Gammaray astronomy at

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Gamma-ray astronomy at

• Abelardo Moralejo Olaizola
• on behalf of the MAGIC group
• IFAE Jamboree, January 30th 2009

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Outline

• Gamma-ray astronomy
• The MAGIC telescopes
• MAGIC-I highlights
• MAGIC-II status
• The Cherenkov Telescope Array

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(No Transcript)
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Space-borne ?-ray telescopes
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Limit of space-borne ?-ray telescopes

• Peak eff. area of Fermi 0.8 m2
• From strongest flare ever recorded of very high
  energy (VHE) ?-rays
• 1 photon / m2 in 8 h above 200 GeV
• (PKS 2155, July 2006)
• The strongest steady source is 15 times weaker!
• Besides calorimeter depth ? 10 X0

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Ground-based ?-ray astronomy

• Observe particle showers induced in the
  atmosphere (28 X0 at s.l.) by ?-rays
• Most successful technique
• Imaging
• Atmospheric
• Cherenkov
• Telescopes

Very High Energy E? gt 30 GeV
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The IACT principle
?-ray
Cherenkov light
Huge ?-ray collection area ?
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The IACT principle
Telescope closer to shower axis
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The IACT principle
Telescope further away from shower axis
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Stand-alone IACT
Event 1
Event 2
Event 3

• First detection of a ?-ray source from the ground
  (Crab Nebula) reported in 1989

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IACT array ( 2 telescopes)
Gamma-ray source
Stereoscopic view of each shower better
reconstruction of ?-ray direction and impact
parameter
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Arrival of Cherenkov light on the ground
MC, Cosmic Ray proton, 200 GeV
MC, Gamma-ray, 100 GeV
Signal / CR Background 10-3 -10-4 at trigger
level! (efficient offline background suppression
needed)

• Few nanosecond flashes ?
• Fast photodetectors (? 280 - 700 nm)

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Cherenkov light yield

• Inside the plateau, light density ? E
• Larger light collection ? lower energy threshold

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Suppression of showers initiated by charged
cosmic rays
Based on the different lateral and longitudinal
development of gamma- and hadron - initiated
showers Signal / Background 10-3 -10-4 at
trigger level ?
Fabian Schmidt, Leeds university http//www.ast.le
eds.ac.uk/fs/showerimages.html
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Goals of VHE ?-ray Astronomy
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VHE ?-rays

• Originate in the most energetic and violent
  phenomena in the universe
• Cosmic particle accelerators (hadronic, leptonic)
• Heavy particle annihilation or decay ?

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Physics goals of ground-based ?-ray astronomy
Pulsars, PWN
AGNs
Binaries ?QSRs
Astrophysics
GRBs
Fundamental Physics
SNRs
Origin of Cosmic Rays
EBL and ?-Ray Horizon
Cold Dark Matter
Quantum Gravity
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Evolution of high-energy astronomy
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Ground-based ?-ray astronomy in the World
TIBET ARGO-YBJ
MILAGRO
TACTIC
PACT
GRAPES
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The MAGIC telescope(s)
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The MAGIC telescope(s)
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The MAGIC collaboration

• Started in 1995. Design report in 1997
• Goal build lowest E threshold IACT
• MAGIC-1 Inauguration October 2003
• First Physics results published in March 2006
  (now 43 refereed papers)
• Currently 140 physicists from 24 institutes in
  9 countries (Germany, Spain, Italy....)

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MAGIC - 1 elements
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The IFAE MAGIC group

• Joined MAGIC in 1996
• Principal Investigator _at_ IFAE
• Until 2006 Manel Martínez
• currently Juan Cortina
• Other 5 senior researchers
• Abelardo Moralejo (Ramón y Cajal)
• Javier Rico (ICREA researcher)
• Daniel Mazin (Marie Curie)
• Stefan Klepser (Juan de la Cierva)
• Oscar Blanch (CPAN post-doc)
• 6 Ph. D. students
• Engineers technicians

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Responsibilities of IFAE in MAGIC

• Manel Martínez Chair of the Collaboration board
• ( spokesman 2003 - 2005, co-sp. 1999-2003)
• Juan Cortina Operations and Safety
  coordinator
• Abelardo Moralejo Software coordinator
• ? 3 members in the MAGIC executive board (out of
  7)

