Latest Mission News
— Calibration
When collecting data, it is important to be as precise and accurate as possible. In astronomy, one part of data collection is filtering out photons that are in a similar energy range but coming from sources other than the target of study. These photons are generally from sources much farther away but in the same field of view. To adjust for this noise, detectors periodically turn their attention to a seemingly empty region to take measurements of this background. Subtracting this noise provides more accurate data. (Of course, "noise" is in the eye of the beholder. Background noise for one astronomer may be a target for another!)
In upcoming weeks, Suzaku will go through this process with the Lockman Hole, an area routinely used to calibrate X-ray telescopes. The Lockman Hole was identified in recent years as a region of the Milky Way almost free of noise but containing hundreds of X-ray sources (left -XMM-Newton/ Guenther Hasinger (Astrophysikalisches Institut Potsdam).
Dr. Koji Mukai at Goddard Space Flight Center, and a member of the Suzaku science team, explains why this calibration is so important: "One of the major discoveries of astronomy is that, if you observe an apparently blank patch of sky with high spatial-resolution instruments over a long period of time, you'll discover it is filled with distant galaxies. You then realize that whichever direction you look - whether observing astronomer X's favorite star A, or Y's favorite supernova remnant B - you're also receiving photons from this "background" of distant galaxies. The Suzaku observation of the Lockman Hole is meant to measure this background level, particularly for the HXD instrument."
Resources for All
— There's a Chill in the Water
As weather warms up, but the memory of winter is still fresh, making liquid water that is colder than its normal freezing point may be particularly appropriate for your students. We have an activity get them started. The "Another Way to Solve a Chilling Problem" lab, on the Suzaku Learning Center site, presents a technique for creating supercooled water. This may be done as a demonstration, but for a better "hands-on" approach, it can be easily integrated into a chemistry or physics class as a lab exercise. This and other ready-made activities based on the Suzaku mission are at: http://suzaku-epo.gsfc.nasa.gov/docs/suzaku-epo/education/lessons/lessons.html.
EDUCATORS - WE NEED YOU! We are hoping you might be the type of educator who enjoys reviewing or trying out new classroom activities. If you are, we would like to have you review and/or classroom test new Suzaku activities. Please respond to suznuzquiz@athena.gsfc.nasa.gov.
About the Crew
— Featuring Scientist F. Scott Porter
Q: What is/was your role for Suzaku?
A: I was a Co-Investigator on the program, meaning that I wrote part of the proposal and was part of the science team that had access to the first year's worth of proprietary data. I was also the lead scientist on the XRS detector front-end assembly, which is the mechanical and electrical interface to the detector. I was also one of the two cryogenic "experts" on the project.
Q: What were you like as a student in high school?
A: I was very involved in sports, spending four years on the varsity track and cross-country teams. I also took a lot of college classes in high school. I was a fairly lazy student however. I did well but didn't learn any real study skills until college. College was quite a shock to me, in that I suddenly needed good study habits and time management skills that I had never really developed.
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: My two college roommates and I were headed in different directions when we left for graduate school. One went to the University of Washington to study astrophysics, and he is now an astronaut. After seeing a particularly dreadful astrophysics seminar, my other roommate and I decided we didn't want anything to do with astrophysics. He went off to study plasma physics and I studied low temperature physics. But we both ended up writing astrophysics-related PhD theses anyway. We hadn't talked in years until we ran into each other in the hallway at GSFC and discovered that we work in the same X-ray astrophysics group and our offices were just down the hall from each other. It is really an amazingly small world.
Q: What are the most exciting and most frustrating parts of your current work?
A: The most exciting part of my work is actually using our current suite of space-borne X-ray observatories to do science. We are now using two of them (Swift and Suzaku) to look at X-ray emission from a comet. The observation planning was fairly difficult because the comet is not stationary, but it all seems to have worked out. The most frustrating part is dealing with the day-to-day new financial bureaucracy at the agency.
Q: What are your hobbies?
A: My work is my primary hobby. As scientists, we tend to find our work interesting and intellectually stimulating, and some of us carry it wherever we go. I also spend my time with my two children, along with reading and working with digital photography.
Q: What do you think the exploration/study of space will be like in 50 years?
A: What we think we will be doing will be very different from what actually happens. However, I think most astrophysics will still be performed from near-Earth orbit; there are good reasons for visiting other planets, but very few good reasons for basing observatories there. I believe we will be surprised by future technologies with very sensitive telescopes that look nearly impossible now.
A Brief History of X-Rays
— The Birth of X-Ray Astronomy
So far we have looked at X rays here on Earth. In early X-ray history, we find the focus was on machines and techniques for producing X rays and developing applications of those machines and techniques. X-ray astronomy is conceptually different, in that the X rays we are studying are not created here by machines, but rather by objects that are at vast distances from us!
In June 1962, a small rocket was launched and escaped the Earth's atmosphere for just under 6 minutes. This rocket, the Aerobee 150, contained an X-ray detector and was able to detect X rays from an astronomical source, Scorpius X-1. You might remember that X rays from space never reach the Earth's surface, and so the beginning of X-ray astronomy had to wait until detectors could be built and launched above the atmosphere. To the left is a picture of the Aerobee's payload. It's not impressive to look at, yet the beginning of a robust branch of astronomy!
As the school year winds down, an interesting and simple research project is to have students build a timeline or poster on X-ray astronomy, which certainly would include the Aerobee 150, and Suzaku. Good research would produce at least 7 missions that were X-ray related, a couple of which we will talk about in our next issue. For more on the birth of X rays, visit: http://imagine.gsfc.nasa.gov/docs/features/exhibit/xray_anniversary.html.
Trivia Question:
It's almost summer (at least in the northern hemisphere!), so we will give you a trivia question about X rays in the movies.
Last year the movie "The Prestige" was released, starring Hugh Jackman and Christian Bale. In the movie, a famous scientist was sought out and hired to create a machine that performed a real magic trick. In reality, this scientist did some early work on the production of X- rays. Name the scientist, the trick, and the former rock music star who portrayed him.
The first person to answer correctly… will win educational materials from the Imagine the Universe! team.
From the last edition:
Who discovered M101, the Pinwheel Galaxy, and what was the year of the discovery?
Answers: Pierre Mechain in 1781.
Congratulations to the winner of the previous trivia question: E. Klonaras of Larissa, Greece
|
