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Hofmann Fest Colloquium 18 April 2013

Where would we be without Cygnus X-3?

Alan Watson

University of Leeds

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Overview

• Cygnus X-3 in the 1980sTales from Kiel, Haverah Park and the γ-ray community

• TeV γ-ray work: Cygnus X-3 had some influence

• HE Cosmic RaysOn CASA-MIA (but not KASCADE)

• Searching for 100 TeV γ-ray sources at the South Pole

Impact on neutrino astronomy – and trips to Antarctica

• The Auger Observatory: its creation and some results

Disclaimer: Not intended to be a review: some personal biases

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• September 1982

Bar in Rome with Jay Perrett and Wolf-Dieter Dau

during 8th European Cosmic Ray Symposium

“History is that certainty produced at the point where the imperfections of memory meet the inadequacies

of documentation”

Wolf-Dieter “I’m surprised that Samorski and Stamm are not here”

Julian Barnes: ‘The Sense of an Ending’

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Samorski and Stamm: ApJ Letters 268 L17 May 1983

4.4 sigma excess1º angular resolution31 events

5 4.8 hours

31 events

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Observations byHaverah Park groupappeared to confirmKiel results

Poorer angularResolution

1.7 sigma DC

Very small temporaloverlap

Nature 305 784 October 1983

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Apparently significant peakat phase of ~ 0.75

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Often forgotten – before Crab detection in 1989 at TeV energies by Whipple and others - that the air-shower results were consistent with prior claims at TeV energies

Also dramatic radio flares, sometimes on 26 September

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So – there was a theory!!

Also Westrand and Eichler (1982)

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Many people from particle physics entered field

In USA: Wisconsin, Hawaii, Minnesota groups at Haleakala and South Pole at TeV energies Cronin in Dugway with CASA at 100 TeV energies Yodh at Los Alamos with CYGNUS

In Europe: Various groups at La Palma from Germany Heinrich Meyer

Eckart Lorentz Werner Hofmann and others

La Jolla Conference 1985: Rapporteur talk/aaw

Explorations with the existing air-shower arrays – and many 2 to 2.5 sigma results from objects that were in the beam of the array

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ICRC Adelaide 1990

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The Heidelberg Drift Chamber

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Problems and worries began to appear

• Muons were found by Kiel group in some of the Cygnus showers

•Workers on proton decay experiment inSoudan Mine claimed signals from Cygnus X3

• The whole subject became a complete mess

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Marshak et al PRL 54 2079 1985

Battistoni et al Phys Lett 155B 465 1985

Ruddick PRL 57 531 1986 CYGNETS

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Cronin pressed on with CASA

On La Palma people edged from cosmic rays into TeV astronomy

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The Whipple Observatory - led by Trevor Weekes - – having observed Cygnus X3 early on -moved rapidly to exploit a new method using the Hillas parameters

1989: Birth of gamma-ray astronomy from the ground

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37 pixel camera

Cygnus X-3 work had little or no impact here

Markarion 421

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Fall-out fromCygnus X-3?

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• Cosmic rays of intermediate energies

Jim Cronin: CASA detector: 1 km2 specifically designed to look for Cygnus X-3

- had signal been there would have seen several events per transit

- supplemented by MIA detectors for muons

- results related to mass composition

- main science return was probably γ-ray limit from Galactic Plane

Gerd Schatz: KASCADE: Designed to study knee regionCygnus X-3 reports were largely irrelevant

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Following a suggestion by Michael Hillas

Leeds group joined with team from Bartol Research Institute (Pomerantz, Gaisser and Stanev) to make search at South Pole for 100 TeV γs from X-ray binaries

Also it was hard to see how one could compete with Jim Cronin’s level of funding and the scale of his project

So, go South!

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SN1987A: explosion of star in Large Magellanic cloud This explosion in February 1987 gave us a new focus - and a lead

Planning and funding of Bartol/Leeds effort began in late 1986 - very largely supported by NSF

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Later

As at 1987

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Lifting a SPASE scintillator box into position: November 1987

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Loading a scintillator block

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Some detectors of the SPASE array at the South Pole

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• Observations started within less than a year of SN1987 explosion

• Objects in sky 24 hours per day at 21º and observations at 3300 m

• No signals seen from SN1987a – theorists had misled us –

and nothing seen from X-ray binaries

• Significant results were:-

Established direction of Greenwich Meridian/aaw

With a Cherenkov light receiver (Trevor Weekes) we showed that the angular resolution was ~ 1º

Learned how hard it was to freeze water (Bob Morse)

Attempts to detect TeV γ-rays (GRASP: Morse, Gaidos et al)

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SPASE Array and AMANDA

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From Simon Hart’sPhD thesis:

“a eureka moment”

but

Disappointing result for AMANDA

Detector in layerof air bubbles

SPASE: 1 day of operation in early 1995

SPASE + 5 pmts fired in 4 strings of AMANDA

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These data were of interest and use to AMANDA and a loose collaboration began

– no collaboration meetings

- no project management to speak of

- but a lot of fun

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Ahrens et al. Astroparticle Physics 21 565 2004 (126 authors!)Evolved to study of mass composition with 10 strings

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Ahrens et al. Astroparticle Physics 21 565 2004 (~ 130 authors)

Amanda led to IceCube and SPASE led to SPASE-2 and IceTop

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In 1995, at Rome ICRC, Jim Cronin gave a review talk on howγ-ray astronomy had evolved in terms of detector developments

• Negative results from CASA which was hugely more sensitive than previous shower arrays

• Studies of the Solar Magnetic field with such as the Tibet array

• AIROBICC and TeV detectors at La Plama

• MILAGRO at Los Alamos

“Old problems remain and new mysteries have appeared and there are new researchers armed with enthusiasm and new technology to solve the old problems and unravel the new mysteries.

This is the legacy of Cygnus X-3.”Another leg

acy w

as the P

ierre

Auger Obser

vatory

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S Swordy(Univ. Chicago)

25 decadesin intensity

11 Decadesin Energy

1 particle m-2 s-1

‘Knee’1 particle m-2 per year

Ankle1 particle km-2 per year

Flux of Cosmic Rays

Air-showers

LHC

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Questions that we want to answer about UHECR

Where and how does Nature accelerate particles to >1020 eV?

Steps to the answers:-

(i) Does the spectrum steepen above 5 x 1019 eV as predicted?

γ2.7 K + p Δ+ n + π+ or p + πo (GZK-effect, 1966)

γ2.7 K + A (A-1) + n

Sources within ~100 Mpc at 1020 eV, ~200 Mpc at 6 x 1019 eV

(ii) Are there excesses from some regions of sky?

(iii) What is the Mass Composition? Implications for photon and neutrino fluxes

PLUS: Hadronic Physics beyond the LHC

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Arrays of water- → Cherenkov detectors

Fluorescence →

The design of the Pierre Auger Observatory marries the twowell-established techniques

the ‘HYBRID’ technique

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AND

The Auger Schematic Design

371390 m above sea level: 875 g cm-2

400 PhD scientists from18 countries

Area inside the M25

30 times area of Paris

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GPS Receiverand radio transmission

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Results from Pierre Auger Observatory - mainly

Data-taking started on 1 January 2004 with

125 (of 1600) water-Cherenkov detectors

6 (of 24) fluorescence telescopes

everything fully operational by June 2008: stable since then Data from 20905 km2 sr yr

> 1019 eV: ~5000 (HiRes : 307 TA: 812 > 5 x 1019 eV: 59 : 19 46 > 1020 eV: 3 : 1 2) 3600 2640 km2 sr yr 17% 13%

TA 700 km2 vs Auger 3000 km2

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Robust checks on energy estimates

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Correction for missing energy- hadronic physics needed

10%

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839 events

7.5 x 1019 eV

Auger Energy Calibration

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Auger spectrum from ~ 64000 events

44Kotera and Olinto, Ann Rev Ast Astrph 49 1056 2010

GZK effect or Source Exhaustion?

45log Energy

JE3Remember Von Neumann’s elephant

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photons

protons

Fe

Data

log (Energy)

Xmax

How we try to infer the variation of mass with energy

Energy per nucleon is crucial

< 2% above 10 EeV

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Some Longitudinal Profiles measured with Auger

rms uncertainty in Xmax = 20 g cm-2 from stereo-measurements

1000 g cm-2 = 1 Atmosphere ~ 1000 mb

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Mean Xmax from 3754 events

685

138 71 34

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RMS(Xmax) for same events

138 71 34

685

50T Pierog ECRS Moscow 2012

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T Pierog ECRS Moscow 2012

After LHC

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Implications of mass result for detection of cosmogenic neutrinos (Ave, Busca, Olinto, aaw, Yamamoto 2005, Hooper, Taylor and Sarkar 2005)

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So ‘where would we be without Cygnus X-3?

• Obviously a very personal question: several people in this room had enhanced travel experiences

• TeV field perhaps accelerated by a year or two. La Palma team were up and running earlier than had they started post-1989 (Crab at Whipple)

• IceCube would surely have happened but again the SPASE-AMANDA interaction surely saved a year or so

• Without this saga that the Auger Observatory would probably still not have happened

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Was there really something going on?

It was, over-all, a very strange episode

- but good did come from it!