This morning I woke up with a jolt as I saw on Twitter that a supernova had been discovered in the relatively nearby galaxy M82. This is one of the best chances to observe a supernova for professional and amateur astronomers in the Northern Hemisphere in recent history!
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Things in the night sky are fairly static thanks to the long, long timescales of most astrophysical phenomena. So a supernova, the death knoll of a star blowing itself apart, is jarring and exciting when it happens so close by.
11.4 million light-years away might not seem close-by, but by cosmological standards, that’s right next door. M82 is the nearest “starburst galaxy,” meaning that it is undergoing a high rate of star formation. Such sites are typically home to core-collapse supernovae, or the event where a massive star runs out of nuclear fuel and explodes. This supernova, however, is not that type.
The spectrum shows this to be a Type 1a supernova, or a white-dwarf supernova. These can happen anywhere there are old stars, since white dwarfs are the remnants of smaller stars that have run out of fuel and finished their main life cycles.
Type 1a supernovae have distinguished themselves in astronomy as “standard candles.” That is, their peak brightness is predictable based on observations of the light curve, or how the brightness changes with time. These white dwarfs probably detonate when they collect too much mass, getting closer and closer to the Chandrasekhar limit where they can’t support themselves anymore.
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This predictability in brightness means that they can be used to accurately measure the distance to very distant galaxies. They are an important rung in the “cosmological distance ladder,” or the way we measure distances in astronomy, and were famously used in the discovery that our Universe’s expansion was accelerating due to dark energy.
Are all Type 1a supernovae really alike, though? There is evidence that the amount of heavy elements in the progenitor white dwarf can affect the brightness, introducing an uncertainty in distance calculations. These uncertainties haven’t been enough to overthrow indirect observations of dark energy, especially in light of other lines of evidence, but astronomers are always after more accuracy.
There is also some debate about the exact nature of a white dwarf supernova explosion. In one case, it may be a white dwarf collecting material from a nearby massive star, such as a red giant. However, it could also be the result of the in-spiral and collision of two white dwarfs. Having such a nearby explosion means we’ll get a much better look at the details in the way that Supernova 1987A is still giving us an amazing view of core-collapse supernovae.
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The supernova itself doesn’t appear to have reached peak brightness just yet, so it is expected to get brighter. It is already in range of amateur optical telescopes, as demonstrated by the image below, taken during the Virtual Star Party last Sunday night, two days before the announced discovery. Astronomers can report their measured magnitudes to the IAU’s Central Bureau for Astronomical Telegrams.
I don’t have an imaging camera myself, but I’ll be sure to look for it during my public observing nights in the coming weeks with our school’s 8-inch telescope! Universe Today has a map that can help you find M82 in the night sky. Phil Plait at Bad Astronomy also has more information on this exciting discovery.
Sometimes it pays to check Twitter when you’re dealing with insomnia. It may lead to a breathless early morning blog post, such as what I already wrote up for CosmoQuest. We’ll be following this story as it unfolds. Happy observing!
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Quelle: D-News
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Brand new supernova spotted in the cigar galaxy: How to see it
Supernova bei Galaxie M82
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A new supernova has just been discovered, and if you have access to a telescope and clear skies, you may be able to see it yourself.
Supernovas are extremely bright stellar explosions that can briefly glow brighter than an entire galaxy. This one is a Type Ia supernova, which means it used to be a white dwarf star. Then it exploded so powerfully that its stellar remains shot through the universe at more than 12,500 miles per second, according to Sky and Telescope.
Although the light from this supernova is just reaching us now, the dramatic event actually occurred roughly 12 million years ago in a cigar-shaped galaxy called Messier 82. At the center of the galaxy is a gas-filled, star-forming region. As you can see in the image above, the star explosion occurred slightly to the right of that stellar nursery. (Click through the gallery to find a picture of the galaxy before the supernova exploded).
One of the first people to see and report the new supernova was a group of students from the University College London, who spotted it on Tuesday evening. And the good news is that it appears to be two weeks away from its peak brightness.
