Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: February 19-25, 2012

Messier 41 - Credit: NOAO/AURA/NSF

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Greetings, fellow SkyWatchers! It’s going to be an awesome week as we watch the planets – Mars, Saturn, Jupiter, Venus and Mercury – dance along the ecliptic plane. You don’t even need a telescope for this show! But that’s not all. We’ll take a look at a wealth of bright star clusters, challenging studies and lots more. I’ll see you in the back yard…

Sunday, February 19 – Today is the birthday of Nicolas Copernicus. Born in 1473, he was the creator of the modern solar system model which illustrated the retrograde motion of the outer planets. Considering this was well over 530 years ago, and in a rather “unenlightened” time, his revolutionary thinking about what we now consider natural is astounding.

Have you been observing retrograde motion while keeping track of Mars? Good for you! You may have also noticed that Mars has dimmed slightly over the last few weeks. Right now it’s around -1.0. Keep track of its many faces!

While we still have dark skies on our side, let’s head for a handful of difficult nebulae in a region just west of Gamma Monocerotis. For binoculars, check out the region around Gamma, it is rich in stars and very colorful! You are looking at the very outer edge of the Orion spiral arm of our galaxy. For small scopes, have a look at Gamma itself – it’s a triple system that we’ll be back to study. For larger scopes? It’s Herschel hunting time…

NGC 2183 (Right Ascension: 6 : 10.8 – Declination: -06 : 13 ) and NGC 2185 (Right Ascension: 6 : 11.1 – Declination: -06 : 13 ) will be the first you encounter as you move west of Gamma. Although they are faint, just remember they are nothing more than a cloud of dust illuminated by faint stars on the edge of the galactic realm. The stars that formed inside provided the light source for these wispy objects and at their edges lay in intergalactic space.

To the southwest is the weaker NGC 2182 (Right Ascension: 6 : 09.5 – Declination: -06 : 20), which will appear as nothing more than a faint star with an even fainter halo about it, with NGC 2170 (Right Ascension: 6 : 07.5 – Declination: -06 : 24) more strongly represented in an otherwise difficult field. While the views of these objects might seem vaguely disappointing, you must remember that not everything is as bright and colorful as seen in a photograph. Just knowing that you are looking at the collapse of a giant molecular cloud that’s 2400 light-years away is pretty impressive!

Monday, February 20 – Today in history celebrates the Mir space station launch in 1986. Mir (Russian for “peace”) was home to both cosmonauts and astronauts as it housed 28 long duration crews during its 15 years of service. To date it is one of the longest running space stations and a triumph for mankind. Spasiba! Today in 1962, John Glenn was onboard Friendship 7 and became the first American to orbit the Earth. As Colonel Glenn looked out the window, he reported seeing “fireflies” glittering outside his Mercury space capsule. Let’s see if we can find some…

The open cluster M41 (Right Ascension: 6 : 46.0 – Declination: -20 : 44) in Canis Major is just a quick drift south of the brightest star in the northern sky – Sirius. Even the smallest scopes and binoculars will reveal this rich group of mixed magnitude stars and fill the imagination with strange notions of reality. Through larger scopes, many faint groupings emerge as the star count rises to well over 100 members. Several stars of color – orange in particular – are also seen along with a number of doubles.

First noted telescopically by Giovanni Batista Hodierna in the mid-1500s, ancient texts indicate that Aristotle saw this naked-eye cluster some 1800 years earlier. Like other Hodierna discoveries, M41 was included on Messier’s list – along with even brighter clusters of antiquity such as Praesepe in Cancer and the Pleiades in Taurus. Open cluster M41 is located 2300 light years away and recedes from us at 34km/sec – about the speed Venus moves around the Sun. M41 is a mature cluster, around 200 million years old and 25 light years in diameter. Remember M41… Fireflies in night skies.

Tuesday, February 21 – Tonight is New Moon! Tonight let’s take a journey just a breath above Zeta Tauri and spend some quality time with a pulsar embedded in the most famous supernova remnant of all. Factually, we know the Crab Nebula to be the remains of an exploded star recorded by the Chinese in 1054. We know it to be a rapid expanding cloud of gas moving outward at a rate of 1,000 km per second, just as we understand there is a pulsar in the center. We also know it as first recorded by John Bevis in 1758, and then later cataloged as the beginning Messier object – penned by Charles himself some 27 years later to avoid confusion while searching for comets. We see it revealed beautifully in timed exposure photographs, its glory captured forever through the eye of the camera — but have you ever really taken the time to truly study M1 (Right Ascension: 5 : 34.5 – Declination: +22 : 01)? Then you just may surprise yourself…

In a small telescope, M1 might seem to be a disappointment – but do not just glance at it and move on. There is a very strange quality to the light which reaches your eye, even though initially it may just appear as a vague, misty patch. Allow your eyes to adjust and M1 will appear to have “living” qualities – a sense of movement in something that should be motionless. The “Crab” holds true to many other spectroscopic studies. The concept of differing light waves crossing over one another and canceling each other out – with each trough and crest revealing differing details to the eye – is never more apparent than during study. To observe M1 is to at one moment see a “cloud” of nebulosity, the next a broad ribbon or filament, and at another a dark patch. When skies are stable you may see an embedded star, and it is possible to see six such stars.

Many observers have the ability to see spectral qualities, but they need to be developed. From ionization to polarization – our eye and brain are capable of seeing to the edge of infra-red and ultra-violet. Even a novice can see the effects of magnetism in the solar “Wilson Effect.” But what of the spinning neutron star at M1’s heart? We’ve known since 1969 that M1 produces a “visual” pulsar effect. About once every five minutes, changes occurring in the neutron star’s pulsation affect the amount of polarization, causing the light waves to sweep around like a giant “cosmic lighthouse” and flash across our eyes. M1 is much more than just another Messier. Capture it tonight!!

Wednesday, February 22 – Today in 1966, Soviet space mission Kosmos 110 was launched. Its crew was canine, Veterok (Little Wind) Ugolyok (Little Piece of Coal); both history making dogs. The flight lasted 22 days and held the record for living creatures in orbit until 1974 – when Skylab 2 carried its three-man crew for 28 days.

Since we’ve studied the “death” of a star, why not take the time tonight to discover the “birth” of one? Our journey will start by identifying Aldeberan (Alpha Tauri) and move northwest to bright Epsilon. Hop 1.8 degrees west and slightly to the north for an incredibly unusual variable star – T Tauri.

Discovered by J.R. Hind in October 1852, T Tauri and its accompanying nebula, NGC 1555 (Right Ascension: 4 : 22.9 – Declination: +19 : 32), set the stage for discovery with a pre-main sequence variable star. Hind reported the nebula, but also noted that no catalog listed such an object in that position. His observations also included a 10th magnitude uncharted star and he surmised that the star in question was a variable. On each count Hind was right, and both were followed by astronomers for several years until they began to fade in 1861. By 1868, neither could be seen and it wasn’t until 1890 that the pair was re-discovered by E.E. Barnard and S.W. Burnham. Five years later? They vanished again.

