TeV Gamma-Ray Results and Links to mm-Surveys

Gavin Rowell (University of Adelaide)

(H.E.S.S. results - for the H.E.S.S. collab.)(Future TeV plans - for the Adelaide group)

- How & Why : TeV Gamma-Ray Astronomy - TeV & mm-wavelength connections- Some relevant TeV & mm results- Recent MOPRA obs.- Future TeV Gamma-Ray instrument ideas/plans

Large-Scale mm Mapping WorkshopSwinburne Uni. of TechnologyJun 12-13 2008

Ground-Based Gamma-Ray Detection via Cherenkov Imaging

Focal Plane array of light detectors (x500 – 1000)

Gamma-ray origin somewhere alongmajor axis -->

- ang. res > 10 arcmins- energy res > 20%- HUGE collection area > 0.1 km2

Primary TeV gamma-ray or cosmic-ray

Extensive air shower > 108 particles (e± )

Cherenkov light 'pool'

~8km

Telescopemirror > 10m2

Ground-Based Gamma-Ray Detection via Stereoscopic Cherenkov Imaging

Focal Plane array of light detectors (x500 - 1000)

Intersection of image axes gives accurateshower direction

- ang. res ~ few arcmins- energy res ~ 10-15%- improved cosmic-ray rejection

Primary TeV gamma-ray or cosmic-ray

Extensive air shower > 108 particles (e± )

Cherenkov light'pool'

>1 Telescopes

Jim Hinton MPI-R, Bonn

3.12.04

120 m

4 x 12m diam dishes

focal-plane cameras 5 deg FoV

H.E.S.S. >25 Institutions (Europe,Africa,Australia)

http://www.mpi-hd.mpg.de/hfm/HESS/HESS.htm

http://www.mpi-hd.mpg.de/hfm/HESS/public/som/current.htm

“Source of the Month”

H.E.S.S. Array: 4 x Cherenkov Imaging Telescopes (22o S 1800m a.s.l. Namibia)

CANGAROO III(Japan & Austral.)

VERITAS VERITAS (USA/IR/UK)(USA/IR/UK)

MAGICMAGICGerman/Spanish//German/Spanish//Ital. & 6 other Ital. & 6 other countriescountries

H.E.S.S.:H.E.S.S.:German/French & German/French & other countriesother countries

TeV Gamma-Ray ExperimentsTeV Gamma-Ray Experiments

MILAGROMILAGROUSA/MexicoUSA/Mexico

Jim Hinton MPI-R, Bonn

3.12.04

(50hrs obs. 5sigma)

H.E.S.S., VERITAS....

~0.01 Crab @ 1 TeV F ~ 10-13 erg/s/cm2

Gamma Rays from multi-TeV hadrons (Cosmic-Rays - CRs)

.

p+p --> o -> 2

MOLECULAR CLOUD

Gamma-Rays (+ Neutrinos)

Molecular Clouds act as targets for particle accelerators.

Key Signatures - Broad-band flat spectra GeV to multi-TeV emission

- TeV gamma + Mol Cloud spatial correlation Need TeV gamma and arc-min mm-wave observations to establish sources of hadronic multi-TeV cosmic-rays

We also have! p+p --> ± -> ± + () --> e± secondary radio to X-ray synchrotron continuum!

CR deflected by magnetic fields

CR accelerator + Molecular Cloud (passive target) further discussion see also Drury etal 1984, Naito et al 1984, Aharonian etal 1986

TeV Gamma Flux from pi-zero decay above energy E

Aharonian (1991) Ap & SS. 180, 305

dkpc

– distance (kpc)k(E) – E-dependent scaling factor: For 'Earth-like' CR spectrum k(E) = 1

M5 – Mol. cloud mass (units: 105 M

sun)

from line tracers CO, CS etc......

If F& M5 known --> can determine CR spectrum

at source

Gamma Rays from multi-TeV electrons

.

Accelerated TeV Electrons

e +(soft) -> e´ + (TeV) (inverse Compton scattering) e +B (G) -> e´ + (keV) (X-ray synchrotron emission)

Accelerated GeV Electrons

e + B (G) -> e´ + (~eV) (Radio - optical synchrotron emission) also recall sync. from 'secondary' electrons

TeV Gamma-RaysCMB, IR, UV photon fields

keV X-Rays

Objectives (a growing list) of Objectives (a growing list) of TeV Gamma-ray AstronomyTeV Gamma-ray Astronomy Oldest question

in modern astrophysics!Probe the extreme non-thermal Universe

Origin of (Galactic) Cosmic Rays (CRs) Shell-SNRs, Molecular clouds, Diffuse radiation of the Galactic Disk..