So, how can you see it? According to Sky and Telescope, it is at a magnitude of 11.5, which means you will need a telescope. The galaxy lies between the Big Dipper and the Little Dipper constellations. (Check out Sky and Telescope's sky map).
Alan MacRobert, a senior editor at the magazine, writes that the galaxy is up in the northeastern sky by 7 or 8 p.m. local time for sky watchers at mid-northern latitudes.
Happy viewing!
Quelle: Sciencenow
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M82, a nearby galaxy, is home to a type Ia supernova.
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UCL students discover a supernova
Students and staff at UCL’s teaching observatory, the University of London Observatory, have spotted one of the closest supernova to Earth in recent decades. At 19:20 GMT on 21 January, a team of students – Ben Cooke, Tony Brown, Matthew Wilde and Guy Pollack – assisted by Dr Steve Fossey, spotted the exploding star in nearby galaxy Messier 82 (the Cigar Galaxy).
The discovery was a fluke – a 10 minute telescope workshop for undergraduate students that led to a global scramble to acquire confirming images and spectra of a supernova in one of the most unusual and interesting of our near–neighbour galaxies.
“The weather was closing in, with increasing cloud,” Fossey says “so instead of the planned practical astronomy class, I gave the students an introductory demonstration of how to use the CCD camera on one of the observatory’s automated 0.35–metre telescopes.”
The students chose M 82, a bright and photogenic galaxy as their target, as it was in one of the shrinking patches of clear sky. While adjusting the telescope’s position, Fossey noticed a ‘star’ overlaid on the galaxy which he did not recognise from previous observations.
They inspected online archive images of the galaxy, and it became apparent that there was indeed a new star–like object in M 82. With clouds closing in, there was hardly time to check: so they switched to taking a rapid series of 1 and 2 minute exposures through different coloured filters to check that the object persisted, and to
be able to measure its brightness and colour.
Meanwhile, they started up a second telescope to obtain a second source of data, to ensure the object was not an instrumental artefact. By about 19:40 GMT, the cloud cover was almost complete, but it was just possible to make out the new object in the
second data set: this was a real astronomical source.
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The supernova in M 82
Credit: UCL/University of London Observatory/Steve Fossey/Ben Cooke/Guy Pollack/Matthew Wilde/Thomas Wright
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One of ULO’s two 0.35-metre Celestron C14 telescopes. These were used to find the supernova in M 82
Photo: UCL MAPS/O. Usher
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There were no online reports of any prior discoveries of this object, so it seemed clear that this was a new transient source, such as a supernova. It was important to move quickly to alert astronomers worldwide to confirm the discovery, and most importantly, to obtain a spectrum – which would confirm whether or not it was a supernova, rather than some other phenomenon, such as an asteroid that happened to lie in front of the galaxy.
Fossey prepared a report for the International Astronomical Union’s Central Bureau for Astronomical Telegrams, the organisation that catalogues supernovae. He also alerted a US-based supernova search, team who have access to spectroscopic facilities.
Spectra collected by astronomers at other observatories around the world suggest that it is a Type Ia supernova, caused by a white dwarf star pulling matter off a larger neighbouring star until it becomes unstable and explodes.
The IAU’s official report has not yet been issued, and the supernova is therefore still nameless, but UCL appears to have been among the first, if not the first, to spot the event.
The two images here show the Cigar Galaxy before and during the event. Above, an image taken on 10 December 2013, and below the image taken by the students on 21 January 2014. A bright spot of light (labelled) is clearly visible, even though the exposure is shorter and the rest of the galaxy appears darker.
The supernova is one of the nearest to be observed in recent decades. The closest by far since the invention of the telescope was Supernova 1987A (the remnant of which was recently studied by UCL astronomers) in February 1987, located at a distance of 168 000 light years. This discovery is more distant at around 12 million light years, about the same as the 1993 discovery of a supernova in nearby Messier 81.