T Tauri is the prototype of this particular class of variable stars and is itself totally unpredictable. In a period as short as a few weeks, it might move from magnitude 9 to 13 and other times remain constant for months on end. It is about equal to our own Sun in temperature and mass – and its spectral signature is very similar to Sol’s chromosphere – but the resemblance ends there. T Tauri is a star in the initial stages of birth!

T Tauri are all pre-main sequence and are considered “proto-stars”. In other words, they continuously contract and expand, shedding some of their mantle of gas and dust. This gas and dust is caught by the star’s rotation and spun into an accretion disc – which might be more properly referred to as a proto-planetary disc. By the time the jets have finished spewing and the material is pulled back to the star by gravity, the proto-star will have cooled enough to have reached main sequence and the pressure may have allowed planetoids to form from the accreted material.

Thursday, February 23 – If you have an open western horizon, then be out at twilight! Right now the speedy inner planet – Mercury – will make a brief appearance. Depending on your time zone, you might also spot a very young Moon just above it! For curiosity seekers, you can also find asteroid Vesta to the south of the Moon, along with planet Uranus to the south-east. How cool is that?!

In 1987, Ian Shelton made an astonishing visual discovery – SN 1987a. This was the brightest supernova in 383 years. More importantly, before it occurred, a blue star of roughly 20 solar masses was already known to exist in that same location within the Large Magellanic Cloud. Catalogued as Sanduleak -69-202, that star is now gone. With available data on the star, astronomers were able to get a “before and after” look at one of the most extraordinary events in the universe! Tonight, let’s have a look at a similar event known as “Tycho’s Supernova.”

Located northwest of Kappa Cassiopeia, SN1572 appeared so bright in that year that it could be seen with the unaided eye for six months. Since its appearance was contrary to Ptolemaic theory, this change in the night sky now supported Copernicus’ views and heliocentric theory gained credence. We now recognize it as a strong radio source, but can it still be seen? There is a remnant left of this supernova, and it is challenging even with a large telescope. Look for thin, faint filaments that form an incomplete ring around 8 arc minutes across.

Friday, February 24 – Tonight the slender first crescent of the Moon makes its presence known on the western horizon. Before it sets, take a moment to look at it with binoculars. The beginnings of Mare Crisium will show to the northeast quadrant, but look just a bit further south for the dark, irregular blotch of Mare Undarum – the Sea of Waves. On its southern edge, and to lunar east, look for the small Mare Smythii – the “Sea of Sir William Henry Smyth.” Further south of this pair and at the northern edge of Fecunditatis is Mare Spumans – the “Foaming Sea.” All three of these are elevated lakes of aluminous basalt belonging to the Crisium basin.

For telescope users, wait until the Moon has set and return to Beta Monocerotis and head about a fingerwidth northeast for an open cluster challenge – NGC 2250 (Right Ascension: 6 : 32.8 – Declination: -05 : 02). This vague collection of stars presents itself to the average telescope as about 10 or so members that form no real asterism and makes one wonder if it is indeed a cluster. So odd is this one, that a lot of star charts don’t even list it!

Today in 1968, during a radar search survey, the first pulsar was discovered by Jocelyn Bell. The co-directors of the project, Antony Hewish and Martin Ryle, matched these observations to a model of a rotating neutron star, winning them the 1974 Physics Nobel Prize and proving a theory of J. Robert Oppenheimer from 30 years earlier.

Would you like to get a look at a region of the sky that contains a pulsar? Then wait until the Moon has well westered and look for guidestar Alpha Monocerotis to the south and bright Procyon to its north. By using the distance between these two stars as the base of an imaginary triangle, you’ll find pulsar PSR 0820+02 at the apex of your triangle pointed east.

Saturday, February 25 – As the Moon begins its westward journey after sunset in a position much easier to observe. The lunar feature we are looking for is at the north-northeast of the lunar limb and its view is often dependent on libration. What are we seeking? “The Sea of Alexander von Humboldt”…

Mare Humboldtianum can sometimes be hidden from view because it is an extreme feature. Spanning 273 kilometers, the basin in which it is contained extends for an additional 600 kilometers and continues around to the far side of the Moon. The mountain ranges which accompany this basin can sometimes be glimpsed under perfect lighting conditions, but ordinarily are just seen as a lighter area. The mare was formed by lava flow into the impact basin, yet more recent strikes have scarred Humboldtianum. Look for a splash of ejecta from crater Hayn further north, and the huge, 200 kilometer strike of crater Bel’kovich on Humboldtianum’s northeast shore.

When the Moon begins to wester, let’s head for Beta Monocerotis and hop about 3 fingerwidths east for an 8.9 magnitude open cluster that can be spotted with binoculars and is well resolved with a small telescope – NGC 2302 (Right Ascension: 6 : 51.9 – Declination: -07 : 04). This very young stellar cluster resides at the outer edge of the Orion spiral arm. While binoculars will see a handful of stars in a small V-shaped pattern, telescope users should be able to resolve 40 or so fainter members.

Until next week, may all of your journeys be at light speed!

If you enjoy the weekly observing column, then you’ll love the book, The Night Sky Companion 2012 written by Tammy Plotner. This fully illustrated observing guide includes star charts for your favorite objects and much more!

Posted on by Tammy Plotner

Light Echoes: The Re-Run Of The Eta Carinae “Great Eruption”

The color image at left shows the Carina Nebula, a star-forming region located 7,500 light-years from Earth. The massive double-star system Eta Carinae resides near the top of the image. The star system, about 120 times more massive than the Sun, produced a spectacular outburst that was seen on Earth from 1837 to 1858. The three black-and-white images at right show light from the eruption illuminating dust clouds near the doomed star system as it moves through them. The effect is like shining a flashlight on different regions of a vast cavern. The images were taken over an eight-year span by the U.S. National Optical Astronomy Observatory's Blanco 4-meter telescope at the CTIO. Credit: NASA, NOAO, and A. Rest (Space Telescope Science Institute, Baltimore, Md.)

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In this modern age, we’re used to catching a favorite program at a later time. We use our DVR equipment and, not so long ago, a VCR to record now and watch later. Once upon a great time ago we relied upon a quaint customer called the “re-run” – the same program broadcast at a later date. However, a re-run can’t occur when it comes to astronomy event… Or can it? Oh, you’re gonna’ love this!

Way back in 1837, Eta Carinae had an event they called the “Great Eruption”. It was an outburst so powerful that it was observable in the southern night sky for 21 years. While it could be seen, sketched and recorded for astronomy posterity, one thing didn’t happen – and that was study with modern scientific instruments. But this great double star was about to do an even greater double-take as the light from the eruption continued away from Earth and on towards some dust clouds. Now, 170 years later, the “Great Eruption” has returned to us again in an effect known as a light echo. Because of its longer path, this re-run only took 17 decades to play again!

“When the eruption was seen on Earth 170 years ago, there were no cameras capable of recording the event,” explained the study’s leader, Armin Rest of the Space Telescope Science Institute in Baltimore, Maryland. “Everything astronomers have known to date about Eta Carinae’s outburst is from eyewitness accounts. Modern observations with science instruments were made years after the eruption actually happened. It’s as if nature has left behind a surveillance tape of the event, which we are now just beginning to watch. We can trace it year by year to see how the outburst changed.”

