Latest Suzaku News and Object of Interest
— Pinwheel Galaxy
The "star" of this edition of the newsletter is the Pinwheel Galaxy, also known as M101 (the 101st object cataloged by Charles Messier in the late 18th century). The name comes from the shape that you see, in this optical image to the left, of the spectacularly well-defined spirals. This galaxy has been a prime target of interest for Suzaku and scientists because of an interesting phenomenon discovered a few years ago.
Here are some facts and figures about M101. M101 is an extremely large spiral galaxy. Even at a distance of 27 million light years, it still sprawls its 170,000 light year diameter across a large patch of sky. This image only shows the central third of its span. Many of the bright star-forming regions in the spiral arms have their own catalogue designations. Note that the background points of light are more distant galaxies.
But there is another important component in the X-ray emission from M101 and other galaxies: the hot, diffuse gas (the red glow in this second image) that follows the pattern of the spiral arms. This is where stars have formed in the recent past. From an analysis of the Chandra data, we know that some of the gas is at a temperature of 2,000,000 K, and other portions of the gas are at 7,000,000 K. Researchers suspect that there is gas of many other temperatures as well.
We can find this information using Suzaku. For that reason, Dr. Kip Kuntz (of Johns Hopkins University) and his colleagues have recently observed M101 with Suzaku. They hope to use the better temperature information to figure out the details of how interstellar gas is heated and then cools. Suzaku will provide data that will help to test existing theories.
Want to know more? The visible image at the top is from the National Optical Astronomy Observatory (NOAO) at http://www.noao.edu/outreach/aop/observers/m101.html. The Chandra X-ray (second) image is available at http://chandra.harvard.edu/photo/2004/m101/.
Resources for All
— A Quick Opener for Your Class
In M101, the diffuse gas is at temperatures ranging from 2,000,000 K to 7,000,000 K. A good and quick physics class opener would be to calculate the energy of X rays emitted by blackbodies at 2,000,000 K and at 7,000,000 K. (Hint: Use Wien's Law: E = hc/λ)
IF YOU CAN COMMIT TO DOING AN ACTIVITY AND PROVIDING FEEDBACK... We are hoping that you might be the type of educator who enjoys reviewing new classroom activities, or even perhaps using them in your classroom. If you are, we would be interested in having you review and/or classroom test the activities that have been developed around Suzaku. Please respond to suznuzquiz@athena.gsfc.nasa.gov.
About the Crew
— Kai-Wing Chan
Q: What is/was your role for Suzaku?
A: I am a scientist on the X-Ray Telescope (XRT) team, which developed, built and tested the telescopes on Suzaku. Specifically, I tested processes for the fabrication of mirror segments, integrated and aligned the telescopes from their components, analyzed their performance in optical and X-ray wavelengths, and served as the mirror team's Technical Representative.
Q: From high school to the present, were there any interesting twists and turns or ironies concerning what you planned to do and where you are now?
A: Well, this is not an easy question to answer, because there was no "plan" to begin with, and every twist and turn just seemed a happy natural course to me. Ignorance is bliss indeed. Perhaps the plan just changed. In high school, I was sure mathematics was it: the most beautiful, most logical and most rigorous of all "science". But laziness had me, and I chose physics in college perhaps because it seemed easier. (Or was it the interview question from the math professor that gave me cold feet: "What do you think is the most important theorem in mathematics?" I was sure the answer was "the Fundamental Theorem of Algebra". That is not it, but it was the only theorem I knew that is "fundamental" - even in its title.)
Q: What is the most exciting part of your current work? The most frustrating part?
A: The most exciting part, no doubt, is getting to build telescopes that are put into orbit and are used to observe some of the most energetic phenomena of the cosmos. The most frustrating part? ... is to build telescopes that are put into orbit. Why this dilemma? Processes with a space mission sometimes can be frustrating, with lots of things that are mundane, like making sure that all 6,944 pieces of reflectors are produced correctly in their proper dimensions and on time, or out of our control, like being surprised by the failure of a piece of equipment at a time that is, usually, just when you need it.
Q: What are your hobbies?
A: And this one is easy: reading, and in particular, technical materials. They can sometimes be an effective way to stay as far away as one possibly can from doing laundry, dishes, or mowing the lawn. "Honey, I am calculating the polarization of the cosmic radiation of the Universe, would you do the dishes?" Yes, astrophysicists do have dishes to do.
A Brief History of X-Rays
— Coolidge and the Tubes
How were X rays produced in the decades after their discovery? A look at late 19th and early 20th century physics quickly brings one to notice a myriad of tubes. These tubes are part of the story of the discovery of the electron by J. J. Thompson. The cathode ray tube, a closed tube with electrodes at either end, was an important part of research. In 1913, William Coolidge, pictured to the left, tried replacing the cathode with a heated spiral cathode, and the traditional anode with tungsten. This new tube produced X rays that were easier to control. Unfortunately, the "Coolidge Tube", as it became known, was so prolific at producing X rays that it grew extremely hot when used. His invention was so important that it earned him the distinction of being the only person ever inducted into the Inventor's Hall of Fame before he died!
Eventually, new and improved designs were developed and produced in the US by Victor and General Electric and all over Europe. Several later design improvements by Philips Inc., addressing the problem of heat dissipation, led to the eventual wide use of the Coolidge tube.
An in depth look at the invention may be found at: http://www.orau.org/PTP/collection/xraytubescoolidge/coolidgeinformation.htm.
Trivia Question:
A relatively simple question to begin 2007: Who discovered M101, the Pinwheel Galaxy, and what was the year of the discovery?
The first person to answer correctly… will win educational materials from the Imagine the Universe! team.
From the last edition:
Who was the first to use X rays for orthodontic diagnosis?
Answer: E. S. Talbot. Talbot also was one of the first to alert people to the dangers of using mercury amalgam in dental procedures.
There was no winner last time.
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