Early Stars, Stellar Clusters - Stellar Wind Interactions Shock accel in wind/wind/ISM interactions, Superbubbles

Particle acceleration/interaction & Photon production/transport.....

Pulsar Wind Nebulae, Compact Binaries.....

Relativistic flows – Galactic & Extragalactic Pulsars, Pulsar Winds, Microquasars, Small and Large Scale jets of

AGN, GRBs

Observational Gamma Ray Cosmology Clusters of Galaxies, Dark Matter Halos (indirect search), Diffuse Extragalactic Background radiation (constraints), Pair Halos

F. Aharonian

WKE

~ 1051erg

Power budget inGalactic CRs W

CR total ~ 1041 erg/s

SNRs most likelysources? To supplyGalactic CRs, need:W

CR_SNR ~ 1050erg

ie. ~10% SNR KEGinzburg & Syrovatski 1964

TeV Gamma-Ray Visibility of Shell-Type SNRs TeV Gamma-Ray Visibility of Shell-Type SNRs

Drury, Aharonian, Voelk 1994n

For CR spectrumFor CR spectrumdN/dE ~ EdN/dE ~ E-2-2

Wcr : KE in CRs

(Wp : KE in protons)

d: distance

n : Density of gas around SNR from mm studies!

eg. HESS sensitivity

Jim HintonICRC 2007

Jim HintonICRC 2007

71 TeV sources -each a cosmic particle accelerator,where gamma rays traceprimary electrons or nuclei

Supernova Remnants (SNR) 7Pulsar Wind Nebulae (PWN) 18Unidentified Galactic Sources 21Diffuse Sources 2 Binary systems 4 Active Galactic Nuclei (AGN) 19(Hinton, ICRC 2007)

We want to know: Nature of primary particles (leptons or hadrons?) Their spatial and momentum distribution Acceleration mechanism Propagation characteristics New types of multi-TeV particle accelerators

HESS Survey as of mid 2007

For new results see: Heidelberg Gamma Symposium 2008 http://www.mpi-hd.mpg.de/hd2008/pages/news.php(July 2008)

Longitude profile-- H.E.S.S. -- CS Data (Tsuboi etal 1999)

After Strong Source SubtractionContours: CS line: Mol. Cloud tracer

Diffusion from central 104 yr kCR

~ 3-9 (E>1 TeV) CR source (see Roland's Talk for more discussion!!)

Galactic Centre Region: Diffuse Emission Galactic Centre Region: Diffuse Emission Aharonian et al (2005) Nature 439, 695Aharonian et al (2005) Nature 439, 695

Continuation of a Survey of OH (1720 MHz) Maser

EmissionTowardsSNRs Green, Frail, Goss, Otrupcek 1997 AJ 114, 2058

Indication

for SNR &

Mol. Cloud

interaction.

eg. Frail etal

Target these

SNRS with

TeV

telescopes!

W28: SNR & Molecular Cloud InteractionRadio/IR image

W28 mixed-morphology SNRd ~ 2-3 kpc

35 – 150 kyr age

H II regions

W28-A2

Brogan et al. 200620/90 cm VLAMSX 8 micron

NE region

SNR shock + mol. cloud interaction

- 1720 MHz OH Masers Claussen etal 1999

12CO(J=3-2) (J=1-0) eg. Arikawa etal 1999

see also Reach etal 2005

Zeeman splitting in masers B ~ mG Hoffman etal

HESS 4,5,6 sigmasignificance contours

TeV ComponentsLuminosity 1-2 x 1033 erg/s (2 kpc)

EGRET source GRO J1801-2320

HII regions to S

PSR J1801-23Edot ~6.2x1034 erg/s d > 9 kpc

TeV emission towards NE rim of W28 and 0.5 deg SouthA&A 2008 481, 401arXiv:0801:3555

Radioeg. Dubner etal, Brogan etal Synchrotron N/NE rim + possible thermal component

Additional SNRs andSNR candidates Yusef-Zadeh etal

X-ray Centre-filled thermal dominant.(ROSAT, ASCA Rho & Borkowski)Non-thermal hint towards NE 'Ear'(XMM Ueno etal)IRHII regions prominentW28 A2 UC-HII region

Jim Hinton MPI-R, Bonn

3.12.04

Moriguchi,Fukui

d ~ 0 to 2.5 kpc d~2.5 to 4 kpc

V. good TeV & CO spatial association --> indication for hadronic origin

However, several cloud velocity components present. Are clouds connected or just projection effects?