As one of the largest and brightest systems in the Milky Way, Eta Carinae is at home some 7,500 light years from Earth. During the outburst, it shed around one solar mass for every 20 years it was active and it became the second brightest star in the sky. During that time, its signature twin lobes formed. Being able to study an event like this would help us greatly understand the lives of powerful, massive stars on the eve of destruction. Because it is so close, Eta has also been prime candidate for spectroscopic studies, giving us insight on its behavior, including the temperature and speed of the ejected material.

But there’s more…

Eta Carinae could possibly be considered more famous for its “misbehavior”. Unlike stars of its class, Eta is more of a Luminous Blue Variable – an uber bright star known for periodic outbursts. The temperature of the outflow from Eta Carinae’s central region, for example, is about 8,500 degrees Fahrenheit (5,000 Kelvin), which is much cooler than that of other erupting stars. “This star really seems to be an oddball,” Rest said. “Now we have to go back to the models and see what has to change to actually produce what we are measuring.”

Through the eyes of the U.S. National Optical Astronomy Observatory’s Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile, Rest and the team first spotted the light echo in 2010 and then again in 2011 while comparing visible light observations. From there he quickly compared it with another set of CTIO observations taken in 2003 by astronomer Nathan Smith of the University of Arizona in Tucson and pieced together the 20 year old puzzle. What he saw was nothing short of amazing…

“I was jumping up and down when I saw the light echo,” said Rest, who has studied light echoes from powerful supernova blasts. “I didn’t expect to see Eta Carinae’s light echo because the eruption was so much fainter than a supernova explosion. We knew it probably wasn’t material moving through space. To see something this close move across space would take decades of observations. We, however, saw the movement over a year’s time. That’s why we thought it was probably a light echo.”

While the images would appear to move with time, this is only an “optical illusion” as each parcel of light information arrives at a different time. Follow up observations include more spectroscopy pinpointing the outflow’s speed and temperature – where ejected material was clocked at speed of roughly 445,000 miles an hour (more than 700,000 kilometers an hour) – a speed which matched computer modeling predictions. Rest’s group also cataloged changes in the light echo intensity using the Las Cumbres Observatory Global Telescope Network’s Faulkes Telescope South in Siding Spring, Australia. Their results were then compared the historic measurements during the actual event and the peak brightness findings matched!

You can bet the team is continuing to monitor this re-run very closely. “We should see brightening again in six months from another increase in light that was seen in 1844,” Rest said. “We hope to capture light from the outburst coming from different directions so that we can get a complete picture of the eruption.”

Original Story Source: HubbleSite News Release. For Further Reading: Nature Science Paper by A. Rest et al.

Posted on by Tammy Plotner

Young Star Cluster In Disintegrated Galaxy Reveals First-Ever Intermediate Mass Black Hole

This spectacular edge-on galaxy, called ESO 243-49, is home to an intermediate-mass black hole that may have been stripped off of a cannibalized dwarf galaxy. Credit: NASA, ESA, and S. Farrell (Sydney Institute for Astronomy, University of Sydney)

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Score another first for NASA’s Hubble Space Telescope! Along with observations taken with the Swift X-ray telescope, a team of astronomers have identified a young stellar cluster of stars pointing the way towards the first verified intermediate mass black hole. This grouping of stars provides significant indication that black holes of this type may have been at the center of a now shredded dwarf galaxy – a finding which increases our knowledge of galaxy evolution.

“For the first time, we have evidence on the environment, and thus the origin, of this middle-weight black hole,” said Mathieu Servillat, a member of the Harvard-Smithsonian Center for Astrophysics research team.

Designated as ESO 243-49 HLX-1, this incredible intermediate mass black hole was discovered in 2009 by Sean Farrell, of the Sydney Institute for Astronomy in Australia, using the European Space Agency’s XMM-Newton X-ray space telescope. Hyper-Luminous X-ray Source 1 is a 20,000 solar mass beauty which resides at the edge of galaxy ESO 243-49 some 290 million light years away. However, the Newton’s findings weren’t the only contribution – HLX-1 was also verified with NASA’s Swift observatory in X-ray and Hubble in near-infrared, optical, and ultraviolet wavelengths. What stands out is the presence of a cluster of young stars encircling the black hole and stretching out across about 250 light years of space. While the stars themselves are too far away to be resolved, their magnitude and spectra match with other young clusters seen in similar galaxies.

Just what clued the team to the presence of a star cluster? In this case their instruments revealed the blue spectrum of hot gases being emitted from the accretion disk located at the periphery of the black hole… and there was more. They also noted the presence of red light spawned by cooler gases which may indicate the presences of stars. Time to match up the findings against computer modeling.

“What we can definitely say with our Hubble data is that we require both emission from an accretion disk and emission from a stellar population to explain the colors we see.” said Farrell.

Why is the presence of a young star cluster unusual? According to what we know so far, they just don’t occur outside a flattened disk such as HLX-1. This finding may indicate the intermediate mass black hole may have once been at the heart of a dwarf galaxy engaged in a merger event. The dwarf galaxy’s stars were stripped away, but not its capabilities to form new. During the interaction, the gas around the black hole was compressed and star formation began again… but how long ago?

“The age of the population cannot be uniquely constrained, with both very young and very old stellar populations allowed. However, the very old solution requires excessively high levels of disc reprocessing and an extremely small disc, leading us to favour the young solution with an age of ~13 Myr.” says the team. “In addition, the presence of dust lanes and the lack of any nuclear activity from X-ray observations of the host galaxy lead us to propose that a gas-rich minor merger may have taken place less than ~200 Myr ago. Such a merger event would explain the presence of the intermediate mass black hole and support a young stellar population.”

Discoveries such as HLX-1 will help astronomers further understand how supermassive black holes are formed. Current conjecture is that intermediate mass black holes may migrate together to form their larger counterparts. Studying the trajectory of this new find may provide valuable information… even if it is unknown at this point. HLX-1 may be drawn into a merger event and it may just end up orbiting ESO 243-49. Regardless of what happens, chances are it will fade away in X-ray as it exhausts its gas supply.

“This black hole is unique in that it’s the only intermediate-mass black hole we’ve found so far. Its rarity suggests that these black holes are only visible for a short time,” said Servillat.

Original Story Source: Harvard Center for Astrophysics News Release. For Further Reading: A Young Massive Stellar Population Around the Intermediate Mass Black Hole ESO 243-49 HLX-1.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast – February 12-18, 2012

Spirograph Nebula Courtesy of the Hubble Space Telescope

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Greetings, fellow SkyWatchers! As the Moon fades away, dark sky studies return and so do we as we take a look at a great collection of nebulae this week and expand your Herschel studies. Get out your binoculars and telescopes, because here’s what’s up!

Sunday, February 12 – Today is the anniversary (2001) of NEAR landing on asteroid Eros. The Near Earth Asteroid Rendezvous (NEAR) mission was the first to ever orbit an asteroid, successfully sending back thousands of images. Although it was not designed to land on Eros, it survived the low speed impact and continued to send back data. Would you like to view Eros for yourself? It will be visible a few hours after sky dark. At somewhere between magnitude 11 and 12, Eros will require at least a mid-sized telescope, but is very viewable to both hemispheres along the Hydra/Crater border… and about a handspan southwest of Mars! Be sure to check resources for a planetarium program or on-line service which will give you a precise location for your time and area.

