition of the first galaxies, including the first generation of supermassive black holes. How these came about at such an early time is a mystery. As well, the transition of gas from neutral and opaque to transparent and ionized, something astronomers call the epoch of reionization, is not well understood. JADES team member Andrew Bunker, professor of astrophysics at the University of Oxford in the United Kingdom, who is also part of the ESA team behind the Webb telescope, said:

This transition is a fundamental phase change in the nature of the universe. We want to understand what caused it. It could be that it’s the light from very early galaxies and the first burst of star formation … It is kind of one of the Holy Grails, to find the so-called Population III stars that formed from the hydrogen and helium of the Big Bang.

People have been trying to do this for many decades and results have been inconclusive so far.

Magnetic Monster? NASA’s Hubble Sees Unexplained Brightness from Colossal Explosion

In our infinite universe, stars can go bump in the night. When this happens between a pair of burned-out, crushed stars called neutron stars, the resulting fireworks show, called a kilonova, is beyond comprehension. The energy unleashed by the collision briefly glows 100 million times brighter than our Sun. What’s left from the smashup? Typically an even more crushed object called a black hole. But in this case Hubble found forensic clues to something even stranger happening after the head-on collision. The intense flood of gamma-rays signaling astronomers to this event has been seen before in other stellar smashups. But something unexpected popped up in Hubble’s near-infrared vision. Though a gusher of radiation from the aftermath of the explosion—stretching from X-rays to radio waves—seemed typical, the outpouring of infrared radiation was not. It was 10 times brighter than predicted for kilonovae. Without Hubble, the gamma-ray burst would have appeared like many others, and scientists would not have known about the bizarre infrared component. The most plausible explanation is that the colliding neutron stars merged to form a more massive neutron star. It’s like smashing two Volkswagen Beetles together and getting a limousine. This new beast sprouted a powerful magnetic field, making it a unique class of object called a magnetar. The magnetar deposited energy into the ejected material, causing it to glow even more brightly in infrared light than predicted. 

Magnetar-Powered Kilonova Blast. Credit: NASA, ESA, and D. Player (STScI)

(If a magnetar flew within 100,000 miles of Earth, its intense magnetic field would erase the data on every credit card on our planet!)

This image shows the glow from a kilonova caused by the merger of two neutron stars. The kilonova, whose peak brightness reaches up to 10,000 times that of a classical nova, appears as a bright spot (indicated by the arrow) to the upper left of the host galaxy. The merger of the neutron stars is believed to have produced a magnetar, which has an extremely powerful magnetic field. The energy from that magnetar brightened the material ejected from the explosion. Credit: NASA, ESA, W. Fong (Northwestern University), and T. Laskar (University of Bath, UK)

Long ago and far across the universe, an enormous burst of gamma rays unleashed more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. In May of 2020, light from the flash finally reached Earth and was first detected by NASA’s Neil Gehrels Swift Observatory. Scientists quickly enlisted other telescopes — including NASA’s Hubble Space Telescope, the Very Large Array radio observatory, the W. M. Keck Observatory, and the Las Cumbres Observatory Global Telescope network — to study the explosion’s aftermath and the host galaxy. It was Hubble that provided the surprise.

Based on X-ray and radio observations from the other observatories, astronomers were baffled by what they saw with Hubble: the near-infrared emission was 10 times brighter than predicted. These results challenge conventional theories of what happens in the aftermath of a short gamma-ray burst. One possibility is that the observations might point to the birth of a massive, highly magnetized neutron star called a magnetar.

“These observations do not fit traditional explanations for short gamma-ray bursts,” said study leader Wen-fai Fong of Northwestern University in Evanston, Illinois. “Given what we know about the radio and X-rays from this blast, it just doesn’t match up. The near-infrared emission that we’re finding with Hubble is way too bright. In terms of trying to fit the puzzle pieces of this gamma-ray burst together, one puzzle piece is not fitting correctly.”

