Transcript auger_p213_slides_small - Cosmic Ray Observatory Project

The Pierre Auger Observatory
Capturing Messengers from the
Extreme Universe
A new cosmic ray observatory designed for a high
statistics study of the
The Highest Energy Cosmic Rays
Using
Two Large Air Shower Detectors
Colorado, USA
(in planning)
Gregory Snow / University of Nebraska
Mendoza, Argentina
(construction nearing completion)
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The Pierre Auger Observatory
Auger
north is
planned in
Colorado
Auger south
is here.
Malargue is a small town on
the high plains not far from
a ski area in the Andes.
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The Auger Collaboration
67 Institutions, 369 Collaborators
Argentina
Australia
Bolivia*
Brazil
Czech Republic
France
Germany
Italy
Mexico
Netherlands
Poland
Portugal
Slovenia
Spain
United Kingdom
USA
Vietnam*
True International Partnership
- by non-binding agreement -
No country, region or
institution dominates – No
country contributes more than
25% to the construction.
* associate
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Primary cosmic ray
Development of an extensive air
shower in the Earth’s
atmosphere
Mostly muons, electrons and
photons at Earth’s surface
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How a cosmic-ray air shower is formed and detected
Primary cosmic rays (mostly protons or light nuclei)
impinge on earth’s atmosphere from outer space
“Air shower”
of secondary
particles
formed by collisions
with air molecules
Grid of particle detectors
intercept and sample
portion of secondaries
1. Number of secondaries
related to energy of primary
2. Relative arrival time
reveals incident direction
3. Depth of shower maximum
related to primary particle
type
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Event timing
and direction
determination
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Detecting Cosmic Ray Air Showers
Air shower
measurements are
made by two
techniques
Fly’s Eye
1)
Surface Arrays
2)
Fluorescence
Telescopes (Fly’s
Eyes)
Surface Array
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The Hybrid Design
Surface detector array + Air fluorescence detectors
A unique and powerful design
•
Nearly calorimetric energy
calibration of the fluorescence
detector transferred to the
event gathering power of the
surface array.
•
A complementary set of mass
sensitive shower parameters.
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Different measurement
techniques force understanding
of systematic uncertainties
•
Determination of the angular
and core position resolutions
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The Surface Array
Detector Station
Communications
antenna
Electronics
enclosure
GPS antenna
Solar panels
Battery box
3 – nine inch
photomultiplier
tubes
Plastic tank with
12 tons of water
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The Fluorescence Detector
11 square meter
segmented mirror
440 pixel camera
Aperture stop
and optical filter
FD telescopes in closed
environment
Corrector lens
minimizes spherical
aberrations, filter
brackets 350 nm
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fluorescence light
Installation nearly complete
As of October 20, 2007, 1500 of 1600 SD stations
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Aerial Photos of Fluorescence Buildings
November 2006
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Event seen by all 4 fluorescence
detectors and many surface detectors
20 May 2007
E ~ 1019 eV
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Major result from the Observatory will be
featured in the November 9 issue of Science (cover story)
Super-galactic
plane
Galactic
coordinates
“Correlation of the highest energy cosmic rays with
nearby extragalactic objects”
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Some details
• AGN locations from “V-C” (Véron-Cetty and Véron) catalog, D < 75 Mpc
• Data set 1 Jan. 2004 – 26 May 2006: 12 events among 15 with E > 56 EeV,
Zenith angle < 60o correlate with AGN positions within 3.1o
3.2 expected by chance if flux were isotropic
• Data set 27 May 2006 – 31 Aug. 2007: 8 among 13 events correlate, 2.7 expected
from isotropic flux
• Probability to
happen by
chance
1.7 10-3
• Two events
within 3o of
Centaurus A,
one of the
closest AGNs
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Centaurus A, D=3.4 Mpc
2 UHECRs correlated.
Infrared
X-ray
radio+optical images
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