Tonight we’ll continue onward with our studies of Lepus as we head for two more of the coveted Herschel 400 objects. Our hop starts with beautiful Gamma and NGC 2073. Located less than a fingerwidth northeast of Gamma (RA 05 45 53.90 Dec -21 59 59.0), NGC 2073 might be magnitude 12.4, but its small size makes it anything but easy. Even if it does have some highly studied molecular cloud structure, be prepared to see nothing but a tiny, egg-shaped contrast change in the elliptical Herschel 241.

Continue northeast a little more than 2 degrees (RA 05 54 52.30 Dec -20 05 03.0) to encounter Herschel 225 – NGC 2124. Although it is slightly fainter, we are at least picking up something with more recognizable structure. Oriented north/south, Herschel 225 is an inclined spiral with a bright nucleus. Set in a wonderfully rich star field, it’s difficult to spot at first with low power, but its slim structure holds up well to magnification. This one is really a pleasure.

Monday, February 13 – Today is the birthday of J.L.E. Dreyer. Born in 1852, the Danish-Irish Dreyer came to fame as the astronomer who compiled the New General Catalogue (NGC) published in 1878. Even with a wealth of astronomical catalogs to chose from, the NGC objects and Dreyer’s abbreviated list of descriptions still remain the most widely used today.

Tonight let’s make Dreyer proud as we finish up our Herschel 400 studies for Herschel 267. At magnitude 13, NGC 2076 (Right Ascension: 5 : 46.8 – Declination: -16 : 46 ) is a lot less forgiving of scope size and sky conditions than some galaxies, but if aperture and sky cooperate, you are in for a real treat! Although it is fairly small and somewhat faint, NGC 2076 is an edge-on that will show indications of a dark dustlane across its brighter nucleus, when using aversion. The lane itself has been highly studied for dust extinction and star forming properties and as recently as 2003 a supernova event was reported just south of the nucleus.

Now let’s drop south about one degree and pick up Herschel 270! Far brighter at magnitude 11.9, don’t let the ordinary elliptical NGC 2089 (Right Ascension: 5 : 47.8 – Declination: -17 : 36) fool you. What would appear to be a stellar nucleus is indeed stellar. Studies done by AAVSO have shown that the bright point of light is actually a line of sight star. Congratulations on your studies and be sure to write down your Herschel “homework!”

Tuesday, February 14 – Happy Valentine’s Day! Today is the birthday of Fritz Zwicky. Born in 1898, Zwicky was the first astronomer to identify supernovae as a separate class of objects. His insights also proposed the possibility of neutron stars. Among his many achievements, Zwicky also catalogued galaxy clusters and designed jet engines.

In mythology, Lepus the Hare is hiding in the grass at Orion’s feet. As we have seen, there are many objects of beauty hidden within what seems to be a very ordinary constellation. Before we leave the “Rabbit” for this year, there is one last object that is worthy of attention. If you look to the feet of Orion and the brightest star of Lepus, you will see that they make a triangle in the sky. Tonight we are headed towards the center of that triangle for a singular object – the Spirograph Nebula.

Shown in all its glory through the eye of the Hubble Telescope, the light you see tonight from the IC 408 (Right Ascension: 5 : 17.9 – Declination: -25 : 05) planetary nebula left in the year 7 AD. Its central star, much like our own Sol, was in the final stages of its life at that time, and but a few thousand years earlier was a red giant. As it shed its layers off into about a tenth of a light-year of space, only its superheated core remained – its ultraviolet radiation lighting up the expelled gas. Perhaps in several thousand years the nebula will have faded away, and in several billion years more the central star will have become a white dwarf – a fate that also awaits our own Sun.

At magnitude 11, it is well within reach of a small to mid-size telescope. Like all planetary nebulae, the more magnification – the better the view. The central star is easily seen against a slightly elongated shell and larger telescopes bring an “edge” to this nebula that makes it very worthwhile studying. Spend some quality time with this object. With larger scopes, there is no doubt a texture to this planetary that will delight the eye…and touch the heart!

Wednesday, February 15 – Born on this day in 1564 was the man who fathered modern astronomy – Galileo Galilei. Two and a half centuries ago, he became first scientist to use a telescope for astronomical observation and his first target was the Moon. Just before dawn this morning you will have the opportunity to observe the waning crescent and the tiny crater named for Galileo. Almost central along the terminator and caught near the edge of Oceanus Procellarum, you will see a small, bright ring. This is Reiner Gamma and you will find Galileo just a short hop to the northwest as a tiny, circular crater. What a shame the cartographers did not pick a more vivid feature to name after the great Galileo!

With absence of the Moon in our favor tonight, it’s time to learn the constellation of Monoceros as the skies darken and Orion begins to head west. By using the red giant Betelgeuse, diamond-bright Sirius and the beacon of Procyon, we can see these three stars form a triangle in the sky with Sirius pointing towards the south. The “Unicorn” is not a bright constellation, and most of its stars fall inside this area with its Alpha star almost a handspan south of Procyon.

Using the belt of Orion as a guide, look a handspan east, this is Delta. A fistwidth away to the southeast is Gamma; with Beta about two fingerwidths further along. About a palmwidth southeast of Betelguese is Epsilon. Although this might seem simplistic, knowing these stars will help you find many wonderful objects. Let’s start our journey tonight two fingerwidths northwest of Epsilon… NGC 2186 (Right Ascension: 6 : 12.2 – Declination: +05 : 2) is a triangular open cluster of stars set in a rich field that can be spotted with binoculars and reveals as many as 30 or more stars to even a small telescope. Not only is this a Herschel 400 object that can be spotted with simple equipment, but a highly studied galactic cluster that contains circumstellar discs!

Thursday, February 16 – On this day in 1948, Gerard Kuiper was celebrating his discovery of Miranda – one of Uranus’ moons. Just 42 years earlier on this day, both Kopff and Metcalf were also busy – discovering asteroids! Today is the birthday of Francois Arago. Born in 1786, Arago became the pioneer scientist in the wave nature of light. His achievements were many and he is also credited as the inventor of the polarimeter and other optical devices.

Tonight let’s celebrate Arago’s achievements in polarization as we return again to Epsilon Monocerotis. Our destination is around a fingerwidth east as we seek out another star cluster that has an interesting companion – a nebula!

NGC 2244 (Right Ascension: 6 : 32.4 – Declination: +04 : 52) is a star cluster embroiled in a reflection nebula spanning 55 light-years and most commonly called “The Rosette.” Located about 2500 light-years away, the cluster heats the gas within the nebula to nearly 18,000 degrees Fahrenheit, causing it to emit light in a process similar to that of a fluorescent tube. A huge percentage of this light is hydrogen-alpha, which is scattered back from its dusty shell and becomes polarized.

While you won’t see any red hues in visible light, a large pair of binoculars from a dark sky site can make out a vague nebulosity associated with this open cluster. Even if you can’t, it is still a wonderful cluster of stars crowned by the yellow jewel of 12 Monocerotis. With good seeing, small telescopes can easily spot the broken, patchy wreath of nebulosity around a well-resolved symmetrical concentration of stars. Larger scopes, and those with filters, will make out separate areas of the nebula which also bear their own distinctive NGC labels. No matter how you view it, the entire region is one of the best for winter skies.

