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Post by auntym on Aug 22, 2015 14:36:51 GMT -6
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Post by auntym on Nov 8, 2015 13:14:31 GMT -6
www.space.com/31046-milky-way-has-great-dark-lane.html?cmpid=514648_20151107_54999856&adbid=662789071236759552&adbpl=tw&adbpr=15431856 Our Milky Way Galaxy Has a Mysterious 'Great Dark Lane'by Nola Taylor Redd, Space.com Contributor / www.space.com/contact_author.php?a=VG05c1lTQlVZWGxzYjNJZ1VtVmtaQ3B1YjJ4aEtqUXFZWE4wY205M2NtbDBaWEl1WTI5dA== November 06, 2015 The NASA/ESA Hubble Space Telescope captured this striking image of the galaxy NGC 7049, with its dust lanes backlit by the stars in its central halo. Credit: NASA/ESA/W. Harris A previously unidentified highway of dust extends across the Milky Way, between the sun and the central bulge of the galaxy, scientists have found. Called the "Great Dark Lane" by the astronomers who announced it, the dusty road twists in front of the bulge of the galaxy. "For the first time, we could map this dust lane at large scales, because our new infrared maps cover the whole central region of the Milky Way," Dante Minniti, a researcher at Universidad Andres Bello in Chile and lead author of a study describing the findings, told Space.com by email. Mapping the Milky Way The center of a spiral galaxy contains a collection of stars that bulge above and below the flatter spirals, much like an egg yolk. The arms that give the galaxies their classification twist around the bulge, often in a beautiful spiral (although sometimes they are more elongated). Lanes of dust often lie between these arms, which present a particular challenge to map out. [Stunning Photos of Our Milky Way Galaxy (Gallery)] "It is very difficult to map the structure of our galaxy because we are inside, and it is very large and covered with dust clouds that are opaque in the optical," Minniti said. Working with a team of astronomers, Minniti used the European Space Observatory's Vista Variables in the Via Lactea Survey (VVV), a project to scan the Milky Way using the VISTA telescope in Chile, to study the galaxy in the near-infrared. At this wavelength, telescopes are able to peer through the clouds of dust to a group of objects known as red clump (RC) stars lying within the bulge. Red clump stars have helium-burning cores that generate a similar brightness no matter what their age or composition is. This makes them reliable distance indicators for astronomers. Based on the measurement of 157 million stars, Minniti and his team found that the RC stars of the Milky Way's bulgewere split into two colors — a difference they determined was caused by dust between the stars and the observers. The astronomers could see a sharp transition between the two distinct groups — the dusty Great Dark Lane dividing them. CONTINUE READING: www.space.com/31046-milky-way-has-great-dark-lane.html?cmpid=514648_20151107_54999856&adbid=662789071236759552&adbpl=tw&adbpr=15431856
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Post by swamprat on Nov 18, 2015 14:18:17 GMT -6
Stellar Graveyard Reveals Clues About Milky Way's Ancient Birthby Nola Taylor Redd, Space.com Contributor November 18, 2015
By studying the motion of stars over nearly a decade in the Hubble SWEEPS Field, shown here, scientists have been able to better understand the early years of the Milky Way. Credit: NASA, ESA, A. Calamida and K. Sahu (STScI), and the SWEEPS Science Team
NASA's Hubble Space Telescope has peered far back in time, detecting clues about how the Milky Way galaxy came together, shortly after the universe's birth.
Astronomers trained Hubble on the Milky Way's dense central bulge and spotted a population of superdense stellar corpses called white dwarfs that are remnants of stars that formed about 12 billion years ago. These stars are archeological evidence of the first few billion years of the galaxy's history, researchers said.
"It is important to observe the Milky Way's bulge, because it is the only bulge we can study in detail," study lead author Annalisa Calamida, of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, said in a statement. "You can see bulges in distant galaxies, but you cannot resolve the very faint stars, such as the white dwarfs."
Like other spiral galaxies, the Milky Way harbors a dense central bulge surrounded by wispy spiral arms. Scientists think that such bulges formed first, while the outer arms came later.
"The Milky Way's bulge includes almost a quarter of the galaxy's stellar mass," Calamida said. "Characterizing the properties of the bulge stars can then provide important ways to understand the formation of the entire Milky Way galaxy and that of similar, more-distant galaxies."
But studying the Milky Way's core is a challenge; Earth's sun orbits on one of the outlying arms, with stars lying between Earth and the galaxy's star-packed heart.
An image of the heart of the Milky Way shows the location of ancient white dwarfs. At left is a ground-based image of the galaxy's central bulge; the upper right shows a small section of Hubble's view of this region, while the lower-right image depicts four white dwarfs spied by Hubble. Credit: NASA, ESA, A. Calamida and K. Sahu (STScI), and the SWEEPS Science Team; A. Fujii
Using Hubble, the team studied the motion of about 240,000 Milky Way stars over nearly a decade. By comparing how the positions of these stars changed over that time, the researchers were able to pick out 70,000 that inhabit the bulge.
The team found that the galactic center contains slightly more low-mass stars compared to the outskirts.
"These results suggest that the environment in the bulge may have been different than the one in the disk, resulting in different star-formation mechanisms," Calamida said.
The astronomers also identified 70 white dwarfs in the bulge sample, by comparing the stars' colors to those predicted for white dwafs by theoretical models. Finding white dwarfs is no small feat; since these corpses no longer undergo fusion, they are quite dim. Indeed, NASA officials compared isolating a white dwarf from the background to searching for the glow of a pocket flashlight held by an astronaut on the moon.
But studying white dwarfs is worth the effort, the researchers said. Doing so can reveal information about the stars that built the Milky Way's core nearly 12 billion years ago, researchers said. (For comparison, the universe is approximately 13.8 billion years old.)"These 70 white dwarfs represent the peak of the iceberg," study leader Kailash Sahu, also of STScI, said in the same statement. "We estimate that the total number of white dwarfs is about 100,000 in this tiny Hubble view of the bulge."
With Hubble pushing the limits of what can be seen, it will fall to other instruments to capture even fainter stars, Sahu said.
"Future telescopes such as NASA's James Webb Space Telescope will allow us to count almost all of the stars in the bulge, down to the faintest ones, which today's telescopes, even Hubble, cannot see," Sahu said.
The researchers said they intend to analyze other portions of the same field of sky, ultimately leading to a more precise estimate for the age of the galactic heart.
The results were published in September in the Astrophysical Journal.
www.space.com/31150-milky-way-white-dwarfs-hubble-photo.html
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Post by auntym on Feb 18, 2016 14:49:55 GMT -6
apod.nasa.gov/apod/ap160217.html2016 February 17
Milky Way over the Pinnacles in AustraliaImage Credit: Michael Goh Explanation: What strange world is this? Earth. In the foreground of the featured image are the Pinnacles, unusual rock spires in Nambung National Park in Western Australia. Made of ancient sea shells (limestone), how these human-sized picturesque spires formed remains unknown. In the background, just past the end of the central Pinnacle, is a bright crescent Moon. The eerie glow around the Moon is mostly zodiacal light, sunlight reflected by dust grains orbiting between the planets in the Solar System. Arching across the top is the central band of our Milky Way Galaxy. Many famous stars and nebula are also visible in the background night sky. The featured 29-panel paannama was taken and composed last September after detailed planning that involved the Moon, the rock spires, and their corresponding shadows. Even so, the strong zodiacal light was a pleasant surprise.
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Post by auntym on Feb 18, 2016 14:56:11 GMT -6
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Post by swamprat on Feb 18, 2016 16:31:19 GMT -6
Wow! This is an excellent resource! Thanks, Auntym!
