From European Space Agency: “What remains of the stars-Past and future generations of stars in NGC 300”

From European Space Agency

25/02/2019
ESA/XMM-Newton (X-rays); MPG/ESO (optical); NASA/Spitzer (infrared). Acknowledgement: S. Carpano, Max-Planck Institute for Extraterrestrial Physics

MPG/ESO 2.2 meter telescope at Cerro La Silla, Chile, 600 km north of Santiago de Chile at an altitude of 2400 metres

This swirling palette of colours portrays the life cycle of stars in a spiral galaxy known as NGC 300.

Located some six million light-years away, NGC 300 is relatively nearby. It is one of the closest galaxies beyond the Local Group – the hub of galaxies to which our own Milky Way galaxy belongs. Due to its proximity, it is a favourite target for astronomers to study stellar processes in spiral galaxies.

The population of stars in their prime is shown in this image in green hues, based on optical observations performed with the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at La Silla, Chile.

ESO WFI LaSilla 2.2-m MPG/ESO telescope at La Silla, 600 km north of Santiago de Chile at an altitude of 2400 metres

Red colours indicate the glow of cosmic dust in the interstellar medium that pervades the galaxy: this information derives from infrared observations made with NASA’s Spitzer space telescope, and can be used to trace stellar nurseries and future stellar generations across NGC 300.

A complementary perspective on this galaxy’s composition comes from data collected in X-rays by ESA’s XMM-Newton space observatory, shown in blue. These represent the end points of the stellar life cycle, including massive stars on the verge of blasting out as supernovas, remnants of supernova explosions, neutron stars, and black holes. Many of these X-ray sources are located in NGC 300, while others – especially towards the edges of the image – are foreground objects in our own Galaxy, or background galaxies even farther away.

The sizeable blue blob immediately to the left of the galaxy’s centre is especially interesting, featuring two intriguing sources that are part of NGC 300 and shine brightly in X-rays.

One of them, known as NGC 300 X-1, is in fact a binary system, consisting of a Wolf-Rayet star – an ageing hot, massive and luminous type star that drives strong winds into its surroundings – and a black hole, the compact remains of what was once another massive, hot star. As matter from the star flows towards the black hole, it is heated up to temperatures of millions of degrees or more, causing it to shine in X-rays.

The other source, dubbed NGC 300 ULX1, was originally identified as a supernova explosion in 2010. However, later observations prompted astronomers to reconsider this interpretation, indicating that this source also conceals a binary system comprising a very massive star and a compact object – a neutron star or a black hole – feeding on material from its stellar companion.

Data obtained in 2016 with ESA’s XMM-Newton and NASA’s NuSTAR observatories revealed regular variations in the X-ray signal of NGC 300 ULX1, suggesting that the compact object in this binary system is a highly magnetized, rapidly spinning neutron star, or pulsar.

The large blue blob in the upper left corner is a much more distant object: a cluster of galaxies more than one billion light years away, whose X-ray glow is caused by the hot diffuse gas interspersed between the galaxies.

Explore NGC 300 in ESASky

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The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

From Instituto de Astrofísica de Canarias – IAC: “Stars shrouded in iron dust”

From Instituto de Astrofísica de Canarias – IAC

Flavia Dell’Agli
fdellagli@iac.es

Aníbal García Hernández
agarcia@iac.es

Manu Astrónomus

From Manu Garcia, a friend from IAC.

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

Infrared image of the Large Magellanic Cloud (LMC) obtained with the Spitzer Space Telescope.

top panel: comparing the spectrum Spitzer / IRS (line solid black) Star SSID 4486 and the theoretical spectrum of best fit of a star AGB 5 solar masses (continuous red line) wrapped by ~ 70% powder iron; green dashed line refers to the theoretical spectrum for the same model but iron powder. lower box: Artistic impression of a giant star ejecting AGB matter to the interstellar medium. Credit: Image LMC: Aladin-color Spitzer software; Artistic Image: Jaxa.

The Institute de Astrofísica (IAC) in a study presented by the discovery of a group of very poor stars metals and high fraction of iron powder, located in the LMC. To carry out this work have combined theoretical models of dust formation in circumstellar envelopes with infrared observations made with the Spitzer Space Telescope and predictions for the future James Webb Space Telescope.

The stars with masses between one to eight times the mass of the Sun evolve through the asymptotic giant branch (AGB, the acronym ‘Asymptotic Giant Branch’) before ending their lives as white dwarfs. It is during this evolutionary, rapid but crucial phase, when the stars are expanded to gigantic proportions and cooled, losing almost all of its mass due to strong stellar winds. The low temperature and high density wind provide perfect conditions to favor the condensation of the powder grains in their circumstellar envelopes.

