CTA KEY SCIENCE PROJECTS

RENE ONG

FOR THE CTA CONSORTIUM

INAF Workshop – 2 July 2015 (INAF-Brera, Milano) 1

OUTLINEOUTLINE

Brief introduction to VHE γ-rays and CTA

CTA Science: Core programme, GO programmeCTA Science: Core programme, GO programme

Introduction to CTA Key Science Projects (KSPs)Th SThe SurveysGalactic KSPsExtragalactic KSPsExtragalactic KSPsSummary of time allocations; scheduling the KSPs

ConclusionsConclusions

(note: DM/Fund Physics covered in separate talk)

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(note: DM/Fund Physics covered in separate talk)

SNRsSNRs

Exploring the nonExploring the non--thermal Universe thermal Universe SNRsSNRs

Pulsars/PWN Pulsars/PWN AGNAGNBinariesBinariesStarburstsStarbursts

NSdynamo

winds Shocks SN activity

SMBH accretion, jets

GRBsGRBsFermi Mech.Jets, winds SN activity

Cosmic rays

VHE raysVHE γ-rays?

UnknownsUnknowns(Gal Center)(Gal Center)

Dark Dark MatterMatter Cosmological FieldsCosmological FieldsPBHs, PBHs, QGrQGr

gg

Probing New Physics at Probing New Physics at GeVGeV//TeVTeV scale scale

Imagingatmospheric

Image in camera

atmosphericCherenkovarraysarrays

Cherenkov light pool:Cherenkov light pool:~250 m diameterfew ns duration

Collection area ~ > 105 m2

Ang. Res ~ few arc-minsEn Res 10%En. Res ~ 10%

CTA Design (S array)Science Optimization under budget constraints

Low energiesEnergy threshold 20-30 GeV23 m diameter4 t l

Medium energies100 GeV – 10 TeV

Hi h i4 telescopes (LST’s)

9.5 to 12 m diameter25 single-mirror telescopes

up to 24 dual-mirror telescopes(MST’s/SCTs)

High energies10 km2 area at few TeV

4 to 6 m diameter70 telescopes(MST s/SCTs) 70 telescopes

(SST’s)

Requirements & DriversEnergy coverage d t 20 G V

Energy coverage up t 300 T Vdown to 20 GeV

(Discovery domain: GRBs, Dark Matter)

to 300 TeV(Pevatrons, hadronacceleration)

Large Field of view 8-10°(Surveys, extended sources, flares)

Good energy resolution, ~10-15%:(Lines, cutoffs)(Lines, cutoffs)

10x Sensitivity & Collection Area

Rapid Slew (20 s) to catch flares:(Transients)

Angular resolution < 0.1°above most of E range(Source morphology)Collection Area

(Nearly every topic)

CTA ConsortiumCTA is being developed by the CTA Consortium:

31 countries, ~1200 participants, ~180 institutes, ~400 FTE

THE CTA SCIENCE PROGRAMMEPROGRAMME

(INCLUDING MATERIAL FROM JIM HINTON & ANDREAS ZECH)

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Science Themes

Theme 1: Cosmic Particle Acceleration ?How and where are particles accelerated?

How do they propagate?What is their impact on the environment?

Theme 2: Probing Extreme Environments Processes close to neutron stars and black holes?Processes close to neutron stars and black holes? Processes in relativistic jets, winds and explosions? Exploring cosmic voids

Theme 3: Physics Frontiers – beyond the SMWhat is the nature of Dark Matter? How is it distributed?What is the nature of Dark Matter? How is it distributed? Is the speed of light a constant for high energy photons?Do axion-like particles exist?

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KEY SCIENCE PROJECTS

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KEY SCIENCE PROJECTS (KSPS)KEY SCIENCE PROJECTS (KSPS)

The CTA KSPs are:

to ensure that important science questions for CTA are addressed, in a coherent fashion and with a well-defined strategy,

planned, proposed, and carried out by the CTA Consortium under guaranteed time,

typically hard to carry out in the Guest Observer program,

conceived to provide legacy data sets for the entire community and

proposed to use 40-50% of CTA observation time in first ten years.

Key point:Key point:

We expect that the KSPs will be reviewed (and adjusted accordingly) on a regular basis before, and during, the operational g y) g , g, pphase.

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CTA KEY SCIENCE

Transients

GalaxyClusters

ExGalS

Dark MatterProgramme

Star Forming

ClustersSurveyProgramme

Sta o gSystems

LMC

AGN

GalacticPl S

LMC Survey

G l ti

PeVatronsPlane Survey

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Galactic Centre

MAPPING SCIENCE OBSERVATIONSMAPPING SCIENCE OBSERVATIONS

KSPsDMNine KSPs and one DM Programme are proposedDM was discussed in detail on Tuesday 22

KSPsDM

THE SURVEY KSPSTHE SURVEY KSPS

Extragalactic Survey:Unbiased survey of ¼ sky to 6 mCrabUnbiased survey of ¼ sky to ~6 mCrabVHE population study, duty cycleNew, unknown sources; 1000 h Galactic Centre Survey:

ID of the central sourceSpectrum, morphology of diffuse emissionDeep DM searchCentral exposure: 525 h 10ox10o : 300 hCentral exposure: 525 h, 10 x10 : 300 h

Galactic Plane Survey:Survey of entire plane to ~2 mCrabG l ti l ti SNR PWN t

Large Magellanic Cloud Survey:Face-on satellite galaxy with high SFR

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Galactic source population: SNRs, PWNe, etc.PeVatron candidates, early view of GC, 1620 h

Face on satellite galaxy with high SFRExtreme Gal. sources, diffuse emission (CRs)DM search; 340 h in six pointings

GALACTIC KSPS

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GALACTIC KSPSGALACTIC KSPS

Galactic Plane Survey (GPS) 1620 hGalactic Plane Survey (GPS), 1620 h

Unbiased survey of Galactic plane: provides basis for all Galactic science programs and will be a major legacy of CTAscience programs and will be a major legacy of CTA

Targeted KSPsg

Galactic Centre KSP (525 h + 300 h): determining the VHE astrophysics of the GC region, deep DM searchPeVatron KSP (50 h per source): identifying sources of CR’s up to the knee in spectrum; follow-up of five candidates from GPSSt F i S t KSP (270 h C C i Wd 1)Star Forming Systems KSP (270 h Cygnus, Carina, Wd 1): impact of SFR & CRs on VHE particle acceleration at all scalesTransients KSP: follow up of Galactic transient sourcesp

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GALACTIC PLANE SURVEY KSPGALACTIC PLANE SURVEY KSP

Scientific objectivesScientific objectives

Discover new VHE source classes and new phenomenaSurvey entire galaxy complete census of Galactic populationIncrease population of known Galactic sources (PWNe, SNRs) by factor of ~5 enabling better population studiesfactor of ~5, enabling better population studiesSearch for Galactic cosmic ray PeVatronsDetect new gamma-ray binaries and other Galactic transientsDetect new gamma-ray binaries and other Galactic transientsUnveil cosmic ray injection into the ISM the propagation of cosmic rays through large-scale diffuse emission mappingProvide first-look science data to other KSPs and GO ProgrammeProduce a major multi-purpose legacy dataset

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GALACTIC PLANE REGIONSGALACTIC PLANE REGIONS

Fermi-LAT skymap

Cygnus Inner regionLocal Arm

Persus Sagitarius-Carina

Anti-center

Vela

150o 120o 90o 60o 30o 0o 330o 300o 270o 240o 210o

Carina Vela

Orion

27CTA CDR - SCIENCE, 24June 2015

VHE GALACTIC SURVEYSVHE GALACTIC SURVEYS

Previous SurveysPrevious Surveys

Present/future Surveys

CTA GPS: Full-plane survey with graded exposureWide energy range and unprecedented angular resolution

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Order of magnitude improvement in sensitivity

GALACTIC SOURCE POPULATIONGALACTIC SOURCE POPULATION

R d 2009log N – log S from existing population (mostly PWNe)

t l h d d f Renaud, 2009expect several hundreds of sources

T

spiral arms

TARG

thin disk

ET

RRANGE

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1.5-3.0 mCrab

GPS IMPLEMENTATIONGPS IMPLEMENTATION

Strategy

Both CTA-S and CTA-N Dark time, full arrays, zenith < 45o

D bl i ti h ith 3 i LST ti i ti tillDouble-row pointing scheme with 3o spacing; LST participation still under studySensitivity-graded with deepest exposure in the inner Cygnus andSensitivity graded with deepest exposure in the inner, Cygnus and Carina regionsCarried out over ten years, but with significant exposure in Years 1-2 to provide early bright-source list (Year 2) and first catalog (Year 3)Transients detected are followed-up in context of Transients KSPTotal time: 1020 h (S), 600 h (N)

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GPS SENSITIVITYGPS SENSITIVITY

Entire plane surveyed to < 3.8 mCrab - several 100’s of sources

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The HE Milky Way (2015)The HE Milky Way (2015)H E S S (TeV)

Extended sources, size typically few 0.1o

few 10 pcH.E.S.S. (TeV) few 10 pc

Fermi-LAT (GeV)W. Hofmann

CTA Galactic Plane Survey

CTA Galactic Plane Survey

GPS EXPECTATIONSGPS EXPECTATIONS

Entire plane surveyed to < 3.8 mCrab - several 100’s of sources

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COSMIC RAY PEVATRONS KSPCOSMIC RAY PEVATRONS KSP

Objectives & StrategyObjectives & Strategy

Origin of cosmic rays (CRs) is a century old problem; SNRs can satisfy CR energy budget; several SNRs now provide good evidencesatisfy CR energy budget; several SNRs now provide good evidence for CR acceleration – both in evolved SNRs (IC 443, W44) and in young SNRs (Tycho, Cas A)

but no evidence at E ~20 TeV and above

This KSP aims to identify PeVatrons – sources that accelerate CRs to PeV energies;Hypothesize that young SNRs may accelerate CRs to PeV energies at beginning of Sedov phase when shock speed is high it is likelyat beginning of Sedov phase when shock speed is high – it is likely that only a small handful of these exist in the Galaxy;Target RX J1713.7-3946 and up to five candidates detected in GPS

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gfor deep observations (50 h each).