Friday, February 17 – Tonight is a good time for us to go hunting some obscure objects that will require the darkest of skies. Once again, we’ll use our guide star Epsilon and tonight we’ll be heading about three fingerwidths northeast for a vast complex of nebulae and star clusters.

To the unaided eye, 4th magnitude S Monocerotis is easily visible and to small binoculars so are the beginnings of a rich cluster surrounding it. This is NGC 2264 (Right Ascension: 6 : 41.1 – Declination: +09 : 53). Larger binoculars and small telescopes will easily pick out a distinct wedge of stars. This is most commonly known as the “Christmas Tree Cluster,” its name given by Lowell Observatory astronomer Carl Lampland. With its peak pointing due south, this triangular group is believed to be around 2600 light-years away and spans about 20 light-years. Look closely at its brightest star – S Monocerotis is not only a variable, but also has an 8th magnitude companion. The group itself is believed to be almost 2 million years old.

The nebulosity is beyond the reach of a small telescope, but the brightest portion illuminated by one of its stars is the home of the Cone Nebula. Larger telescopes can see a visible V-like thread of nebulosity in this area which completes the outer edge of the dark cone. To the north is a photographic only region known as the Foxfur Nebula, part of a vast complex of nebulae that extends from Gemini to Orion.

Northwest of the complex are several regions of bright nebulae, such as NGC 2247, NGC 2245, IC 446 and IC 2169. Of these regions, the one most suited to the average scope is NGC 2245 (Right Ascension: 6 : 32.7 – Declination: +10 : 10), which is fairly large, but faint, and accompanies an 11th magnitude star. NGC 2247 (Right Ascension: 6 : 33.2 – Declination: +10 : 20) is a circular patch of nebulosity around an 8th magnitude star, and it will appear much like a slight fog. IC 446 is indeed a smile to larger aperture, for it will appear much like a small comet with the nebulosity fanning away to the southwest. IC 2169 is the most difficult of all. Even with a large scope a “hint” is all!

Enjoy your nebula quest…

Saturday, February 18 – On this day in 1930, a young man named Clyde Tombaugh was very busy checking out some photographic search plates taken with the Lowell Observatory’s 13″ telescope. His reward? The discovery of Pluto! And just where is the planet that isn’t a planet any more? You can find it before dawn! The little rascal is hiding out in a very stellar field just east of M25 and a couple of degrees northwest of the slender crescent Moon. How do you know which faint “star” is Pluto? Well, if you set a computerized telescope to RA 18h 24m 59s – Dec 19°18’44”, it will be precisely in the center of the field if you are perfectly polar aligned. If you are using a manual telescope, you will need to sketch the field and return over a period of several days to see which “star” moves. It would be a great lesson – since early astronomers did it that way!

This evening let us return to the realm of binoculars and small telescopes as we head now for Beta Monocerotis and a little more than a fingerwidth north for NGC 2232 (Right Ascension: 6 : 26.6 – Declination: -04 : 45). This wonderful collection of stars sparkles with chains and various magnitudes – the brightest of which is 5th magnitude 10 Monocerotis. Well resolved with a small telescope, its apparent size of about a full moon-width makes it a true delight and it can even be spotted unaided from a dark sky site. Be sure to note it, because it is on many open cluster study lists.

Now head back to Beta and about the same distance west for Class D cluster NGC 2215 (Right Ascension: 6 : 21.0 – Declination: -07 : 17). At magnitude 8, it is still within the realm of binoculars, but will look like a small fuzzy patch beyond resolution. Try this one with a telescope! Set in a rich field, the compressed area of near equal magnitude stars isn’t the most colorful in the sky, but you can add another to your Herschel hits!

Until next week, may all your journeys be at light speed!

Posted on by Tammy Plotner

Ancient Antarctic Ice Sampled In Lake Vostok Drill

Panoramic photo of Vostok Station showing the layout of the camp. Credit: Todd Sowers LDEO, Columbia University, Palisades, New York (Image from physorg.com)

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Sealed off for millions of years beneath an almost impenetrable layer of ice, Lake Vostok has kept a vast archive of ancient history waiting for just the right moment to reveal itself. Here is a unique closed ecosystem captured in time below four kilometers of ice. Saved from environmental contamination, its water has been isolated from Earth’s atmosphere, and the outside world, long before man existed. Only one burning question remains… Could this pristine pocket of Lake Vostok show signs of early life?

“According to our research, the quantity of oxygen there exceeds that on other parts of our planet by 10 to 20 times. Any life forms that we find are likely to be unique on Earth,” says Sergey Bulat, the Chief Scientist of Russia’s Antarctic Expedition to Russian Reporter magazine.

So why be so excited over finding a few organisms? The reason is clear as the hidden waters. If a life form could exist here, it could also exist on a similar world…. Jupiter’s satellite, Europa.

“The discovery of microorganisms in Lake Vostok may mean that, perhaps, the first meeting with extra-terrestrial life could happen on Europa,” said Dr Vladimir Kotlyakov, Director of the Geography Institute at the Russian Academy of Sciences to Vzglyad newspaper.

Image from earth.columbia.edu
However, drilling through over 3,700 meters of pure ice hasn’t been an easy process – especially when you’re working in temperatures as low as minus 80 centigrade. The chill thrill drill began in 1970, but it was over 25 years later before Russian specialists discovered the hidden lake beneath the ice sheet. Along with British support, they then began sonar and satellite imagining to reveal one of the world’s largest undisclosed fresh water reservoirs. Now, speculation began in earnest. What might these waters contain? Could it be tiny microbes? Or perhaps even a dangerous organism… There was only one way to find out. Drill and sample.

“Everything but the samples themselves will be carefully decontaminated using radiation. There is no need to worry,” Valeriy Lukin, Head of the Antarctic Expedition told Russian Reporter Magazine. According to researchers at the Russian Arctic and Antarctic Research Institute, they surmise the findings as “the only giant super-clean water system on the planet.” and pristine water will be “twice cleaner than double-distilled water.”

Over the last few decades, there had been a lot of discord over anti-freeze drilling methods – each with its pros and cons. From kerosene to Freon – even hot water – the end result needed to be the same. No chance of contamination… either to the samples or the native environment. As it ended up, the Russian method of using the former turned out to be fine when 40 liters of frozen, pure water came to light on February 4. Just a day later, 1,500 liters of kerosene and Freon poured into special containers with no problems and the sample proved to be immaculate. The clear waters are now safely tucked away in sterile containers and are heading back home.

“I can say that everyone at Bellingshausen on the Antarctic Peninsula could probably tell you down to the meter what the daily progress of the drilling was at the Vostok Station in the center of the continent.” says reporter, Sean Thomas. ” After all, the work at Lake Vostok was a Russian project, at a Russian base with Russian scientists, so there is a lot of pride in the work that is being done there.”

Original Story Source: RT News.

