Raggi Gamma e X dal cosmo

1
Raggi Gamma e X dal cosmo

• R. Bellazzini

2
Gamma-Rays in our domain from MeV to TeV
3
Detection techniques

• (30MeV - 300 GeV) Pair conversion telescopes
• Imaging detector (reconstructing the ee- vertex)
• Anticoincidence detector for shielding the
  detector from the CR flux
• ( 50 GeV - TeV) IACT
• Reflective mirror
• Background rejection (Photons/Hadrons)

4
IACT Cherenkov EAS experiments

• Cherenkov experiments consist of
  almost-optical telescopes devoted to detect
  Cherenkov light.
• EAS (Extensive Air Shower) experiments are
  huge arrays or carpets of particle detectors.
• Cherenkov experiments have lower energy
  thresholds, but also a lower duty-cycle as well
  as a smaller field of view.

5
Impact of g-ray space experimentsthe case of
COS-B and EGRET
Its difficult to give an exact value for the
impact of the g-ray experiments.
COS B (1975-1982) EGRET (1991-2000)
A rough estimate could be the number of papers
that contains in the title and/or abstract the
experiment name
6
The evolution of g-ray science
What we know about the high energy Universe
Number of papers regarding 2 fields of research
of astroparticle interest Pulsars and AGN in
g-rays
The 3 EGRET catalog is one of the most cited
source in g-ray astrophysics
Clearly visibile the impact of COS-B (end in
1982) and CGRO (end in 2000)
7
GLAST

• Flight August 2007
• Big INFN contribution
• LAT Tracker
• Assembly and Tests
• Software development, science preparation
• E 30 MeV - 300 GeV

8
(No Transcript)
9
MAGIC

• Inauguration 10/2003
• Big INFN contribution
• Mirrors
• Trigger
• Ethr 50 GeV
• Data taking 09/2004
• Efficiency 90
• Publications
• ICRC 2005 29 papers
• First publications in 08/2005

10
MAGIC Targets

• CRAB
• AGNs
• Mrk421/Mrk501/1ES1959/1ES1218/1ES1553
• Galactic Sources
• Galactic Center
• HESS J1813/HESS J1834/CygOB/GRS1915
• Gamma Ray Bursts (via GCN alert system)
• GRB050713a(gtCern Courier)/GRB050904

Galactic Center
GRB050713a
z0.184
11
GLAST MAGIC

• Cherenkov experiments
• Secondary detection.
• Strong MC dependence.
• High background.
• Energy gt 100 GeV.
• Effective area 1045m2.
• Duty-cycle 20.
• FoV 0.0010.01 sr.
• Low cost.

• Satellite experiments
• Primary detection.
• Test beam.
• Low background.
• Energy lt 30 GeV.
• Effective area m2.
• Duty-cycle 100.
• Field of view 1 sr.
• High cost.

?

?
12
IACT vs. SatelliteComplimentary
13
Sensitivities to Gamma rays

• Large zenith angle observation
• High threshold energy
• Large acceptance

14
MAGIC GLAST

• Share a large energy interval 200 GeV
• Unique chance of
• common physics programs
• inter-calibration

15
Detector Sensitivities For TeV Blazarsby P.Copi
Mrk 501 (1ES 1959650)Mrk 421

• EXIST Synchrotron Emission from Blue TeV
  Blazars

16
Different point of view

• GLAST
• Large FoV
• Scanning mode
• Discovery space
• Fill the gap
• Unexplored energy range
• ACD

• MAGIC
• Small FoV
• Pointing mode
• Photon Hadron separation
• Low E threshold
• High redshift (EBL)
• High latitude src

• HESS
• Small FoV
• Pointing mode
• Photon Hadron separation
• High angular resolution
• Galactic surveys

17
Atmospheric Imaging Cherenkov Telescope
Observe Cherenkov light from gamma ray
showers Effective area 105m2
18
Data taking Timing info g/h sep.
19
Alpha (Orientation angle) distribution
Hadron rejection by orientation a90
Gamma Rays
C.R. Protons
Before Image Orientation cut NS/NB
1/1000 After Image Orientation cut NS/NB 1/1
20
Array System or Single Big Telescope
HESS, VERITAS, CANGAROO Concepts High Precision
measurement
MAGIC Concepts Low Threshold Energy Eth gt 40GeV
21
Stereo system
Cherenkov Images
Multiple Telescopes improve angular
resolution improve energy resolution reduce
background
22
The case of H.E.S.S. catalog
Citations to published papers on H.E.S.S. sources
(year 2004-2005)
Some very interesting sources the 2 most cited
are the Galactic Center and a Supernova Remnant
23
The Galactic Center in VHE g-rays

• Study the presence of the central black hole
• Resolve contribution of different sources
• Study acceleration mechanism around black holes

HESSJ1745-290
HESSJ1745-290 viewed by HESS

• Important results
• Point source at 1 from Sgr A
• Measured flux above 165 GeV of (1.850.22)x 10-7
  m-2s-1
• Spectral index of G 2.20.090.15

24
The Galactic Center in VHE g-rays
HESS spectrum differs significantly from that
obtained by CANGAROO and WHIPPLE
(Aharonian,AA2004) ?It could be due to
variability of the source or to different
contributions.