The powder supplied by AGB stars in its stage the interstellar medium is key to the life of galaxies, as this is essential for the formation of new stars and planets element. Thus, characterizing the type of dust (organic solid compounds against inorganic) and the amount of dust produced by these giant stars is very interesting for the astronomical community.

The journal The Astrophysical Journal Letters published today a study in which the mystery of a peculiar group of massive AGB stars, located in the Large Magellanic Cloud is resolved. Comparing infrared observations from the Spitzer Space Telescope (and predictions for the future James Webb Space Telescope) with theoretical models developed by this team have discovered that these stars have masses around 5 solar masses, formed about 100 million years ago and are poor metals (metals such as Fe, Mg and Si. Iron, magnesium and silicon). Unexpectedly, the team has found that their spectral energy distributions, in the infrared range, can only be reproduced if the iron powder is the main species of dust in their circumstellar envelopes. This situation is rare around AGB massive stars. It was previously known to produce mainly silicates. That is, powder grains rich in oxygen, magnesium and silicon. But this finding is even more surprising considering the metal – poor environment surrounding the stars studied.

“We first characterized this kind of star with unique spectral properties. The low metallicity of these giant stars is the essential ingredient that provides a peculiar conditions which allow the formation of larger amounts of iron powder” explains Ester Marini, lead author article and doctoral student at the University Roma Tre. He adds: “In fact, metal-poor environments, complex active stellar nucleosynthesis within the massive AGB stars is so advanced that runs almost all the magnesium and oxygen necessary to form other species such as silicates dust.”

Under these particular conditions, the iron powder becomes the main component powder consisting of these stars. “This result represents an important theoretical confirmation for the formation of iron powder in poor environments metals, as evoked by independent observational evidence,” the IAC researcher Aníbal García Hernández, co-author and one of the founders of the fruitful collaboration between the IAC and Astronomico Osservatorio di Roma (INAF-OAR) for this type of study in giant stars in the AGB phase.

“The arrival of the James Webb Space Telescope (JWST) will open new possibilities to investigate this case in depth,” says Flavia Dell’Agli, postdoctoral researcher at the IAC and second author of the article adds. “This future facility will greatly increase the number of AGB stars extragalactic resolved “and that the MIRI instrument that will be housed on the JWST will be” ideal to identify this class of stars in other galaxies in the Local Group “.

See the full article here.

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The Instituto de Astrofísica de Canarias(IAC) is an international research centre in Spain which comprises:

The Instituto de Astrofísica, the headquarters, which is in La Laguna (Tenerife).
The Centro de Astrofísica en La Palma (CALP)
The Observatorio del Teide (OT), in Izaña (Tenerife).

These centres, with all the facilities they bring together, make up the European Northern Observatory(ENO).

The IAC is constituted administratively as a Public Consortium, created by statute in 1982, with involvement from the Spanish Government, the Government of the Canary Islands, the University of La Laguna and Spain’s Science Research Council (CSIC).

The International Scientific Committee (CCI) manages participation in the observatories by institutions from other countries. A Time Allocation Committee (CAT) allocates the observing time reserved for Spain at the telescopes in the IAC’s observatories.

The exceptional quality of the sky over the Canaries for astronomical observations is protected by law. The IAC’s Sky Quality Protection Office (OTPC) regulates the application of the law and its Sky Quality Group continuously monitors the parameters that define observing quality at the IAC Observatories.

The IAC’s research programme includes astrophysical research and technological development projects.

The IAC is also involved in researcher training, university teaching and outreachactivities.

The IAC has devoted much energy to developing technology for the design and construction of a large 10.4 metre diameter telescope, the ( Gran Telescopio CANARIAS, GTC), which is sited at the Observatorio del Roque de los Muchachos.

Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, SpainGran Telescopio CANARIAS, GTC

From Spitzer via Manu Garcia: “Umuamua intergalactic visitor”.

From Manu Garcia, a friend from IAC.

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

News Media Contact
Calla Cofield
Jet Propulsion Laboratory, Pasadena, California.
626-808-2469
calla.e.cofield@jpl.nasa.gov

From Spitzer

NASA learns more about the interstellar visitors’ Oumuamua.

