CTA / ALMA synergies. C. Boisson. Zech

Transcription

1 CTA / ALMA synergies C. Boisson LUTh, Observatoire de Paris Zech thanks to H. Sol & A.

2 Particle acceleration is a wide-spread phenomena in the Universe

3 CTA Key Science Cosmic Rays Origin of cosmic rays Acceleration physics Impact on environment Atelier CTA 2014 (J. Knödlseder) Black Holes Fundamental physics Role as particle accelerators Acceleration physics Probes of the Universe Nature of dark matter Test Lorentz invariance 3

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7 Why Cherenkov Telescopes? Gamma-ray astronomy In general big advantages over other methods of probing high energy particles (probes hadrons + leptons, photon cross-section,.) Advantages to satellite Only way to build sensitive > TeV instruments High statistics / short timescale Large collection areas O(km2) Advatages to ground particle detectors Superior energy/angular resolution Superior background rejection Limitations Smaller duty cycle, smaller field of view

8 2-5 Telescopes pixel cameras FoV ~0.1 angular res. ~15% energy res. Sensitivity <1% Crab ~30 GeV < E < ~50 TeV

9 High Energy Sky > 100 GeV H.E.S.S. MAGIC VERITAS H.E.S.S., MAGIC, TevCat 55 blazars, 2 starburst 150 sources The extragalactic TeV sky is dominated by blazars (mainly BL Lacs)

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12 @ J. Hinton 2013

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15 How to do better with IACT arrays? More events more photons = better spectra, images, fainter sources > Larger collection area for gamma-rays Better events more precise measurements of atmospheric cascades and hence primary gammas > Improved angularresolution > Improved background rejection power More telecopes

16 CTA Consortium ALMA

17 Cherenkov Telescope Array facts High sensitivity > 4 orders of magnitude dynamic range in flux between strongest and faintest sources; a factor of 10 more sensitive than current IACT Wide spectral range > 4 orders of magnitude coverage in energy from 10 GeV to above 100 TeV; 10-15% energy resolution; overlap with FERMI bridging the gap Well-resolved light curves Minute-scale variability of many AGN Resolved source morphology Up to 0.02 deg. angular resolution; source localization Large field of view (5 to 10 deg) serendipitous AGN discoveries Surveying capabilities full-sky survey at 1% Crab in about 1 year ; sub-array observing mode

18 CTA facts

19 CTA facts ACS : ALMA array operating software

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21 CTA Science case : probing the non-thermal Universe at GeV-TeV using gamma-rays High energy phenomena in the Galaxy Extragalactic exploration Super massive black holes, jets, gamma-ray bursts, galaxy clusters Understand the origin of Cosmic rays Supernova remnants, black holes, starbursts, pulsars, binary stars Discovered on 1912, their origin is still uncertain Study the fundamental laws of the uiverse Search for dark matter, test Lorentz invariance The CTA observatory = 2 infrastructures hosting > 100 telescopes * Northern and Southern hemispheres for full sky coverage - Unprecedent sensitivity : access VHE populations across whole Galaxy; sample fast variability (AGN, GRB) - Unprecedent angular resolution : resolve extended sources (SNR, starbursts) - FoV > 8deg : measure diffuse emissions, efficient survey of large fields - Broad energy coverage : < 100 GeV to reach higher redshifts ; > 10 TeV to search for PeVatrons

22 High Energy Sky > 1 GeV 2FGL (2 years): 1873 sources (Nolan et al 2012) Upcoming 3FGL (4 years): 3000 sources

23 High Energy Sky > 10 GeV 1FHL (3 years) Ackermann et al sources

24 High Energy Sky > 100 GeV H.E.S.S. MAGIC VERITAS H.E.S.S., MAGIC, TevCat 55 blazars, 2 starburst 150 sources The extragalactic TeV sky is dominated by blazars (mainly BL Lacs)

25 Basic scenarii for SED modeling leptonic acceleration Synchrotron γ (ev-kev) e- (TeV) hadronic acceleration B γ (TeV) p+ (>>TeV) γγ (TeV) π0 matter (or photons) γ (ev) Inverse Compton SSC or EC ππ+ VHE emission strongly linked to the population of radio/mm emitting emwl data mandatory to constrain SED/lightcurves and models IC π0decay energy E (adapted from De Lotto, 2009)

26 AGN population FSRQs + BL Lacs = blazars Small viewing angle wrt the jet Large viewing angle wrt the jet FR I and FR II (Fanaroff & Riley 1974) considered as parent populations of blazars

27 Blazar sequence(s) Characteristic SED is double peaked Anti-correlation between bolometric luminosity and E peak blazar sequence (Fossati et al 1998) FSRQs to BL Lacs Low synchrotron peak (LBL or LSP) to high synchrotron peak (HBL or HSP) BL Lacs + J. Ballet