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Post by auntym on Feb 18, 2016 16:47:15 GMT -6
Wow! This is an excellent resource! Thanks, Auntym! you're welcome...
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Post by auntym on Feb 29, 2016 13:10:50 GMT -6
www.astrobio.net/topic/deep-space/atlasgal-survey-of-milky-way-completed/ ATLASGAL Survey of Milky Way CompletedFeb 24, 2016 The Southern Plane of the Milky Way from the ATLASGAL Survey. Credit: ESO/APEX/ATLASGAL consortium/NASA/GLIMPSE consortium/ESA/Planck A spectacular new image of the Milky Way has been released to mark the completion of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL). The APEX telescope in Chile has mapped the full area of the Galactic Plane visible from the southern hemisphere for the first time at submillimetre wavelengths — between infrared light and radio waves — and in finer detail than recent space-based surveys. The pioneering 12-metre APEX telescope allows astronomers to study the cold Universe: gas and dust only a few tens of degrees above absolute zero. APEX, the Atacama Pathfinder EXperiment telescope, is located at 5100 metres above sea level on the Chajnantor Plateau in Chile’s Atacama region. The ATLASGAL survey took advantage of the unique characteristics of the telescope to provide a detailed view of the distribution of cold dense gas along the plane of the Milky Way galaxy. The new image includes most of the regions of star formation in the southern Milky Way. The new ATLASGAL maps cover an area of sky 140 degrees long and 3 degrees wide, more than four times larger than the first ATLASGAL release. The new maps are also of higher quality, as some areas were re-observed to obtain a more uniform data quality over the whole survey area. The ATLASGAL survey is the single most successful APEX large programme with nearly 70 associated science papers already published, and its legacy will expand much further with all the reduced data products now available to the full astronomical community. At the heart of APEX are its sensitive instruments. One of these, LABOCA (the LArge BOlometer Camera) was used for the ATLASGAL survey. LABOCA measures incoming radiation by registering the tiny rise in temperature it causes on its detectors and can detect emission from the cold dark dust bands obscuring the stellar light. This comparison shows the central regions of the Milky Way observed at different wavelengths. Credit: ESO/ATLASGAL consortium/NASA/GLIMPSE consortium/VVV Survey/ESA/Planck/D. Minniti/S. Guisard - CONTINUE READING: www.astrobio.net/topic/deep-space/atlasgal-survey-of-milky-way-completed/
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Post by auntym on Mar 1, 2016 15:20:02 GMT -6
www.dailygalaxy.com/my_weblog/2016/02/-milky-ways-enigmatic-central-zone-no-place-else-in-the-galaxy-remotely-like-it.htmlFebruary 29, 2016 Milky Way's Enigmatic Central Zone --"No Place Else In the Galaxy Remotely Like It"The center of our Milky Way galaxy lies about 27,000 light-years away in the direction of the constellation of Sagittarius. At its core is a black hole about four million solar masses in size. Around the black hole is a donut-shaped structure about eight light-years across that rings the inner volume of neutral gas and thousands of individual stars. Around that, stretching out to about 700 light-years, is a dense zone of activity called the Central Molecular Zone (CMZ). The CMZ contains almost eighty percent of all the dense gas in the galaxy - a reservoir of tens of millions of solar masses of material - and hosts giant molecular clouds and massive star forming clusters of luminous stars, among other regions many of which are poorly understood. For example, the CMZ contains many dense molecular clouds that would normally be expected to produce new stars, but which are instead eerily desolate. It also contains gas moving at highly supersonic velocities - hundreds of kilometers per second (hundreds of thousands of miles per hours). An infrared and multi-wavelength image of the Central Molecular Zone in the Milky Way shown above. Dense gas is shown in red, and warm and cold dust in green and blue respectively. Several key objects in the region are labeled, along with a set of embedded young stellar clusters seen at 24 microns. - See more at: www.cfa.harvard.edu/news/su201609#sthash.7uJpe0rc.dpufWhere did the CMZ come from? No place else in the Milky Way is remotely like it (although there may be analogues in other galaxies). How does it retain its structure as its molecular gas moves, and how do those rapid motions determine its evolution? One difficulty facing astronomers is that there is so much obscuring dust between us and the CMZ that visible light is extinguished by factors of over a trillion. Infrared, radio, and some X-ray radiation can penetrate the veil, however, and they have allowed astronomers to develop the picture just outlined. CONTINUE READING: www.dailygalaxy.com/my_weblog/2016/02/-milky-ways-enigmatic-central-zone-no-place-else-in-the-galaxy-remotely-like-it.html
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Post by auntym on Mar 28, 2016 11:34:22 GMT -6
www.nasa.gov/image-feature/goddard/2016/hubble-looks-into-a-cosmic-kaleidoscopeMarch 25, 2016 Hubble Looks Into a Cosmic KaleidoscopeAt first glance, this cosmic kaleidoscope of purple, blue and pink offers a strikingly beautiful — and serene — snapshot of the cosmos. However, this multi-colored haze actually marks the site of two colliding galaxy clusters, forming a single object known as MACS J0416.1-2403 (or MACS J0416 for short). MACS J0416 is located about 4.3 billion light-years from Earth, in the constellation of Eridanus. This image of the cluster combines data from three different telescopes: the NASA/ESA Hubble Space Telescope (showing the galaxies and stars), the NASA Chandra X-ray Observatory (diffuse emission in blue), and the NRAO Jansky Very Large Array (diffuse emission in pink). Each telescope shows a different element of the cluster, allowing astronomers to study MACS J0416 in detail. As with all galaxy clusters, MACS J0416 contains a significant amount of dark matter, which leaves a detectable imprint in visible light by distorting the images of background galaxies. In this image, this dark matter appears to align well with the blue-hued hot gas, suggesting that the two clusters have not yet collided; if the clusters had already smashed into one another, the dark matter and gas would have separated. MACS J0416 also contains other features — such as a compact core of hot gas — that would likely have been disrupted had a collision already occurred. Together with five other galaxy clusters, MACS J0416 is playing a leading role in the Hubble Frontier Fields program, for which this data was obtained. Owing to its huge mass, the cluster is in fact bending the light of background objects, acting as a magnifying lens. Astronomers can use this phenomenon to find galaxies that existed only hundreds of million years after the big bang. For more information on both Frontier Fields and the phenomenon of gravitational lensing, see Hubblecast 90: The final frontier. : www.spacetelescope.org/videos/hubblecast90a/Text credit: European Space Agency Image credit: NASA, ESA, CXC, NRAO/AUI/NSF, STScI, and G. Ogrean (Stanford University), Acknowledgment: NASA, ESA, and J. Lotz (STScI), and the HFF team Last Updated: March 25, 2016 Editor: Ashley Morrow www.nasa.gov/image-feature/goddard/2016/hubble-looks-into-a-cosmic-kaleidoscope
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Post by auntym on Apr 1, 2016 15:13:28 GMT -6
www.spacetelescope.org/news/heic1606/?utm_medium=SocialSignIn&utm_source=Twitter HUBBLE ✔ @hubble_space