An artistic concept of interstellar asteroid 1I / 2017 U1 ( ‘Oumuamua) while passing through the solar system after its discovery in October 2017. The observations of’ Oumuamua indicate that must be very long due to its dramatic brightness variations as fell space. Image Credit: European Southern Observatory / M. Kornmesser.

‘Oumuamua was too weak to detect when Spitzer looked more than two months after the closest to Earth the object approach in early September. However, the “no detection” put a new limit on the size of the foreign object. The results are reported in a new study published today in Astronomical Journal and coauthor of scientists at the Jet Propulsion Laboratory of NASA in Pasadena, California, The Astronomical Journal.

The new size limit is consistent with the findings of a research paper published earlier this year, suggesting that the degassing was responsible for slight changes in speed and direction of ‘Oumuamua as were screened last year: authors of this paper concluded that the expelled gas acted as a small pusher gently pushing the object. That determination depended on ‘Oumuamua is relatively smaller than typical comets in the solar system. (The conclusion that ‘Oumuamua experienced degassing suggested consisted of frozen gases, comet-like.)

‘Oumuamua has been full of surprises from the first day, so we were eager to see what Spitzer could show,” said David Trilling, senior author of the new study and a professor of astronomy at the University of Northern Arizona. “The fact that ‘Oumuamua was too small to detect what Spitzer is actually a very valuable result.”

‘Oumuamua was first detected by the Pan-STARRS 1 telescope at the University of Hawaii at Haleakala, Hawaii (the object name is a Hawaiian word meaning “visitor from afar come first”) in October 2017, while the telescope was looking for asteroids near Earth.

Pann-STARSR1 Telescope, U Hawaii, Mauna Kea, Hawaii, USA, Altitude 3,052 m (10,013 ft)

Subsequent detailed observations made by multiple ground-based telescopes and the Hubble Space Telescope detected NASA sunlight reflected on the surface of Oumuamua.

Large variations in the brightness of the object suggested that ‘Oumuamua is highly elongated and probably less than half a mile (2,600 feet or 800 meters) at its longest dimension.

But Spitzer tracks asteroids and comets using infrared energy, or heat, radiating, which can provide more specific information about the size of an object optical observations of sunlight reflected.

The fact that ‘Oumuamua was too weak to detect Spitzer sets a limit on the total surface area of the object. However, since non-detection can not be used to infer the shape, size limits are presented as what the diameter if spherical Oumuamua. Using three separate models that slightly different assumptions about the composition of the object, the non-detection of Spitzer limited the “spherical diameter” of Oumuamua to 1,440 feet (440 meters), 460 feet (140 meters) or perhaps as little as 320 feet (100 meters) . The wide range of results stems from assumptions about the composition of ‘Oumuamua, which influences how visible (or weak) would seem to Spitzer if a particular size.

Scientists have concluded that the vents on the surface of ‘Oumuamua must have emitted gas jets, which gave the object a slight increase in speed, the researchers detected by measuring the position of the object as it passed through the earth in 2017. Credit: NASA / JPL -Caltech.

Small but thoughtful.

The new study also suggests that ‘Oumuamua can be up to 10 times more reflective than comets reside in our solar system, a surprising result, according to the authors of the article. Because infrared light is largely the heat radiation produced by the “hot” objects, can be used to determine the temperature of a comet or asteroid; in turn, this can be used to determine the reflectivity of the object surface, which scientists call albedo. Like a dark shirt to sunlight warms up faster than a light, an object with low reflectivity retains more heat than an object with high reflectivity. So a lower temperature means higher albedo.

The albedo of a comet can change throughout your life. When passing near the Sun, ice comet is heated and converted directly into a gas, sweeping dust and dirt from the surface of the comet and revealing more reflective ice.

‘Oumuamua has been traveling through interstellar space for millions of years, far from any star that could cool its surface. But it may have had its renewed surface through such “degassing” when he made an extremely close approach to the Sun, a little more than five weeks before it was discovered. In addition to sweep the dust and dirt of the released gas may have covered the surface of ‘Oumuamua with a reflective layer of ice and snow, a phenomenon also observed in comets of our solar system.

‘Oumuamua are leaving our solar system, almost as far from the Sun as the orbit of Saturn, and is far beyond the reach of existing telescopes.

“Usually, if we get a measure of a comet is something strange, we go back and measure again until we understand what we’re seeing,” said Davide Farnocchia, Study Center Near-Earth Object (CNEOS) at JPL . and co-author on both papers. “But this is gone forever, probably know as much as ever know.”