The students said:
Ben Cooke: “The chances of finding anything new in the sky is astronomical but this was particularly astounding as it was one of the first images we had taken on this telescope. My career plan had been to continue my studies in astrophysics. Its going to be hard to ever top this though!“
Guy Pollack: “It was a surreal and exciting experience taking images of the unidentified object as Steve ran around the observatory verifying the result. I’m very chuffed to have helped in the discovery of the M82 Supernova.“
Tom Wright: “One minute we’re eating pizza then five minutes later we’ve helped to discover a supernova. I couldn’t believe it. It reminds me why I got interested in astronomy in the first place”
Notes
The formal designation of the Supernova, as well as the confirmed first observation, will be announced by the International Astronomical Union.
Magnitudes of the supernova were measured from discovery images in R and V filters, obtained in poor sky conditions, with reference to the nearby star BD +70 587. The object's magnitude is estimated to be: V=11.7 (2014 Jan 21.818), R=10.5 (2014 Jan 21.805). This is bright enough to see with a good quality amateur telescope.
Quelle: UCL Physics & Astronomy – University of London Observatory
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Where to find the galaxy M82 in the sky. A line through γ and α in Ursa Major will point to it. Credit: Skymania
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Helle Supernova im Sternbild Grosser Bär
Am Dienstagabend entdeckten Studenten und Angestellte des University College London einen vergleichsweise hellen Stern in der Galaxie M82 im Sternbild Grosser Bär, der Tage zuvor noch nicht sichtbar war. Folgeuntersuchungen des zu 11.3 Grössenklassen geschätzten Objekts deuten auf die der Erde am nächsten liegende Supernova seit Jahrzehnten hin. Mit einer Deklination von 69°40.4' ist das Objekt zirkumpolar und kulminiert über den Monatswechsel Januar/Februar um 2 Uhr in rund 70° Höhe im Norden. Seine Rektaszension beträgt 9h55.7m (J2000).
Die Supernova vom Type Ia wurde noch vor dem Maximum entdeckt - damit gehört M82 in den folgenden Wochen auf den Beobachtungsplan. Die vorerst PSN J09554214+6940260 genannte Supernova befindet sich 54" westlich und 21" südlich des Kerns von M82. Für die Beobachtung ist ein Amateurteleskop notwendig.
Quelle:astroinfo .
Quelle: Langkawi National Observatory, MALAYSIA
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Galloway Astronomy Centre, SW Scotland, UK
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Update: 25.01.2014
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NASA Spacecraft Take Aim At Nearby Supernova
An exceptionally close stellar explosion discovered on Jan. 21 has become the focus of observatories around and above the globe, including several NASA spacecraft. The blast, designated SN 2014J, occurred in the galaxy M82 and lies only about 12 million light-years away. This makes it the nearest optical supernova in two decades and potentially the closest type Ia supernova to occur during the life of currently operating space missions.
To make the most of the event, astronomers have planned observations with the NASA/ESA Hubble Space Telescope and NASA's Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Gamma-ray Space Telescope, and Swift missions.
As befits its moniker, Swift was the first to take a look. On Jan. 22, just a day after the explosion was discovered, Swift's Ultraviolet/Optical Telescope (UVOT) captured the supernova and its host galaxy.
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These Swift UVOT images show M82 before (left) and after the new supernova (right). The pre-explosion view combines data taken between 2007 and 2013. The view showing SN 2014J (arrow) merges three exposures taken on Jan. 22, 2014. Mid-ultraviolet light is shown in blue, near-UV light in green, and visible light in red. The image is 17 arcminutes across, or slightly more than half the apparent diameter of a full moon.
Image Credit:
NASA/Swift/P. Brown, TAMU
Remarkably, SN 2014J can be seen on images taken up to a week before anyone noticed its presence. It was only when Steve Fossey and his students at the University of London Observatory imaged the galaxy during a brief workshop that the supernova came to light.
"Finding and publicizing new supernova discoveries is often the weak link in obtaining rapid observations, but once we know about it, Swift frequently can observe a new object within hours," said Neil Gehrels, the mission's principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md.
Although the explosion is unusually close, the supernova's light is attenuated by thick dust clouds in its galaxy, which may slightly reduce its apparent peak brightness.