Without Hubble, the gamma-ray burst would have appeared like many others, and Fong and her team would not have known about the bizarre infrared behavior. “It’s amazing to me that after 10 years of studying the same type of phenomenon, we can discover unprecedented behavior like this,” said Fong. “It just reveals the diversity of explosions that the universe is capable of producing, which is very exciting.”

Light Fantastic

The intense flashes of gamma rays from these bursts appear to come from jets of material that are moving extremely close to the speed of light. The jets do not contain a lot of mass — maybe a millionth of the mass of the Sun — but because they’re moving so fast, they release a tremendous amount of energy across all wavelengths of light. This particular gamma-ray burst was one of the rare instances in which scientists were able to detect light across the entire electromagnetic spectrum.

This illustration shows the sequence for forming a magnetar-powered kilonova, whose peak brightness reaches up to 10,000 times that of a classical nova. 1) Two orbiting neutron stars spiral closer and closer together. 2) They collide and merge, triggering an explosion that unleashes more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. 3) The merger forms an even more massive neutron star called a magnetar, which has an extraordinarily powerful magnetic field. 4) The magnetar deposits energy into the ejected material, causing it to glow unexpectedly bright at infrared wavelengths. Credit: NASA, ESA, and D. Player (STScI)

“As the data were coming in, we were forming a picture of the mechanism that was producing the light we were seeing,” said the study’s co-investigator, Tanmoy Laskar of the University of Bath in the United Kingdom. “As we got the Hubble observations, we had to completely change our thought process, because the information that Hubble added made us realize that we had to discard our conventional thinking, and that there was a new phenomenon going on. Then we had to figure out what that meant for the physics behind these extremely energetic explosions.”

Gamma-ray bursts — the most energetic, explosive events known — live fast and die hard. They are split into two classes based on the duration of their gamma rays.

If the gamma-ray emission is greater than two seconds, it’s called a long gamma-ray burst. This event is known to result directly from the core collapse of a massive star. Scientists expect a supernova to accompany this longer type of burst.

If the gamma-ray emission lasts less than two seconds, it’s considered a short burst. This is thought to be caused by the merger of two neutron stars, extremely dense objects about the mass of the Sun compressed into the volume of a city. A neutron star is so dense that on Earth, one teaspoonful would weigh a billion tons! A merger of two neutron stars is generally thought to produce a black hole.

These two images taken on May 26 and July 16, 2020, show the fading light of a kilonova located in a distant galaxy. The kilonova appears as a spot to the upper left of the host galaxy. The glow is prominent in the May 26 image but fades in the July 16 image. The kilonova’s peak brightness reaches up to 10,000 times that of a classical nova. A merger of two neutron stars—the source of the kilonova—is believed to have produced a magnetar, which has an extremely powerful magnetic field. The energy from that magnetar brightened the material ejected from the explosion, causing it to become unusually bright at infrared wavelengths of light. Credit: NASA, ESA, W. Fong (Northwestern University), T. Laskar (University of Bath, UK) and A. Pagan (STScI)

Neutron star mergers are very rare but are extremely important because scientists think that they are one of the main sources of heavy elements in the universe, such as gold and uranium.

Accompanying a short gamma-ray burst, scientists expect to see a “kilonova” whose peak brightness typically reaches 1,000 times that of a classical nova. Kilonovae are an optical and infrared glow from the radioactive decay of heavy elements and are unique to the merger of two neutron stars, or the merger of a neutron star with a small black hole.

Magnetic Monster?

Fong and her team have discussed several possibilities to explain the unusual brightness that Hubble saw. While most short gamma-ray bursts probably result in a black hole, the two neutron stars that merged in this case may have combined to form a magnetar, a supermassive neutron star with a very powerful magnetic field.

“You basically have these magnetic field lines that are anchored to the star that are whipping around at about a thousand times a second, and this produces a magnetized wind,” explained Laskar. “These spinning field lines extract the rotational energy of the neutron star formed in the merger, and deposit that energy into the ejecta from the blast, causing the material to glow even brighter.”

