1. Multi-Channel Astrophysics & Cosmology at the Highest Energies Vasiliki Pavlidou University of Chicago

2. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 Outline oThe need for multi-channel studies in High-Energy Astrophysics oThe next 10 years of High-Energy Messengers oWhat to look forward to: Breaking the degeneracy: AGNs, SNRs, GRBs, UHECRs Serendipitous discoveries Astrophysics with high-energy observations: measuring cosmic star formation

3. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 Why multi-channel and multi- wavelenght?

4. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 Multi-channel and multi-wavelength studies: a must for high-energy astrophysics oTested and tried: low energy photons + high energy observations or GeV + TeV photons source identifications (GRBs, gamma-ray loud blazars, pulsars, PWN) better monitoring of system variability, local conditions large spectral dynamical range, better tests for emission models Pian, Vacant, Tagliaferri, Ghisellini, Maraschi, Treves, Urry, Fiore, Giommi, Palazzi, Chiappetti, & Samburna 1998 Markarian 501 Reimer & Funk 2006 NRAO 530 / 2EG 1735-1312 Bower, Backer, Wright, Forster, Aller, & Aller 1997

5. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 High-Energy observations in the Next Decade oGLAST: continuous full-sky coverage in GeV gamma rays oGround-based TeV telescopes: (CTA/AGIS/HAWC): full sky accessible in TeV gamma rays, high angular resolution oIceCube, KM3NeT: continuous full-sky coverage in TeV neutrinos oAuger South + North: continuous full-sky coverage in UHE CRs, photons, neutrinos oPerks: LIGO, LISA, JWST

6. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 The future: 1. Breaking the degeneracy oWhat is the origin of cosmic rays? oAGNs, SNRs: hadronic or leptonic processes? oAGNs, leptonic emission: SSC or EC? oAGNs, GRBs: how high do they go? (GLAST, CTs, UHECRs) oWhat is making the highest energy particles? Top-down or bottom up? UHECRs, GLAST A success story from cosmology

7. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 The future: 2. Serendipitous discoveries oXXX2017: winning the jackpot nearby transient (merger between compact objects ?) GLAST detects it as a very bright transient gamma-ray source. Follow up with Cherenkov detectors - high angular resolution. LIGO detects gravitational wave emission; nature of progenitor known at high confidence Low-energy multi-wavelength campaign Neutrino detectors pick up the -spike Auger picks up the UHE particle signature (time broadening small and understood!) A success story from neutrino astrophysics

8. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 The future: 3. Low-E astrophysics with high-E observations oThe Cosmic Star Formation Rate: how much gas mass is converted to stars per unit time per unit cosmic volume oAn essential measure of: baryonic energy production, feedback processes in structure formation oContributes to reionization oLinks all of the messengers of interest! oTraditional measures: SF makes stars - young stars emit in UV, IR compilation by Hopkins & Beacom 2006

9. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 The SF - high-energy connection oStar Formation -> Supernovae -> Cosmic ray acceleration - > interaction with ISM -> , oStar Formation -> gamma-ray bursts -> UHECRs?, , oStar Formation -> Background starlight (EBL) -> interaction with: , UHECR EBL imprinted on spectra of: individual  -ray sources,  -ray background, UHECRs Cosmogenic , Blain & Natarajan 2000 Starforming galaxies (VP & Fields 2002) Unidentified sources (VP, Siegal-Gaskins, Fields, Olinto & Brown 2007) Blazars (VP & Venters 2007) EGRET gamma-ray background, conservative (Strong et al 2004) Maximal EGRET gamma-ray background (Sreekumar et al 1998) Stecker 1999 Kalashev, Semikoz & Sigl 2007 Allard, Ave, Busca, Malkan, Olinto, Parizot, Stecker & Yamamoto 2006

10. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 How do we utilize this connection? oUntil now: use knowledge of CSFR to predict signal/effects for high-energy telescopes oThe future: concurrent high-E observations in different channels allow inversion of the problem: use observations of high-E signal/effects to constrain CSFR oUncertainties: significant, BUT largely uncorrelated with uncertainties of low-E methods Strigari, Beacom, Walker & Zhang 2005

11. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 CSFR teaser: 15 yrs from now oGLAST has detected: CSFR peak in gamma-ray background @E ≈ 1 GeV pileup/suppression of gamma-ray background @ E  20GeV unabsorbed spectra of hundreds of low-z blazars oGLAST+Cerenkov Telescopes have detected: EBL absorption signatures in high-E tail of hundreds/thousands of high-z blazar spectra oIceCube/KM3NeT have detected: Cosmogenic neutrino signature oAuger has determined: Spectrum, composition, sources and their cosmological evolution, acceleration mechanism of UHECRs, Exact shape of GZK Prodanovic, VP & Fields preliminary + improved IR CSFR observations by Spitzer, JWST + good sampling of GRB afterglows, strong constraints of z-distribution of GRBs

12. Vasiliki Pavlidou Ultra high energy photons, protons and neutrinos Penn State, May 17 Conclusions oMulti-channel, multi-wavelength observations give unique new insight into high-E astro oThe time to do high-energy astrophysics is now: Combined data from different upcoming instruments + improved low-E observations => unprecedented possibilities for: multi-channel, multi-wavelength monitoring of the high-E sky, resolution of model degeneracies A new era: high-E observations can quantitatively map the cosmic history of baryonic energy generation and feedback