• Javier Rico convener of Galactic Sources Data
  Center Coordinator

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IFAE contributions to MAGIC-1
Data Center
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MAGIC-1 camera
Josep Flix

• Construction coordinated by George Blanchot and
  Lluís Miralles (mechanics)

• Responsible of maintenance Miquel Barceló
• Ferrán Grañena Javier Gaweda

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MAGIC-1 camera

• Most complex element of the telescope
• Largest IACT camera of the time
• Light weight (500 kg)
• Highest efficiency (30 peak QE)
• Arguably the most complex instrument fully
  designed and built at IFAE

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MAGIC-1 upgrades

• Faster signal sampling introduced in Feb 2007
  (0.3 ? 2.0 GHz)
• Parallel low-energy trigger system (sum
  trigger) November 2007

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MAGIC-1 events, 2 GHz sampling
?-rings
all events
?-candidates
Use of 2GHz signal sampling ? improved
performance (BG suppression E resolution) D.
Tescaros master thesis Astroparticle Physics 30
(2009)
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MAGIC data center _at_ PIC

• Official data center for the whole collaboration
  since February 2007
• (after DAQ upgrade)
• IFAE
• Javier Rico
• Ignasi Reichardt
• (Ph. D. student)
• PIC
• Roger Firpo
• Esther Acción

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MAGIC - 1 performance

• Energy resolution ?E/E 25 above 100 GeV
• Angular resolution 0.1 - 0.2?
• Lowest E-threshold IACT 25 - 50 GeV
• Point-source flux sensitivity in 50 hours

• 1.8?10-8 ph m-2 s-1 (gt280 GeV)
• 1.6 of the Crab Nebula flux
• Lower E
• 5 Crab 100 - 280 GeV
• 20 Crab 50 - 100 GeV

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MAGIC-1 Highlights
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The binary system LS I 61 303

• Giant star Compact object (black hole or
  neutron star)

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VHE radiation from LSI 61 303

• First discovered by MAGIC Science 312 (2006)

Leading institute IFAE ?
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The Crab Nebula and pulsar
Chandra / Hubble / Spitzer
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?-rays above 25 GeV from the Crab pulsar

• Sum trigger introduced in Nov 2007 (T.
  Schweizer)
• Energy threshold 50 ? 25 GeV ? Pulsar detection
  feasible!

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?-rays above 25 GeV from the Crab pulsar
Science 322 (2008)

• Clear detection of two pulses, in phase with
  other Es
• Highest energy radiation ever measured from a
  pulsar
• Lowest energy ?-rays ever detected by an IACT

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?-rays above 25 GeV from the Crab pulsar

• Measured energy spectrum strongly constrains
  emission models
• Outer gap models better suited to explain MAGIC
  data

IFAE current participation in Pulsar group Javi,
Ignasi, Stefan, Juan
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?-rays above 25 GeV from the Crab pulsar
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Extragalactic astronomy with MAGIC
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Active Galaxies

• ? Radiation from nucleus dominates
• AGN
• Active Galactic Nucleus

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Attenuation of ?-rays in the Extragalactic
Background Light
AGN
?max 1.24 ?m (E / 1TeV)
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Spectral energy distribution of Extragalactic
Background Light

• An imprint of the history of the Universe (star
  formation, galaxy evolution)
• Direct measurements challenging (foregrounds)
• ? Large uncertainties

Redshifted star light
Redshifted dust emission
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3C 279 (z 0.536) the most distant VHE ?-ray
source
Science 320 (2008)

• MAGIC detects a clear signal from 3C 279 in
  February 2006
• First VHE quasar

• Measurements constrain EBL models under safe
  assumptions about the intrinsic spectrum

IFAE involved in this study
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EBL constraints
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?-ray horizon
MAGIC, 3C 279

• Only narrow band left between lower limits (from
  galaxy counts) and IACT constraints

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Fundamental physics
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Tests of speed of light invariance
L
observer
source

• Need fast-varying source (AGN flares...)