28 Blazar sequence(s) Characteristic SED is double peaked Strong anti-correlation between bolometric luminosity and E peak blazar sequence (Fossati et al 1998) Cooling model with external radiation for FSRQs (Ghisellini et al.1998) Physical models galaxy evolution through reduction of fuel from surrounding gas and dust (Böttcher & Dermer, 2002) The NLS1 (PMN J , z=0.585) detected by Fermi does not fit in the picture. Foschini et al. (2009)

29 Blazar sequence(s) Giommi et al, 2012 Indeed, varying mix of - Doppler boosted, radiation from the jet emission - radiation from the accretion disk - from the BLR - the host galaxy Anti-correlation most likely due to selection effect : bright radio sources drawn from high end luminosity function while BL Lac in flux limited samples are mostly high synchrotron peaked. FSRQs BL Lacs

30 H. Sol

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32 @ Hada et al

33 Emergence of a new VLBI superluminal component from the core, at the time of a TeV flare in BL Lac

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35 Nuclei of radio loud AGN mm and sub-mm observations can probe closer to the base of the jet than any other waveband except X-ray much closer than cm observations because synchrotron self-absorption opacities are lower Monitoring of variability and polarization of blazars study correlation between mm and gamma-ray -ray flares derive time lags linear/quadratic, SSC/IC

36 2 starbursts detected at TeV : NGC 253 by H.E.S.S. & M 82 by VERITAS

37 ALMA CO map Full convection diffusion model for energetic electron and proton propagation solely on the spectral description of the electron and proton distribution

38 @ H. Sol

39 The central engine of AGN ALMA: Study jet physical properties and production mechanisms Discover new classes of AGN Observations of the galactic center Structure of the torus and ISM in the vicinity of the AGN most sensitive element of a mm-vlbi array Monitor the total flux and polarization variability of blazars Real synergy with CTA science

40 @ P. Martin

41 γ-rays from TeV cosmic rays (p, He, etc) CRs deflected by magnetic fields 0 p+p pi 2γ GAS CLOUD Gamma-Rays (+ neutrinos) Observational Signature Gamma-rays & gas are spatially correlated mm-radio astronomy traces the gas...we expect gamma-ray flux Fγ ~ kcr Mgas.

42 γ-rays from multi-tev electrons Inverse-Compton (IC) TeV Gamma-Rays Synchrotron radio to X-Rays Accelerated TeV Electrons e + (soft) e + (TeV) inverse-compton (IC) scattering e + G e + (GHz) Radio synchrotron Observational Signature. May be differences in TeV & radio morphologies B-field estimates possible (+ X-rays, optical, IR)

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44 SNR W49B & Starburst region W49A

45 SNR G (Age < 10 ) 4 years) TeV image from H.E.S.S. SNR mapped in radio continuum (ATCA) and X-rays (ROSAT) Diffusive shock acceleration at forward shock (Lazendic et al. 2004; Ellison et al. 2001)

46 Mature SNR W28 & HII region Image: VLA, ATCA Brogan et al. (2006) Nanten2 12CO(J=2-1) (Nakashima et al 2008) SNR shock interaction with molecular cloud CRs source of grays Southern g-ray sources a mystery? From SNR or HII regions? image -10 to 25km/s

47 Passive source Eger et al. (2011) Unidentified HESS source J Associated with CO cloud maybe passive target for CR protons accelerated by nearby SNR?? Suggests hadronic process. Need for magnetic fields & turbulence estimates, detailed CO, HI

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49 SNRs / Molecular clouds The study of SNRs/ MC interactions at intermediate angular resolution is an invaluable tool to understand several issues of great interest at present: Star birth induced by dying stars Origin of galactic cosmic rays Nature of gamma-ray sources Properties of the cold ISM Great synergy with CTA project

50 What ALMA can do for us Snapshot observations add points to the SED of southern AGN in a key part of the spectrum to help differentiate between models Snapshot observations will identify sources with structure on ALMA baselines for detailed imaging follow-up High spectral resolution observations could use these bright sources to probe the intervening material Polarisation variations also valuable VLBI (bands 1 and 2) challenging but importantes

51 What ALMA can do for us Most efficient use of these sources relies on knowing their current flux density, which a flux density monitoring program like this can contribute to Detailed mapping of molecular material surrounding high energy sources toconstrain the broad non thermal SED and allow resolution of non-thermal emission in nearby sources that cannot be acheived in X-rays

52 ALMA SKA staff

53 astroph Vaupré et al.

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55 The CTA concept E < 100 GeV High4intensity flux LST (Ø23m) Faint showers 4.5o FoV Large telescope 2500 pixels GRB alerts0,1o TeV 0,1 25 MST (Ø12 m) Precision 8o FoV Shower sampling 1500 pixels Dense network 0,18o Southern site only E > 10 TeV SST-GATE/GCT 70 SST (Ø4 m) Low fluxes 8 10o FoV Wide~ area network pixels Bright showers ~ 0,2o 0,3o Small Stolarczick