Take a journey to the centre of our galaxy with Hubble Journey to the centre of our galaxy31 March 2016 Peering deep into the heart of our home galaxy, the Milky Way, the NASA/ESA Hubble Space Telescope reveals a rich tapestry of more than half a million stars. Apart from a few, blue, foreground stars, almost all of the stars pictured in the image are members of the Milky Way nuclear star cluster, the densest and most massive star cluster in the galaxy. Hidden in the centre of this cluster is the Milky Way’s resident supermassive black hole. The centre of the Milky Way, 27 000 light-years away in the constellation of Sagittarius, is a crowded place. This region is so tightly packed that it is equivalent to having one million stars crammed into the volume of space between us and Alpha Centauri, located 4.3 light-years away. At the very hub of our galaxy, this dense nuclear star cluster surrounds the Milky Way’s central supermassive black hole, known as Sagittarius A*, which alone is about four million times the mass of the Sun. Sagittarius A* is not the only mystery lurking in this part of the galaxy. The crowded centre contains numerous objects that are hidden at visible wavelengths by thick clouds of dust in the galaxy’s disc. In order to truly understand the central part of our galaxy astronomers used the infrared vision of Hubble to peer through this obscuring dust. To reveal the image in all its glory the scientists then assigned visible colours to the different wavelengths of infrared light, which is invisible to human eyes. The blue stars in the image are foreground stars, which are closer to Earth than the nuclear star cluster, whilst the red stars are either behind much more intervening dust, or are embedded in dust themselves. Some extremely dense clouds of gas and dust are seen in silhouette, appearing dark against the bright background stars. These clouds are so thick that even Hubble’s infrared capability cannot penetrate them. In addition to the stars hidden by the dust astronomers estimate that there are about 10 million stars in the cluster which are too faint to see, even for Hubble. Using Hubble’s vantage point above the atmosphere and its high resolution, astronomers were able not only to reveal the stars in this cluster but also to measure their movements over a period of four years. Using this information, they inferred important properties of the nuclear star cluster, such as its mass and structure. The motion of the stars may also offer astronomers a glimpse into how the nuclear star cluster was formed — whether it was built up over time from globular star clusters that happened to fall into the centre of the galaxy, or from gas spiralling in from the Milky Way’s disc to form stars at the core. The data for this picture was gathered in September 2011 and is a mosaic stitched together from nine separate images taken with the Wide Field Camera 3 (WFC3). More information The Hubble Space Telescope is a project of international cooperation between ESA and NASA. Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) Acknowledgment: NASA, ESA, T. Do and A. Ghez (UCLA), and V. Bajaj (STScI) Mathias Jäger ESA/Hubble, Public Information Officer Garching, Germany Tel: +49 176 62397500 Email: mjaeger@partner.eso.org www.spacetelescope.org/news/heic1606/?utm_medium=SocialSignIn&utm_source=Twitter
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Post by Deleted on Apr 6, 2016 10:54:16 GMT -6
I just can't get enough of this kind've stuff.... Lol.
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Post by auntym on Apr 19, 2016 12:50:22 GMT -6
www.sciencealert.com/astronomers-just-discovered-a-huge-galaxy-orbiting-our-own The Milky Way Has Another Galactic Groupie Astronomers just discovered a huge galaxy orbiting our own by FIONA MACDONALD 18 APR 2016 A huge galaxy orbiting our own Milky Way has seemingly appeared out of nowhere. The newly spotted dwarf galaxy, which has been named Crater 2, sits around 400,000 light-years away, and has already earned the title of the fourth largest known galaxy circling our own. So how does a galaxy that big stay hidden for so long? Crater 2 has always been there, quietly circling our own giant galaxy. But its stars are so diffuse that it's incredibly dark, and it's been masked up until now by its brighter neighbours. In fact, it's one of the dimmest galleries ever detected in the Universe. "This is indeed a very rare discovery," lead researcher Vasily Belokurov from the University of Cambridge in the UK told The Huffington Post. "A galaxy like Crater 2 is a sort of invisible object." As far as we know, the Milky Way is orbited by 49 other galaxies, but this research suggests that perhaps there are other dark galaxies, inside our own cosmic neighbourhood, that have remained hidden because of their diffuse, ghostly appearance. Crater 2 was first detected in January, when astronomers used a computer algorithm to study images taken by the Very Large Telescope in Chile, and then pinpoint regions where there might be unusual clustering of stars - one of those clusters turned out to be Crater 2. Because galaxies don't tend to have defined edges, astronomers often describe them in terms of their 'half-light diameter', which basically means the diameter of the part of the galaxy that emits half its light. Based on the analysis so far, the astronomers calculate that Crater 2 has a half-light diameter of around 7,000 light-years, which means if we could see it in the night sky, it would look twice as big as the full moon - but also a whole lot more diffuse, because of how far apart its stars are. CONTINUE READING: www.sciencealert.com/astronomers-just-discovered-a-huge-galaxy-orbiting-our-own
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Post by auntym on Apr 23, 2016 12:09:46 GMT -6
www.scientificamerican.com/article/the-mystery-of-phantom-galaxies-may-soon-be-solved/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciam%2Fspace+%28Topic%3A+Space%29 The Mystery of Phantom Galaxies May Soon Be SolvedA new theory says these mysterious “ultradiffuse” oddball galaxies are dwarfs born in a whirl By Ken Croswell / www.scientificamerican.com/author/ken-croswell/ April 22, 2016 Pale and ghostly, ultradiffuse galaxies, such as this one in the Coma Cluster, abound in large numbers, but no one knows exactly how they arose. Credit: Hubble Space Telescope. NASA, ESA and Pieter van Dokkum (Yale University) et al Astronomers have long recognized that galaxies come in a variety of forms, and that any galaxy’s size and shape offer a glimpse of its history. A fast-spinning giant galaxy whips up a beautiful spiral pattern like that of our familiar Milky Way; if two giant spiral galaxies collide, they may become an even bigger star swarm called an elliptical galaxy. Around all these mighty giants, diminutive “dwarf” galaxies dance by the dozens—these may be leftovers from the giants’ formation. Recently, however, observers have uncovered enormous numbers of galaxies in an odd new form that is not so easily explained. In 2014 astronomers led by Pieter van Dokkum of Yale University pointed a sensitive array of small telescopes at a galaxy cluster in the constellation Coma Berenices and were astonished to discover 47 “smudges” all over the resulting images. The smudges were not somebody's fingerprints; they were ghostly galaxies that appeared to be bizarre hybrids of giants and dwarfs. Like giants, they were as large as the Milky Way; like dwarfs, they were dim, emitting roughly a thousandth as much light. The two opposing traits account for their strange appearance: They look dim and ghostly because their relatively few stars are spread out over a huge volume of space. Moreover, these “ultradiffuse” galaxies proved to be surprisingly common. When astronomers looked more closely at the Coma cluster using the 8.3-meter Subaru Telescope, they spotted more than 800 additional examples, and searches through archival data revealed that the first few members of the class appeared in observations from the 1980s. Faced with so many oddities, theorists are now crafting new models to explain how this profusion of galactic phantoms arose. CONTINUE READING: www.scientificamerican.com/article/the-mystery-of-phantom-galaxies-may-soon-be-solved/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+sciam%2Fspace+%28Topic%3A+Space%29
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Post by auntym on May 5, 2016 11:43:01 GMT -6
www.dailygalaxy.com/my_weblog/2016/05/mystery-signals-coming-from-milky-ways-center-swarms-of-pulsar-or-dark-matter-todays-galaxy-insight.html Mystery Signals from the Milky Way's Center --"Swarms of Ancient Pulsars or Dark Matter?" (Today's 'Galaxy' Insight)May 04, 2016 "Our analysis suggests that what we are seeing is evidence for a new astrophysical source of gamma rays at the center of the galaxy," said Mariangela Lisanti, an assistant professor of physics at Princeton. "This is a very complicated region of the sky and there are other astrophysical signals that could be confused with dark matter signals." The center of the Milky Way galaxy is thought to contain dark matter because it is home to a dense concentration of mass, including dense clusters of stars and a black hole. A conclusive finding of dark matter collisions in the galactic center would be a major step forward in confirming our understanding of our universe. "Either we find hundreds or thousands of millisecond pulsars in the upcoming decade, shedding light on the history of the Milky Way, or we find nothing. In the latter case, a dark matter explanation for the gamma ray excess will become much more obvious," says Christoph Weniger from the University of Amsterdam. Bursts of gamma rays from the center of our galaxy (shown above) are not likely to be signals of dark matter but rather other astrophysical phenomena such as fast-rotating stars called millisecond pulsars, according to two studies published this past January, one from a team based at Princeton University and the Massachusetts Institute of Technology and another based in the Netherlands. Statistical analyses of the Fermi data by Weniger and the research group from Princeton/MIT, strongly suggest that the excess emission does indeed originate from unresolved point sources. The best candidates are millisecond pulsars, the researchers conclude. Millisecond pulsars, or rapidly rotating neutron stars, were often formed billions of years ago. They are among the most extreme objects in the Galaxy. A population of hundreds or thousands of these millisecond pulsars must be lurking in the galactic centre, hidden from detection due to present day instrument sensitivity. Future radio surveys with existing and upcoming telescopes (e.g. Green Bank Telescope, Square Kilometre Array) will be able to further test this hypothesis in the coming years. CONTINUE READING: www.dailygalaxy.com/my_weblog/2016/05/mystery-signals-coming-from-milky-ways-center-swarms-of-pulsar-or-dark-matter-todays-galaxy-insight.html
