Incontri di Fisica delle Alte EnergieIncontri di Fisica delle Alte Energie

IFAE 2006 PaviaIFAE 2006 Pavia

Vincenzo VitaleVincenzo Vitale

Recent Results in Gamma Recent Results in Gamma Ray Astronomy with IACTsRay Astronomy with IACTs

IntroductionIntroduction

Instruments and techniquesInstruments and techniques

Scientific highlights and observationsScientific highlights and observations

SummarySummary

OutlineOutline

IntroductionIntroductionCosmic gamma-ray observation:

- directly from satellites (HE) < O(10 GeV) and

- indirectly from ground-based installations (VHE) > O(100 GeV)

Satellites: EGRET -> HE gamma-ray astronomy already consolidated.

EGRET: Around 350 sources (250 unidentified)

Ground based vs satelliteGround based vs satelliteSatellite :

primary detection small effective area ~1m2

lower sensitivity large angular opening large duty-cycle large cost lower energy low bkg

IACT/ground based Secondary detection huge effective area ~104 m2

Higher sensitivity small angular opening small duty-cycle low cost high energy high bkg

Sensitivity of Sensitivity of γγ detectorsdetectors

High galactic latitudesb=2 10-5 cm-2 s-1 sr -1 (100 MeV/E)1.1). Cerenkov telescopes sensitivities (Veritas, MAGIC, Whipple, Hess, Celeste, Stacee, Hegra) are for 50 hours of observations.Large field of view detectors sensitivities (AGILE, GLAST, Milagro, ARGO, AMS) are for 1 year of observation.

STACEECACTUS

MILAGRO

TIBETARGO-YBJ

PACT

GRAPES

TACTIC

VERITAS

MAGIC

HESS CANGAROO

TIBETMILAGRO

STACEE

TACTIC

VHE γ detectors

Observation tecniqueObservation tecnique

~ 10 kmParticleshower

Detection of Detection of TeV gamma TeV gamma

rays rays

using Cherenkovusing Cherenkovtelescopestelescopes

~ 1o

Che

renk

ov li

ght

~ 120 m

Image intensity Shower energy

Image orientation Shower direction

Image shape Primary particle

Better bkgd reduction Better angular resolutionBetter energy resolution

Slide fro Pr W. Hofmann

Galactic SourcesGalactic Sources

Acceleration of Galactic cosmic rays in SNR

Galactic center emissions New type of sources

HESS galactic plane surveyHESS galactic plane survey

330°

Sources > 6 sigma: 9 new, 11 total

Sources > 4 sigma: 7 new

Most sources:

• Shell-type SNR

• Pulsar-Wind-Nebulae

• Unidentified

• New objects

RX J1713-3946RX J1713-3946

Unambiguous evidence for particle acceleration in an SNR shell

Resolved shell in VHE g-rays

Close correlation between X-rays and g-rays

RX J1713-3946RX J1713-3946

Preliminary

Index ~ 2.1 – 2.2Little variation across SNRNo evidence of cutoff or break at high energy

Acceleration ofprimary particlesin SNR shock towell beyond 100 TeV

Galactic CenterGalactic Center

Sgr ASgr A

Diffuse Diffuse emissionemission

Nature, Feb. 9th 2006

Galactic CenterGalactic Center

Unbroken power law, index 2.3

Good agreement between HESS andMAGIC (large zenith angle observation).

PSR B1259-63PSR B1259-63

Binary systemStrong stellar wind Shock at wind-pulsar interaction

Extragalactic SourcesExtragalactic Sources

Physics of AGN jets Cosmological

extragalactic background light (EBL)

AGN summaryAGN summary

SourceSource RedshiftRedshift TypeType First Detection First Detection ConfimationConfimation

M87M87 0.0040.004 FR IFR I HEGRAHEGRA HESSHESS

Mkn 421Mkn 421 0.0310.031 BL LacBL Lac WhippleWhipple ManyMany

Mkn 501Mkn 501 0.0340.034 BL LacBL Lac WhippleWhipple ManyMany

1ES 2344+5141ES 2344+514 0.0440.044 BL LacBL Lac WhippleWhipple HEGRAHEGRA

1ES 1959+6501ES 1959+650 0.0470.047 BL LacBL Lac Tel. ArrayTel. Array ManyMany

PKS 2005-489PKS 2005-489 0.0710.071 BL LacBL Lac HESSHESS

PKS 2155-304PKS 2155-304 0.1160.116 BL LacBL Lac Mark VIMark VI HESSHESS

H1426+428H1426+428 0.1290.129 BL LacBL Lac WhippleWhipple ManyMany

H2356-309H2356-309 0.1650.165 BL LacBL Lac HESSHESS

1ES 1218+3041ES 1218+304 0.1820.182 BL LacBL Lac MAGICMAGIC

1ES 1101-2321ES 1101-232 0.1860.186 BL LacBL Lac HESSHESS

Extrag. Background Light Extrag. Background Light Cosmological radiation from star formation and evolution.Cosmological radiation from star formation and evolution. Spectral signature from gg absorption for Eg ~ 50-2000 Spectral signature from gg absorption for Eg ~ 50-2000

GeV.GeV. Use measured AGN spectra to constrain EBL.Use measured AGN spectra to constrain EBL.

eeEBLHE

1ES 1101-232 (HESS col.)