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Results before MAGIC and HESS
Pulsars, E up to 2 GeV, L about 10 kpc, (Kaaret,
1999)
Mrk 421, E up to 10 TeV, L about 100 Mpc
(Biller et al, 1999)
35 GRBs, E up to MeV, L beyond 7000 Mpc (Ellis
et al, 2005)
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MAGIC observations of Mrk 501 in July 2005
Astrophys. J. 669 (2007)

• z 0.034
• (L?100 Mpc)
• Hint (2.5 ?) of energy-dependent delay of fast
  flare

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MAGIC results Phys.Lett B 668 (2008)
Linear
Quadratic
MQG lower limits (95 C.L.)
gt 6 times better than previous limits
gt 4 times better than previous limits
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HESS observation of PKS2155 (z 0.116) flare in
2006

• No delay observed ? MQG1 gt 0.52 x 1018 GeV

MQG2 gt 1.4 x 109 GeV
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(obvious) caveat of method

• Source-intrinsic E-dependent delays are possible.
  
• Limits depend on the assumption of simultaneous
  emission at all Es
• Many sources at different distances are needed

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Dark Matter
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SUSY dark matter searches with IACTs

• Indirect detection WIMP annihilation in
  extraterrestrial objects

• IACTs FoV too small for all-sky scans
• Candidates regions with high ?DM2
• Galactic Center outshined by bright source
• Andromeda clusters many potential VHE emitters
• Spheroidal Dwarf Galaxies with large M / L ratios

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SUSY dark matter searches with IACTs

• Ground-based ?-ray astronomy is a unique tool
  for DM searches!
• Accelerators may find candidate particles, but
  not prove they are the DM
• Direct searches probe local DM
• Other indirect searches
• Neutrino astronomy far from needed sensitivity
• Charged particles cannot pinpoint source
• Space-borne ?-ray telescopes may not reach high
  enough energies to identify DM spectral features

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MAGIC DM searches

• 2006 MAGIC confirms HESS observation of emission
  from Galactic Center. Most likely not DM
• Spheroidal dwarf galaxies
• Draco upper limit (ApJ 679)
• Willman-1 upper limit (submitted to ApJ)
• Segue-1 known only since 2007 (found in Sloan
  Digital Sky Survey). Highest M/L. Observations
  ongoing.

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MAGIC DM searches

• Future strategies
• Observe more high M/L objects from all-sky
  optical surveys (SDSS, Pan-STARRS, DES)
• Observe Fermi dark sources (no counterpart at
  other wavelengths) with hard spectra

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MAGIC - II
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MAGIC-II

• Second telescope near completion
• Commissioning of subsystems ongoing

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MAGIC - I vs. MAGIC - II

• Most relevant improvements all-finely pixelized
  camera larger trigger FoV
• General improvement in technologies

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IFAE contributions to MAGIC-II

• Multipurpose boards for the readout (receivers)
• convert analog optical signals from the camera
  into electrical signals
• Perform level - 0 trigger (discriminators)

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IFAE contributions to MAGIC-II
Data Acquisition software (D. Tescaro)
Control software for receivers, trigger,
digitizers and readout cooling (D. Mazin)
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IFAE contributions to MAGIC-II
Central control SuperArehucas Roberta Zanin
(Ph. D. student)
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Jan 29, 2009

• First muon ring on the M-II DAQ display

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MAGIC-II First light ceremony to be held on April
25 Substantial improvement in performance
foreseen through stereoscopic event
reconstruction!
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Cherenkov Telescope Array
The next generation Cherenkov Observatory
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Next step towards better sensitivity in the VHE
range Large arrays of IACTS 100 telescopes
unavoidable
Aims at full-sky coverage North - South
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CTA milestones

• ApPEC review in July 2003
• Recommendation join European efforts in VHE
  astronomy
• Fall 2005 baseline design presented to ESFRI
• CTA Design Study kick-off meeting Barcelona
  January 24-25 2008
• Definition of Work packages
• Tentative schedule
• October 2008 CTA among AstroNet priorities for
  the future of European astronomy

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IFAE involvement in CTA

• Atmospheric monitoring and Calibration
• Manel Martínez convener of the working package
• Work already ongoing LIDAR (J. Boix, M. Barceló)
• Design optimization using MC
• Readout electronics for the large telescopes
• First money application to FPA to be submitted
  soon in coordination with other Spanish groups

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Conclusions

• Ground-based Gamma-ray astronomy is a well
  established discipline
• MAGIC-I has already made a sizable impact in the
  field
• MAGIC-II nearly operational
• CTA has become a priority of European science