This animation shows the sequence for forming a magnetar-powered kilonova, whose peak brightness reaches up to 10,000 times that of a classical nova. In this sequence, two orbiting neutron stars spiral closer and closer together before colliding and merging. This triggers an explosion that unleashes more energy in a half-second than the Sun will produce over its entire 10-billion-year lifetime. The merger forms an even more massive neutron star called a magnetar, which has an extraordinarily powerful magnetic field. The magnetar deposits energy into the ejected material, causing it to glow unexpectedly bright at infrared wavelengths. Credit: NASA, ESA, and D. Player (STScI)

If the extra brightness came from a magnetar that deposited energy into the kilonova material, then within a few years, the team expects the ejecta from the burst to produce light that shows up at radio wavelengths. Follow-up radio observations may ultimately prove that this was a magnetar, and this may explain the origin of such objects.

“With its amazing sensitivity at near-infrared wavelengths, Hubble really sealed the deal with this burst,” explained Fong. “Amazingly, Hubble was able to take an image only three days after the burst. Through a series of later images, Hubble showed that a source faded in the aftermath of the explosion. This is as opposed to being a static source that remains unchanged. With these observations, we knew we had not only nabbed the source, but we had also discovered something extremely bright and very unusual. Hubble’s angular resolution was also key in pinpointing the position of the burst and precisely measuring the light coming from the merger.”

NASA’s upcoming James Webb Space Telescope is particularly well-suited for this type of observation. “Webb will completely revolutionize the study of similar events,” said Edo Berger of Harvard University in Cambridge, Massachusetts, and principal investigator of the Hubble program. “With its incredible infrared sensitivity, it will not only detect such emission at even larger distances, but it will also provide detailed spectroscopic information that will resolve the nature of the infrared emission.”

The team’s findings appear in an upcoming issue of The Astrophysical Journal.

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.

New Clues About How Ancient Galaxies Lit up the Universe

NASA's Spitzer Space Telescope has revealed that some of the universe's earliest galaxies were brighter than expected. The excess light is a byproduct of the galaxies releasing incredibly high amounts of ionizing radiation. The finding offers clues to the cause of the Epoch of Reionization, a major cosmic event that transformed the universe from being mostly opaque to the brilliant starscape seen today. In a new study, researchers report on observations of some of the first galaxies to form in the universe, less than 1 billion years after the big bang (or a little more than 13 billion years ago). The data show that in a few specific wavelengths of infrared light, the galaxies are considerably brighter than scientists anticipated. The study is the first to confirm this phenomenon for a large sampling of galaxies from this period, showing that these were not special cases of excessive brightness, but that even average galaxies present at that time were much brighter in these wavelengths than galaxies we see today. No one knows for sure when the first stars in our universe burst to life. But evidence suggests that between about 100 million and 200 million years after the big bang, the universe was filled mostly with neutral hydrogen gas that had perhaps just begun to coalesce into stars, which then began to form the first galaxies. By about 1 billion years after the big bang, the universe had become a sparkling firmament. Something else had changed, too: Electrons of the omnipresent neutral hydrogen gas had been stripped away in a process known as ionization. The Epoch of Reionization - the changeover from a universe full of neutral hydrogen to one filled with ionized hydrogen - is well documented.

Before this universe-wide transformation, long-wavelength forms of light, such as radio waves and visible light, traversed the universe more or less unencumbered. But shorter wavelengths of light - including ultraviolet light, X-rays and gamma rays - were stopped short by neutral hydrogen atoms. These collisions would strip the neutral hydrogen atoms of their electrons, ionizing them.

But what could have possibly produced enough ionizing radiation to affect all the hydrogen in the universe? Was it individual stars? Giant galaxies? If either were the culprit, those early cosmic colonizers would have been different than most modern stars and galaxies, which typically don't release high amounts of ionizing radiation. Then again, perhaps something else entirely caused the event, such as quasars - galaxies with incredibly bright centers powered by huge amounts of material orbiting supermassive black holes.

"It's one of the biggest open questions in observational cosmology," said Stephane De Barros, lead author of the study and a postdoctoral researcher at the University of Geneva in Switzerland. "We know it happened, but what caused it? These new findings could be a big clue."