"Interstellar dust preferentially scatters blue light, which is why Swift's UVOT sees SN 2014J brightly in visible and near-ultraviolet light but barely at all at mid-ultraviolet wavelengths," said Peter Brown, an astrophysicist at Texas A&M University who leads a team using Swift to obtain ultraviolet observations of supernovae.
However, this super-close supernova provides astronomers with an important opportunity to study how interstellar dust affects its light. As a class, type Ia supernovae explode with remarkably similar intrinsic brightness, a property that makes them useful "standard candles" -- some say "standard bombs" -- for exploring the distant universe.
Brown notes that X-rays have never been conclusively observed from a type Ia supernova, so a detection by Swift's X-ray Telescope, Chandra or NuSTAR would be significant, as would a Fermi detection of high-energy gamma rays.
A type Ia supernova represents the total destruction of a white dwarf star by one of two possible scenarios. In one, the white dwarf orbits a normal star, pulls a stream of matter from it, and gains mass until it reaches a critical threshold and explodes. In the other, the blast arises when two white dwarfs in a binary system eventually spiral inward and collide.
Either way, the explosion produces a superheated shell of plasma that expands outward into space at tens of millions of miles an hour. Short-lived radioactive elements formed during the blast keep the shell hot as it expands. The interplay between the shell's size, transparency and radioactive heating determines when the supernova reaches peak brightness. Astronomers expect SN 2014J to continue brightening into the first week of February, by which time it may be visible in binoculars.
M82, also known as the Cigar Galaxy, is located in the constellation Ursa Major and is a popular target for small telescopes. M82 is undergoing a powerful episode of star formation that makes it many times brighter than our own Milky Way galaxy and accounts for its unusual and photogenic appearance.
Quelle: NASA
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Update: 9.02.2014
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Image Release: Starbursting in the Galaxy M82
Messier 82 (M82), the galaxy in which the nearest supernova in decades recently exploded, also is the closest galaxy that is undergoing a rapid burst of star formation, known as a starburst. About 12 million light-years away, it is seen nearly edge-on, as shown in the larger, visible-light image from the Hubble Space Telescope. The inset is a new radio image, made with the Karl G. Jansky Very Large Array (VLA), that reveals fresh information about the central 5200 light-years of the galaxy. The radio emission seen here is produced by ionized gas and by fast-moving electrons interacting with the interstellar magnetic field. The bright dots are a mix of star-forming regions and supernova remnants, the debris from stellar explosions; analysis of the VLA data tells scientists which of these are which. Scientists also are studying the faint, wispy features, many of which were previously unseen, to investigate their relationship with this galaxy's starburst-driven superwind. Supernova 2014J is located outside the inset, to the right. VLA observations to date show that, like all other supernovae of its particular type, SN 2014J has not yet been found to be emitting radio waves.
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Credit: Josh Marvil (NM Tech/NRAO), Bill Saxton (NRAO/AUI/NSF), NASA
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Messier 82, seen in radio frequencies by the Karl G. Jansky Very Large Array.
Credit: Josh Marvil (NM Tech/NRAO), Bill Saxton (NRAO/AUI/NSF), NASA
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Quelle: NRAO
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Update: 14.02.2014
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Urban supernova-spotting at London's hidden observatory
Domes, sweet domes (Image: ULO/UCL)
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NESTLED among community gardens in a sleepy north London suburb, there is a place where you can watch stars explode.
The University of London Observatory (ULO) in Mill Hill is only a few miles down the road from my childhood home. I had no idea it existed until a few weeks back, when astronomers there announced the discovery of a supernova called 2014J, the closest star explosion to Earth in 27 years.
Usually such finds come from observatories in remote locations, such as volcanic peaks in Hawaii or high desert plateaus in Chile, where the skies are clear and dark. Visiting such places can involve weeks of planning and travel. By contrast, I jump on a London overground train to ULO after work. The forecast says the cloudy skies should clear by nightfall, tempting me with the prospect of seeing 2014J with my own eyes.