Galactic l-v picture covering W28 Gal-b range:CO emission may 'surround' W28 extending to ~ +20 km/s ---> possible disruption by W28 SN ---> v ~ 10-15km/s consistent with W28's current shock speedBut. Still cannot rule out cloud components at d~4 kpc (Scutum-Crux arm)

W28 systemic velocity +7km/s from HI studies(Velazquez etal 2002)

kCR

= CR density enhancement above 'Earthlike' levelk

CR ~ 10 to 30 may be expected from an old (105 yr) SNR with W

CR=1050erg

for slow CR diffusion (D10GeV

~ 1026cm2/s) Aharonian & Atoyan 1996

HESSJ1800-240B – Related to W28 A2?

W28 A2 is an 'Ultra Compact HII region'

- v.early type star or protostar in formation (O5V type) (stellar winds present > 1000 km/s?)- molecular outflows or jets observed see recent paper Watson, Churchwell etal 2007

Radio images: Continuum & Lines Sollins et al. 2004

Bipolar outflowsobserved

~ 5x1047 erg dumped into ISM

over lifetime 103 to 104 yr

Is multi-TeV particle acceleration taking place?

MOPRA Observations of the W28 TeV Sources G. Rowell, M. Burton, Y. Fukui (& NANTEN team) Obs. 31 May, 1 Jun 2008

OTF mapping + Deep obs. for spectral lines

NH3 (1,1) primary line but aiming also for

NH3 (2,2) – (6,6)

Pointings: ~20x20 arcmin scans

around TeV sources

Largest-scale mapping so far

in ammonia lines for this region

Density profile important for

CR diffusion into clouds.

(eg. Gabici etal 2007)

NANTEN2 CO(4-3), CO(7-6) detected

HESS J1745-303 CR acceleration by G359.1-0.5?

Interaction of SNR G359.1-0.5 (dist ~ 7.6 kpc; age ~104 yr) with Mol cloud?

- OH masers at 1720 Mhz towards SNR boundary.- 12CO contours (Bitran etal -100 to -60 km/s Cerra Tololo) overlap N part of TeV src.

Hadronic CR scenario : Requires ~ 30% of the SN explosion energy into CRs

PSR B1743-30 (Edot/d2 = 2x1033 erg/s/kpc) may power S parts of TeV src.

A&A 483 509A 2008

HESS J1714-385 & CTB 37A (G348.5+0.1)

G348.5+0.1 (d ~ 10 kpc; age ~1600 yr) interacting with several molecular clouds

- OH masers (1720 MHz) - Dense molecular clouds - 12CO observations (Reynoso & Mangum 2000)

- TeV Gamma-ray energetics requires 4-30% of the SN energy in CRs

- But recent X-ray obs. suggest pulsar wind nebula (Edot implied 1037 erg/s) => TeV energetics requires only ~0.1% conversion

IC-443 - Another composite SNR IC-443 - Another composite SNR MAGIC MAGIC

MAGICJ0616+225MAGICJ0616+225Albert etal 2007 ApJ in pressAlbert etal 2007 ApJ in press

20cm VLA Condon etal 1998EGRET MeV/GeV sourceROSAT X-ray Asaoka etal 199412CO Dame etal 2001 (-20 to 20 km/s

IC-443

d ~ 1.5 kpc

1720MHz OH maser Claussen etal 1997

New TeV sourcecoincident withMol. Cloud..

MILAGRO: Diffuse TeV from the Cygnus MILAGRO: Diffuse TeV from the Cygnus Region Region

Abdo etal 2006Abdo etal 2006

E >~ 12 TeVE >~ 12 TeV

contours of contours of matter densitymatter densityfrom HI (Kalberla from HI (Kalberla etal 2005) CO etal 2005) CO (Dame etal 2001(Dame etal 2001surveyssurveys

See also MILAGROSee also MILAGROGal. Plane SurveyGal. Plane SurveyAbdo etal 2007Abdo etal 2007

