Profile: Dr. Kirpal (Paul) Nandra
Dr. Paul Nandra was born and raised in North Shields, England.
Now, he works at Goddard Space Flight Center through a contract
appointment with Universities Space Research Association. He received
a prize in 2000 from the American Astronomical Society for outstanding
achievement by a young astronomer.
Paul came from a family of scientists - both his parents are
biochemists. How did Paul wind up in astrophysics, then? "My mother claims
I was always interested in the stars, but I can't remember that,"
Paul says. "My dad encouraged me to do science since he thought it
would help me get a good job. At about 16 I got excited about the
things going on at CERN (a particle physics laboratory in Europe,
where scientists smash sub-atomic particles together at near the speed
of light), and I decided I wanted to be a particle physicist. When
I got to University, though, I realized I wasn't clever enough to do
that," Paul quips.
He goes on, "In fact, I was so disillusioned with
Physics that I almost changed in my final year of College and became
a Computer Scientist. Luckily I didn't, since that year I took
two Astronomy courses, which I really liked and even vaguely understood.
So of course I decided to do a Ph.D."
Paul attended Churchill College at Cambridge (http://www.chu.cam.ac.uk/) in the UK for his undergraduate work. He then went to
Leicester University (http://www.leicester.ac.uk/), also in
Great Britain, for his Ph.D.
Paul had the good fortune to be in graduate school when data was
pouring down from a new X-ray telescope orbiting the earth.
Named Ginga (http://heasarc.gsfc.nasa.gov/docs/ginga/ginga.html), the satellite was launched by the Japanese in 1987,
and allowed astronomers to study the heavens in never-before-seen
detail. Ginga means "galaxy" in Japanese, and although the
satellite made discoveries about many different kinds of objects,
it turned out to be excellent for studying galaxies. And that's
just what Paul did: his thesis was on the spectrum of X-rays from
"active" galaxies seen by the Ginga satellite.
"My main interest is in the X-ray emission from the nuclei of
active galaxies," Paul says. "By
looking at the spectrum and variability of the X-rays, we try to
work out whether there's a black hole there." Many leading theories
hold that supermassive black holes exist at the center of active
galaxies, and that matter being sucked into the black holes produces
the enormous energy output we see. Paul tries to work out, "what
the properties of the black hole are, how much material is being
[pulled] onto it," and how it turns that material into energy,
The Advanced Satellite for Cosmology
and Astrophysics (ASCA)
Tell me more about black holes!
Paul was part of an international team of scientists that in 1995 announced
evidence for matter swirling around a black hole at the center of a
distant galaxy. This time using a new Japanese/US X-ray satellite called
team examined an active galaxy known as MCG-6-30-15. ASCA's
incredible precision showed something astronomers had predicted but
never seen before: the unique X-ray signature of matter orbiting close to
a black hole at the center of an active galaxy.
Matter caught by a black hole's gravity forms an
accretion disk, spiraling around
the black hole before eventually being sucked in. Theories predicted
that the extreme gravity of a supermassive black hole in an active galaxy
would distort the light we see from the accretion disk.
In the same way that a person has to expend energy to climb a hill,
light gives up some energy when escaping from close to a black hole.
The black hole is at the bottom of a "gravity hill", and the light
looses energy "climbing" out.
Paul and the rest of the team used ASCA to isolate X-rays coming
from the accretion disk very near the black hole (red crosses in the
data plot below). If there was no extreme gravitational field near
the inner edge of the disk, the scientists would expect to see two
"peaks" in the X-ray spectrum. Instead, the team was delighted to
find the lower energy peak was "smeared out," just exactly as
the theories for light near a supermassive black hole predicted
(blue line in plot).
Signature of a Black Hole
Paul went on to use ASCA and another US X-ray satellite,
the Rossi X-ray Timing Explorer (RXTE) (http://rxte.gsfc.nasa.gov/docs/xte/learning_center/) to probe deeper into the nuclei
of active galaxies. In 1999, he lead a team of researchers that
announced another important breakthrough: they detected X-rays from
what looked like matter actually falling into a supermassive black hole
at the center of an active galaxy. Before, researchers had detected
matter in the accretion disk around a supermassive black hole (like above).
Now, however, Paul's team saw the "final cry" of this matter as it
actually streamed toward the black hole at more than 6 million miles
an hour. ASCA observations had again captured the groundbreaking
result, this time in the X-ray spectrum of active galaxy NGC 3516.
Tell me what Paul is working on now!