Looking for Light

To peer back in time to the era just before the Epoch of Reionization ended, Spitzer stared at two regions of the sky for more than 200 hours each, allowing the space telescope to collect light that had traveled for more than 13 billion years to reach us.

As some of the longest science observations ever carried out by Spitzer, they were part of an observing campaign called GREATS, short for GOODS Re-ionization Era wide-Area Treasury from Spitzer. GOODS (itself an acronym: Great Observatories Origins Deep Survey) is another campaign that performed the first observations of some GREATS targets. The study, published in the Monthly Notices of the Royal Astronomical Society, also used archival data from NASA's Hubble Space Telescope.

Using these ultra-deep observations by Spitzer, the team of astronomers observed 135 distant galaxies and found that they were all particularly bright in two specific wavelengths of infrared light produced by ionizing radiation interacting with hydrogen and oxygen gases within the galaxies. This implies that these galaxies were dominated by young, massive stars composed mostly of hydrogen and helium. They contain very small amounts of "heavy" elements (like nitrogen, carbon and oxygen) compared to stars found in average modern galaxies.

These stars were not the first stars to form in the universe (those would have been composed of hydrogen and helium only) but were still members of a very early generation of stars. The Epoch of Reionization wasn't an instantaneous event, so while the new results are not enough to close the book on this cosmic event, they do provide new details about how the universe evolved at this time and how the transition played out.

"We did not expect that Spitzer, with a mirror no larger than a Hula-Hoop, would be capable of seeing galaxies so close to the dawn of time," said Michael Werner, Spitzer's project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California. "But nature is full of surprises, and the unexpected brightness of these early galaxies, together with Spitzer's superb performance, puts them within range of our small but powerful observatory."

NASA's James Webb Space Telescope, set to launch in 2021, will study the universe in many of the same wavelengths observed by Spitzer. But where Spitzer's primary mirror is only 85 centimeters (33.4 inches) in diameter, Webb's is 6.5 meters (21 feet) - about 7.5 times larger - enabling Webb to study these galaxies in far greater detail. In fact, Webb will try to detect light from the first stars and galaxies in the universe. The new study shows that due to their brightness in those infrared wavelengths, the galaxies observed by Spitzer will be easier for Webb to study than previously thought.

"These results by Spitzer are certainly another step in solving the mystery of cosmic reionization," said Pascal Oesch, an assistant professor at the University of Geneva and a co-author on the study. "We now know that the physical conditions in these early galaxies were very different than in typical galaxies today. It will be the job of the James Webb Space Telescope to work out the detailed reasons why."

Hubble in Safe Mode as Gyro Issues are Diagnosed

NASA is working to resume science operations of the Hubble Space Telescope after the spacecraft entered safe mode on Friday, October 5, shortly after 6:00 p.m. EDT. Hubble's instruments still are fully operational and are expected to produce excellent science for years to come. Hubble entered safe mode after one of the three gyroscopes (gyros) actively being used to point and steady the telescope failed. Safe mode puts the telescope into a stable configuration until ground control can correct the issue and return the mission to normal operation. Built with multiple redundancies, Hubble had six new gyros installed during Servicing Mission-4 in 2009. Hubble usually uses three gyros at a time for maximum efficiency, but can continue to make scientific observations with just one. The gyro that failed had been exhibiting end-of-life behavior for approximately a year, and its failure was not unexpected; two other gyros of the same type had already failed. The remaining three gyros available for use are technically enhanced and therefore expected to have significantly longer operational lives.Two of those enhanced gyros are currently running. Upon powering on the third enhanced gyro that had been held in reserve, analysis of spacecraft telemetry indicated that it was not performing at the level required for operations.

As a result, Hubble remains in safe mode. Staff at NASA's Goddard Space Flight Center and the Space Telescope Science Institute are currently performing analyses and tests to determine what options are available to recover the gyro to operational performance.

