Welcome to the Pulsar Search Collaboratory (PSC) – West! NRAO University Wisconsin – Milwaukee...

Welcome to the Pulsar Search Collaboratory (PSC) – West!

NRAOUniversity Wisconsin – Milwaukee

West Virginia UniversityYerkes 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)

ARCC@UWM NRAO, WVU, Funded by the NSF

Some of the people involved . .Sue Ann HeatherlyEducation Director, NRAO

Rachel RosenAstronomer,Program Director ofPSC

Maura McLaughlin,Astronomer, WVU

Duncan LorimerAstronomer, WVU

From UWM

Xavier Siemens , Physicist, UWM Larry Price, postdoc, UWM

Jean Creighton, Planetarium Director

David Kaplan, Astronomer, UWM

Dawn Erb, 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!

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A light wave is a light wave, no matter how A light wave is a light wave, no matter how long...long...

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Electromagnetic radiationElectromagnetic radiation

A traveling, massless packet of energy --OR an oscillating electric and magnetic field Also known as: radiation, light wave, photon

Animation from Nick Strobel’s Astronomy Notes (www.astronomynotes.com)

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

All EM waves follow the equation:

• Let’s try a problem:– What do the above variables stand for?– (one or two problems will be added – simple,

c f

c

What is the difference between radio waves and sound waves?

• This is a confusing point to a lot of students and non-science people

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Radio Waves are NOT sound!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

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.

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Optical and Radio can be done from the ground!Optical and Radio can be done from the ground!

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Radio TelescopeRadio Telescope

Optical TelescopeOptical Telescope

Nowadays, there are more Nowadays, there are more similarities between optical similarities between optical and radio telescopes than and radio telescopes than ever before.ever before.

• 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.

Chart recordings from Reber's telescope made in

1943.

First Surveys of the Radio Sky

Pioneer of Radio Astronomy

Grote Reber

In 1967, Cambridge graduate studentJocelyn Bell was using a radio array to study interplanetary scintillation – SURPRISE!

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Accelerating charged particles emit Accelerating charged particles emit radio waves.radio waves.

One Way: high speed electrons and One Way: high speed electrons and magnetic fieldsmagnetic fields

How Radio Waves are producedHow Radio Waves are produced

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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 starsPressure 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)

• 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/sf1 car - 100 m/snormal stars - 10 km/s

Pulsar Properties

Why do they pulse?• Pulsars sweep their

beam of radio (electromagnetic) waves across the face of the earth at a very periodic rate.

beam of radio waves

magnetic field

rotation axis

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 . .