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Post by auntym on Jun 2, 2016 14:32:55 GMT -6
www.astronomy.com/news/2016/06/measuring-the-milky-way-one-massive-problem-one-new-solution
Measuring the Milky Way: one massive problem, one new solution The mass of the Milky Way, so far, is 7 x 1011 solar masses.By McMaster University, Hamilton, Canada Published: Wednesday, June 01, 2016 The Milky Way / NASA It is a galactic challenge, to be sure, but Gwendolyn Eadie is getting closer to an accurate answer to a question that has defined her early career in astrophysics: what is the mass of the Milky Way? The short answer, so far, is 7 x 1011 solar masses. In terms that are easier to comprehend, that's about the mass of our Sun, multiplied by 700 billion. The Sun, for the record, has a mass of two nonillion (that's 2 followed by 30 zeroes) kilograms, or 330,000 times the mass of Earth. "And our galaxy isn't even the biggest galaxy," Eadie said. Measuring the mass of our home galaxy, or any galaxy, is particularly difficult. A galaxy includes not only stars, planets, moons, gases, dust, and other objects and material, but also a big helping of dark matter, a mysterious and invisible form of matter that is not yet fully understood and has not been directly detected in the lab. Astronomers and cosmologists, however, can infer the presence of dark matter through its gravitational influence on visible objects. Eadie from McMaster University has been studying the mass of the Milky Way and its dark matter component since she started graduate school. She uses the velocities and positions of globular star clusters that orbit the Milky Way. The orbits of globular clusters are determined by the galaxy's gravity, which is dictated by its massive dark matter component. What's new about Eadie's research is the technique she devised for using globular cluster (GCs) velocities. The total velocity of a GC must be measured in two directions: one along our line-of-sight, and one across the plane of the sky (the proper motion). Unfortunately, researchers have not yet measured the proper motions of all the GCs around the Milky Way. Eadie, however, has developed a way to use these velocities that are only partially known, in addition to the velocities that are fully known, to estimate the mass of the galaxy. Her method also predicts the mass contained within any distance from the center of the galaxy, with uncertainties, which makes her results easy to compare with other studies. Eadie and her academic supervisor William Harris have co-authored a paper on their most recent findings, which allow dark matter and visible matter to have different distributions in space. Even after all this work, she said, she still loves looking into the night sky. In fact, she loves it more. "Every so often I think, 'I'm measuring the mass of the Milky Way.' That's pretty neat." www.astronomy.com/news/2016/06/measuring-the-milky-way-one-massive-problem-one-new-solution
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Post by auntym on Jun 6, 2016 12:55:43 GMT -6
www.dailygalaxy.com/my_weblog/2016/06/new-species-of-enormous-spiral-galaxies-dwarf-the-milky-way-shockingly-gone-unnoticed-weekend-featur.html New 'Species' of Enormous Spiral Galaxies --"Dwarf the Milky Way, Shockingly Gone Unnoticed" (Weekend Feature)June 05, 2016 "We have found a previously unrecognized class of spiral galaxies that are as luminous and massive as the biggest, brightest galaxies we know of," said Patrick Ogle, an astrophysicist at the Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology in Pasadena and lead author of a paper on the findings published this March in The Astrophysical Journal. "It's as if we have just discovered a new land animal stomping around that is the size of an elephant but had shockingly gone unnoticed by zoologists." "Super spirals could fundamentally change our understanding of the formation and evolution of the most massive galaxies," said Ogle. "We have much to learn from these newly identified, galactic leviathans." A strange new kind of galactic beast has been spotted in the cosmic wilderness. Dubbed "super spirals," these unprecedented galaxies dwarf our own spiral galaxy, the Milky Way, and compete in size and brightness with the largest galaxies in the universe. Super spirals have long hidden in plain sight by mimicking the appearance of typical spiral galaxies. A new study using archived NASA data reveals these seemingly nearby objects are in fact distant, behemoth versions of everyday spirals. Rare, super spiral galaxies present researchers with the major mystery of how such giants could have arisen. Ogle and colleagues chanced upon super spirals as they searched for extremely luminous, massive galaxies in the NASA/IPAC Extragalactic Database (NED), an online repository containing information on over 100 million galaxies. NED brings together a wealth of data from many different projects, including ultraviolet light observations from the Galaxy Evolution Explorer, visible light from Sloan Digital Sky Survey, infrared light from the Two Micron All-Sky Survey, and links to data from other missions such as Spitzer and the Wide-field Infrared Survey Explorer, or WISE. "Remarkably, the finding of super spiral galaxies came out of purely analyzing the contents of the NASA/IPAC Extragalactic Database, thus reaping the benefits of the careful, systematic merging of data from many sources on the same galaxies," said George Helou, a study co-author and the executive director of IPAC. "NED is surely holding many more such nuggets of information, and it is up to us scientists to ask the right questions to bring them out." CONTINUE READING: www.dailygalaxy.com/my_weblog/2016/06/new-species-of-enormous-spiral-galaxies-dwarf-the-milky-way-shockingly-gone-unnoticed-weekend-featur.html
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Post by auntym on Dec 11, 2017 17:45:33 GMT -6
www.space.com/39048-milky-way-arcs-above-zabriskie-point-photo.html?utm_source=twitter&utm_medium=social#?utm_source=twitter&utm_medium=social&utm_campaign=2016twitterdlvrit WOW... so beautiful... Milky Way Arcs Above Zabriskie Point in Death Valley (Photo)By Miguel Claro, Space.com Contributor December 11, 2017 The arc of the Milky Way lights up the sky over Zabriskie Point in California's Death Valley National Park in a paannamic photograph captured by veteran astrophotographer Miguel Claro. Credit: Miguel ClaroMiguel Claro is a Lisbon, Portugal-based professional photographer, author and science communicator who creates spectacular images of the night sky. As a European Southern Observatory photo ambassador, a member of The World At Night and the official astrophotographer of the Dark Sky Alqueva Reserve, he specializes in astronomical "skyscapes" that connect Earth and the night sky. Join him here as he takes us through his photograph "Milky Way from Zabriskie Point in Death Valley." The shimmering arc of the Milky Way stretches high in the sky in this view of Zabriskie Point in California's Death Valley National Park. Forming a perfect half circle, the galaxy's structure extends so high that it seems to touch the zenith, or the point in the sky directly overhead, which made it very difficult to fit in a single frame. [Gallery: Stunning Photos of Our Milky Way Galaxy] In the top center of this paannamic shot is the bright blue star Vega, which shines with an apparent magnitude of 0.0 and serves as the midpoint on the stellar brightness scale. Vega is part of the Lyra constellation and is one of three stars that form a star pattern, or asterism, known as the Summer Triangle. The other two stars in the asterism are Deneb (in the constellation Cygnus) and Altair (in the constellation Aquila). The bright, elliptical and diffuse dot at the left side of the photo is the Andromeda galaxy. In the opposite direction, near the right edge of the picture, is the orange-red supergiant star Antares, located in the constellation Scorpius. Antares is setting below the hot horizon of Death Valley's landscape. On the night that this shot was captured, in August, the air temperature near midnight was 106 degrees Fahrenheit (41 degrees Celsius). In the center right, and below the arc, is a faint white light known as gegenschein, or "counterglow." This is a faint brightening in the region of the sky opposite the sun. Like the zodiacal light, a faint glow created by sunlight scattering on particles in the atmosphere, the gegenschein is caused by sunlight scattering off of interplanetary dust. WATCH VIDEO: www.space.com/39048-milky-way-arcs-above-zabriskie-point-photo.html?utm_source=twitter&utm_medium=social#?utm_source=twitter&utm_medium=social&utm_campaign=2016twitterdlvrit
