Celebrating 50 Years of X-ray Astronomy:
The Present
NASA doesn't work in isolation; it often collaborates with other space
science organizations in other countries, helping to share resources and
information for everyone's mutual benefit. One example of this is the
work with
Suzaku.
Working from Goddard Space Flight Center, Dr. Koji Mukai helps
everyone in the astronomy community use Suzaku by demonstrating the best
uses for the equipment, as well as maintaining documentation about
software and data products. Mukai also does his own research, which
makes it easier for him to help others use the satellite by staying in
practice using it himself, and keeping up with the tricks of the trade.
Koji Mukai
"Over the recent years, we figured out that Suzaku is a very good
satellite to study the outskirts of ... clusters of galaxies. In visible light, you
would see a bunch of galaxies in the same part of the sky. But the
cluster is also filled with X-ray emitting hot gas. For the central
part, other X-ray telescopes have done a very good job. But Suzaku has a
sensitivity for low surface brightness X-ray emissions from the
outskirts. By doing a careful job, we can study the entirety of the
cluster, because other missions were studying maybe 1/3 of the mass of
the X-ray emitting gas, in the center, where it is brightest. That is
important, but if you want the complete picture, you need to go to the
outskirts, too. That's where Suzaku has made a big contribution."
Suzaku works in conjunction with
Chandra
and XMM-Newton.
Mukai says that both of those have better angular resolution, and can
make better images, which is useful in the central region of a target,
where the brightness changes significantly from one part of the sky to
the next. But Suzaku is better at the diffuse glow of the X-ray sky.
Technicians with NASA's NuSTAR just after they joined the spacecraft
with the Orbital Sciences Pegasus XL rocket inside an environmental
enclosure at Vandenberg Air Force Base's processing facility in
California. (Credit: NASA/Randy Beaudoin; February 2012)
Astronomers are excited for data from NuSTAR,
a new satellite to study cosmic X-rays, launched on June 13, 2012.
NuSTAR carries an X-ray imager similar to the one planned for the next
Japanese X-ray mission currently in the works, Astro-H. Richard
Mushotzky talks about how NuSTAR will lead into Astro-H.
Richard Mushotzky
"NuSTAR is a survey-type instrument, used to define what's new and
exciting in the hard X-ray bands. With Astro-H, we're going to study
them, so we'll have much longer exposures. The main goal of NuSTAR is to
go find it, and take a picture, and the main science goal with Astro-H
is to study in detail."
Katja Pottschmidt, a member of Goddard's guest observer facility for the
Suzaku mission, is excited to see results from NuSTAR. Her main role is
to support users of Suzaku data, which she has done in the past for the
INTEGRAL and
RXTE missions.
Katja Pottschmidt
"We currently have several active high-energy missions with
different and complementary strengths that are all providing exciting
results. This has been stated and explained in this year's report of
NASA's senior review committee. Personally, I think multi-mission
observations often provide the most useful results, either simultaneous
observations or using different techniques to answer the same question.
A good example is recent spin measurements for black holes in X-ray
binaries and active galactic nuclei, which now allows us to determine
one of only two measurable and very fundamental properties of black
holes.
Artist's conception of Cygnus X-1. (Credit:
Moritz Boeck, Remeis-Observatory Bamberg / ECAP, FAU, and Univ.
Wuerzburg)
The development of new missions is always exciting, since they will
provide us with new windows for observing and understanding X-ray
sources. I am keen on being able to work with NuSTAR data soon, on
observations of several accreting pulsars that show cyclotron line
absorption features in their hard X-ray spectra – they can be used
to measure the 1012 Gauss magnetic fields of these sources
– which NuSTAR will observe with higher sensitivity than ever
before. I am also especially looking forward to Astro-H, which will
provide the first observations in the soft X-ray band with calorimeter
resolution. With Suzaku, Chandra, and XMM, we became much more aware of
signatures of the material that is accreted in X-ray binaries and the
need for observations with Astro-H, which will combine high spectral
resolution and sensitivity, in order to be able to draw firm
conclusions, such as how much of each element there is, and whether the
material is ionized and/or clumped."
Kimberly Weaver, another
Goddard X-ray astronomer, is also looking forward to NuSTAR.
Kim Weaver
"NuSTAR will open up a new area of research because this is the
first time we will be able to take X-ray pictures using the most extreme
X-ray energies. Scientists will be able to map out the energetic parts
of relativistic jets near black holes, for example."
Publication Date: June 2012
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