Science operations with Hubble have been suspended while NASA investigates the anomaly. An Anomaly Review Board, including experts from the Hubble team and industry familiar with the design and performance of this type of gyro, is being formed to investigate this issue and develop the recovery plan. If the outcome of this investigation results in recovery of the malfunctioning gyro, Hubble will resume science operations in its standard three-gyro configuration.

If the outcome indicates that the gyro is not usable, Hubble will resume science operations in an already defined "reduced-gyro" mode that uses only one gyro. While reduced-gyro mode offers less sky coverage at any particular time, there is relatively limited impact on the overall scientific capabilities.

Astronomers find first evidence of possible moon outside our Solar System

Using NASA's Hubble and Kepler space telescopes, astronomers have uncovered tantalizing evidence of what could be the first discovery of a moon orbiting a planet outside our solar system. This moon candidate, which is 8,000 light-years from Earth in the Cygnus constellation, orbits a gas-giant planet that, in turn, orbits a star called Kepler-1625. Researchers caution that the moon hypothesis is tentative and must be confirmed by follow-up Hubble observations. "This intriguing finding shows how NASA's missions work together to uncover incredible mysteries in our cosmos," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate at Headquarters, Washington. "If confirmed, this finding could completely shake up our understanding of how moons are formed and what they can be made of." Since moons outside our solar system - known as exomoons - cannot be imaged directly, their presence is inferred when they pass in front of a star, momentarily dimming its light. Such an event is called a transit, and has been used to detect many of the exoplanets cataloged to date. However, exomoons are harder to detect than exoplanets because they are smaller than their companion planet, and so their transit signal is weaker when plotted on a light curve that measures the duration of the planet crossing and the amount of momentary dimming. Exomoons also shift position with each transit because the moon is orbiting the planet.

In search of exomoons, Alex Teachey and David Kipping, astronomers at Columbia University in New York, analyzed data from 284 Kepler-discovered planets that were in comparatively wide orbits, longer than 30 days, around their host star. The researchers found one instance in planet Kepler-1625b, of a transit signature with intriguing anomalies, suggesting the presence of a moon.

"We saw little deviations and wobbles in the light curve that caught our attention," Kipping said.

Based upon their findings, the team spent 40 hours making observations with Hubble to study the planet intensively - also using the transit method - obtaining more precise data on the dips of light. Scientists monitored the planet before and during its 19-hour transit across the face of the star. After the transit ended, Hubble detected a second, and much smaller, decrease in the star's brightness approximately 3.5 hours later. This small decrease is consistent with a gravitationally-bound moon trailing the planet, much like a dog following after its owner. Unfortunately, the scheduled Hubble observations ended before the complete transit of the candidate moon could be measured and its existence confirmed.

In addition to this dip in light, Hubble provided supporting evidence for the moon hypothesis by finding the planet transit occurring more than an hour earlier than predicted. This is consistent with a planet and moon orbiting a common center of gravity that would cause the planet to wobble from its predicted location, much the way Earth wobbles as our Moon orbits it.

The researchers note the planetary wobble could be caused by the gravitational pull of a hypothetical second planet in the system, rather than a moon. While Kepler has not detected a second planet in the system, it could be that the planet is there, but not detectable using Kepler's techniques.

"A companion moon is the simplest and most natural explanation for the second dip in the light curve and the orbit-timing deviation," Kipping explained. "It was definitely a shocking moment to see that Hubble light curve, my heart started beating a little faster as I kept looking at that signature. But we knew our job was to keep a level head and essentially assume it was bogus, testing every conceivable way in which the data could be tricking us."

In a paper published in the journal Science Advances, the scientists report the candidate moon is unusually large - potentially comparable to Neptune. Such large moons do not exist in our own solar system. The researchers say this may yield new insights into the development of planetary systems and may cause experts to revisit theories of how moons form around planets.

The moon candidate is estimated to be only 1.5 percent the mass of its companion planet, and the planet is estimated to be several times the mass of Jupiter. This mass-ratio is similar to the one between Earth and the Moon. In the case of the Earth-Moon system and the Pluto-Charon system, the moons are thought to be created through dust leftover after rocky planetary collisions. However, Kepler-1625b and its possible satellite are gaseous and not rocky, so the moon may have formed through a different process.

