INTEGRAL Observatory Highlights THE INTE RNATIONAL G AMMA- R AY A STROPHYSICS L ABORATORY

1. INTEGRAL Observatory HighlightsTHE INTERNATIONAL GAMMA-RAY ASTROPHYSICS LABORATORY Pietro Ubertini Institute for Space Astrophysics and Planetology IAPS/INAF, Rome, Italy Roma International Conference on AstroParticle Physics, 23 May 2013

2. 10 years – 7 months in orbit From the discovery of the first X-Ray source, in 1962, a factor of about 100 millionimprovement in sensitivityhavebeenachieved in X-Rayastronomy INTEGRAL hasallowed a similarstep-up in the soft gamma ray ESA medium-size mission (“Horizon 2000”) Collaboration with Russia and NASA Launch: 17 October 2002, Baikonur Cosmodrome

3. Integral: hard X-ray/soft γ-ray observatory • INTEGRAL will remain the only observatory worldwide providing these capabilities to the community in this decade. Soft X-ray to high-energy gamma-ray observatories in operation • Broad energy range (3 keV – 10 MeV) • Fine imaging (12’ FWHM) in very wide field-of-view (~ 100 ☐°) • High resolution spectroscopy (2 keV FWHM @ 1 MeV) • ms timing resolution • Polarimetry capabilities

4. The High Energy Regime Different wavelenght ranges within the electromagnetic spectrum specific information. The nuclear radiation window is located above the non-thermal emission regime INTEGRAL istruments cover the low end of the large domain of gamma rays as well as the high end. From Diehl, 2013

5. Unique Science Capabilities • For the foreseeable future, INTEGRAL will remain the only observatory allowing nucleosynthesis and positron/electron annihilation to be studied. Large FOV + long-term monitoring + broad energy band + sub-arcmin localization + <ms timing • Diffuse emission and point source requirements benefit from each other, and, the variable high-energy sky demands this ! • Discover new sources for extensive multi-λ follow-up observations • Study the physics of emission mechanisms of white dwarfs, neutron stars and black holes • Key to identify GeV/TeV sources (Fermi/H.E.S.S) • Study super-massive black hole activation, unification and evolution • Synergy with current and future missions & simultaneous observations of violent phenomena across the spectrum is providing a unique suite of tools • ..see common program of observations with Nustar Gamma-ray polarimetry ..the only available! • Bright sources (NS, BHC, pulsars) & GRB • Gamma-ray line spectroscopy and imaging • Nucleosynthesis through γ-ray lines from elements formed in massive stars and SNe and Novae • Positron production and positron annihilation with electrons

6. Main Selected Scientific Results • INTEGRAL discovery of • a new class of binaries enshrouded by massive stellar wind (“strongly absorbed HMXB”) • a new regime of intermittent accretion in wind-fed relativistic binaries (“SFXT”) • dominance of accreting WD in the “diffuse” galactic ridge hard X-ray emission • hard spectral tails in extremely magnetized neutron stars: e± pairs dominated fireball • the most distant QSO seen in hard X-rays • a population of faint GRB with long spectral lags • INTEGRAL detection of • 44Ti lines fomSNCas A • hard X-ray emission from black holes, LMXB, and accreting ms pulsars • polarized hard X-ray emission in Crab and in GRB041219a • cyclotron line strength correlated with the height of the accretion column • pulsed hard X-ray emission up to ~150 keV from rotation-powered pulsars • INTEGRAL best results • proved the Galaxy wide origin of the26Algamma-ray line • determined the Galactic cc-SN rate independently • determined the 26Al/60Fe yield ratio constraining SN models • monitored the past activity of Sgr A* via its Compton echo • determined the hard X-ray luminosity function of AGN • the first large-scale sky-map at 511 keV (electron-positron annihilation) • the first measurement of the true fraction of Compton-thick AGN

7. Evolution Of The Catalogs Population With Time Cat 1000 • The galactic sources account for ½ of the know sources with an emerging population of High Mass X-Ray Binaries (most have a Supergiant companion) • The spatial density distribution correlates with the star formation rate distribution in the Galaxy • Gamma-ray binaries often revealed in hard-X survey: the INTEGRAL Galactic Plane coverage has significantly impacted on knowledge of this population. • The mechanism responsible for the emission in Gamma-ray is still unclear: • Particle acceleration leading to a jet or a jet-wind or a wind-wind shock region (similar to pulsar wind nebulae though contained within the circum-stellar environment) are all possible solutions  INTEGRAL Quest is continuing!!