The bright lights of London were a minor concern when ULO opened in 1929, but the city's urban sprawl has since engulfed the telescope domes, and spotting supernovas and exoplanets there can be a challenge (see "For the love of exoplanets"). Still, 2014J highlights the unique power of urban astronomy.
Larger, more remote facilities find supernovas by automatically scanning the sky. Software sifts through the images and sends alerts if it finds something. But the new supernova resides in the nearby Cigar Galaxy, which has a complex structure that fooled the automatons. "The professional facilities missed it. They have it in their images but they didn't spot it because they rely on software checking," says staff astronomer Steve Fossey.
ULO's oldest telescope, dating back to 1862, is anything but automated. Three metres long and adorned with gleaming brass, it requires careful hand-positioning and uses weights and clockwork to compensate for Earth's motion. I'd love to take it for a spin, but the dreary clouds refuse to budge.
Instead I am shown the next best thing: first images of the supernova. They were taken by a more modern ULO telescope that is hooked up to computers but is controlled and monitored by human beings. An eyepiece still juts out awkwardly to one side, like a vestigial limb.
Fossey then takes me to ULO's central building, where we climb the stairs to a much larger dome which houses the observatory's biggest telescope. Its grey, bolt-studded body and circular wooden handles remind me of an early-20th-century ship – not surprising, as it was built in 1901.
Suddenly, the domed roof appears to rush towards me, accompanied by the sound of roaring motors: the telescope is so large that the floor has been designed to move up and down to accommodate its use. Originally powered by weights and pulleys, the floor is now moved by electric motors operated from a dashboard bristling with buttons. The electronics also control the telescope's position. The system was retrofitted in 1994 when the telescope's photographic plates were replaced with a camera mount.
The final stop on my tour is a telescope equipped with a spectrograph, an instrument that splits light into its constituent wavelengths. Each cosmic object emits its own spectrum, revealing clues to its chemical make-up.
Fossey is aiming to obtain a spectrum from 2014J. The supernova is of an exciting variety called a type Ia, which are all thought to have the same brightness. Astronomers use them as "standard candles" to measure cosmic distances, so they are key tools for understanding dark energy, the mysterious force credited with the accelerating expansion of the universe.
Because 2014J is so close, astronomers hope to learn enough about it to put better limits on the nature of dark energy. Ultimately, stubborn clouds block my view from ULO, but when the skies clear, London's hidden gem will continue the quest.
This article appeared in print under the headline "Urban astronomy goes supernova"
Quelle: NewScientist
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Update: 26.02.2014
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Spitzer Stares into the Heart of New Supernova in M82
The closest supernova of its kind to be observed in the last few decades has sparked a global observing campaign involving legions of instruments on the ground and in space, including NASA's Spitzer Space Telescope.
Image Credit: NASA/JPL-Caltech/Carnegie Institution for Science
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The closest supernova of its kind to be observed in the last few decades has sparked a global observing campaign involving legions of instruments on the ground and in space, including NASA's Spitzer Space Telescope. With its dust-piercing infrared vision, Spitzer brings an important perspective to this effort by peering directly into the heart of the aftermath of the stellar explosion.
Dust in the supernova's host galaxy M82, also called the "Cigar galaxy," partially obscures observations in optical and high-energy forms of light. Spitzer can, therefore, complement all the other observatories taking part in painting a complete portrait of a once-in-a-generation supernova, which was first spotted in M82 on Jan. 21, 2014. A supernova is a tremendous explosion that marks the end of life for some stars.
"At this point in the supernova's evolution, observations in infrared let us look the deepest into the event," said Mansi Kasliwal, Hubble Fellow and Carnegie-Princeton Fellow at the Observatories of the Carnegie Institution for Science and the principal investigator for the Spitzer observations. "Spitzer is really good for bypassing the dust and nailing down what's going on in and around the star system that spawned this supernova."