Researchers note that if this is indeed a moon, both it and its host planet lie within their star's habitable zone, where moderate temperatures allow for the existence of liquid water on any solid planetary surface. However, both bodies are considered to be gaseous and, therefore, unsuitable for life as we know it.

Future searches for exomoons, in general, will target Jupiter-size planets that are farther from their star than Earth is from the Sun. The ideal candidate planets hosting moons are in wide orbits, with long and infrequent transit times. In this search, a moon would have been among the easiest to detect because of its large size. Currently, there are just a handful of such planets in the Kepler database. Whether future observations confirm the existence of the Kepler-1625b moon, NASA's James Webb Space Telescope will be used to find candidate moons around other planets, with much greater detail than Kepler.

"We can expect to see really tiny moons with Webb," Teachey said.

'Red and dead' NGC 1277 offers insights on the early universe

New analysis of a "relic galaxy" promises insights into the nature of the early universe. Formed some 12 billion years ago, the NGC 1277 galaxy birthed all of its stars within a span of 100 million years -- a star formation rate 1,000 times greater than that of the Milky Way. But nearly as quickly as the galaxy sprang to life, it died out. For the last 10 billion years, NGC 1277 has remained unchanged -- a relic of an earlier time in galactic evolution. To better understand the dynamics of the early universe, scientists used the Hubble Space Telescope to study NGC 1277. The lenticular galaxy is what's known as a "red and dead" galaxy. Most dead and red galaxies are found in the distant universe, too far away to be imaged in great detail. But at 240 million light-years away from Earth, NGC 1277 is close enough to offer insights. Most galaxies feature both red globular clusters, full of metal-rich stars, and blue clusters, globs of metal-poor stars. Models of galactic evolution suggest red clusters form during the earliest stages of a galaxy's formation, with blue clusters acquired later as new star forming material is pulled from the galaxy's surroundings. The lack of blue globular clusters is a sign that a galaxy stopped evolving -- that it is in a "state of arrested development."

Red and dead galaxies host mostly red clusters. NGC 1277 has only red clusters.

"I've been studying globular clusters in galaxies for a long time, and this is the first time I've ever seen this," Michael Beasley, a researcher with the Astrophysics Institute of the Canary Islands, said in a news release.

Scientists believe the massive black hole at the center of NGC 1277 grew quickly, pulling in stellar materials at a prodigious rate, inspiring the formation of the galaxy. But it's development stopped suddenly when it ran out of stellar material. As a result, the galaxy hosts a massive stellar popular but is extremely compact.

NGC 1277 is surrounded by other galaxies from which it could steal new material, but the latest Hubble findings show it is moving too fast to merge with other galaxies or acquire significant amounts of debris.

Described this week in the journal Nature, NGC 1277 is just one of 50 dense, compact relic galaxies identified by the Sloan Digital Sky Survey. Scientists hope future surveys of similar candidates will help astronomers better understand the nuances of galactic evolution in the early universe.

Scientists also hope newer, more powerful telescopes will help them study the role of dark matter in the formation and evolution of oddball galaxies like NGC 1277.

Hubble Delivers First Insight Into Atmospheres Of Potentially Habitable Planets Orbiting Trappist-1

An international team of astronomers has used the NASA/ESA Hubble Space Telescope to look for atmospheres around four Earth-sized planets orbiting within or near TRAPPIST-1's habitable zone. The new results further support the terrestrial and potentially habitable nature of three of the studied planets. The results are published in Nature Astronomy. Seven Earth-sized planets orbit the ultracool dwarf star TRAPPIST-1, 40 light-years away from the Earth. This makes TRAPPIST-1 the planetary system with the largest number of Earth-sized planets discovered so far. These planets are also relatively temperate, making them a tantalizing place to search for signs of life beyond our Solar System. Now, an international team of astronomers has presented a study in which they used the NASA/ESA Hubble Space Telescope to screen four planets in the system - TRAPPIST-1d, e, f and g - to study their atmospheres. Three of the planets orbit within the system's habitable zone, the region at a distance from the star where liquid water - the key to life as we know it - could exist on the surface of a planet. The fourth planet orbits in a borderline region at the inner edge of the habitable zone. The data obtained rule out a cloud-free hydrogen-rich atmosphere for three of the planets - but for the fourth planet, TRAPPIST-1g, such an atmosphere could not be excluded.