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Post by auntym on Jan 14, 2018 18:37:44 GMT -6
news.nationalgeographic.com/2018/01/milky-way-galaxy-facts-black-hole-stars-space-science/ 10 Weird Things You (Probably) Didn't Know About the Milky Way Sarlaccs might live in a galaxy far, far away, but our star-studded home has plenty of its own strange wonders.The bright band of the Milky Way stretches across the Wyoming sky in Grand Teton National Park. Photograph by Babak Tafreshi, National Geographic CreativeBy Nadia Drake / www.nationalgeographic.com/contributors/d/nadia-drake/PUBLISHED January 12, 2018 OXON HILL, MARYLAND, United States, EARTH, SOLAR SYSTEM, MILKY WAYWhen we look up, every star we see is in the Milky Way, the spiral galaxy we call home. The Milky Way holds every alien planet humans have ever spotted, and the billions more that likely exist in the galaxy. On a dark night, the dense plane of the Milky Way winds like a ribbon across the sky. On a really dark night, in areas free from light pollution, that ribbon becomes so intensely spangled with stars that it’s possible to see the dark, dusty clouds of dust and gas deep in space that blot out their light. Those clouds are so prominent that Australia’s Aboriginal people saw them create the shape of an emu. Our galactic home is one of trillions of galaxies in the universe. Astronomers have been ardently studying them for almost a century, ever since Edwin Hubble discovered that neighboring Andromeda was not just another nearby dusty nebula, but a galaxy in its own right. And yet, humans are still trying to unravel the secrets of our galactic home and how it fits in the tapestry of the universe. “I would love to see a movie in time of the assembly of the Milky Way,” says Jay Lockman of the Green Bank Observatory, who presented new observations about our galaxy this week at the 231st meeting of the American Astronomical Society in Maryland. Here are some of the fun, weird facts and questions we have about the 13.6-billion-year-old space oddity we inhabit.A Hundred Million Stars in 3 Minutes In January 2015, NASA released the largest image ever of the Andromeda galaxy, taken by the Hubble telescope. By zooming into the incredible shot, filmmaker Dave Achtemichuk creates an unforgettable interactive experience. The Milky Way Is (Mostly) FlatOur galaxy is, on average, a hundred thousand light-years across but only a thousand light-years thick. Within this flattened (though somewhat warped) disc, the sun and its planets are embedded in a curving arm of gas and dust, putting the solar system about 26,000 light-years away from the galaxy’s turbulent core. A bulge of dust and stars swaddles the galactic center, looking like a dollop of whipped cream plopped on both sides of a pancake. Earth Is 18 Galactic Years OldThe solar system is zooming through interstellar space at around 500,000 miles an hour. Even at that rate, it takes about 250 million years to travel once around the Milky Way. The last time our 4.5-billion-year-old planet was in this same spot, continents fit together differently, dinosaurs were just emerging, mammals had yet to evolve, and the most profound mass extinction in the planet’s history—an event called the Great Dying—was in progress. There’s a Monster Black Hole in the Galaxy’s MiddleCalled Sagittarius A*, the supermassive black hole weighs in at more than four million times the mass of the sun. We’ve never seen this object directly—it’s hidden behind thick clouds of dust and gas. But astronomers have been able to follow the orbits of stars and gas clouds near the galactic center, which allowed them to infer the mass of the cosmic heavyweight hiding behind the curtain. It’s thought that supermassive black holes are parked in the cores of most galaxies, and some are feeding on nearby matter so greedily they shoot out jets of powerful radiation visible from millions of light-years away. You can take a spin through the Milky Way’s chaotic center courtesy of a new animation released at the AAS meeting. The Milky Way Won’t Live ForeverIn about four billion years, the Milky Way will collide with its nearest neighbor, the Andromeda Galaxy. The two spiral galaxies are currently hurtling toward each other at 250,000 miles an hour. When they do smash into one another, it won’t be as cataclysmic as you might imagine—Earth will likely survive, and very few stars will actually be destroyed. Instead, the newly formed mega-galaxy will offer a night skyscape with a spectacular blend of stars and streamers unlike anything we see today. Our Sun Is One Star Among Several Hundred BillionThere are a hundred billion stars in the Milky Way. Or is it 300 billion? Or 400 billion? That’s right—we don’t actually know how many stars are in our galaxy. Many of them are dim, low-mass stars that are hard to detect over vast cosmic distances, and there are massive clouds obscuring the bulge of stars nearest to Sagittarius A*. Astronomers have estimated the total number of stars based on the Milky Way’s mass and brightness, but more precise numbers are still elusive. We’re Surrounded By a Dark HaloThe Milky Way is embedded in a clump of dark matter that is far larger and more massive than the galaxy itself. In the late 1960s, astronomer Vera Rubin inferred the presence of these invisible halos around galaxies when she observed that stars near the edge of Andromeda were whipping around the galaxy’s center at speeds that should send them flying off into space. And yet, they weren’t, meaning that some sort of cosmic glue held everything together. That glue, we now know, is dark matter. We Hang Out With Ancient StarsThe Milky Way is also surrounded by more than 150 ancient groups of stars, some of which are among the oldest in the universe. Called globular clusters, these primordial stellar conglomerates live in the Milky Way’s halo and orbit the galactic center. Each is crammed with hundreds of thousands of stars. Also hanging around the Milky Way are dozens of satellite galaxies; most of these are tough to see, but the Small and Large Magellanic Clouds glisten each night in the southern sky. The Galaxy Is an Island in a Stream of StarsThe Milky Way eats galaxies that come too close. Over the years, scientists studying the galaxy’s fringe have detected some two dozen faint streamers of stars that are the remnants of galaxies past. These ghostly stellar rivers formed when the Milky Way’s more powerful gravity ripped apart smaller galaxies, leaving behind glittering strands of leftovers. At the AAS meeting, the Dark Energy Survey team announced that it had detected 11 more of these streamers, some of which have been given Aboriginal names. The Galactic Center Is Blowing Hot AirThe Milky Way is blowing massive bubbles of extremely hot gas and energetic particles. Stretching far above and below the galactic plane, these so-called Fermi bubbles balloon straight out of the galaxy’s center, fueled by a wind blowing at two million miles an hour. Unknown until 2010, it’s not entirely clear why the bubbles exist, but scientists think they could be linked to the frenzy of star death and formation in the region around Sagittarius A*. Gas Clouds Are Fleeing the GalaxyObserved recently with the Green Bank Telescope, more than a hundred hydrogen gas clouds are zooming away from the galaxy’s core at 738,000 miles an hour. Scientists studying the deserting swarm say the clouds can act as tracers for the powerful processes that produce the giant Fermi bubbles. news.nationalgeographic.com/2018/01/milky-way-galaxy-facts-black-hole-stars-space-science/
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Post by swamprat on Feb 22, 2018 13:43:08 GMT -6
Here's looking at you, kid!
