Transcript PSCWest Orientation - GBT

Welcome to the Pulsar Search
Collaboratory (PSC) – West!
NRAO
University Wisconsin – Milwaukee
West Virginia University
Yerkes Observatory
University of Chicago
Let’s introduce ourselves to each
other. . .
(checks lab)
Pretests/Post-tests
• The grant needs to have data!
• Mosart Astro test was taken before arriving (If
not, please take it now!)
• 7 multiple choice questions on pulsars
– Take now
– Take at end of today’s session
• There will also be the always needed
evaluations
Intro to project . . .
Let’s start!
Citizen Scientists
• So much of scientific research today relies on the
analysis of incredible amounts of data.
• Scientists cannot possibly look at it all
– Computers do most, but human element is an
essential ingredient, as it always will be
• We already see some “citizen scientists” at work
– Galaxy Zoo
– Einstein at Home
– Other “Zoo” type things
• Educational outreach is important to
scientists, and NSF is willing to bridge the gap!
– Involving high school, and even middle school
students is highly desirable
• Can undo stereotypes
• Can ignite the interest in science
• Can make science accessible to underserved students
(and to under achievers)
– Involving science teachers is also a plus!
• An opportunity is also available at UWM
Astronomy!
• It can really grab the interest of kids,
• They like to ask the big questions:
– What’s out there?
– How do we know?
– Are there Aliens?
• Here is a way you can involve a student of
any ability.
This opportunity . . .
• National Radio Astronomy Observatory in
Green Bank, West Virginia (NRAO)
• University of Wisconsin – Milwaukee (UWM)
• West Virginia University (Morgantown)
NRAO, WVU,
Funded by the NSF
ARCC@UWM
Some of the people involved . .
Sue Ann Heatherly
Education Director,
NRAO
Maura McLaughlin,
Astronomer, WVU
Rachel Rosen
Astronomer,
Program Director of
PSC
Duncan Lorimer
Astronomer, WVU
From UWM
Xavier Siemens , Physicist, UWM
Larry Price, postdoc, UWM
Jean Creighton, Planetarium Director
Dawn Erb, Astronomer, UWM
David Kaplan, Astronomer, UWM
(Sherry and my involvement – more
pictures?)
The group of teachers Sherry and I
worked with summer 2009
Students at last May’s Capstone at
WVU
For this project . .
• Data is collected by Radio telescopes
• The data is screened by a computer
to a certain point
–Then a human must look at it to see if
it is worth a follow up
• This is where students come in!
A light wave is a light wave, no matter how
long...
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Electromagnetic radiation
 A traveling, massless packet of energy --OR an oscillating electric
and magnetic field
 Also known as: radiation, light wave, photon
Travels at the speed of
light (by definition).
Remarkably, all radiation
travels at this speed,
regardless of whether is
carries a lot of energy or
only a little
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Animation from Nick
Strobel’s Astronomy Notes
(www.astronomynotes.com)
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All EM waves follow the equation:
c  f
c  
• Let’s try a problem:
– What do the above variables stand for?
– (one or two problems will be added – simple,

What is the difference between radio
waves and sound waves?
• This is a confusing point to a lot of students
and non-science people
Radio Waves are NOT sound!
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The spectrum allows us to “see” the sky differently!
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The Visible Sky, Sagittarius Region
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The
Radio
Sky
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Activity Time!
• Detecting Invisible Waves
Let’s look at radio telescopes . . .
Radio waves can be detected night or
day
• They also can travel through dust and gas
• So we can see further into our galaxy with
radio waves than with light waves.
Optical and Radio can be done from the ground!
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Radio Telescope
Optical Telescope
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Nowadays, there are more
similarities between
optical and radio
telescopes than ever
before.
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• Itty Bitty telescope
• Radio Jove
• Let’s go outside . . . .
Radio Astronomy is a relatively young
science
Pioneer of Radio Astronomy
Karl Jansky
1928: Karl Jansky, working for Bell Laboratories discovers radio
waves coming from space.
Pioneer of Radio Astronomy
Grote Reber
First Surveys of the
Radio Sky
Chart recordings from Reber's
telescope made in 1943.
In 1967, Cambridge graduate
student
Jocelyn Bell was using a radio
array to study interplanetary
scintillation – SURPRISE!
How Radio Waves are produced
Accelerating charged particles emit
radio waves.
One Way: high speed electrons and
magnetic fields
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Electrons accelerate around magnetic field lines
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What we’re
looking for!
pulsars –
spinning,
neutron
stars
–Pulsars signals are used to find
gravitational waves.
–Pulsars are used to study
interstellar space.
–Pulsars are inherently interesting in
themselves!
A pulsar is the collapsed core of a
massive star
• It is like taking the mass
of the sun and making it
into a ball the size of
Milwaukee.
• It spins very fast, like an
ice skater who has
brought their arms in.
Pulsars are neutron stars
Pressure becomes so high that electrons and protons
combine to form stable neutrons throughout the
object.
Typical size: R ~ 10 km
Mass: M ~ 1.4 – 3 Msun
What kinds of properties might we expect?
Angular momentum conservation
=> Collapsing stellar core spins up to
periods of ~ a few milliseconds.
Magnetic fields are amplified up to
B ~ 109 – 1015 G.
(up to 1012 times the average magnetic
field of the Sun)
Pulsar Properties
• Extremely dense - 100,000,000,000,000,000 kg m-3
=
Pulsar Properties
• Extremely dense - 100,000,000,000,000,000 kg m-3
• Very rapid rotation - up to 700 Hz
Pulsar Properties
• Extremely
dense - 100,000,000,000,000,000 kg m-3
• Very rapid rotation - up to 700 Hz
• Ultrahigh magnetic fields - 1,000,000,000,000 times Earth’s
Pulsar Properties
• Extremely dense
- 100,000,000,000,000,000 kg m-3
• Very rapid rotation - up to 700 Hz
• Ultrahigh magnetic fields - 1,000,000,000,000 times Earth’s
• High space velocities - up to 1,000 km/s
sprinter - 10 m/s
f1 car - 100 m/s
normal stars - 10 km/s
Why do they pulse?
rotation axis
beam of
radio waves
magnetic field
• Pulsars sweep their
beam of radio
(electromagnetic)
waves across the
face of the earth at
a very periodic rate.
What do the telescopes “see”?
Back to the telescopes:
Process . . .
• A computer program analyzes the data for
possible candidates
• A “viewer” page is produced
• Ratings are made and submitted
• Potential pulsars are followed up with
additional observations
• This is what we will learn next time!
• The basic question:
• Is it a Pulsar?
– Or is it Radio Frequency Interference (RFI)?
Let’s visit the GBT control room . .