Links of interest:

The VLT reveals a dark red and very elongated object.
The first interstellar visitor Solar System dazzles scientists.
ESO’s VLT sees `Oumuamua gaining momentum.
Hubble sees’ Oumuamua is getting a boost, the new findings indicate that interstellar nomad is a comet.
Chasing ‘Oumuamua.
A new study shows what interstellar visitors’ Oumuamua can teach.

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The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory located on the campus of the California Institute of Technology and part of NASA’s Infrared Processing and Analysis Center.

From JPL-Caltech: “Newborn Stars Blow Bubbles in the Cat’s Paw Nebula”

From JPL-Caltech

October 23, 2018

Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
calla.e.cofield@jpl.nasa.gov

The Cat’s Paw Nebula, imaged here by NASA’s Spitzer Space Telescope using the MIPS and IRAC instruments, is a star-forming region that lies inside the Milky Way Galaxy. New stars may heat up the surrounding gas, which can expand to form “bubbles.” Image Credit: NASA/JPL-Caltech

This image from NASA’s Spitzer Space Telescope shows the Cat’s Paw Nebula, so named for the large, round features that create the impression of a feline footprint. The nebula is a star-forming region in the Milky Way galaxy, located in the constellation Scorpius. Estimates of its distance from Earth range from about 4,200 to about 5,500 light-years.

Framed by green clouds, the bright red bubbles are the dominant feature in the image, which was created using data from two of Spitzer’s instruments. After gas and dust inside the nebula collapse to form stars, the stars may in turn heat up the pressurized gas surrounding them, causing it to expand into space and create bubbles.

The green areas show places where radiation from hot stars collided with large molecules called “polycyclic aromatic hydrocarbons,” causing them to fluoresce.

In some cases, the bubbles may eventually “burst,” creating the U-shaped features that are particularly visible in the image below, which was created using data from just one of Spitzer’s instruments.

The Cat’s Paw Nebula, imaged here by NASA’s Spitzer Space Telescope using the IRAC instrument, is a star-forming region inside the Milky Way Galaxy. The dark filament running through the middle of the nebula is a particularly dense region of gas and dust. Image Credit: NASA/JPL-Caltech

Spitzer is an infrared telescope, and infrared light is useful to astronomers because it can penetrate thick clouds of gas and dust better than optical light (the kind visible to the human eye). The black filaments running horizontally through the nebula are regions of gas and dust so dense, not even infrared light can pass through them. These dense regions may soon be sites where another generation of stars will form.

The Cat’s Paw star-forming region is estimated to be between 24 and 27 parsecs (80 and 90 light years) across. It extends beyond the left side of these images and intersects with a similar-sized star-forming region, NGC 6357. That region is also known as the Lobster Nebula – an unlikely companion for a cat.

The top image was compiled using data from the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer (MIPS) aboard Spitzer. MIPS collects an additional “color” of light in the infrared range, which reveals the red-colored features, created by dust that has been warmed by the hot gas and the light from nearby stars. The second image is based on data from IRAC alone, so this dust is not visible.

The images were pulled from data collected for the Galactic Legacy Mid-Plane Survey Extraordinaire project (GLIMPSE). Using data from Spitzer, GLIMPSE created the most accurate map ever of the large central bar of the galaxy and showed that the galaxy is riddled with gas bubbles like those seen here.

More information about Spitzer is available at the following sites:

http://www.spitzer.caltech.edu/
https://irsa.ipac.caltech.edu/data/SPITZER/GLIMPSE/overview.html

See the full article here .

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Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge, on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

From Spitzer via JPL: “The Fading Ghost of a Long-Dead Star”

From JPL-Caltech

via

Spitzer

News Media Contact
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-1821
Calla.e.cofield@jpl.nasa.gov

Thin, red veins of energized gas mark the location of the supernova remnant HBH3 in this image from NASA’s Spitzer Space Telescope. The puffy, white feature in the image is a portion of the star forming regions W3, W4 and W5. Infrared wavelengths of 3.6 microns have been mapped to blue, and 4.5 microns to red. The white color of the star-forming region is a combination of both wavelengths, while the HBH3 filaments radiate only at the longer 4.5 micron wavelength.Credit: NASA/JPL-Caltech/IPAC

Thin, red veins of energized gas mark the location of one of the larger supernova remnants in the Milky Way galaxy in this image from NASA’s Spitzer Space Telescope.

