Field of Science

Antimatter trapped

A Nature letter recently reported on trapping antihydrogen. Researchers at CERN snagged 38 antihydrogen atoms in magnetic trap in what promises to the begining of fruitful research on deep symmetries in nature like charge, parity and time. I wrote up an article discussing the research for Ars Technia (where I am now an occasional contributor in case you hadn't heard) and I figure I should shamelessly self promote. From the article:
Researchers at CERN have created and trapped antihydrogen in an attempt to study the underpinnings of the standard model of physics. Antihydrogen is made of antiparticles, specifically an antiproton and a positron, instead of the proton and an electron that are present in natural hydrogen. It has the same mass but opposite charge of its normal matter counterparts.

Antimatter has a bad reputation for being dangerous because it annihilates on contact with regular matter, releasing prodigious amounts of energy. However, the clever reader will note that they have not been annihilated by the antimatter produced at CERN. The reality is that if you gathered all of the antimatter CERN has ever created, you wouldn't garner enough energy to power your laptop through reading this article.

The Universe seems to be made of mostly regular matter, so any antimatter encounters matter and is annihilated immediately after it has been created. Production and detection of cold antihydrogen atoms also happened at CERN in 2002, but those were short-lived. The new Nature letter describes how to overcome the difficulty of containing antihydrogen so that it isn't immediately destroyed.
Continue reading CERN snags 38 antihydrogen atoms in magnetic trap.

A possible young black hole

Thirty years ago a supernova exploded 50 million light years away (right, so it actually exploded 50 million plus thirty years ago if you take into account the space and time like separation from this event) in the grand spiral design galaxy M100. A year ago a paper titled  Evidence for a Black Hole Remnant in the Type IIL Supernova 1979C appeared on the astrophysics preprint archive claiming that the continued X-ray emission from the object was consistent with a 5-10 solar mass black hole. Five days ago NASA announced it was going to make an an announcement. Today NASA made a press release claiming that NASA's Chandra satellite had found the youngest black hole ever. It is a beautiful discovery.

Or is it? Lets peer inside to see the inner beauty of this discovery. The original version of the paper was submitted to Astrophysical Journal Letters , but was not accepted and only after a revision was it submitted again this time to Monthly Notices of the Royal Astronomical Society Letters. Today along with the press release a third revision of the paper went up. The excitement really just boils down to the fact that SN1979c has been a remarkably consistent and bright X-ray source for its 30 year lifetime.

The object seems to have been an approximately 20 solar mass star before it collapsed, but the core which really counts when a star collapse was around 3 solar masses. A core that is much larger than 3 solar masses would collapse into a black hole, a core a little less than 3 solar masses would form a neutron star, but there is no way to know the exact size of the  progenitor star's core. Previous theories suspected the object was a magnetar or pulsar wherein the super hot dense objected emitted vast amounts of energy as it cooled and hence this induced the X-ray brightness. The new theory posits that the object is an accreting black hole remnant.

But seriously, an announcement of an accoutrement? It is a little sad how this paper hiding in plane sight was overlooked by bloggers and science writers alike. Even blogs, like Bad Astronomy, that normally expose flimsy stories like this have taken it easy. I think all press releases should come with a warning, science in progress.

Milky Way Hides Gamma Ray Lobes

The Milky Way has some nerve (or after you see the picture you may think, excuse my language, big cojones) for hiding a massive structure that about equals the size of the visible Milky Way. The Fermi gamma ray satellite observed the structure mired in a fog of gamma rays which are pervasive through our sky. Fermi has been making a survey of the complete sky for some time, but only through careful data analysis and removal of diffuse sources were the lobes readily apparent.

Spotting the lobes inside the Milky Way was difficult because from our view within we can't see the forest for the trees, but astrophysics expect that some galaxies have gamma ray lobes and Fermi has spotted such lobe structures like this in other galaxies such as Centarus A. So this result isn't that unexpected, except that it is. These gamma ray lobes are comparable to the entire size of our galaxy and they are just now being seen for the first time.

The structures are orthogonal to the plane of the Milky Way and have distinct edges; they are surprisingly geometrically perfect. They span about 7.5 kiloparsecs (or 25,000 light years). The lobes are composed of gamma rays which are super high energy photons; the photons obtain such high energies by interacting with particles, like free electrons, which are themselves moving close to the speed of light which then interact with the lower energy photons in their vicinity to boost the photons up to gamma ray energies.

The distinct edges of the lobes are indicative of a large and rapid formation event. The structures may have been formed by a massive burst of star formation followed by stellar explosions which seeded the lobes with gas, dust, and hot electrons over millions of years. There is a supper massive black hole at the center of many galaxies, including the Milky Way, which may create high energy lobes, but those lobes would only form when the black hole is actively undergoing accretion of matter. So this may be evidence that the 4 million solar mass black hole at the center of our galaxy underwent an active period where it accreted a large amount of matter and simultaneously released massive jets of energetic particles just a few million years ago.
It is an exciting discovery, but I don't have anything other than a press release to go on as of yet though a paper is accepted for publication in ApJ so more to come.