MILAGRO is a water Cherenkov detector : MILAGRO is a water Cherenkov detector : With ~2With ~2 sr Field of view. sr Field of view.More sensitive version....HAWC at Sierra Negra (Mexico ~4.5km)More sensitive version....HAWC at Sierra Negra (Mexico ~4.5km)

HESS J1825-137: An asymmetric pulsar wind nebula (PWN):

> 2.5 TeV1 – 1.5 TeV< 1 TeV

> 2.5 TeV1 – 2.5 TeV< 1 TeV

> 2.5 TeV 1 – 2.5 TeV< 1 TeV consistent with leptonic origin due to synchrotron & IC losses

Aharonian etal 2006 A&A

HESS J1825-137 & NANTEN 12CO(J=1-0)

Funk etal 2007

Why asymmetric? Answer:Why asymmetric? Answer:Dense mol. cloud at N edge.Dense mol. cloud at N edge.

PWN 'crushed' /distortedPWN 'crushed' /distortedby SNR reverse shock afterby SNR reverse shock afterinteraction with mol. cloud. interaction with mol. cloud. see eg. Blondin etal 2001see eg. Blondin etal 2001Gaensler etal 2003Gaensler etal 2003van derSwaluw etal 2004van derSwaluw etal 2004

A New Gamma-Ray Instrument for multi - TeV (> few TeV) Studies – the TenTen project Lessons from H.E.S.S. etal.

- Growing number of Galactic TeV sources (few – 10 TeV), most with hard spectra --> there are definitely E>10 TeV sources

- Present instruments reach gamma-ray energies few x 10 TeV ie few x 100 TeV Cosmic Rays .... >=100 hrs obs time reqd.

- Need to search for and understand Particle PeVatrons PeV CR Acceleration much less well understood cf. Multi-TeV energies No obvious source type(s).. A major mystery in high energy astrophysics

- E>10 TeV: Easier to separate hadronic & leptonic components in magnetised environments (synchrotron 'cooling' of electrons, reduced IC cross-section)There is great potential for Gamma Ray telescopes optimised for E > 10 TeV studies

TenTen concept

Plyasheshnikov et al. (2000), ongoing work at Adel. Uni.

Requirements 4 or 5 telescope 'Cell'- Smaller mirror area/size (~10-30 m2) HESS ~100 m2

- Larger camera field of view (8°-10°) HESS ~5° - Larger telescope spacing (L >200 m) HESS 120 m

(see also de la Calle Perez 2006, LeBohec etal 2006, Yoshikoshi 2005)

Key Aim: Photon Statistics !!

Extend to ~10 x Cells 10 km2 at 10 >TeV ---> 'TenTen' and >1km2 at ~1 TeV

x5-10 better flux sensitivitiy than H.E.S.S.

Sites: Sea-level altitude are perfect. --> Australian sites are under investigation

eg. HEGRA IACT

System Telescope

CTA

Cherenkov TelescopeArray

One option under simulation:

23m tel 5deg fov 0.1 deg pixels10m tel 7deg fov 0.16deg pixels

possibly wide fov 12deg telescopes

many options still open

North array 50 MEuro

South array 100 MEuro

FP7 design study 34 institutes15 countries design study 5MEuro 2008-2010

CTA – listed in ESFRI 2006 report

Future: at Future: at Lower EnergiesLower Energies H.E.S.S. Phase II H.E.S.S. Phase II

30 metre diameter telescope at centre of H.E.S.S. array

- now under construction

Improved sensitivity at E~100 GeV (stereo with H.E.S.S. I) Lower threshold E <= 50 GeV (stand-alone)Astrophysics: AGN, pulsars, gamma-ray bursts strong synergy with GLAST (<20 GeV)

Summary/Conclusions - A growing TeV Gamma Ray catalogue due to HESS, MILAGRO et al. now we're doing TeV astronomy

- Several TeV sources show spatial match with molecular clouds Gal Centre Region, W28+Field (best cases) plus several others

- Pulsar Wind Nebulae – Molecular clouds influence evolution:

- mm studies (NANTEN, MOPRA...) of HESS TeV sources underway - key ingredient in establishing origin of multi-TeV particles and understanding development of shocks in ISM. - Looking forward to NANTEN2 results – mol. cloud dynamics

2008 - MOPRA obs of W28 – NH3 cores (cloud density profile) + others

Future TeV plans

- TenTen: A new E>10 TeV Gamma Ray instrument. --> mysterious PeV accelerators & large-scale surveys - HESS-II Lower E threshold to ~20-30 GeV (under construction)- CTA 10's GeV to 10's TeV improve sens x10

--> bright prospects for the future of TeV & mm studies

Jim Hinton MPI-R, Bonn

3.12.04

HESSJ1023-575 : HESSJ1023-575 : (Aharonian etal A&A 2007)(Aharonian etal A&A 2007)

A young open cluster TeV source?A young open cluster TeV source?