A supernova “remnant” refers to the collective, leftover signs of an exploded star, or supernova. The red filaments in this image belong to a supernova remnant known as HBH 3 that was first observed in 1966 using radio telescopes. Traces of the remnant also radiate optical light. The branches of glowing material are most likely molecular gas that was pummeled by a shockwave generated by the supernova. The energy from the explosion energized the molecules and caused them to radiate infrared light.

The white, cloud-like formation also visible in the image is part of a complex of star-forming regions, simply named W3, W4 and W5. However, those regions extend far beyond the edge of this image. Both the white star-forming regions and the red filaments are approximately 6,400 light years away and lie inside our Milky Way galaxy.

HBH 3 is about 150 light-years in diameter, ranking it amongst the largest known supernova remnants. It is also possibly one of the oldest: Astronomers estimate the original explosion may have happened anywhere from 80,000 to one million years ago.

In 2016, NASA’s Fermi Gamma-Ray Telescope detected very high-energy light — called gamma rays — coming from the region near HBH 3. This emission may be coming from gas in one of the neighboring star-forming regions, excited by powerful particles emitted by the supernova blast.

The Spitzer Space Telescope is one of NASA’s four Great Observatories — along with the Hubble Space Telescope, the Chandra X-ray Observatory and the Compton Gamma-Ray Observatory — and will celebrate its 15th birthday in space on Aug. 25. Spitzer sees the universe in infrared light, which is slightly less energetic than the optical light we can see with our eyes. In this image, taken in March 2010, infrared wavelengths of 3.6 microns have been mapped to blue, and 4.5 microns to red. The white color of the star-forming region is a combination of both wavelengths, while the HBH3 filaments radiate only at the longer 4.5-micron wavelength.

More information on Spitzer can be found at its website:

http://www.spitzer.caltech.edu/

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From Spitzer via Manu: “Fire Within the Antennae Galaxies” 09.07.04

Manu Garcia, a friend from IAC.

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

From Spitzer

This image from NASA’s Spitzer Space Telescope reveals hidden populations of newborn stars at the heart of the colliding “Antennae” galaxies. These two galaxies, known individually as NGC 4038 and 4039, are located around 68 million light-years away and have been merging together for about the last 800 million years. The latest Spitzer observations provide a snapshot of the tremendous burst of star formation triggered in the process of this collision, particularly at the site where the two galaxies overlap.

The main image is a composite of infrared data from Spitzer and visible-light data from Kitt Peak National Observatory, Tucson, Ariz. Visible light from stars in the galaxies (blue and green) is shown together with infrared light from warm dust clouds heated by newborn stars (red).

The two nuclei, or centers, of the merging galaxies show up as yellow-white areas, one above the other. The brightest clouds of forming stars lie in the overlap region between and left of the nuclei.

The upper right panel shows the Spitzer image by itself. This picture was taken by the infrared array camera and is a combination of infrared light ranging from 3.6 microns (shown in blue) to 8.0 microns (shown in red). The dust emission (red) is by far the strongest feature in this image. Starlight was systematically subtracted from the longer wavelength data (red) to enhance dust features.

The lower right panel shows the true-color, visible-light image by itself. Here, we find a strikingly different view, with the bright star-forming features seen in the Spitzer image buried within dark clouds of dust.

Throughout the sky, astronomers have identified many of these so-called “interacting” galaxies, whose spiral discs have been stretched and distorted by their mutual gravity as they pass close to one another. The distances involved are so large that the interactions evolve on timescales comparable to geologic changes on Earth. Observations of such galaxies, combined with computer models of these collisions, show that the galaxies often become forever bound to one another, eventually merging into a single, spheroidal-shaped galaxy.

In the Spitzer image, wavelengths of 3.6 microns are represented in blue, 4.5 microns in green and 5.8-8.0 microns in red. In the composite image, wavelengths of .44 microns are represented in blue, .70 microns in green and 8.0 microns in red. The Spitzer image was taken on Dec. 24, 2003.

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From NASA Chandra: “Messier 82: Images From Space Telescopes Produce Stunning View of Starburst Galaxy” 2006

From NASA Chandra

Release Date April 24, 2006 [In social media 5.8.18

Messier 82:
Images From Space Telescopes Produce Stunning View of Starburst Galaxy

Credit X-ray: NASA/CXC/JHU/D.Strickland; Optical: NASA/ESA/STScI/AURA/The Hubble Heritage Team; IR: NASA/JPL-Caltech/Univ. of AZ/C. Engelbracht

Images from three of NASA’s Great Observatories were combined to create this spectacular, multiwavelength view of the starburst galaxy Messier 82 [Cigar Galaxy]. Optical light from stars (yellow-green/Hubble Space Telescope) shows the disk of a modest-sized, apparently normal galaxy.

