Astronomers using two different telescopes and two different systems have started learning about microquasars. They’re learning new things that can then hopefully be applied to full size quasars as well.

A quasar is an extremely powerful, luminous and distant active galactic nucleus. While there was initially some controversy over the nature of these objects, there is now a scientific consensus that a quasar is a compact region surrounding the central supermassive black hole of a galaxy. Quasars show a very high redshift, meaning they are located a great distance from us. Quasars are active because the central black hole is accreting a lot of material. Near the black hole, intense magnetic fields in the disk accelerate material into tight jets that flow in opposite directions away from the hole.

Microquasars is a two-body system consisting of a stellar mass size black hole and a star, usually a red giant. The giant star is feeding material to the black hole. Which, needless to say creates some interesting dynamics. Astronomers have been looking at two systems, Swift1753.3-0127 and GX339-4, with the European Southern Observatory’s Very Large Telescope and NASA’s Rossi X-ray Timing Explorer to study microquasars. Microquasars are not only closer but change more rapidly, so a process that may take a normal quasar a year to undergo might only take a microquasar a few minutes.

Astronomers had thought that the visible light emission coming form microquasars was coming form far out in the accretion disk and thus did not give much information about the main actions going on. However, they were wrong. They now know that the optical and x-ray emission are intrinsically linked, probably by the same immense magnetic fields that hurl material into near light speed jets.

The data shows that light output typically drops just before x-ray output undergoes a large spike. The rapid variations in the x-ray and optical emission must have a common origin. The cool thing about discovering such patterns that stand out amidst chaotic fluctuations of light is that they give us a new handle on understanding the underlying physics. The best candidate is the strong magnetic fields as the dominant process behind it all.

So again what we once thought was wrong, we learned something new, but realize how much we don’t know yet. This data is a new clue about very mysterious and not yet understood systems. We still don’t know exactly what’s going on in these dynamic systems, but we have one more piece of the puzzle.

Scientists believe they have found the answer to a mystery about a thought to be nearby galaxy. The funny thing is this answer was found by rather serendipitously after finding out our current estimates for the distance of the galaxy were wrong.

The galaxy named NGC 1569 was a bit of a mystery. It is an irregular shaped dwarf galaxy, which isn’t in itself strange, but the galaxy was going through a burst of star formation with no discernable reason. The galaxy was forming stars much faster than any other galaxies in its nearby region. Well then we realized that the problem with that statement was not NGC 1569 itself but the galaxies we thought were nearby it.

Scientists recently pointed the Hubble Space telescope at NGC 1569 to scan for red giant stars. The astronomers were hoping to get an estimate of the galaxies age by looking for red giants, as red giants can be used as reliable standard candles for measuring distance since they all burn at the same known brightness. However, the astronomers were only able to see the brightest red giants, even using Hubble, the stars were too dim to be resolved. This fact lead astronomers to question the previous estimate for how far away the galaxy actually is. And now after looking at the data astronomers have realized the galaxy is actually about one and a half times farther away than previously thought, making it about 11 million light years away.

The problem was before this the galaxy had only been studied with ground based telescopes, which have much less resolving power than space based telescopes, which can make estimates less accurate. With this new information the galaxy’s star formation makes more sense. This distance puts the galaxy in the middle of a cluster of ten other galaxies. The gravitational interaction of the galaxies tugging on each other would be enough to explain the high rate of star formation we see in this galaxy.

So using Hubble we have answered yet another question, good ol’Hubble. However, this instance makes one wonder how many other numbers that we have for things like distance or mass etc might be inaccurate after only being studied by ground-based telescopes. How many things should we go back over with space-based telescopes to make sure? And how many mysteries or unexplainable phenomena might be answered by simply rechecking our data??

Magnetars are a bizarre form of star, with mysteries that have eluded astronomers for a long time. Recently with the help of the European Space Agency’s XMM Newton and Integral Satellite astronomers have been able to test and explain one of the unknown aspects of what magnetars are really doing.

Magnetars are a special kind of neutron star. Neutron stars, for a quick reminder, are what is left after a massive star dies in a supernova. They are very small, maybe 20 km in diameter, but very dense, a teaspoon worth of neutron star would weigh about one hundred million tons. Magnetars form a special class of neutron stars that have incredibly strong magnetic fields, about a thousand times stronger than that of a normal neutron star, and they have incredibly fast rotation. Magnetars are also known to shine bright in X-rays, but scientists have been unable to test any theories because they are unable to reproduce the strong magnetic properties in a lab.

We have found about 15 magnetars. One type known as SGR, or soft gamma repeaters, sporadically release bursts of short gamma rays and hard x-rays. The other type is known as AXPs, or anomalous X-ray pulsars, pulse periodically with x-rays. While once thought to be two different objects we now know they share many of the same properties. Magnetars strong magnetic fields are thought to be so strong that they can twist the crust of the star. This twist would produce currents in the form of a cloud of electrons flowing around the star. Its thought that these currents interact with radiation coming from the stellar surface to produce x-rays.

Using data from XMM Newton and Integral astronomers have looked at all known magnetars and actually found evidence of these electron clouds. They found that the electron density around these magnetars is about a thousand times stronger than for a normal pulsar. They were also able to measure the velocity of the electron clouds going around the magnetars.

This data has provided scientists the chance to find a link between an observed phenomenon and the physical process behind it. The team is now working to try and develop more detailed models of what exactly is happening on the surface of the magnetar. These objects are very bizarre and are an example of a celestial object with extreme conditions. It is something that challenges current theories and provides us with examples of new and interesting phenomenon that we could never observe on earth. Studying the is an exciting and interesting challenge for astronomers and physicists.

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New information about a neighboring star has shed some light on our theories of solar system formation and given hope to terrestrial planet hunters. The near by star Epsilon Eridani has features very similar to our own solar system, it is however much younger than our own system, perhaps giving us a glimpse to how our solar system might have looked in its very early stages.

The star itself is about 10.5 light years away. It is the third brightest star seen with the naked eye. The star is a K2 spectral type star; it is slightly smaller and less massive than the sun. It is thought to be less than a billion years old, where our sun is close to 5 billion years old. Because of it’s young age it has a much higher level of magnetic activity than the sun and a stellar wind about 30 times as strong.

Recently, using the Spitzer Space Telescope, astronomers have identified two areas of rocky rings, or asteroid belts, just like our solar system. It has an inner asteroid belt at an equivalent distance from its star as our asteroid belt to the sun. An outer asteroid belt is also present at about the position where our Uranus is. This outer belt contains about 20 times more material than the inner belt. A third ring of icy materials is set out about 35 to 100 AU from the star, very similar to our Kuiper Belt but with about 100 times more material. This extra material makes sense, given the systems age. Our solar system is much older and thus has had more time for collisions to take place and either destroy material or send it out of orbit.

Spitzer also noticed large gaps in these rings. The most logical explanation for these gaps is the presence of planets. Astronomers predict at least three planets with masses between that of Neptune and Jupiter, and another possible smaller planet may lie near the innermost ring. These gaps and the closeness of this star, plus evidence from other planet hunting techniques such as observing radial velocities, makes this star high on the list of planet hunters trying to find earth like planets, and even possibly life. With all the similarities noticed thus far between the two systems, one might think it surprising not to find smaller rocky planets in the inner part of the system.

Studying this system is exciting ad enlightening for astronomers. Seeing that our solar system is not totally unique means that our theories about how solar systems for may not be completely off base. Also, studying this solar system more intensely may show us things about our early solar system we wouldn’t have otherwise known. As the resolving power of our telescopes improve new discoveries from this system should be something to watch out for.

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