TeV Gamma IR/Optical

Westerlund2 – Young open cluster with several Wolf-Rayet stars WR20a (binary); WR20b. CR acceleration in colliding wind shocksin WR20a and/or collective effects of WR + many O-stars? Similar to TeVJ2032+4130 + Cygnus OB2?

Jim Hinton MPI-R, Bonn

3.12.04

Molecular Cloud Studies of Westerlund2 (Wd2)

Dame etal 2007

(Columbia CO survey from Dame etal 2001)

Wd2 may have disrupted a GMC at ~6kpc (V

lsr = +11 km/s)

HESSJ1023-575

Jim Hinton MPI-R, Bonn

3.12.04RX J1713.7-3946RX J1713.7-3946

ASCA: X-Ray1 – 3 keV Uchiyama 2002

H.E.S.S.: Gamma-Ray

- Gamma-ray & X-ray

morphology are very similar.

TeV gamma-ray emission from electrons and/or hadrons??

Aharonian et al. 2004, 2006,2007

(CANGAROO) Muraishi etal 1999, (CANGAROO) Muraishi etal 1999, Enomoto et al 2002)Enomoto et al 2002)

Jim Hinton MPI-R, Bonn

3.12.04

RXJ1713 – H.E.S.S & NANTEN 12CO (J=1-0)

H.E.S.S. contours overlaid on NANTEN CO map (colours) Fukui et al. 2003V

lsr = -11 to -3 km/s (0.4 to 1.5 kpc)

Azimuth profile of H.E.S.S. & NANTEN data

Global agreement but CO changes by factor ~100 cf. TeV change factor ~2-3

Jim Hinton MPI-R, Bonn

3.12.04

HADRONIC SCENARIO

p + ISM --> o --> 2

proton spectrum dN/dE ~ E-2 exp(-E/Ec)

Hadronic scenario favoured. Can allowmuch higher B-fields > 100 GX-ray & TeV correlation from similaracceleration sites.

Uchiyama etal 2007 B up to mG !

LEPTONIC SCENARIO

Synchrotron & Inverse Compton (IC) Scenario

electron spectrum dN/dE ~ E-2 exp(-E/E

c)

IC on (CMB + IR photons)Requires uncomfortably low B-fieldsDiffusive shock accel. theory suggest B >> 10 G

Fg ~ Fx / B2

GLAST will do much better here!

RX J1713.7-3946 – Compare with Models

Jim Hinton MPI-R, Bonn

3.12.04

RX J0852.0-4622 'Vela Junior'2004 & 2005 HESS ObsAharonian etal 2005, 2007

dN/dE E-2.24±0.05

~ 1 Crab flux in total L (1-10 TeV) ~ 1032 (d/200pc)2 erg s-1

Distance uncertainty 0.2 to ~1kpc

ASCA0.7 – 10 keVSlane 2001

1st detect, (CANGAROO) Katagiri etal 2005

ROSAT contours>1.3 keVAll Sky Survey

Jim Hinton MPI-R, Bonn

3.12.04

NANTEN 12CO(J=1-0)Moriguchi etal 2001

Vela Molecular Ridge(VMR) (d~1kpc) prominent

No spatical correlation of CO vs. HESS TeV contours.

for d = -0.2 to 3.2 kpc

12CO(3-2) & (1-0) lines

Arikawa et al. 1999 PASJ 51, L7

Distribution of

'unshocked' (JCMT)

'shocked' gas (Nobeyama)

beam sizes ~15arcsec

Unshocked gas – V ~ 3 km/s

Shocked gas – V > 20 km/s

concentrated along SNR/cloudboundary

Eshocked

~ 3x1048 erg based on gas Temp & mass

Previous large-scaleCO Observations

VLA - Brogan et al. 2006

Radio Continuum

eg. Dubner etal, Brogan etal

Synchrotron N/NE rim + possible thermal component

Additional SNRs andSNR candidates

Yusef-Zadeh etalBrogan etal

X-ray & IR Views

X-ray Centre-filled thermal dominant.

