Transcript - Fermi Gamma-ray Space Telescope

Exploring the Extreme Universe
with GLAST -
The Gamma-ray Large Area Space
Telescope
Lynn Cominsky
GLAST Education and Public Outreach Lead
[email protected]
http://www.nasa.gov/glast
1
What first
turned David
Banner into
the Hulk?
Gamma Rays!
Because
gamma rays
are powerful
The Electromagnetic Spectrum
The Many Forms of Light
Each type of light carries different information.
Gamma rays, the highest-energy type of light, tell us
about the most energetic processes in the Universe.
3
Why study gamma rays?
•
Universe as seen by eye is peaceful
4
But what if you had gamma-ray vision?
5
The Gamma-ray Sky in False Color – from EGRET/Compton Gamma Ray Observatory
Milky Way – Gamma rays
from powerful cosmic ray
particles smashing into
the tenuous gas between
the stars.
The Unknown –
over half the
sources seen by
EGRET remain
mysterious
Blazars –
supermassive
black holes with
huge jets of
particles and
radiation pointed
right at Earth.
Pulsars – rapidly
spinning neutron
stars with
enormous
magnetic and
electric fields

Gamma-ray bursts –
extreme exploding
stars or merging
black holes or
neutron stars.
6
Exploding Stars
• At the end of a star’s life, if it is large enough, it
will end with a bang (and not a whimper!)
HST/WFPC2
Credit: Dana Berry
SN1987A - HST
7
Supernova Remnants
Cas A - Chandra
CGRO/g-ray
Chandra/X-ray
•
Radioactive decay of chemical elements
created by the supernova explosion
8
Pulsars
• Stellar corpses - size of a city, mass of the
Sun, spinning up to 1000 times per second
9
Gamma-ray Bursts
• Discovered in 1967 while looking for nuclear
test explosions
10
Gamma-ray Bursts
• Signal the birth
of a black hole?
• Or the death of
life on Earth?
11
Monstrous black holes
• At the heart of
every galaxy lies
a black hole,
millions to billions
times the mass
of our Sun
HST/NGC 4261
12
Blazing Galaxies
•
Gravity is so strong
inside its “event
horizon” that not even
light can escape
Credit: Genzel et al.
Stars orbiting the Black
Hole in the center of
the Milky Way
Credit: Dana Berry
13
Jet Mysteries
•
So, how do black
holes emit jets of
particles and light?
• And, how do the
particles in the
jets accelerate to
near light speed?
HST/ M87
14
Gamma-ray Jets
•
Jets flare
dramatically in
gamma rays
• Galaxies that
point their jets at
us are called
“blazars”
Credit: Aurore Simonnet
15
Dark Matter
•
Dark Matter makes
up over 90% of the
matter in the Universe
• You can’t see it, but
you can feel it!
HST/CL0024+1654
16
Shining light on dark matter
• Dark Matter can
be traced by
studying X-rays
from hot gas in
clusters of galaxies
ROSAT X-ray over visible light image
17
WIMPs
• Dark matter may
be Weakly
Interacting
Massive Particles
• Annihilating
WIMPs may
produce gamma
rays
A calculation of WIMPs
around our galaxy
18
The Gamma-ray Sky – An Overview
We know some of the “what,” “when,” and
“where” – the Universe is populated with
powerful, exotic objects and processes that
produce gamma rays. Many are variable, and
some of these are at cosmological distances.
We have only scratched the surface of “how”
and “why” for these gamma-ray phenomena.
We have much to learn about how they work
and affect the Universe.
This is where GLAST comes in.
19
How to study Gamma rays?
• Absorbed by the
Earth’s atmosphere
• Use rockets, balloons or
satellites
• Can’t image or focus
gamma rays
• Special detectors:
CCDs, crystals, siliconstrips
Balloon
experiment
20
Gamma-ray Large Area Space
Telescope
21
GLAST Mission
• First space-based collaboration between
astrophysics and particle physics
communities
• Launched 6/11/2008
• Expected duration 5-10 years
• Over 3000 gamma-ray sources will be
seen
22
GLAST instruments
Large Area
Telescope
GLAST Burst
Monitor
23
How does a gamma-ray telescope work?
g
• The key is “high-energy”
Anticoincidence
Detector
(background
rejection)
• A gamma ray is a packet of
energy – lots of energy.
Conversion
Foil
Particle Tracking
Detectors
e+
e–
Calorimeter
(energy
measurement)
Prof. Einstein, what do we do with something that
is just a large amount of energy?
Energy? That’s E, and E = mc2
Convert the energy to mass.
24
Real data: LAT Single GR Event Displays
The green crosses show
the detected positions of
the charged particles,
the blue lines show the
reconstructed track
trajectories, and the
yellow line shows the
candidate gamma-ray
estimated direction. The
red crosses show the
detected energy
depositions in the
calorimeter. The
anticoincidence detector
shows no incoming
charged particles in these
events.
25
CGRO/EGRET View of the Universe
26
GLAST view of the Universe
• GLAST expects to see thousands of sources!
27
GLAST Launch 6/11/08
GLAST’s Delta II Rocket
takes off from Cape
Canaveral Air Force
Station.
Next stop: Earth orbit!
Expected in August:
• A new name for
GLAST!
• First light press
conference
So stay tuned……
28
Global Telescope Network
• Ground-based
observations of GRBs
and flaring galaxies
• Coordinated with Swift
and GLAST satellite
data
• Sign up to use our
telescope or contribute
data of your own!
• http://gtn.sonoma.edu
GORT
29
Fly the Extreme Skies
• Follow GRBs as they happen on the GRB Skymap
website
• Read about each burst, see its time history,
location in the sky, constellation and the satellite
that discovered it
• http://grb.sonoma.edu
30
Play the GRB Lottery
• Closest guess to next GRB wins a prize!
http://swift.sonoma.edu/grb_lotto/index.php
31
Epo’s Chronicles
• Follow the adventures of Epo and
Alkina as they travel through the
Universe, trying to determine
their origins
• New “eposodes” every Monday!
• You can find all of our projects
at:
• http://epo.sonoma.edu
32
Backups Follow
33
Hypernova
• A billion trillion times the power from the Sun
34
Catastrophic Mergers
•
Death spiral of 2 neutron stars or black holes
35