8. A Galactic Bulge view at 20-100 and 100-300 keV

9. Few Selected Recent Results • Detection of nuclear 44Ti line emission from SN 1987A in LMC • Polarized high-energy emission from the black-hole candidate Cyg X-1 • Integral discovery of high Z, giant Blazars • The soft gamma ray spectrum of the whole Galaxy Plane • The origine of Positrons producing the 511 keV Line  DM? • The Galactic Centre multi-messenger astrophysics: from IR to Gamma

10. Detection of 44Ti from SN87a: first image after 25 years!

11. SN87a HST image & IBIS 44Ti line Authors: Grebenev, S., et al. Nature, 490, pp 373-375, 2012 An initial mass of 44Ti was estimated to be 3.1 × 10-4 MSun, which is near the upper bound of theoretical predictions Two direct-escape lines of 44Ti at 67.9 and 78.4 keV

12. Nucleosynthesis: metallic abundance in Cas A and SN87a The ratio of radioactive isotopes 56 Ni and 44 Ti is a sensitive probe of the location of the mass cut, the separation between the ejecta material and the neutron-star remnant of a core-collapse supernova. Measurements for Cas A and SN1987A appear consistent with the ratio as inferred from solar abundances of the stable daughter isotopes. Models assuming spherical symmetry (black dots) fall below observation in this representation, while non-spherical explosion models indicate a better agreement (Diehl, 2013).

13. Polarimetry INTEGRAL’s polarimetry capability (E > 100 keV) will remain unmatched for a long time. GRB 041219A • Scattered polarised γ-rays: count distribution is modulated in azimuth • Crab: High-energy electrons responsible for the polarized photons are produced in a highly ordered structure close to the pulsar. (SPI: Dean et al., Science 321, 1183, 2008; IBIS: Forot et al., ApJ 688, L29, 2008, Jourdain et al., ApJ, 2013) • Cyg X-1: High energy excess emission has been identified via polarization  jet emission. (SPI: Jourdain et al., ApJ, 2012; IBIS: Laurent et al., Science 332, 438, 2011) • GRB 041219A: Synchrotron radiation from a relativistic outflow with B field contained in plane perpendicular to jet velocity. (SPI: McGlynn et al., A&A 466, 895, 2007; IBIS: Götz et al., ApJ 695, L208, 2009) IBIS • Future deep polarimetry observations of bright hard X-ray sources - to study jet emission and to constrain the emission geometry in neutron stars, black holes & GRB SPI Crab Cyg X-1

14. INTEGRAL view of the EXTRAGALACTIC SKY: 272 AGNwith complete optical & X-ray data (Malizia et al. 2012) 4th IBIS catalogue (Bird et al. 2010) + All-Sky Hard X-ray Survey (Krivonos et al. 2010 + updates) IGR J22517+2218 z=3.7 Log L=47.7, M109 M0 NGC4395 z=0.001 Log L=40.7, M ̴ 4× 105 M0

15. INTEGRAL Finds EARLY and HEAVY Black Holes Blazars In very powerful FSRQs the hard X–ray flux is close to the emission peak (Ghisellini et al. 2011) --> hard X–rays carry a very significant fraction of the jet luminosity, making them visible and detectable at very high redshift INTEGRAL high redshift blazars Swift J0218.0+7348 z= 2.367 PKS 0528+134 z= 2.060 QSO J0539-2839 z= 3.104 QSO B0836+710 z= 2.172 Swift J1656.3-3302 z= 2.400 PKS 1830-211 z= 2.507 PKS 2149-306 z= 2.345 IGR J22517+2218 z= 3.668 IGR J12319-0749 z= 3.12 Mostpowerfuljets!

16. INTEGRAL has discovered the most extreme blazars at z up to ≈ 4 arising new questions • Why the more massive QSOs have giant BH in the center?..stars and SMBHs grow in parallel? • When and how the first star has been generated?...and • How back into the reionization period we can see?.. z>10- ? • These are among the more fundamental and open questions we could answer in the next decades

17. Doppler shift of the 26Al gamma-ray line at 1.8 MeV due to large-scale galactic rotation, detected from the SN exploded in the last million of years. (Diehl et al., 2006, Nature)

18. Electron-positron Annihilation THE ORIGIN OF POSITRONS PRODUCING THE 511 KEV LINE IS A 40-YEAR OLD MYSTERY. • Theoretical studies suggest e+ transport over large distances: annihilation site is not production site • Morphology of e± emission • Origin of the bright bulge • Offsets relative to Galactic Centre • Symmetry of the galactic disk • Spatial structures in the diffuse emission • The origin of positrons • Annihilation with electrons: How ? Where ? • 511 keV emission from galactic bright X-ray nova • Precision study of BH accretion, e± production Weidenspointner et al., Nature 451, 159, 2008 • Key topics in next 4 years: • …or Dark (D3?) matter decay?... 1043 decay/s Bouchet et al., ApJ 720, 1772, 2010 • Provide key clues as to: Churazov et al, MNRAS 411, 1727, 2011 • No single 511 evidence from binaries: BH, NS, WD…