(ROSAT, ASCA Rho & Borkowski)

Non-thermal hint towards NE 'Ear'(XMM Ueno etal)

IRHII regions prominent – dustW28 A2 UC-HII region

v. prominent

Jim Hinton MPI-R, Bonn

3.12.04

Linear Polarisation of Maser LineHoffman et al 2004 astro-ph/0410577

--> B-field aligns well with the cloud-SNR shock

Masers E & F: B-field position-angle overlaid on the CO (J=3->2) map of Arikawa et al. 1999

approx shock alignment

Jim Hinton MPI-R, Bonn

3.12.04Monoceros SNRMonoceros SNRHESS J0632+057HESS J0632+057

Nanten CO map

Aharonian etal 2007 A&A

At rim of Monoceros SNR Point source (< 2’)

No obvious counterpart

- RX J063258.3+054857 ?- Be star MWC148 ?- 3EGJ0634+0521 ??- No obvious molecular clouds

Jim Hinton MPI-R, Bonn

3.12.04

Jim Hinton MPI-R, Bonn

3.12.04Diffuse Emission from the GC RegionDiffuse Emission from the GC Region

GC & Sgr-B Spectral index= 2.29 ± 0.07 ± 0.20

Implies harderCR spectrum than insolar neighborhood

CR Enhancement factor 3-9 (E>1 TeV)

--> Proximity of accelerator and Target (to avoid CR transport losses)

eg. Aharonian 1991

Diffuse ModelEarth-like CR fluxM

cloud = 1.7 - 4.4x107 M

sun

HESS J1813-178HESS J1813-178Funk etal astro-ph/0611646Funk etal astro-ph/0611646

assoc. withassoc. with SNR G12.82-0.02SNR G12.82-0.02 radio shellradio shell X-ray coreX-ray core

W33 HII region toW33 HII region to southsouth

NANTEN CONANTEN CO MMcloudcloud ~ 2.5x10 ~ 2.5x1055 M Msunsun

VVlsrlsr =30-40 km/s =30-40 km/s d ~ 4 kpcd ~ 4 kpc

Mol. Cloud has influencedMol. Cloud has influencedG12.82-0.02 developmentG12.82-0.02 development

NANTEN 12CO(J=1-0))

20cm VLA 20cm VLA Brogan etal 2005Brogan etal 2005

HESSJ1813-178 HESSJ1813-178 locationlocationcontourscontours

SNR interacting with several molecular clouds–OH masers (1720 Mhz)–Dense molecular clouds detected in CO observations●Hadronic scenario?–Gamma-ray energetics compatible with CRs accelerated by CTB 37A=> [4% - 30%] of the SN explosion energy into CRs

Recent X-ray observations–Chandra & XMM-Newton–Complex region in X-rays●Thermal emission discovered from the interior of the remnant●PWN candidate discovered coincident with the remnant–Possibly associated with CTB 37A–X-ray luminosity implies a spin-down luminosity around 1037 erg/s=> ~0.1% conversion in gamma-rays=> scenario possible

HESS coverage of inner Gal. Plane(2004)

Hadronic TeV gamma-ray sources could mimic galactic gas structures (scale ~few deg) --> Large FoV

NANTEN 12CO survey Onishi etal 2005

TenTen FoV TenTen FoV 8x8 deg

F. Aharonian

F ~ 10-13 erg/s/cm2

History of Cherenkov Telescopes Whipple 1968 - 2004

– 1989 Detection of Crab Nebula above 1 TeV

– 1992 First AGN, Mrk 421

HEGRA 1992 - 2002

– First Stereo system. Cas-A at 1 TeV

– First Unidentified TeV source

CANGAROO 1992 -

– Southern hemisphere. SNR RX J1713

Also Durham Mrk 6, CAT... + non-imaging expts.

Since 2004: 3rd Generation instruments:

– HESS and MAGIC-II, VERITAS, CANGAROO-III

– Dramatic increase in TeV source catalogue ~6 to > 30 sources

– Detailed spatial & spectral studies of sources

Gamma-Ray Astronomy

A branch of high energy astrophysics studying the Universe at MeV, GeV, TeV (& above) photon energies. It provides crucial window in the spectrum of cosmic EMradiation for exploration of nonthermal phenomena inthe Universe in their most extreme and violent forms

It is the last window in the spectrum of cosmic EM radiation to be opened.... It is now finally opened!