Another Hubble observation designed to image 10,000 degree Celsius hydrogen gas (orange) reveals a startlingly different picture of matter blasting out of the galaxy. The Spitzer Space Telescope infrared image (red) shows that cool gas and dust are also being ejected.

Chandra’s X-ray image (blue) reveals gas that has been heated to millions of degrees by the violent outflow. The eruption can be traced back to the central regions of the galaxy where stars are forming at a furious rate, some 10 times faster than in the Milky Way Galaxy.

Many of these newly formed stars are very massive and race through their evolution to explode as supernovas. Vigorous mass loss from these stars before they explode, and the heat generated by the supernovas drive the gas out of the galaxy at millions of miles per hour. It is thought that the expulsion of matter from a galaxy during bursts of star formation is one of the main ways of spreading elements like carbon and oxygen throughout the universe.

The burst of star formation in Messier 82 is thought to have been initiated by shock waves generated in a close encounter with a large nearby galaxy, Messier 81, about 100 million years ago. These shock waves triggered the collapse of giant clouds of dust and gas in M82. In another 100 million years or so, most of the gas and dust will have been used to form stars, or blown out of the galaxy, so the starburst will subside.

See the full article here .

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NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass.

From NASA Chandra: “RCW 108: Massive Young Stars Trigger Stellar Birth” October 06, 2008

NASA Chandra

Credit X-ray: NASA/CXC/CfA/S.Wolk et al; IR: NASA/JPL-Caltech

RCW 108 is a region where stars are actively forming within the Milky Way galaxy about 4,000 light years from Earth. This is a complicated region that contains young star clusters, including one that is deeply embedded in a cloud of molecular hydrogen. By using data from different telescopes, astronomers determined that star birth in this region is being triggered by the effect of nearby, massive young stars.

This image is a composite of X-ray data from Chandra (blue) and infrared emission detected by Spitzer (red and orange).

More than 400 X-ray sources were identified in Chandra’s observations of RCW 108. About 90% of these X-ray sources are thought to be part of the cluster and not stars that lie in the field-of-view either behind or in front of it. Many of the stars in RCW 108 are experiencing the violent flaring seen in other young star-forming regions such as the Orion Nebula. Gas and dust blocks much of the X-rays from the juvenile stars located in the center of the image, explaining the relative dearth of Chandra sources in this part of the image.

The Spitzer data show the location of the embedded star cluster, which appears as the bright knot of red and orange just to the left of the center of the image. Some stars from a larger cluster, known as NGC 6193, are also visible on the left side of the image. Astronomers think that the dense clouds within RCW 108 are in the process of being destroyed by intense radiation emanating from hot and massive stars in NGC 6193.

Taken together, the Chandra and Spitzer data indicate that there are more massive star candidates than expected in several areas of this image. This suggests that pockets within RCW 108 underwent localized episodes of star formation. Scientists predict that this type of star formation is triggered by the effects of radiation from bright, massive stars such as those in NGC 6193. This radiation may cause the interior of gas clouds in RCW 108 to be compressed, leading to gravitational collapse and the formation of new stars.

See the full article here .

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From Chandra: “Crab Nebula: A Crab Walks Through Time”

NASA Chandra

March 14, 2018

Composite

X-ray

Optical

Infrared

Credit X-ray: NASA/CXC/SAO; Optical: NASA/STScI; Infrared: NASA-JPL-Caltech

A new composite of the Crab Nebula with Chandra (blue and white), Hubble (purple), and Spitzer (pink) data has been released.

The star that exploded to create the Crab Nebula was reportedly first seen from Earth in 1054 A.D.

Since its launch in 1999, Chandra has frequently observed the Crab.

X-ray observations have helped astronomers better understand this spectacular object.

Next year marks the 20th anniversary of NASA’s Chandra X-ray Observatory launch into space. The Crab Nebula was one of the first objects that Chandra examined with its sharp X-ray vision, and it has been a frequent target of the telescope ever since.

There are many reasons that the Crab Nebula is such a well-studied object. For example, it is one of a handful of cases where there is strong historical evidence for when the star exploded. Having this definitive timeline helps astronomers understand the details of the explosion and its aftermath.