Posted on by Tammy Plotner

Requiem For Astronaut Janice Voss

Dr. Janice Voss - Photo Courtesy of NASA

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Please take the time to respectfully recognize the passing of veteran astronaut, Janice Voss. She was a former science director for a NASA exoplanet-hunting spacecraft and also a member of five manned spaceflights. She lost her battle with cancer today at the young age of 55. “Just got the very sad news that U.S. astronaut Janice Voss passed away last night,” the Association of Space Explorers, an international organization representing more than 350 individuals who have flown in space, wrote on Facebook. “Our thoughts go out to her family and friends.” NASA confirmed Voss’ passing in a statement issued on Tuesday (Feb. 7), saying she had passed away overnight.

Janice was born on October 8, 1956, in South Bend, Indiana, but she called Rockford, Illinois home. Some of her passions for life included flying, volleyball, dancing and reading science fiction. She graduated from from Minnechaug Regional High School, Wilbraham, Massachusetts, in 1972, continued on to Purdue University for her bachelor of science degree and achieved a master of science degree in electrical engineering and a doctorate in aeronautics/astronautics from the Massachusetts Institute of Technology in 1977 and 1987, respectively. From there, Janice continued her education by taking some correspondence courses from the University of Oklahoma and did some graduate work in space physics at Rice University in 1977 and 1978.

Astronaut Janice Voss pictured in 2000 on the flight deck of the space shuttle Endeavour during the STS-99 mission. (NASA)
In 1990, Janice Voss was chosen by NASA for the astronaut corps and served as a mission specialist on five space shuttle missions, including the only repeat flight in the program’s 30 year history. But that’s not all. She also flew with the first commercial lab, rendezvoused with Russia’s Mir space station and helped create the most complete digital topographic map of the Earth. In June 1993, Janice took part in biomedical and material science experiments as a member of the Spacehab module – a commercial laboratory attached to the orbiter’s payload bay. In February 2000, Voss again launched on Endeavour as part of the Shuttle Radar Topography Mission crew. After deploying a nearly 200-foot (60-meter) mast, Voss and her team labored through two full shifts to map more than 47 million square miles (122 million square kilometers) of the Earth’s land surface. The shuttle Endeavour served as both her first and final mission.

The first time a space shuttle came close to the Russian Space Station, Mir, Dr. Voss was there. As her second mission, she and her STS-63 crew mates met with the Russians to discuss flight techniques, communications, sensors aids and navigation. The February 1995 “Near-Mir” mission set the stage for the first shuttle-Mir docking later that year. Janice also served on another historic mission – the only time a crew was launched twice to perform the same mission. The first launch came on April 4, 1997 and three days later it returned to Earth after a fuel cell problem. Ninty days later, the Columbia was restored and it launched again into a successful 15 day flight. This time Voss and crew engaged their time inside a European Spacelab module, conducting experiments as part of the Microgravity Science Laboratory (MSL) mission.

Janice Voss, shown in April 1997 working with communications systems on the aft flight deck of space shuttle Columbia. (NASA)
Over her career, astronaut Janice Voss totaled over 49 days in space, traveling 18.8 million miles (30.3 million km) while circling the Earth 779 times. Her five missions tied her with the record for the most spaceflights by a woman. When she at last touched down on Earth, she went on to the Johnson Space Center in Houston, Texas to NASA’s Ames Research Center at Moffett Field, California, where she headed the science program for the agency’s Kepler space observatory. She stayed at Ames until 2007 and spent the rest of her time as the payload lead in the astronaut office’s space station branch at the Johnson Space Center.

Janice Voss, pictured looking over a checklist on space shuttle Endeavour's aft flight deck during her final spaceflight. (NASA)
“As payload commander of two shuttle missions, Janice was responsible for paving the way for experiments that we now perform on a daily basis on the International Space Station,” chief astronaut Peggy Whitson said in a statement. “By improving the way scientists are able to analyze their data, and establishing the experimental methods and hardware necessary to perform these unique experiments, Janice and her crew ensured that our space station would be the site of discoveries that we haven’t even imagined.”

“During the last few years, Janice continued to lead our office’s efforts to provide the best possible procedures to crews operating experiments on the station today,” she said. “Even more than Janice’s professional contributions, we will miss her positive outlook on the world and her determination to make all things better.”

Godspeed, Janice… Godspeed.

Original Story Source: CollectSpace News and NASA Files.

Posted on by Tammy Plotner

The Milky Way Galactic Disk – Forever Blowing Bubbles

Ten Milky Way Project images most-favourited by volunteers, in no particular order. Coordinates are image centres, image sizes are indicated by the zoom level (zoom).

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Score another one for citizen science! In a study released just days ago, a new catalog containing over five thousand infrared bubble entries was added through the “Milky Way Project” website. The work was done independently by at least five participants who measured parameters for position, radius, thickness, eccentricity and position angle. Not only did their work focus on these areas, but the non-professionals were responsible for recovering the locations of at least 86% of additional bubble and HII catalogs. Cool stuff? You bet. Almost one third of the Milky Way Project’s studied bubbles are located at the edge of an even larger bubble – or have more lodged inside. This opens the door to further understanding the dynamics of triggered star formation!

Just what is the Milky Way Project? Thanks to the Galaxy Zoo and Zooniverse, scientists have been able to enlist the help of an extensive community of volunteers able to tackle and analyze huge amounts of data – data that contains information which computer algorithms might miss. In this case it’s visually searching through the Galactic plane for whole or broken ring-shaped structures in images done by Spitzer’s Galactic Legacy Infrared Survey Extraordinaire (GLIMPSE) project. Here the bubbles overlap and the structures are so complex that only humans can sort them out for now.

Screenshot of the Milky Way Project user interface.
Screenshot of the Milky Way Project user interface.
“The MWP is the ninth online citizen science project created using the Zooniverse Application Programming Interface
(API) tool set. The Zooniverse API is the core software supporting the activities of all Zooniverse citizen science projects.” says R. J. Simpson (et al). “Built originally for Galaxy Zoo 2, the software is now being used by 11 different projects. The Zooniverse API is designed primarily as a tool for serving up a large collection of `assets’ (for example, images or video) to an interface, and collecting back user-generated interactions with these assets.”

Through the interface, users mark the location of bubbles and other areas of significance such as small bubbles, green knots, dark nebulae, star clusters, galaxies, fuzzy red objects or simply unknowns. During this phase, the citizen scientist can make as many annotations as he or she wants before they submit their findings and receive a new assignment. Each annotated image is then stored in a database as a classification and the user can access their image again in an area of the website known as “My Galaxy”. However, images may only be classified once.

Example of raw user drawings and reduced, cleaned result using a sample MWP image. A GLIMPSE-only colour sam- ple is included to illustrate the dierences in the appearance of images inspected by CP06 and the MWP users.
When identifying galactic bubbles, the user creates a circle around the area which can be scaled to size and stretched into an elliptical configuration. Initially as the object is identified and marked, the user can control the position and size of the bubble. Once annotated the parameters can be edited, such as the ellipticity, annular thickness and rotation. The program even allows for regions where no obvious emission is present, such as a broken or partial bubble. This allows the user to match the bubbles they find in individual images to achieve an accurate representation You can even mark a favorite or interesting configuration as well!