The Eye of the Cosmos, Helix Nebula
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Post by auntym on Mar 8, 2018 16:01:26 GMT -6
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Post by auntym on Mar 30, 2018 21:24:26 GMT -6
www.space.com/25959-how-many-stars-are-in-the-milky-way.html?utm_source=twitter&utm_medium=social How Many Stars Are in the Milky Way?By Elizabeth Howell, Space.com Contributor / March 29, 2018 Night sky photographer Amit Ashok Kamble captured this amazing paannama of the Milky Way over Pakiri Beach, New Zealand by stitching 10 images together into a complete mosaic. Image submitted May 5, 2014. Credit: Amit Ashok KambleThe Milky Way is the galaxy in which the Earth resides. Part of it is visible on a clear night from Earth, as a thick band of stars stretching across the sky. We can see thousands of these stars with the naked eye, and many more in a telescope. But how many stars are in the Milky Way? "It's a surprisingly difficult question to answer. You can't just sit around and count stars, generally, in a galaxy," said David Kornreich, an assistant professor at Ithaca College in New York. He was the founder of the "Ask An Astronomer" service at Cornell University. Even in the Andromeda Galaxy — which is bright, large and relatively close by Earth, at 2.3 million light-years away — only the largest stars and a few variable stars (notably Cepheid variables) are bright enough to shine in telescopes from that distance. A sun-size star would be too difficult for us to see. So astronomers estimate, using some of the techniques below. The Milky Way's structureFrom observations, astronomers know that the Milky Way is a barred spiral galaxy that is about 100,000 light-years across. A view outside the galaxy would reveal a central bulge surrounded by four arms, two major and two minor. The Milky Way's major arms are known as Perseus and Sagittarius. The sun is located in one of two minor spurs, which is called the Orion Arm. The galaxy also has a huge hot-gas halo around it that is several hundreds of thousands of light-years in diameter. Astronomers estimate that the halo is just as massive as all of the stars in the Milky Way. Many of the Milky Way's stars, however, are tough to view. That is because the center of the galaxy has a galactic bulge filled with stars, gas and dust — as well as a supermassive black hole. This area is so thick with material that even powerful telescopes cannot see through it. Astronomers aren't sure when and how the bulge formed; some suggest that the Milky Way's early history was changed when the galaxy collided with another one. Astronomers used to think that all of the stars in the universe were located inside of the Milky Way, but that changed in the 1920s. Astronomer Edwin Hubble used a star called a Cepheid variable to measure distances in the sky. From there, astronomers learned that there were whole galaxies in the universe separate from the Milky Way. Massive investigation The primary way astronomers estimate stars in a galaxy is by determining the galaxy's mass. The mass is estimated by looking at how the galaxy rotates, as well as its spectrum using spectroscopy. All galaxies are moving away from each other, and their light is shifted to the red end of the spectrum because this stretches out the light's wavelengths. This is called "redshift." In a rotating galaxy, however, there will be a portion that is more "blueshifted" because that portion is slightly moving toward Earth. Astronomers must also know what the inclination or orientation of the galaxy is before making an estimate, which is sometimes simply an "educated guess," Kornreich said. A technique called "long-slit spectroscopy" is best for performing this type of work. Here, an elongated object such as a galaxy is viewed through an elongated slit, and the light is refracted using a device such as a prism. This breaks out the colors of the stars into the colors of the rainbow. Some of those colors will be missing, displaying the same "patterns" of missing portions as certain elements of the periodic table. This lets astronomers figure out what elements are in the stars. Each type of star has a unique chemical fingerprint that would show up in telescopes. (This is the basis of the OBAFGKM sequence astronomers use to distinguish between types of stars.) Any kind of telescope can do this sort of spectroscopy work. Kornreich often uses the 200-inch telescope at the Palomar Observatory at the California Institute of Technology, but he added that almost any telescope of sufficient size would be adequate. The ideal would be using a telescope in orbit because scattering occurs in Earth's atmosphere from light pollution and also from natural events — even something as simple as a sunset. The Hubble Space Telescope is one observatory known for this sort of work, Kornreich added. A successor observatory called the James Webb Space Telescope is expected to launch in 2020. The challenge, however, is that Hubble is a telescope in high demand – and the same is expected of Webb after its launch. So the observatories can't spend all of their time estimating galaxy mass. How much of the mass is stars?Between different galaxies of the same mass, there could be variances as to the types of stars and the overall mass. Kornreich cautioned this would be very hard to speak about generally, but said that one difference could be looking at elliptical galaxies vs. spiral galaxies such as our own, the Milky Way. Elliptical galaxies tend to have more K- and M-type red dwarf stars than spiral galaxies. Because elliptical galaxies are older, they will have less gas because that was blown away during their evolution. Once a galaxy's mass is determined, the other tricky thing is figuring out how much of that mass is made of stars. Most of the mass will be made up of dark matter, a type of matter that emits no light but which is believed to make up most of the mass of the universe. "You have to model the galaxy and see if you can understand what the percentage of that mass of stars is," Kornreich said. "In a typical galaxy, if you measure its mass by looking at the rotation curve, about 90 percent of that is dark matter." With much of the remaining "stuff" in the galaxy made up of diffuse gas and dust, Kornreich estimated that about 3 percent of the galaxy's mass will be made up of stars, but that could vary. Further, the size of the stars itself can greatly vary from something that is the size of our sun, to something dozens of times smaller or bigger.The number of stars is approximately … So is there any way to figure out how many stars are for sure? In the end, it comes down to an estimate. In one calculation, the Milky Way has a mass of about 100 billion solar masses, so it is easiest to translate that to 100 billion stars. This accounts for the stars that would be bigger or smaller than our sun, and averages them out. However, the mass is tough to calculate — other estimates have said the galaxy has a mass of between 400 billion and 700 billion solar masses. The European Space Agency's Gaia mission is mapping the locations of approximately 1 billion stars in the Milky Way. ESA says Gaia will map 1 percent of the stellar content in the Milky Way, which puts the estimate of the total stars in our galaxy at 100 billion. Gaia's goal is to make the best-ever three-dimensional map of the Milky Way. The caveat, Kornreich said, is that these numbers are approximations. More advanced models can make the approximation more accurate, but it would be very difficult to count the stars one by one and tell you for sure how many are in the galaxy. www.space.com/25959-how-many-stars-are-in-the-milky-way.html?utm_source=twitter&utm_medium=social
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GALAXIES
Apr 2, 2018 10:09:08 GMT -6
via mobile
Post by jcurio on Apr 2, 2018 10:09:08 GMT -6
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GALAXIES
Apr 3, 2018 10:27:34 GMT -6
via mobile
Post by jcurio on Apr 3, 2018 10:27:34 GMT -6
OOOoooooooooooo
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Post by auntym on Apr 6, 2018 13:30:32 GMT -6