• Key observational factors
• Favorable location on southern emisphere
• Angular resolution of arcminute
• Long exposure (4.7h 11.8h on source)
• Good energy resolution to determine spectral
  index
• More observations are needed to check consistency
  and potential variability

25
Supernova Remnants as probes for CR physics

• Supernova remnants (SNR) are believed to be the
  sites where CR are produced and accelerated
• About 10 of mechanical energy converted to non
  thermal particles
• Probe for physics of shocks

RXJ1713.7-3946 detected by HESS (Aharonian et
al., Nature 2004)

• Important results
• Resolved SNR structure
• Spectral index G 2.19 0.09 0.15
• Estimated energy flux (1TeV-10 TeV) 3.5 x 10-11
  erg cm-2s-1

26
Detecting SNR with IACTs (I)
In order to detect and study SNR efficiently at
TeV energies some important experimental features
are fundamental
Pixelation of the MAGIC telescope camera
HESS image compared to X-Ray ASCA (1-3 keV)
contours
Compare to other l, e.g. X-rays ? Resolve
structure of extended source ? Angular resolution
wide F.O.V. HESS Pixelation (960 PMT 0.16),
Total F.O.V. about 5 MAGIC Pixelation (397PMT
0.1 180 PMT 0.2), Total F.O.V. about 4
27
Detecting SNR with IACTs (II)
Spectral analysis ? Wide E coverage and high
DE/E HESS DE/E 15-20 in 100 GeV-10TeV
stereo approach better _at_ high E. MAGIC DE/E
10-30 in 30 GeV-10 TeV push energy threshold
down to 30 GeV
Stereo vs. single telescope approach privileges
different energy ranges
RXJ17137-3946 spectrum by HESS compared with
CANGAROO II. Not consistent probably because
CNAGAROO II observed only the NW part of SNR
Higher sensitivity required to detect low flux
extended sources as SNR. MAGIC II will push down
the MAGIC sensitivity by a factor of about 2
(Teshima, ICRC2005)
28
MAGIC HESS

• 18/12/04 HESSMAGIC simultaneous observation
• 1 Crab _at_ 300 GeV

MAGIC
HESS
29
Extension of HESS, MAGICNo rule in competition
HESS-II 28m diameter telescope Lower threshold
energy
MAGIC-II 2x17m, High Q.E. detectors Lower
threshold energy High Precision
30
MAGIC II

• Identical mechanical structure
• Foundations ready
• Frame being built
• New technological developments
• Large area mirrors (1 m2)
• High quantum efficiency camera (PMT,SiPM,HPD)
• New Flash ADC system _at_ 2 GHz

31
Major Cherenkov Telescopesstill increasing
sensitivities
32
The European Roadmap
http//www.cordis.lu/esfri/

• Participation to ESFRI (European Strategy Forum
  on Research Infrastructures)
• ESFRI is the European Roadmap for Research
  Infrastructures
• Common program HESS-MAGIC-VERITAS
• Letter of Intent for a Large Array of Imaging
  Atmospheric Cherenkov Telescopes for High-Energy
  Astrophysics, to be included in the ESFRI
  Roadmap"

2005 2006 2007 2008 2009 2010 2011 2012
HESS
MAGIC
VERITAS
GLAST
MAGIC II
Large Array of Imaging Atmospheric Cherenkov
Telescopes
33
MAGIC GRB fast follow-up observation
10sec GRB trigger Satellite to MAGIC lt20sec
MAGIC slewing time (at present, 30 performance)
34
Technical development
35
MAGIC-II R9792U-40 18mm GaAsP HPD by Hamamatsu
GaAsP photocathode
36
Next generation Telescope SiPM development in
MPI MEPhI
70-80 Q.E. will be achieved with Back
Illumination technique!!

• 3mm x 3mm was successfully
• Made in the collaboration.
• Next step
• 5mm ? or 10mm ?
• Drift Back illumination

37
MAGIC-II 2GHz sampling Domino Ring Sampler
Domino Ring Sampler developed by Stefan Ritt in
PSI 2.0GSamples/sec with gt10bit resolution DAQ
system for MAGIC-II is in development in U-Siena,
U-Pisa
38
HESS-II electronics 2-3GHz sampling by P.Goret
39
MACE in Indian Himalaya, Hanle
Big challenge!!
21m telescope At the site of 4200m
By R.Koul
40
Competition in Scientific view

• Precision measurement (Stereo)
• HESS, VERITAS, CANGAROO, MAGIC-II
• Low threshold energy bridge between Satellite
  and ground based IACTs
• MAGIC, MAGIC-II, HESS-II, MACE
• Fast follow up observation of GRBs MAGIC
• Wide angle telescope
• Tibet AS-?, MILAGRO, ARGO

41
Competition in technical view

• Huge telescope
• HESS-II (28m), ECO-1000(34m design study)
• High Q.E. photon detectors
• HPD, SiPM developments for MAGIC-II and future
• New electronics
• Ultra-Fast FADCs (2GHz sampling)
• High Altitude lower threshold energy
• MACE, 5_at_5 (design study)