Paul's done so much to "illuminate" the inner regions of active
galactic nuclei that the American Astronomical Society awarded him the
2000 Newton Lacy Pierce Prize. The Pierce Prize is awarded annually
for outstanding achievement in observational astronomical research by a
young astronomer. As part of the Prize, Paul will give a lecture to
astronomers from around the world at the January 2001 meeting of the
American Astronomical Society, to be held in San Diego, California.
"I am surprised and delighted to win the award," Paul said. "It feels
great to be recognized ... but many others here at NASA and elsewhere
deserve a lot of the credit. I'm lucky to have had the opportunity to
work with those people and make a contribution to such an exciting
Paul has studied X-ray astronomy and active galaxies for over 10 years now.
He's traveled all over the world to do his research, made
important discoveries and won awards for his work. Still,
he says, the thing he likes most about working in science is, "the
opportunity to look at data that nobody else has looked at before.
Who knows what might be in there?"
A "Typical" Day at the Office
When asked what a "typical" day at the office involves, Paul
jokes, "Come in late. Drink coffee. Read my e-mail. Have lunch.
Think for a bit. Leave early. Perhaps it would be better if
I made something up?"
More seriously, Paul's day involves a number of things. First
up is usually reading e-mail: Paul stays in touch with colleagues
and collaborators around the world, exchanging science results
and coordinating research. Many of Paul's collaborators are in
Japan or the UK, and frequently they've sent e-mail during the night
describing what they've discovered during their work days.
Next, Paul might check any of several online sites where scientific
papers are archived and new results are posted. Here, he catches
up on the latest discoveries, researches current projects,
or seeks inspiration for new ones.
Almost every day involves some work on the computer analyzing data
from a satellite telescope of one type or another. Paul uses
sophisticated software to model the predicted spectrum of a given
astronomical object, and then compares that prediction with actual
data taken from space. He might also spend some time writing a
proposal to use one or more telescopes to perform new observations.
In this way, the discoveries he makes lead to new questions, which
in turn suggest new observations and lead to new discoveries.
Paul takes advantage of living in Washington, DC, and on weekends
indulges a variety of outside interests. He enjoys music, "especially
playing the guitar and bass. I am occasionally seen making an idiot
of myself in front of a small audience," he jokes.
Paul also likes playing pool, fishing, cooking, and eating, whether
it's a meal he's created or something from one of the many tantalizing
restaurants in the Washington area. Having lived in the United States
for several years now, Paul's interests also reflect both American
and British pastimes: "I like watching baseball and especially cricket (http://www.cricket.org/), but never get the chance to do
the latter in this blighted colony," he laughs.
Questions and Answers
Q: As a scientist, you must be in contact with people from
all over the world. What is the most unusual question or comment you have
"fan" e-mail, from one "Mindy B", after my press release
on the possible signature of matter falling into the black hole at the
center of the galaxy NGC 3516.
Q: If you weren't a scientist, what would you be?
A: I don't know if I would be, but if I weren't a
scientist I'd like to have a go at running my own restaurant. I love
cooking, especially fancy things, and seeing the reaction of people
eating it. Mind you, if they were actually paying for it they might
not be quite so polite about what it tastes like ...
Q: Who was your favorite teacher in school? What was
this teacher like and how did he/she influence your life?
A: Mr. Gordon the Chemistry Teacher. He ran the Table
Tennis club after school and I liked him because he treated us like
human beings rather than "schoolkids."
Q: If you could invite three people from throughout
history to your house for dinner, who would you invite and why?
A: Motorhead. [Motorhead is a 3-person
heavy metal band from Great Britain.]
Q: What one question in science would you like to see
answered in your lifetime?
A: The universe is mostly made up of matter that we
can't see. It would be nice to know what this matter is and it's one
of those things which is currently a real mystery.
Q: Do you have a family? A dog? A fish? A camel?
A: I have a fiancee/co-mortgage-holder, Dinah. We have 9
fish in a pond in the back garden who are occasionally pursued unsuccessfully
by our cat, Timmy, who is grey, white and fat.
Q: What is the one big dream you have, or the one thing
that you would like to accomplish during your lifetime?
A: To make a century on my Test debut at Lords.
[A "century" is 100 runs at cricket, a British game similar to
baseball. A "Test" is a cricket match at the national level,
and "Lords" is a famous playing field in Britain where cricket
games are held. Paul's comment is the equivalent of an American
saying his big dream is, "To hit a grand-slam home run in my first World
Series at-bat at Yankee Stadium!"]
Publication Date: September, 2000