mysteriousuniverse.org/2018/04/astronomers-struggle-to-explain-mysterious-ghost-galaxy/ Astronomers Struggle to Explain Mysterious ‘Ghost’ Galaxyby Brett Tingley / mysteriousuniverse.org/author/bbtingley/April 6, 2018 The search for dark matter is one of the strangest enduring scientific mysteries. Astronomers and astrophysicists believe that up to 95% of the universe could be composed of so-called dark matter and energy, “dark” meaning these forms of matter do not reflect light, x-rays, or any other radiation like all other the other stuff in the known universe does. Thus, the presence of dark matter and energy is often inferred from the gravitational effects they have on other objects and forms of energy. Dark matter is thought to be distributed throughout the entire universe, but a new discovery made by Yale astronomers might turn that thinking on its head. If we can only detect a small fraction of the 'stuff' out there in the cosmos, who knows what mysteries and wonders lie just beyond the scope of our sense? If we can only detect a small fraction of the ‘stuff’ out there in the cosmos, who knows what mysteries and wonders lie just beyond the scope of our sense? A team of astronomers mostly from Yale University have detected the first known galaxy which is completely devoid of dark matter, revealing a cosmic mystery which has left them at a loss to explain it. A study of this “ghostly” galaxy has been published in Nature. According to the astronomers’ findings thus far, the presence of this unique galaxy may challenge the current thinking about dark matter and its distribution throughout the cosmos: NGC1052–DF2 enables us to make the complementary point that dark matter does not always coincide with galaxies: it is a distinct ‘substance’ that may or may not be present in a galaxy. Furthermore, and paradoxically, the existence of NGC1052–DF2 may falsify alternatives to dark matter The galaxy was detected using the world’s largest telescopes at the W. M. Keck Observatory in Hawaii, as well as the Hubble Space Telescope. Pieter van Dokkum, lead author of the study, says this galaxy, named, NGC1052-DF2 leaves a “ghostly glow in the sky” due to its lack of dark matter. The Keck telescopes in Hawaii.It’s currently unknown how the galaxy formed, although a few theories suggest clouds of cosmic gases could have been blown out of other galaxies. Naturally, though, astronomers are cautioning drawing any conclusions since this is such a rare and unique case and there is still little data on the anomalous galaxy. Still, the ‘ghostly’ NGC1052-DF2 reveals ours is truly a mysterious universe. mysteriousuniverse.org/2018/04/astronomers-struggle-to-explain-mysterious-ghost-galaxy/
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Post by auntym on Apr 17, 2018 12:50:08 GMT -6
www.dailygalaxy.com/my_weblog/2018/04/we-truly-dont-know-what-it-is-mystery-milky-way-spectrum-of-light-observed-not-produced-by-any-known.html "We Truly Don't Know What It Is" --Mystery Milky-Way Spectrum of Light Observed 'Not Produced By Any Known Emission'The Daily Galaxy via University of Miami Posted on April 17, 2018 "We use special telescopes to catch X-ray light in the sky, and while looking at these X-rays, the telescopes noticed an unexpected feature and captured a spectrum of light, which is not produced by any known atomic emission," said University of Miami astrophysicist Nico Cappelluti. "This emission line is now called the 3.5 kiloelectron volt (keV). One interpretation of this emission line is that it's produced by the decay of dark matter." "This 3.5 keV emission line is unidentified. We truly don't know what it is," said Esra Bulbul, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and co-author in Cappelluti's study. "But one theory is that it could be a sterile neutrino, which is also known as decaying dark matter. What is truly interesting about Dr. Cappelluti's study is that he found this 3.5 keV line within our own galaxy." In 2014, a team of astronomers led by Bulbul discovered a noticeable spike in intensity at a very specific energy level. While studying the hot gas within the Perseus galaxy cluster (image above), the Chandra and XMM-Newton observatories revealed an unexpected spike, or emission line, corresponding to an energy of 3.5 kiloelectron volts (keV). This wavelength is very difficult to explain, as it cannot be described by previously observed – or even predicted – astronomical objects. "If confirmed, this will tell us what dark matter is and could be one of the major discoveries in physics," said Cappelluti. "We know that the Milky Way is surrounded by dark matter. Think of it as if we are living in a bubble of dark matter. But we also want to have the statistical certainty of our detection, so now we are putting together a Sterile Neutrino Task Force." Cappelluti is intrigued by the cosmic phenomena of super massive black holes, the nature of dark matter, and active galactic nuclei, which is the very bright light source found at the center of many galaxies.His recent published findings that could give insight on a subject scientists and astrophysicists have been investigating for decades: What is dark matter and where does it come from? Cappelluti's study, published in The Astrophysical Journal and entitled, "Searching for the 3.5 keV line in the deep fields with Chandra: the 10 MS observations," examines an interesting light source that was captured by four different telescopes each pointing in a different direction in the sky. The source of light is unfamiliar and unrecognizable to scientists and has caused quite a stir in the world of astrophysics. Bulbul also found the emission line while studying clusters of galaxies in 2014. The atomic emission spectra is shown below for various elements. Each thin band in each spectrum corresponds to a single, unique transition between energy levels in an atom. (Rochester Institute of Technology, CC BY-NC-SA 2.0). The four telescopes that captured the 3.5 keV emission were NASA's NuSTAR telescope, the European Space Agency's (ESA) XMM-Newton telescope, the Chandra telescope, and the Suzaku telescope from Japan. This fall, several scientists from around the world, including Harvard's Bulbul, plan to gather at the University of Miami to organize a massive data-mining project to investigate and research this 3.5 keV emission line. "The goal now is to continue to look at the sky until we obtain more powerful operating telescopes with better resolution, which won't be ready until 2021, and share and analyze data from other scientists who are trying to uncover the secrets of dark matter," said Bulbul. The Daily Galaxy via University of Miami www.dailygalaxy.com/my_weblog/2018/04/we-truly-dont-know-what-it-is-mystery-milky-way-spectrum-of-light-observed-not-produced-by-any-known.html
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Post by auntym on Apr 17, 2018 13:40:54 GMT -6
Hubble Verified account @nasahubble
#HubbleClassic This image of 2 interacting galaxies called Arp194 was released for Hubble's 19th anniversary. A blue-colored "fountain" of material between the galaxies makes them resemble a question mark. What will this year's Hubble anniversary image be? go.nasa.gov/2J1Oor5
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Post by swamprat on Apr 26, 2018 8:43:37 GMT -6
And here is more info on the galaxy some of us call home:Gaia’s 2nd data release: 1.7 billion stars!By Deborah Byrd in SPACE | April 26, 2018
Why did ESA’s director of science say Gaia’s observations are “redefining the foundations” of astronomy? Also, links to virtual reality resources made possible by Gaia, available for you to explore.
Gaia’s view of our home galaxy, the Milky Way, in a 360 degree interactive view (click arrows in upper left) via ESA/Gaia/DPAC; ATG medialab.
It was less than a century ago, in 1920, that astronomers were famously debating the nature of so-called spiral nebulae. Some believed they lay inside our own Milky Way galaxy and were, perhaps, forming solar systems. Others thought they were large and distant separate galaxies. Thus the wisest astronomers of yesteryear couldn’t be sure of the true nature of our home galaxy, the Milky Way. They couldn’t know it is indeed one galaxy of billions in the universe. And they couldn’t have imagined that now, just 100 years later, we’d have a space observatory like Gaia, whose goal is nothing less than to provide a 3D map of our galaxy. This mission had its second data release this week, along with a host of virtual reality resources for scientists and the public. The European Space Agency (ESA) said Gaia’s data makes possible:
"… the richest star catalog to date, including high-precision measurements of nearly 1.7 billion stars and revealing previously unseen details of our home galaxy."
The new data, which ESA called phenomenal, is based on 22 months of Gaia’s charting of the sky. Günther Hasinger, ESA’s director of science, said:
"The observations collected by Gaia are redefining the foundations of astronomy."