42
Cooperation

• Multi wavelength observation is very important
• Radio Optical X-ray Gamma HE gamma
• Cross check of new source discoveries
• Confirmation by independent instruments
• Cross calibration of instruments
• Observation of AGN flares
• Detectors in different longitudes
• wider coverage in time ? light curve of AGN
  flares
• North-South Wider energy coverage
• Observation near the zenith (low energy)
• Large zenith angle observation (high energy)

43
Simultaneous observation with north and south
observatories
Gamma Rays
Atmosphere
Earth
Large zenith angle observation e.g. Southern
hemisphere HESS E 1TeV 100TeV
Near zenith observation e.g. Northern
hemisphere MAGIC E 30GeV 3TeV
44
Crab Observation by HESS and MAGIC
Wider Energy coverage 30GeV30TeV Good
cross-calibration of Instruments
45
Mrk421 HESS MAGIC Joint observation

• December 2004 flare observed by RXTE
• Simultaneous observation with HESS on 18 Dec 04
  allows
• - Cross calibration
• - Observation under different zenith angles gt
  different energy ranges

flux O(1 Crab) observed at E gt 300 GeV
Dedicated poster HESS MAGIC joint observations,
D. Horn, D. Mazin
46
AGN GeV-TeV flare observation

• HEG-Circular ???
• We can learn from GCN circular, IAU circular
• very fast and very effective, but respecting the
  credit
• So far private communication was used in TeV
  community
• Time delay ? a few days
• AGN flare alerts from each observatory
• Alert within a few hrs from flare detection
• We need to make sure the credit for new discovery
  (like IAU circular, GCN circular)

47
Cooperation II

• Technical developments for the next generation
  detectors
• High Q.E. Photon detector development
• Large IACT / Wide angle IACT
• Fully robotic IACT for high altitude experiment
• Share the common future vision
• Next generation IACT must have a order of
  magnitude better sensitivity and may cost
  100MEuro.

48
Future Vision
49
Next generation Ultimate Ground-based Gamma Ray
Telescope (20102015)

• Sensitivity an order of Magnitude improvement
• Capability to access to 10GeV energy
• Three possible options
• 3-4 x 30mf Class Telescopes
• 10-20 MAGIC-class Dense Telescope Array with
  Advanced Camera
• 3-4 x Wide Angle 17mfCherenkov Telescope
• The choice depends on the scientific results
• Number of sources number of variable sources
• The choice also depends on the development of
  photon detectors

50
Hadron rejection below 100GeVAlpha dist. in Crab
observation
51
Problems in low energies

• Hadronic interactions
• Muons can be rejected by multiple telescopes
• p0 ? 2 ?showers are very difficult to reject
• Xmax measurement may help
• separation of two prongs 70MeV/10GeV 0.4 deg in
  max
• Primary electron becomes significant background
• Geomagnetic effect
• alpha distribution is distorted (major axis
  determination is poor)
• Imaging for Gamma / Hadron /electron is moderate
• Angular resolution becomes more important

52
Problems in low energies

• Poor photon statistics (even in MAGIC)
• 30GeV 700photons/telescope ? 80ph.e.
• 10GeV 250photons/telescope ? 30ph.e. (can not
  be triggered)
• Sampling rate in MAGIC HESS
• mirror/light pool 1/100
• Photon ? ph.e. 1/10
• total efficiency 1/1000

53
One possible scenario

• How to improve photon statistics
• Densely arranged 16 x MAGICs (e.g. 40m spacing)
  ? x16
• Cover 10 area of ground
• advanced photo-sensor with high q.e. of 75 ? x3
• 17m telescope becomes equivalent to 30m diameter
  telescope
• 17m telescope collects 100ph.e. signals for 10GeV
  showers
• Total photon collection efficiency becomes ? x50

54
Step to the Next Gen. IACT

• Large international collaboration
• Photon detector development
• Demonstration in MAGIC-II
• Understanding of shower characteristics and
  backgrounds in low energy regime
• Optimization of scientific objectives
• We can not do everything
• Site survey new sites
• ALMA site 4800m nice infrastructure
• Hawaii nice infrastructure, limited space area
• Bolivia 4000m poor infrastructure, very wide
  area
• Tibet 4300m some infrastructure, very wide area
• Himalaya (Hanle) IR telescope by Indian
  astronomers, MACE site

55
2004
2005
2006
2007
2008
2009
2010
Roadmap to the Next Generation Cherenkov Gamma
Ray Telescope
H.E.S.S.
H.E.S.S. II
Science Review
Ultimate Ground- based Cherenkov Telescope
System Larger Dish, High Altitude, Advanced
detector, Wide Angle
Technology for Fully Robotic Telescope
Experimental Study of High Altitude effect
Final Conceptual Design under New collaboration
Design Study of Large Telescope
Site Survey
Characterization of Low Energy Showers
Design Study of Wide Angle Telescope
Advanced photon detector
International collaboration CANGAROO, VERITAS,
etc.
MAGIC
MAGIC II