19. The Milky Way Emission: a Changing View The Milky Way is known to be an abundant source of gamma-ray photons, determined to be mainly diffuse in nature and resulting from interstellar processes. In the soft gamma-ray domain, point sources were expected to dominate, but even the best imaging experiment revealed only a few point sources, accounting for about 50% of the total Galactic flux. Theoretical studies were unable to explain the remaining intense diffuse emission. INTEGRAL just after launch revealed numerous compact sources almostaccounting for flux observed, leaving at most a minor role for diffuse processes. After 10 years of observations, the global galactic emission above 50 keV is no longer attributed to dominating compact sources but produced by the interaction of cosmic ray particles with the interstellar medium. The INTEGRAL stable and low instrumental background coupled with the ability to disentangle individual sources from the diffuse glow of the Galaxy, made possible to measure the very low brightness of this emission as showed in the next VG figure from Krivonos.

20. The Milky Way Emission • Deepest ever obtained image (35-80 keV) of the Galactic plane, not affected by absorption of the interstellar medium. • Contours: surface brightness of the Galaxy in the near infrared spectral band, indicating the typical spatial extent of the Galactic stellar population. • Soft gamma ray sources: mostly accreting compact objects with white dwarfs, neutron stars and black holes, including supermassive black holes in outer galaxies. In total, 164 statistically significant sources were detected by INTEGRAL within the sky area shown (Krivonos et al., 2012). • This extended emission is characterized by spatial variation across the Galaxy and is being now studied with customised INTEGRAL observing programme to build up a legacy dataset for the study of cosmic ray interaction.

21. The Galaxy Centre by INTEGRAL, Nustar and HERSCEL Surface brightness of the Galaxy in the near infrared spectral band, HERSCEL view of Sgr* region, the hot gas is at ≈ 1000 °K Nustar focused image of Sgr* (10-30 KeV) Image credit: NASA/JPL-Caltech

22. Now a short ride into the galaxy (5 m movie)

23. Thanks for your attention

24. The Crabby Crab

26. Recent detection of polarised emission in the high-energy part of the Cygnus X-1 spectrum: after the first measurements using the so-called "Compton" mode in INTEGRAL/IBIS data (Laurent et al., 2011), the analysis of the INTEGRAL/SPI data permits to independently confirm and refine this result. • The SPI data confirmed the IBIS a mean value of the polarisation angle of 42° +/- 3°. • The IBIS Compton mode detected a polarised flux above 400 keV and not below • The SPI data is divided into 3 bands allowing to study the • evolution of the polarisation fraction as a function of energy: an upper limit of 20% between 130-230 keV, • a polarised flux (41%) between 230 - 370 keV, • while the flux is almost completely polarized between 370-850 keV (or at least with a fraction greater than 75%. Such results strongly support an ordered structure like a jet being responsible of the observed emission confirming the scenario proposed by Laurent et al (2011), in which two photon production mechanisms coexist in the hard-X ray/gamma-ray domain: (i) the Comptonisation emission of the disk-corona system plays the main role above 10 keV with a cut off around 100-200 keV, while (ii) the jet synchrotron radiation extending from the radio to the hard-X ray/gamma-ray domain is dominating above 200 keV up to the MeV region.

27. A strong, hard X-ray flare was discovered (IGR J12580+0134) by INTEGRAL, 2011, and is associated to NGC 4845, a Seyfert 2 galaxy never detected at high-energy previously. Follow-up observations with XMM-Newton, Swift, and MAXI with the INTEGRAL data allowed to study the long and short term variability . The spectrum of the source is well described as the one characteristic of an accreting source, plus a soft X-ray excess, likely to be of diffuse nature. The hard X-ray flux increased to maximum in a few weeks and decreased over a year, with the evolution expected for a tidal disruption event. The fast variations observed near the flare maximum allowed to estimate the mass of the central black hole in NGC 4845 as ∼ 3 × 105M⊙. The observed flare corresponds to the disruption of about 10% of an object with a mass of 14-30 Jupiter. The hard X-ray emission should come from a corona forming around the accretion flow close to the black hole. This is the first tidal event where such a corona has been observed (Nikołajuk, 2013). In fact, when such a small object orbits too close to a massive black hole, it could be disrupted by the tidal forces induced by the strong gravitational field and part of the debris may fall into the black hole, emitting a strong burst of high-energy radiation. The top image shows an optical image of NGC 4845 with the error circles showing the position of the X-ray source as observed by XMM-Newton EPIC-pn, right at the centre. The figure at the bottom shows the light-curve observed by INTEGRAL IBIS/ISGRI (red data points), XMM-Newton EPIC-pn and Swift XRT (blue data points). The long-short dash line indicates the prediction of hydro-dynamical simulations for the disruption of a sub-stellar object, whereas the dotted line shows what would be expected for a disrupted star.