Lead author Julien de Wit, from the Massachusetts Institute of Technology, USA, describes the positive implications of these measurements: "The presence of puffy, hydrogen-dominated atmospheres would have indicated that these planets are more likely gaseous worlds like Neptune. The lack of hydrogen in their atmospheres further supports theories about the planets being terrestrial in nature. This discovery is an important step towards determining if the planets might harbour liquid water on their surfaces, which could enable them to support living organisms."

The observations were made while the planets were in transit in front of TRAPPIST-1. In this configuration a small section of the star's light passes through the atmosphere of the exoplanet and interacts with the atoms and molecules in it. This leaves a weak fingerprint of the atmosphere in the spectrum of the star.

While the results rule out one type of atmosphere, many alternative atmospheric scenarios are still consistent with the data gathered by de Wit and his team. The exoplanets may possess a range of atmospheres, just like the terrestrial planets in our Solar System.

"Our results demonstrate Hubble's ability to study the atmospheres of Earth-sized planets. But the telescope is really working at the limit of what it can do," adds co-author Hannah Wakeford from the Space Telescope Science Institute, illustrating both the power and limitation of Hubble.

These latest findings complement the analysis of ultraviolet observations made with Hubble in 2017 (heic1713) and help us understand more about whether life might be possible in the TRAPPIST-1 system.

By ruling out the presence of a large abundance of hydrogen in the planets' atmospheres, Hubble is helping to pave the way for the NASA/ESA/CSA James Webb Space Telescope.

"Spectroscopic observations of the TRAPPIST-1 planets with the next generation of telescopes - including the James Webb Space Telescope - will allow us to probe deeper into their atmospheres," concludes Michael Gillon, from the University of Liege, Belgium.

"This will allow us to search for heavier gases such as carbon, methane, water, and oxygen, which could offer biosignatures for life."

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

By combining the power of a "natural lens" in space with the capability of NASA's Hubble Space Telescope, astronomers made a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang. Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, say researchers. When Hubble photographed the galaxy, astronomers expected to see a chaotic ball of stars formed through galaxies merging together. Instead, they saw evidence that the stars were born in a pancake-shaped disk.

Acting as a “natural telescope” in space, the gravity of the extremely massive foreground galaxy cluster MACS J2129-0741 magnifies, brightens, and distorts the far-distant background galaxy MACS2129-1, shown in the top box. The middle box is a blown-up view of the gravitationally lensed galaxy. In the bottom box is a reconstructed image, based on modeling that shows what the galaxy would look like if the galaxy cluster were not present. The galaxy appears red because it is so distant that its light is shifted into the red part of the spectrum.

Credits: NASA, ESA, S. Toft (University of Copenhagen), M. Postman (STScI), and the CLASH team

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

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

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

This artist's concept shows what the young, dead, disk galaxy MACS2129-1, right, would look like when compared with the Milky Way galaxy, left. Although three times as massive as the Milky Way, it is only half the size. MACS2129-1 is also spinning more than twice as fast as the Milky Way. Note that regions of Milky Way are blue from bursts of star formation, while the young, dead galaxy is yellow, signifying an older star population and no new star birth.

Credits: NASA, ESA, and Z. Levy (STScI)

Previous studies of distant dead galaxies have assumed that their structure is similar to the local elliptical galaxies they will evolve into. Confirming this assumption in principle requires more powerful space telescopes than are currently available.

However, through the phenomenon known as "gravitational lensing," a massive, foreground cluster of galaxies acts as a natural "zoom lens" in space by magnifying and stretching images of far more distant background galaxies. By joining this natural lens with the resolving power of Hubble, scientists were able to see into the center of the dead galaxy.

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

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

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

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

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

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

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