Suzaku News You Can Use

• Latest Mission News

• Objects of Interest in X-Rays

• Resources for All

• A Brief History of X-Rays

• Trivia Question

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Newsletter Archive

Latest Mission News
— The Nature of Science — A Part that is Often "Hidden"

In textbooks there is a treatment of the scientific method or process that goes into some detail as to steps that are mirrored and skills developed in the classroom. It is not, however, a complete description or recipe as to how science is done.

Throughout the history of scientific advancement, science, politics, and economics have been necessarily intermingled. Even Columbus' famous voyages had to be financed by someone! Suzaku, like all NASA missions, requires a continuing accountability for its funding, which is provided by an oversight and review process.

NASA reviews happen all the time at different levels. A recent review, the Senior Review, was performed for the missions under the umbrella of NASA's Astrophysics Science Division, including Suzaku. These reviews happen every two years. They include a look at mission health and status, science strengths, relevancy to a long-term plan, and data accessibility, among other things. The results are a major factor in determining funding starting in 2009. The process is meant to allow for the flow of funding to the best projects and thus that tax dollars support good, valuable science.

What types of things justify the continuing operation of a mission like Suzaku? Past achievement and future plans serve as benchmarks of funding worthiness. Thanks to Suzaku, after more than two years in operations, scientists worldwide have data to fuel a better understanding of the extreme universe. Looking to the future, the third list of target objects for study from Suzaku was recently made public. It is a list of over a hundred targets of interest, where the data collected by Suzaku will serve to further our understanding of black holes, galaxy clusters, and other "extreme" areas of the universe.

Read more about NASA's Astrophysics missions at http://www.nasa.gov/topics/universe/.

Objects of Interest in X-Rays
— I'm Not Dead!

White dwarfs were thought to be relatively inert endpoints of some stars, less exciting than black holes to study perhaps -- until now.

Suzaku recently turned its attention to a white dwarf in a binary star system named AE Aquarii (artist's depiction below). Of those studied, it was the white dwarf most likely to be capable of accelerating charged subatomic particles to near-light speed, particles detected near Earth as galactic cosmic rays. Instead of the dull, lifeless corpse normally found in white dwarfs, researchers discovered this one was pulsing with high-energy (also known as "hard") X-rays!

"This marks the first time such pulsar-like behavior has ever been observed in a white dwarf", according to Suzaku scientist Koji Mukai. A pulsar is a type of neutron star, the much denser endpoint in the life of a star much more massive than a white dwarf.

From previous studies of AE Aquarii and similar binary systems, scientists know that gas from a companion star spirals toward the white dwarf, heating up and glowing in soft (low-energy) X-rays as the two objects rotate around each other. Suzaku's more sensitive observations of AE Aquarii have shown, however, that the "glow" is also in hard X-rays. And the most surprising part is that it appears in a pulse that matches the white dwarf's spin period of once every 33 seconds. From our viewing point, this looks much like pulses of light from a lighthouse. Scientists believe the beam is controlled by a very powerful rotating magnetic field that attracts charged particles and shoots them outward at cosmic ray speeds.

For more on this great find, check out http://www.nasa.gov/centers/goddard/news/topstory/2007/whitedwarf_pulsar_prt.htm.

Resources for All
— A Stellar Podcast

Students who are primarily auditory are few and far between, but the growth of downloadable audio media has provided a mode of reaching learners that was not available previously, and an explosion of such media has occurred. Of course, such presentations also reinforce topics for students of all learning styles.

The Astrophysics Sciences Division (ASD) at Goddard Space Flight Center is producing a series of podcasts, called Blueshift, that are effective on many levels and in different circumstances. Each is approximately 20 minutes in length, fast-moving, packed with information, and well-supplemented at the Blueshift website (http://universe.nasa.gov/blueshift/).

Although Episode 6 is the latest, treat yourself to Episode 3, which is focused on X-ray astronomy and includes discussion of the Suzaku mission. A few of the Suzaku team scientists are heard talking about what they know best. Also, Curtis Odell, the Assistant Director of ASD and Instrument Manager for Suzaku's XRT, discusses in simple terms the idea of a grazing incidence angle and how X-ray mirrors are different. A highlight of the podcast is "hearing" the accretion disk of a black hole! Some shorter but excellent features include a discussion of why we cannot know what is happening right now far across the universe.

Few high school classrooms would not benefit from 20 minute investments in these podcasts.

A Brief History of X-Rays
— Something Worth "Bragging" About

Building on von Laue's work (see last newsletter), a father and son team in the early 20th century used X-rays to discover an important law in optics that applies to the nature of light's behavior. The Braggs, father William Henry and son William Lawrence, were British physicists who collected data on how X-rays reflect off of crystalline structures.

Bragg's law confirmed the existence of atomic particles and provided a powerful new tool to study crystals with X-ray diffraction. In equation form, it states: nλ = 2d sinθ, where n is an integer -- a multiple of the wavelength; λ is the wavelength of the incident beam of X-rays, electrons, protons, or neutrons; d is the spacing between the atomic layers in a crystal, and θ is the angle of incidence.

The Braggs shared the Nobel Prize in 1915 (see http://nobelprize.org/nobel_prizes/physics/laureates/1915/) "for their services in the analysis of crystal structures by means of X-rays".

As a matter of human interest, William H. went on to work on the detection and measurement of sound from submarines in World War I. William L. was the youngest-ever Nobel laureate at the time of his award, and he continued his career using X-rays as a tool to analyze other complex molecules, like proteins and DNA.

Trivia Question:

The white dwarf in AE Aquarii is part of a binary star system. It is actually the smaller of the two stars that share a center of gravity. The white dwarf's gravitational field pulls matter from its normal star companion. What is the common, scientific name for these types of binary systems?

The first person to answer correctly… will win educational materials from the Imagine the Universe! team.