“In order to assist in the data-reduction process, users are given scores according to how experienced they are at drawing bubbles. We treat the first 10 bubbles a user draws as practice drawings and these are not included in the final reduction. Users begin with a score of 0 and are given scores according to the number of precision bubbles they have drawn.” explains the team. “Precision bubbles are those drawn using the full tool set, meaning they have to have adjusted the ellipticity, the thickness and the rotation. This is done to ensure that users’ scores reflect their ability to draw bubbles well. While only precision bubbles are used to score volunteers, all bubbles drawn as included in the data reduction. The scores are used as weights when averaging the bubble drawings to produce the catalogue.”

Now it’s time to combine all that data. As of October of last year, the program has created a database of 520,120 user-drawn bubbles. The information is then sorted out and processed – with many inclusions left for further investigation. However, not all bubbles make the cut. When it comes to this project, only bubbles that have been identified fifty times or more are included into the catalog. What remains is a “clean bubble” – one that has been verified by at least five users and picked out at least 10% of the time by the volunteers when displayed.

“It is not known how many bubbles exist in the Galaxy, hence it is impossible to quantify the completeness of the MWP catalogue. There will be bubbles that are either not visible in the data used on the MWP, or that are not seen as bubbles.” says the team. “Distant bubbles may be obscured by foreground extinction. Faint bubbles may be masked by bright Galactic background emission or confused with brighter nebular structures. Fragmented or highly distorted bubbles present at high inclination angles may not appear as bubbles to the observer.”

Error measurements for MWP bubble MWP1G309059+01661. This bubble has a hit rate of 0.437, and a dispersion of 1.61'. Top gures show reduced and raw bubble drawings. Bottom figures show dispersions in measurements of position and size.
But don’t let it burst your bubble. This citizen science approach is an excellent idea from the the standpoint of observer objectivity and the final, reduced catalogue contains 5,106 visually identified bubbles. Of these, they are divided into a catalogue of 3,744 large bubbles identified by users as ellipses, and a catalogue of 1,362 small bubbles annotated by users at the highest zoom level images in the MWP.

And that’s not all… “In addition to the reduced bubble catalogue, a crowd sourced `heat map’ of bubble drawings has also been produced. The MWP `heat maps’ allow the bubble drawings to be explored without them needing to be reduced to elliptical annuli. Rather, the `heat maps’ allow contours of overlapping classifications to be drawn over regions of the Galactic plane reflecting levels of agreement between independent classifiers. In most cases the structures outlined in these maps are photo-dissociation regions traced by 8 um emission, but more fundamentally they are regions that multiple volunteers agree reflect the rims of bubbles.”

Yep. They are bubbles alright. Bubble produced around huge stars when an HII region is hollowed out by thermal overpressure, stellar winds, radiation pressure or a combination of them all. This impacts the surrounding, cold interstellar medium and creates a visible shell – or bubble. These regions serve as perfect observation points “to test theories of sequential, massive star formation triggered by massive star winds and radiation pressure” and to keep us forever fascinated…

And forever studying bubbles.

Original Story Source: The Milky Way Project First Data Release: A Bubblier Galactic Disk. For Further Reading: The Milky Way Project Zooniverse Blog.

Posted on by Tammy Plotner

The Milky Way’s Magnetic Personality

The sky map of the Faraday effect caused by the magnetic fields of the Milky Way. Red and blue colors indicate regions of the sky where the magnetic field points toward and away from the observer, respectively. The band of the Milky Way (the plane of the Galactic disk) extends horizontally in this panoramic view. The center of the Milky Way lies in the middle of the image. The North celestial pole is at the top left and the South Pole is at the bottom right. (Image Credit: Max Planck Institute for Astrophysics)

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Recently we took a look at a very unusual type of map – the Faraday Sky. Now an international team of scientists, including those at the Naval Research Laboratory, have pooled their information and created one of the most high precision maps to date of the Milky Way’s magnetic fields. Like all galaxies, ours has a magnetic “personality”, but just where these fields come from and how they are created is a genuine mystery. Researchers have always simply assumed they were created by mechanical processes like those which occur in Earth’s interior and the Sun. Now a new study will give scientists an even better understanding about the structure of galactic magnetic fields as seen throughout our galaxy.

The team, led by the Max Planck Institute for Astrophysics (MPA), gathered their information and compiled it with theoretical simulations to create yet another detailed map of the magnetic sky. As NRL’s Dr. Tracy Clarke, a member of the research team explains, “The key to applying these new techniques is that this project brings together over 30 researchers with 26 different projects and more than 41,000 measurements across the sky. The resulting database is equivalent to peppering the entire sky with sources separated by an angular distance of two full moons.” This huge amount of data provides a new “all-sky” look which will enable scientists to measure the magnetic structure of the Milky Way in minute detail.

In this map of the sky, a correction for the effect of the Galactic disk has been made in order to emphasize weaker magnetic field structures. The magnetic field directions above and below the disk seem to be diametrically opposed, as indicated by the positive (red) and negative (blue) values. An analogous change of direction takes place across the vertical center line, which runs through the center of the Milky Way. (Image Credit: Max Planck Institute for Astrophysics)
Just what’s so “new” about this map? This time we’re looking at a quantity called Faraday depth – an idea dependent on a line-of-sight information set on the magnetic fields. It was created by combining more than 41,000 singular measurements which were then combined using a new image reconstruction method. In this case, all the researchers at MPA are specialists in the new discipline of information field theory. Dr. Tracy Clarke, working in NRL’s Remote Sensing Division, is part of the team of international radio astronomers who provided the radio observations for the database. It’s magnetism on a grand scale… and imparts even the smallest of magnetic features which will enable scientists to further understand the nature of galactic gas turbulence.

The concept of the Faraday effect isn’t new. Scientists have been observing and measuring these fields for the last century and a half. Just how is it done? When polarized light passes through a magnetized medium, the plane of the polarization flips… a process known as Faraday rotation. The amount of rotation shows the direction and strength of the field and thereby its properties. Polarized light is also generated from radio sources. By using different frequencies, the Faraday rotation can also be measured in this alternative way. By combining all of these unique measurements, researchers can acquire information about a single path through the Milky Way. To further enhance the “big picture”, information must be gathered from a variety of sources – a need filled by 26 different observing projects that netted a total of 41,330 individual measurements. To give you a clue of the size, that ends up being about one radio source per square degree of sky!

The uncertainty in the Faraday map. Note that the range of values is significantly smaller than in the Faraday map (Fig. 1). In the area of the celestial south pole, the measurement uncertainties are particularly high because of the low density of data points. (Image Credit: Max Planck Institute for Astrophysics)
Even with depth like this, there are still areas in the southern sky where only a few measurements have been cataloged. To fill in the gaps and give a more realistic view, researchers “have to interpolate between the existing data points that they have recorded.” However, this type of data causes some problems with accuracy. While you might think the more exact measurements would have the greatest impact on the map, scientists aren’t quite sure how reliable any single measurement could be – especially when they could be influenced by the environment around them. In this case, the most accurate measurements don’t always rank the highest in mapping points. Like Heisenberg, there’s an uncertainty associated with the process of obtaining measurements because the process is so complex. Just one small mistake could lead to a huge distortion in the map’s contents.

