Gamma ray astronomy The end of the electromagnetic

Gamma ray astronomy. The end of the electromagnetic spectrum Christian Stegmann ICHEP, Valencia July, 8 th 2014

Gamma rays – Messengers from the High Energy Universe > Gamma rays are excellent tracers of the acceleration sites of ultra-relativistic cosmic rays > Production § protons: pion-decay: π0 → γγ § electrons: Inverse Compton Scattering: e± γ → e± γ C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 2

Experimental techniques Me. V Ge. V Te. V Pe. V Satellites (Fermi-LAT) Cherenkov light Particle shower Air Cherenkov Systems (MAGIC, VERITAS, H. E. S. S. ) Water Cherenkov Systems (HAWC) C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 3

Experimental techniques Me. V Fermi-LAT Ge. V Te. V MAGIC Pe. V HAWC VERITAS H. E. S. S. C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 4

Experimental techniques Me. V Ge. V Te. V MAGIC Fermi-LAT Pe. V HAWC Fermi LAT IACTs HAWC Effective area 1 m 2 105 m 2 Field of view 20% of the sky VERITAS 3 o – 5 o 15% of the sky Energy res. 10% 100% – 20% Angular res. 6 o – 0. 3 o 0. 1 o 1 o – 0. 2 o Duty cycle Full year 1400 h/year Full year H. E. S. S. C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 5

Closing the gap to Fermi-LAT > H. E. S. S. II § four 12 m telescopes § one 28 m telescope (Fo. V 3. 5 deg) § energy threshold O(30 Ge. V) C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 6

The Vela pulsar seen with H. E. S. S. II τrot = 89 ms Energy distribution <E> = 40 Ge. V > Closing the gap to Fermi-LAT § calibration source at the threshold in standard observation mode § well prepared for GRB search C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 7

The Vela pulsar seen with H. E. S. S. II τrot = 89 ms Energy distribution <E> = 40 Ge. V > Closing the gap to Fermi-LAT § calibration source at the threshold in standard observation mode § well prepared for GRB search > Pulsar physics (not only Vela) § what is the spectrum above 20 Ge. V? § constraining the cut-off? C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 8

Pulsars seen with Cherenkov Telescopes τrot = 89 ms Energy distribution <E> = 40 Ge. V Crab pulsar τrot = 33 ms Crab pulsar MAGIC, A&A 565, 12, May 2014 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 9

The Vela pulsar spectrum H. E. S. S. II Fermi-LAT ar. Xiv: 1002. 4050 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 10

The HAWC Observatory > Altitude: 4100 m > 20000 m 2 covered with 300 water Cherenkov detectors equipped with 1200 PMTs > Current status: 256 tanks, 195 with water, 662 PMTs > Completion scheduled for this year C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 11

The sky seen with HAWC > 3 months of data, 1/3 rd of array C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 12

Experimental techniques Me. V Fermi-LAT Ge. V Te. V MAGIC Pe. V HAWC VERITAS H. E. S. S. C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 13

The Gamma-ray Sky at Ge. V Energies > Fermi 2 FGL catalogue § 1800 sources; significant fraction Extragalactic; many Galactic sources confused with diffuse Emission C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 14

The Gamma-ray Sky at Te. V Energies > Te. VCat § ~50 extragalactic sources; ~100 Galactic sources C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 15

Scientific Highlights > Imaging of cosmic particle acceleration sites > Physics of pulsars and pulsar winds > Full sky surveys > Probing the extragalactic background light > Extreme variability of AGN > Limits on dark matter and new physics > Major contributions from all current instruments C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 16

Supernova Remnants Gamma rays X rays C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 17

Ge. V-Te. V spectra of supernova remnants from S. Funk C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 18

Ge. V-Te. V spectra of supernova remnants from S. Funk C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 19

Supernova Remnants Fermi-LAT C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 20

Detection of the “pion cutoff” in supernovae remnants > Supernovae are accelerators of hadronic cosmic rays Science 339, 2013 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 21

Extreme SNR > HESS J 1640 -465 § The most luminous Galactic Te. V source § Distance: 8 – 13 kpc > SNR G 349. 7+0. 2 § Distance 22. 4 kpc § The farthest SNR discovered so far Te. VCat Galactic sources G 349. 7+0. 2 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 22

The Galactic Centre C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 23

The Galactic Centre at E > 200 Ge. V H. E. S. S. preliminary > Intrinsic GC source spectrum has a stronger cut-off ~ 7 Te. V > Spectrum of diffuse shows no indication of a cut-off below 25 Te. V and follows a power-law up to at least 50 Te. V Indication of a central source accelerating protons to energies > 500 Te. V ? C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 24

The Galactic Centre with H. E. S. S. II > Observation and analysis § Life time 68. 8 h § Signal with 25 σ Significance map § extended emission > Background needs to be further studied C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 25

Dark Matter Search with Gamma Rays Diffuse emission • Galactic Centre region • Anisotropies, gradients Spectral signatures • Search for line emission Individual sources • Galaxy clusters • Milky Way satellite galaxies e+/e- spectrum Kuhlen et al. (2008) γ-ray predictions for Fermi-LAT C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 26

Search for line emission at Ge. V energies > No significant line emission > Most significant fit at 133 Ge. V in smallest search region § local significance of 3. 3 σ § global significance of 1. 5 σ > Systematics studied in detail § Better understanding of energy dispersion § Line narrower than instrument response § Similar feature seen in Earth-limb data Phys. Rev. D (2013), 88, 082002 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 27

Dwarf galaxies at Te. V energies VERITAS, ICRC 2013 > H. E. S. S. , MAGIC and VERITAS derived DM limits for different (individual) dwarf spheroidals > Dedicated DM search programs for the next ~5 years in place > Combine IACT data sets 2013 2018 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 28

Electron/Positron Spectra M. Di Mauro, F. Donato, N. Formengo, R. Lineros, A. Vittino, ar. Xiv: 1402. 0321 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 29

Our Neighbourhood C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 30

Nearby sources Stefan Klepser, DESY C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 31

Pulsarwind Nebulae C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 32

> Selection results § young pulsars (age < 100 kyr) > Population plots to benchmark models Spin-down power (erg s-1) PWN Population Study H. E. S. S. , ICRC 2013 PWN extension (pc) Efficiency L 1 -10 Te. V /Ė Age (kyr) C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 33

Conclusion > Gamma-ray experiments today offer § an unique view into the high-energy Universe, § from Me. V to Pe. V energies and § deliver unprecedented data of high precision > resulting in an increased understanding of the astrophysical foreground. C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 34

CTA – the Cherenkov Telescope Array > A huge improvement in all aspects of performance § A factor ~10 in sensitivity, much wider energy coverage, much better resolution, fieldof-view, full sky, … > A user facility / proposal-driven observatory § With two sites with a total of >100 telescopes > A 27 nation ~€ 200 M project § Including everyone from HESS, MAGIC and VERITAS C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 35

Science 339, 2013 C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 36

Ge. V Excess in the Galactic Center? > Peter Michelson (PI Fermi-LAT): “The Fermi LAT Collaboration continues to examine the extraordinarily complex central region of the galaxy, but until this study is complete we can neither confirm nor refute this interesting analysis. " C. Stegmann | Gamma ray astronomy | 8. July 2014 | Seite 37