Why all the superlatives? What’s so amazing about Gaia’s data?
Gaia gathers its phenomenal data in the most unglamorous of ways, via what’s called astrometry. Okay, now, hang in there with me. Think about this. Gaia’s job is to scan the sky repeatedly, observing each of its targeted billion stars an average of 70 times over its five-year mission. So, for example, we know our sun and all the stars in the Milky Way are moving continuously in great orderly masses around the center of our galaxy. We know that … but we didn’t have many details about how each star moves. How could we? The data for so many stars would be (are) massive; collecting the data, storing it and analyzing it requires today’s spacecraft and computer technologies.
Over its five years, again and again and again, Gaia will acquire data points on the positions of Milky Way stars. Thus astronomers have already been able to produce an illustration like the very wonderful one below, which shows median velocities (the distances and directions traveled by each star per unit of time) of stars in our Milky Way.
And so we begin to see – not just see in our minds, but actually see via Gaia’s actual data – that, due to the movements of its stars, our Milky Way galaxy is rotating, with us in its midst. You can see that in one illustration of Gaia’s data, below:
All-sky map of median velocities of about a billion stars toward or away from our sun, made possible by the Gaia mission. When you look at this map, you’re seeing a large-scale pattern caused by rotation of our Milky Way galaxy. Image via DPAC/ESA/STFC.
And that’s just one example of the type of insight Gaia’s data can provide. ESA said:
"Gaia was launched in December 2013 and started science operations the following year. The first data release, based on just over one year of observations, was published in 2016; it contained distances and motions of two million stars.
The new data release, which covers the period between July 25, 2014, and May 23, 2016, pins down the positions of nearly 1.7 billion stars, and with a much greater precision. For some of the brightest stars in the survey, the level of precision equates to Earth-bound observers being able to spot a Euro coin lying on the surface of the moon."
Gaia is also gathering other types of data. The illustration below shows some of the ways in which Gaia sees our Milky Way:
Gaia’s all-sky view of our Milky Way galaxy and neighboring galaxies. The maps show the total brightness and color of stars (top), the total density of stars (middle) and the interstellar dust that fills the galaxy (bottom). These images are based on observations performed by the ESA satellite in each portion of the sky between July 2014 and May 2016, which were published as part of the Gaia second data release on April 25, 2018. Image via ESA.
Virtual Reality Resources Also, along with this second data release by Gaia, ESA has released several virtual reality resources to help visualize Gaia’s extraordinary data set, both for public outreach and for scientific purposes.
One of the public offerings is Gaia Sky, a real-time, 3D astronomy visualisation software that runs on Windows, Linux and MacOS, developed in the framework of ESA’s Gaia mission by the Gaia group at the Astronomisches Rechen-Institut (Zentrum für Astronomie Heidelberg, University of Heidelberg, Germany). It contains a simulation of our solar system, a view of the second Gaia data release (with different selections based on parallax relative errors, ranging from a few million to hundreds of millions of stars), and additional astronomical and cosmological data to visualize star clusters, nearby galaxies, distant galaxies and quasars, and the Cosmic Microwave Background. The data are extensive, and you’ll want to explore them yourself here: zah.uni-heidelberg.de/institutes/ari/gaia/outreach/gaiasky/
So you can see … there’s really a lot here to think about and explore, both for the public and for scientists. And maybe you can begin to see that – to those astronomers debating the nature of spiral nebulae in 1920 – Gaia’s data might have seemed nothing short of miraculous!
You can also watch a trailer of "Gaia Sky" here: earthsky.org/space/gaia-milky-way-map-2nd-data-release?utm_source=EarthSky+News&utm_campaign=bd3dc53a45-EMAIL_CAMPAIGN_2018_02_02&utm_medium=email&utm_term=0_c643945d79-bd3dc53a45-394368745
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Post by auntym on Apr 26, 2018 12:23:46 GMT -6
www.latimes.com/science/sciencenow/la-sci-sn-galaxy-mega-merger-20180425-story.html#nws=mcnewsletter A pileup of 14 distant galaxies is set to become the most massive structure in the universeBy Deborah Netburn / www.latimes.com/la-bio-deborah-netburn-staff.htmlApr 25, 2018 An artist's impression of 14 galaxies that are in the process of merging. Eventually, they will form the core of a massive galaxy cluster. (NRAO/AUI/NSF; S. Dagnello)It's a cosmic pileup in the far reaches of the universe and nothing like it has ever been seen before. Using the most powerful telescopes on Earth, astronomers have spotted 14 burning-hot galaxies hurtling toward each other on an inevitable galactic collision course at the edge of the observable universe. Computer models show that when these galaxies do collide they will form the core of a colossal galaxy cluster so large it will be the most massive structure known in the cosmos. This chaotic, energy-filled region, described Wednesday in Nature, is called a protocluster, and researchers say it is more active than any other section of the universe they have ever observed. "There are huge energetics involved, like 10,000 supernova going off at a time, quite literally," said Scott Chapman, a physicist at Dalhousie University in Halifax, Canada, who worked on the study. As if all that wasn't crazy enough, the authors said that the 14 galaxies are known as "starburst galaxies," which means they are forming stars at a furious rate. The research team estimates that they could be making stars as much as 1,000 times faster than the Milky Way. And they are all crammed into a space just three times the size of our own galaxy. In addition, the whole system is located 90% of the way to the edge of the observable universe. It is so far away that it takes light 12.4 billion years to travel across space from the protocluster to telescopes on Earth. That means that this glowing star-generator formed just 1.4 billion years after the universe itself came into being. And it's that fact in particular that has astrophysicists scratching their heads. "We don't know how it is possible," Chapman said. "We don't know how you get those 14 galaxies right down the center of the protocluster at such an early time." Nothing that big and active should have been able to form so long ago, he said. "We see the structure of the universe building up slowly from little bits, and then merging together to make bigger bits. We don't expect bigger galaxies to form until much later," he said. The earliest hint that something strange was going on in this part of the sky came in 2010 from data collected by the South Pole Telescope in Antarctica. Although this instrument was designed to find relatively nearby galaxy clusters, astronomers realized it could also be used to spot extremely bright structures from a great distance away in both space and time. The protocluster described in the new work showed up as a small but unusual smudge of light. Still, astronomers found it compelling enough to request time on the ALMA telescope in the Chilean desert to take a closer look at its structure. An ALMA image of 14 galaxies forming a protocluster known as SPT2349-56. These galaxies are in the process of merging and will eventually form the core of a truly massive galaxy cluster. (ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AUI/NSF))Observations made with ALMA revealed that the center of the smudge was actually 14 distinct galaxies and that the protocluster was a whopping 12.4 billion light-years from Earth. Chapman said that was one of the big "wow" moments. "If it had been much closer it would still be the busiest place in the universe that we know of, but it would be less shocking," he said. ALMA is great at zooming in and seeing details of objects, but it has a very narrow field of view, Chapman said. It could only see the center of the smudge that the South Pole Telescope detected. The authors estimate that there could be 1,000 more galaxies in the surrounding region of space. "Most of them will be too faint to see, even with ALMA, but we can probably find another 50 galaxies," Chapman said. The team has already started looking. Chapman said new observations are coming in even now. "This really launched a massive study," he said. In the meantime, astronomers will be busy puzzling over how such a large structure could form so early in the universe. Expect new hypotheses to come soon. "People are very resourceful at coming up with answers, after the fact," Chapman said. deborah.netburn@latimes.com
www.latimes.com/science/sciencenow/la-sci-sn-galaxy-mega-merger-20180425-story.html#nws=mcnewsletter
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