Thanks to an algorithm crafted by the MPA, scientists are able to face these types of difficulties with confidence as they put together the images. The algorithm, called the “extended critical filter,” employs tools from new disciplines known as information field theory – a logical and statistical method applied to fields. So far it has proven to be an effective method of weeding out errors and has even proven itself to be an asset to other scientific fields such as medicine or geography for a range of image and signal-processing applications.

Even though this new map is a great assistant for studying our own galaxy, it will help pave the way for researchers studying extragalactic magnetic fields as well. As the future provides new types of radio telescopes such as LOFAR, eVLA, ASKAP, MeerKAT and the SKA , the map will be a major resource of measurements of the Faraday effect – allowing scientists to update the image and further our understanding of the origin of galactic magnetic fields.

Original Story Source: Naval Research Laboratory News.

Posted on by Tammy Plotner

Recycling Pulsars – The Millisecond Matters…

An artist's impression of an accreting X-ray millisecond pulsar. The flowing material from the companion star forms a disk around the neutron star which is truncated at the edge of the pulsar magnetosphere. Credit: NASA / Goddard Space Flight Center / Dana Berry

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It’s a millisecond pulsar… a rapidly rotating neutron star and it’s about to reach the end of its mass gathering phase. For ages the vampire of this binary system has been sucking matter from a donor star. It has been busy, spinning at incredibly high rotational speeds of about 1 to 10 milliseconds and shooting off X-rays. Now, something is about to happen. It is going to lose a whole lot of energy and age very quickly.

Astrophysicist Thomas Tauris of Argelander-Institut für Astronomie and Max-Planck-Institut für Radioastronomie has published a paper in the February 3 issue of Science where he has shown through numerical equations the root of stellar evolution and accretion torques. In this model, millisecond pulsars are shown to dissipate approximately half of their rotational energy during the last phase of the mass-transfer process and just before it turns into a radio source. Dr. Tauris’ findings are consistent with current observations and his conclusions also explain why a radio millisecond pulsar appears age-advanced over their companion stars. This may be the answer as to why sub-millisecond pulsars don’t exist at all!

“Millisecond pulsars are old neutron stars that have been spun up to high rotational frequencies via accretion of mass from a binary companion star.” says Dr. Tauris. “An important issue for understanding the physics of the early spin evolution of millisecond pulsars is the impact of the expanding magnetosphere during the terminal stages of the mass-transfer process.”

By drawing mass and angular momentum from a host star in a binary system, a millisecond pulsar lives its life as a highly magnetized, old neutron star with an extreme rotational frequency. While we might assume they are common, there are only about 200 of these pulsar types known to exist in galactic disk and globular clusters. The first of these millisecond pulsars was discovered in 1982. What counts are those that have spin rates between 1.4 to 10 milliseconds, but the mystery lay in why they have such rapid spin rates, their strong magnetic fields and their strangely appearing ages. For example, when do they switch off? What happens to the spin rate when the donor star quits donating?

“We have now, for the first time, combined detailed numerical stellar evolution models with calculations of the braking torque acting on the spinning pulsar”, says Thomas Tauris, the author of the present study. “The result is that the millisecond pulsars lose about half of their rotational energy in the so-called Roche-lobe decoupling phase. This phase is describing the termination of the mass transfer in the binary system. Hence, radio-emitting millisecond pulsars should spin slightly slower than their progenitors, X-ray emitting millisecond pulsars which are still accreting material from their donor star. This is exactly what the observational data seem to suggest. Furthermore, these new findings can help explain why some millisecond pulsars appear to have characteristic ages exceeding the age of the Universe and perhaps why no sub-millisecond radio pulsars exist.”

Thanks to this new study we’re now able to see how a spinning pulsar could possibly brake out of an equilibrium spin. At this age, the mass-transfer rate slows down and affects the magnetospheric radius of the pulsar. This in turn expands and forces the incoming matter to act as a propeller. The action then causes the pulsar to slow down its rotation and – in turn – slow its spin rate.

“Actually, without a solution to the “turn-off” problem we would expect the pulsars to even slow down to spin periods of 50-100 milliseconds during the Roche-lobe decoupling phase”, concludes Thomas Tauris. “That would be in clear contradiction with observational evidence for the existence of millisecond pulsars.”

Original Story Source: Max-Planck-Institut für Radioastronomie News Release>. For Further Reading: Spin-Down of Radio Millisecond Pulsars at Genesis.

Posted on by Tammy Plotner

Hubble Captures Giant Lensed Galaxy Arc

Thanks to the presence of a natural "zoom lens" in space, this is a close-up look at the brightest distant "magnified" galaxy in the universe known to date. Credit: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)

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Less than a year ago, the Hubble Space Telescope’s Wide Field Camera 3 captured an amazing image – a giant lensed galaxy arc. Gravitational lensing produces a natural “zoom” to observations and this is a look at one of the brightest distant galaxies so far known. Located some 10 billion light years away, the galaxy has been magnified as a nearly 90-degree arc of light against the galaxy cluster RCS2 032727-132623 – which is only half the distance. In this unusual case, the background galaxy is over three times brighter than typically lensed galaxies… and a unique look back in time as to what a powerful star-forming galaxy looked like when the Universe was only about one third its present age.

A team of astronomers led by Jane Rigby of NASA’s Goddard Space Flight Center in Greenbelt, Maryland are the parties responsible for this incredible look back into time. It is one of the most detailed looks at an incredibly distant object to date and their results have been accepted for publication in The Astrophysical Journal, in a paper led by Keren Sharon of the Kavli Institute for Cosmological Physics at the University of Chicago. Professor Michael Gladders and graduate student Eva Wuyts of the University of Chicago were also key team members.

“The presence of the lens helps show how galaxies evolved from 10 billion years ago to today. While nearby galaxies are fully mature and are at the tail end of their star-formation histories, distant galaxies tell us about the universe’s formative years. The light from those early events is just now arriving at Earth.” says the team. “Very distant galaxies are not only faint but also appear small on the sky. Astronomers would like to see how star formation progressed deep within these galaxies. Such details would be beyond the reach of Hubble’s vision were it not for the magnification made possible by gravity in the intervening lens region.”

This graphic shows a reconstruction (at lower left) of the brightest galaxy whose image has been distorted by the gravity of a distant galaxy cluster. The small rectangle in the center shows the location of the background galaxy on the sky if the intervening galaxy cluster were not there. The rounded outlines show distinct, distorted images of the background galaxy resulting from lensing by the mass in the cluster. The image at lower left is a reconstruction of what the lensed galaxy would look like in the absence of the cluster, based on a model of the cluster's mass distribution derived from studying the distorted galaxy images. Illustration Credit: NASA, ESA, and Z. Levay (STScI) Science Credit: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)

But the Hubble isn’t the only eye on the sky examining this phenomenon. A little over 10 years ago a team of astronomers using the Very Large Telescope in Chile also measured and examined the arc and reported the distant galaxy seems to be more than three times brighter than those previously discovered. However, there’s more to the picture than meets the eye. Original images show the magnified galaxy as hugely distorted and it shows itself more than once in the foreground lensing cluster. The challenge was to create a image that was “true to life” and thanks to Hubble’s resolution capabilities, the team was able to remove the distortions from the equation. In this image they found several incredibly bright star-forming regions and through the use of spectroscopy, they hope to better understand them.

Original Story Source: Hubble News Release.