In the case of the Crab, observers in several countries reported the appearance of a “new star” in 1054 A.D. in the direction of the constellation Taurus. Much has been learned about the Crab in the centuries since then. Today, astronomers know that the Crab Nebula is powered by a quickly spinning, highly magnetized neutron star called a pulsar, which was formed when a massive star ran out of its nuclear fuel and collapsed. The combination of rapid rotation and a strong magnetic field in the Crab generates an intense electromagnetic field that creates jets of matter and anti-matter moving away from both the north and south poles of the pulsar, and an intense wind flowing out in the equatorial direction.

The latest image of the Crab is a composite with X-rays from Chandra (blue and white), NASA’s Hubble Space Telescope (purple) and NASA’s Spitzer Space Telescope (pink). The extent of the X-ray image is smaller than the others because extremely energetic electrons emitting X-rays radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light.

This new composite adds to a scientific legacy, spanning nearly two decades, between Chandra and the Crab Nebula. Here is a sample of the many insights astronomers have gained about this famous object using Chandra and other telescopes.

1999: Within weeks of being deployed into orbit from the Space Shuttle Columbia during the summer of 1999, Chandra observed the Crab Nebula. The Chandra data revealed features in the Crab never seen before, including a bright ring of high-energy particles around the heart of the nebula.

2002: The dynamic nature of the Crab Nebula was vividly revealed in 2002 when scientists produced videos based on coordinated Chandra and Hubble observations made over several months. The bright ring seen earlier consists of about two dozen knots that form, brighten and fade, jitter around, and occasionally undergo outbursts that give rise to expanding clouds of particles, but remain in roughly the same location.

These knots are caused by a shock wave, similar to a sonic boom, where fast-moving particles from the pulsar are slamming into surrounding gas. Bright wisps originating in this ring are moving outward at half the speed of light to form a second expanding ring further away from the pulsar.

2006: In 2003, the Spitzer Space Telescope was launched and the space-based infrared telescope joined Hubble, Chandra, and the Compton Gamma-ray Observatory and completed the development of NASA’s “Great Observatory” program.

Compton Gamma-ray Observatory schematic

A few years later, the first composite of the Crab with data from Chandra (light blue), Hubble (green and dark blue), and Spitzer (red) was released.

2008: As Chandra continued to take observations of the Crab, the data provided a clearer picture of what was happening in this dynamic object. In 2008, scientists first reported a view of the faint boundary of the Crab Nebula’s pulsar wind nebula (i.e., a cocoon of high-energy particles surrounding the pulsar).

The data showed structures that astronomers referred to as “fingers”, “loops”, and “bays”. These features indicated that the magnetic field of the nebula and filaments of cooler matter are controlling the motion of the electrons and positrons. The particles can move rapidly along the magnetic field and travel several light years before radiating away their energy. In contrast, they move much more slowly perpendicular to the magnetic field, and travel only a short distance before losing their energy.

2011: Time-lapse movies of Chandra data of the Crab have been powerful tools in showing the dramatic variations in the X-ray emission near the pulsar. In 2011, Chandra observations, obtained between September 2010 and April 2011, were obtained to pinpoint the location of remarkable gamma-ray flares observed by NASA’s Fermi Gamma Ray Observatory and Italy’s AGILE Satellite. The gamma-ray observatories were not able to locate the source of the flares within the nebula, but astronomers hoped that Chandra, with its high-resolution images, would.

Two Chandra observations were made when strong gamma-ray flares occurred, but no clear evidence was seen for correlated flares in the Chandra images.

Despite this lack of correlation, the Chandra observations helped scientists to home in on an explanation of the gamma-ray flares. Though other possibilities remain, Chandra provided evidence that accelerated particles produced the gamma-ray flares.

2014: To celebrate the 15th anniversary of Chandra’s launch, several new images of supernova remnants were released, including the Crab Nebula. This was a “three color” image of the Crab Nebula, where the X-ray data were split into three different energy bands. In this image, the lowest-energy X-rays Chandra detects are red, the medium range are green, and the highest-energy X-rays from the Crab are colored blue. Note that the extent of the higher energy X-rays in the image is smaller than the others. This is because the most energetic electrons responsible for the highest energy X-rays radiate away their energy more quickly than the lower-energy electrons.

2017: Building on the multiwavelength images of the Crab from the past, a highly detailed view of the Crab Nebula was created in 2017 using data from telescopes spanning nearly the entire breadth of the electromagnetic spectrum. Radio waves from the Karl G. Jansky Very Large Array (red), Hubble optical data (green), infrared data from Spitzer (yellow), and X-ray data from XMM-Newton (blue) and Chandra (purple) produced a spectacular new image of the Crab.