Gamma ray horizonMartinez et al 2005

AGN with orphan flaresAGN with orphan flares Source observed already by Whipple and HEGRA in flaring state.

Orphan flares (hadronic origin ?)

MAGIC observation: low threshold and low flux (low state).

Two neutrinos in AMANDA data ?.

Two HiRes stereo events ?.

=> Connection btw. Gamma-ray astronomy and neutrino/UHECR astronomy ?.

High resolution flare studyHigh resolution flare study• Huge Mkn 501 flare on 1st July 2005 -> 4 Crab intensity.

• Intensity variation in 2 minute bins -> new, much stronger, constraints on emission mechanism and light-speed dispersion relations (effective quantum gravity scale).

Preliminary

2 minutes time bins

Preliminary

Crab

GRBs observation with MAGICGRBs observation with MAGIC## GRB EventGRB Event SatelliteSatellite Onset Onset

[UTC][UTC]Dt alertDt alert

[sec][sec]

Dt obs.Dt obs.

[sec][sec]

qq

[deg][deg]

zz

11 GRB050408GRB050408 HETEHETE 16:22:5016:22:50 1414 31383138 4848 1.231.23

22 GRB050421GRB050421 SWIFTSWIFT 04:11:5204:11:52 5858 112112 5252

33 GRB050502GRB050502 SWIFTSWIFT 02:14:1802:14:18 1818 990990 3333 3.793.79

44 GRB050505GRB050505 SWIFTSWIFT 23:22:2123:22:21 540540 793793 5050 4.274.27

55 GRB050509AGRB050509A SWIFTSWIFT 01:46:2901:46:29 1616 115115 5757

66 GRB050509BGRB050509B SWIFTSWIFT 04:00:1904:00:19 1515 368368 6969 0.230.23

77 GRB050528GRB050528 SWIFTSWIFT 04:06:4504:06:45 4343 7777 5252

88 GRB050713AGRB050713A SWIFTSWIFT 04:29:0204:29:02 1313 4040 4949

• On 13 July 2005 MAGIC has observed a GRB with only 40 s delay

• Preliminary analysis shows no signal

• Constrain models on prompt emission

Mrk421Mrk501

Crab

Pulsar AGN

The VHE The VHE γγ ray sky ray sky

+ some additional sourcesin galactic plane.

1995

2005

Source CountsSource Counts

Source Type*Source Type* 20032003 2005 2005

Pulsar Wind Nebula (e.g. Crab, MSH 15-52 …)Pulsar Wind Nebula (e.g. Crab, MSH 15-52 …) 1 1 66

Supernova Remnants (e.g. Cas-A, RXJ 1713 …) Supernova Remnants (e.g. Cas-A, RXJ 1713 …) 22 66

Binary Pulsar (B1259-63) Binary Pulsar (B1259-63) 00 11

Micro-quasar (LS 5039)Micro-quasar (LS 5039) 00 11

Diffuse (GC clouds)Diffuse (GC clouds) 00 11

AGN (e.g. Mkn 421, PKS 2155 …)AGN (e.g. Mkn 421, PKS 2155 …) 77 1111

UnidentifiedUnidentified 22 66

TOTALTOTAL 1212 3232

Explosion in the number of VHE sources.

SummarySummary

Galactic Plane rich in number and type of VHE emitters.Galactic Plane rich in number and type of VHE emitters. PWN and SNRs firmly established as TeV sources.PWN and SNRs firmly established as TeV sources. Unprecedented spectrum and morphology studies.Unprecedented spectrum and morphology studies.

Discovery of VHE gamma-ray emission from a binary Pulsar and from a Discovery of VHE gamma-ray emission from a binary Pulsar and from a Microquasar.Microquasar.

Wide-range spectrum of gamma-ray emission from GC. No hint for DM Wide-range spectrum of gamma-ray emission from GC. No hint for DM annihilation signals. annihilation signals.

Increased number of TeV blazars at large redshift. Constraints in Increased number of TeV blazars at large redshift. Constraints in cosmological EBL.cosmological EBL.

2 minutes-resolution light-curve of a fast flare. Constraints in emission 2 minutes-resolution light-curve of a fast flare. Constraints in emission models and light-speed dispersion relations.models and light-speed dispersion relations.

First GRB follow-up in coincidence with X-ray observation. Constraints in First GRB follow-up in coincidence with X-ray observation. Constraints in GRB models.GRB models.

γγ /hadron separation /hadron separation

CR

(2) Shape: –rays are narrowerthan cosmic rays.

γγ /hadron separation /hadron separation

Proton shower

Gamma shower

Crab Nebula

New Cherenkov TelescopesNew Cherenkov Telescopes

HESS-II

• New 28m telescope.

• 2048 pixel camera.

• Lower energy 40-50 GeV

• First light in 2008.

MAGIC-II

• Improved 17m telescope.

• Faster FADCs and a high-QE camera.

• First light in 2007.

MAGIC-IMAGIC-I MAGIC-IIMAGIC-II

85m

VERITAS

• 4x 12m telescopes at Kitt-Peak in 2006.