Supernovas are among the most powerful events in the universe, releasing so much energy that a single outburst can outshine an entire galaxy. The new supernova, dubbed SN 2014J, is of a particular kind known as a Type Ia. This type of supernova results in the complete destruction of a white dwarf star—the small, dense, aged remnant of a typical star like our sun. Two scenarios are theorized to give rise to Type Ia supernovas. First, in a binary star system, a white dwarf gravitationally pulls in matter from its companion star, accruing mass until the white dwarf crosses a critical threshold and blows up. In the second, two white dwarfs in a binary system spiral inward toward each other and eventually collide explosively.
Type Ia supernovas serve a critically important role in gauging the expansion of the universe because they explode with almost exactly the same amount of energy, shining with a near-uniform peak brightness. The fainter a Type Ia supernova looks from our vantage point, the farther away it must be. Accordingly, Type Ia supernovas are referred to as "standard candles," which allow astronomers to pin down the distances to nearby galaxies. Studying SN 2014J will help with understanding the processes behind Type Ia detonations to further refine theoretical models.
Fortuitously, Spitzer had already been scheduled to observe M82 on January 28, a week after students and staff from University College London first spotted SN 2014J on Jan. 21. Subsequent observations, also part of Kasliwal's SPIRITS (SPitzer InfraRed Intensive Transients Survey) program, took place on Feb. 7, 12, 19 and 24 and are slated for March 3.
The supernova is glowing very brightly in the infrared light that Spitzer sees. The telescope was able to observe the supernova before and after it reached its peak brightness. Such early observations with an infrared telescope have only been obtained for a few Type Ia supernovas in the past. Researchers are currently using the data to learn more about how these explosions occur.
Among the other major space-based observatories used in the M82 viewing campaign are NASA's Hubble Space Telescope, Chandra X-ray Observatory, Nuclear Spectroscopic Telescope Array (NuSTAR), Fermi Gamma-ray Space Telescope, and Swift Gamma Ray Burst Explorer. In addition to Spitzer, key infrared observations are being collected by the airplane-borne Stratospheric Observatory for Infrared Astronomy (SOFIA).
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colo. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.
Quelle: NASA
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Update: 27.02.2014
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Hubble Zooms in on Historic Supernova SN 2014J
Supernova SN 2014J as observed by the Hubble Space Telescope on Jan. 31.
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On Jan. 21, astronomers spotted the closest supernova in recent decades flash to life in the galaxy M82, some 11.5 million light-years from Earth. The supernova, designated SN 2014J, suddenly became a superstar as it became so bright that amateur astronomers with modest telescopes could easily pick out the stellar explosion in the night sky. Now, Hubble has slewed in the direction of M82 to snap this dreamy portrait of the historic stellar event.
SN 2014J is known as a Type 1a supernova, a very special kind of supernova. It is thought a Type 1a supernova is triggered by a white dwarf — an ancient small star that is the stellar husk of a star of approximately the same mass as our sun — accumulating material from a binary partner star. When the accumulated mass reaches a certain threshold, the bloated white dwarf ignites a supernova. As the threshold of material is very specific, which generates a very specific quantity of energy, Type 1a supernovae are used by astronomers as “standard candles” to measure the scale of the Universe. If you know the amount of energy released by this supernova, no matter where it is in the Cosmos, you can precisely measure your distance from it.
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SN 2014J as observed by Hubble on Jan. 31.
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In the case of SN 2014J, the closest Type 1a supernova since SN 1972e, this is the perfect opportunity to further understand the mechanisms behind a phenomena that underpins our ability to understand the scale, age and expansion of the Universe. In 1998, astronomers made the groundbreaking discovery that a mysterious force was acting on the expansion of the Universe, dubbed “dark energy,” and Type 1a supernovae were at the root of this revelation.
In this new observation captured by Hubble’s Wide Field Camera 3, the supernova has been superimposed over a photo mosaic of the entire M82 galaxy in 2006 taken with Hubble’s Advanced Camera for Surveys. This supernova portrait was acquired on Jan. 31, just as the explosion was reaching its peak in brightness.
As Hubble is sensitive to ultraviolet wavelengths of light, the impact of the supernova on the surrounding interstellar environment can be studied, building on our knowledge of these important stellar events and how they can impact their host galaxies.