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From Hubble: “NASA’s Great Observatories Team Up to Find Magnified and Stretched Out Image of Distant Galaxy”

NASA/ESA Hubble Telescope

Jan 11, 2018

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu

Release type: American Astronomical Society Meeting

Small, Embryonic Galaxy Formed Just 500 Million Years After the Big Bang.

As powerful as NASA’s Hubble and Spitzer space telescopes are, they need a little help from nature in seeking out the farthest, and hence earliest galaxies that first appeared in the universe after the big bang. This help comes from a natural zoom lens in the universe, formed by the warping of space by intense gravitational fields.

The most powerful “zoom lenses” out there are formed by very massive foreground clusters that bend space like a bowling ball rolling across a soft mattress. The lens boosts the brightness of distant background objects. The farthest candidates simply appear as red dots in Hubble photos because of their small size and great distance.

However, astronomers got very lucky when they looked at galaxy cluster SPT-CL J0615-5746. Embedded in the photo is an arc-like structure that is not only the amplified image of a background galaxy, but an image that has been smeared into a crescent-shape. This image allowed astronomers to estimate that the diminutive galaxy weighs in at no more than 3 billion solar masses (roughly 1/100th the mass of our fully grown Milky Way galaxy). It is less than 2,500 light-years across, half the size of the Small Magellanic Cloud, a satellite galaxy of our Milky Way.

Small Magellanic Cloud. NASA/ESA Hubble and ESO/Digitized Sky Survey 2

The object is considered prototypical of young galaxies that emerged during the epoch shortly after the big bang. Hubble’s clarity, combined with Spitzer’s infrared sensitivity to light reddened by the expanding universe, allowed for the object’s vast distance to be calculated.

The Full Story

An intensive survey deep into the universe by NASA’s Hubble and Spitzer space telescopes has yielded the proverbial needle-in-a-haystack: the farthest galaxy yet seen in an image that has been stretched and amplified by a phenomenon called gravitational lensing.

The embryonic galaxy named SPT0615-JD existed when the universe was just 500 million years old. Though a few other primitive galaxies have been seen at this early epoch, they have essentially all looked like red dots given their small size and tremendous distances. However, in this case, the gravitational field of a massive foreground galaxy cluster not only amplified the light from the background galaxy but also smeared the image of it into an arc (about 2 arcseconds long).

“No other candidate galaxy has been found at such a great distance that also gives you the spatial information that this arc image does. By analyzing the effects of gravitational lensing on the image of this galaxy, we can determine its actual size and shape,” said the study’s lead author Brett Salmon of the Space Telescope Science Institute in Baltimore, Maryland. He is presenting his research at the 231st meeting of the American Astronomical Society in Washington, D.C.

First predicted by Albert Einstein a century ago, the warping of space by the gravity of a massive foreground object can brighten and distort the images of far more distant background objects. Astronomers use this “zoom lens” effect to go hunting for amplified images of distant galaxies that otherwise would not be visible with today’s telescopes.

SPT0615-JD was identified in Hubble’s Reionization Lensing Cluster Survey (RELICS) and companion S-RELICS Spitzer program. “RELICS was designed to discover distant galaxies like these that are magnified brightly enough for detailed study,” said Dan Coe, Principal Investigator of RELICS. RELICS observed 41 massive galaxy clusters for the first time in the infrared with Hubble to search for such distant lensed galaxies. One of these clusters was SPT-CL J0615-5746, which Salmon analyzed to make this discovery. Upon finding the lens-arc, Salmon thought, “Oh, wow! I think we’re on to something!”

By combining the Hubble and Spitzer data, Salmon calculated the lookback time to the galaxy of 13.3 billion years. Preliminary analysis suggests the diminutive galaxy weighs in at no more than 3 billion solar masses (roughly 1/100th the mass of our fully grown Milky Way galaxy). It is less than 2,500 light-years across, half the size of the Small Magellanic Cloud, a satellite galaxy of our Milky Way. The object is considered prototypical of young galaxies that emerged during the epoch shortly after the big bang.

The galaxy is right at the limits of Hubble’s detection capabilities, but just the beginning for the upcoming NASA James Webb Space Telescope’s powerful capabilities, said Salmon. “This galaxy is an exciting target for science with the Webb telescope as it offers the unique opportunity for resolving stellar populations in the very early universe.” Spectroscopy with Webb will allow for astronomers to study in detail the firestorm of starbirth activity taking place at this early epoch, and resolve its substructure.

NASA’s Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington, D.C. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

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The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.