EXISTING CR ACCELERATORSEXISTING CR ACCELERATORSAbdo et al (Fermi Coll.) 2010 Abdo et al (Fermi Coll.) 2010

Cas A

Evolved SNRs:Hadronic acceleratorsBright at GeV faint at TeV

Young SNRs:Hadronic acceleratorsEnergy cutoff at a few TeVBright at GeV, faint at TeV

Not PeVatron accelerators (at least now)Energy cutoff at a few TeVNot PeVatron accelerators (at least now)

PeV particles might be accelerated at the beginning of Sedov phase (~200yrs), p g g g p ( y ),when the shock speed is high (Emax=Vsh*Rsh*B)Look deeper at the surroundings of the SNR for very-high-energy run-away particles⇒ Deep observations (50 h) of RX J1713.7-3946

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⇒ Deep observations of up to five PeVatron candidates found in GPS

RX J1713.7-3946RX J1713.7 3946

CTA can disentangle hadronic/leptonic contributionsExcellent angular resolutionUnprecedented sensitivity

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CR PEVATRON CANDIDATESCR PEVATRON CANDIDATES

StrategygyGPS will identify candidate PeVatrons (hard power-law spectra with 3σ detection above 50 TeV)Deep observations of 50 h each (MST+SST required)Deep observations of 50 h each (MST+SST required)

Measure spectrum extension, localization of source and measurement of source size MWL counterpart to pinpoint the PeVatronPeVatron

Reconstructed spectra forsolid, index 2.0dashed, index 2.2 p

various cut-off energies

In 50 h, the spectrum above

dashed, index 2.2

60 TeV of a PeVatron flux ~10-12 ph/TeV/cm2/s will be reconstructed with an error <10%

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EXTRAGALACTIC KSPS

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EXTRAGALACTIC KSPS

EGAL Survey KSPAGN KSP

EXTRAGALACTIC KSPS

EGAL Survey KSP

blind survey of 1/4 sky

AGN KSP

1. long-term monitoring2. high-quality spectra y y

-> VHE population studies & duty cycle

3. AGN flare programme

-> AGN physics at VHE> γ ray cosmology

T i t KSP G l Cl t KSP

-> new VHE sources / source classes-> γ-ray cosmology-> UHECRs & fundamental physics

Transients KSP

follow-up of external or internal triggers

Galaxy Clusters KSP

deep observations of a galaxy cluster

-> GRB physics at VHE -> probing cosmic rays in clusters

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-> Galactic Transients at VHE -> multi-purpose field of view

AGN KSP - STRATEGYAGN KSP STRATEGY

long-term monitoring programme

- regular full-array observations of 15 archetypal g y ypγ-loud AGN of different classes

- ~30 min / week for each target AGN flare programme

-> long-term light curves over at least 10 years

-> time-resolved spectra

AGN flare programme

- ~25 flare alerts / year from external triggers (Fermi, Swift, HAWC...), p gg ( , , ),~ half followed up

regular bi weekly snapshots with CTA- regular bi-weekly snapshots with CTA subarrays for ~80 AGN of different classes , different z

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-> about 20 flares / year / site

AGN KSP - FOCUS ON VARIABILITYAGN KSP FOCUS ON VARIABILITY

from the longest variations ...5 yr 10 yr 15 yr 20 yr

... to the shortest flares- duty cycle ? - (quasi) periodicities ? - breaks in the power spectra ?

illustration AZ

p p

- size ( location, nature) of the emission region ?

acceleration and cooling

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- acceleration and cooling mechanisms ?

simulation J. Biteau ( H. Sol, AZ, C. Boisson et al. 2013 )

AGN KSP - STRATEGYAGN KSP STRATEGY

high quality spectra programme

~ 40 AGN of different classes at 0.02 < z < 1.11

( small subset of "detectable" Fermi sources others covered by GO )sources - others covered by GO )

-> uniform set of high-quality spectra

deep observations of two radio-galaxies: M87 , Cen A

> spectra extended emission ?p-> spectra, extended emission ?

simulation D Mazin AZ

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D.Mazin, AZ

AGN KSP - FOCUS ON EMISSION PROCESSES

- Signatures for leptonic / hadronic

PROCESSES

from high-frequency peaked blazars...g p

origin of VHE emission ?

- Signatures of γ-ray interaction with photon fields ?

... to radio galaxies

with photon fields ?

simulation M.Cerruti, AZ

wide energy range, different AGN classes / redshifts-> Separation of intrinsic spectral features

from propagation-induced effects.from propagation induced effects.

- Origin of VHE emission in radio galaxies ?

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g g- Link to VHE blazars ?

illustration with image from NASA/DOE/Fermi LAT, Capella et al.

The importance of pointing precision

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AGN KSP - EBL & IGMF

measurement of the EBL at z 0 from mid UV

AGN KSP EBL & IGMF

Extragalactic Background Light- measurement of the EBL at z~0 from mid UV

to far IR with a precision of +/-10%

- characterize its evolution up to z > 1

steady blazars

flares

InterGalactic Magnetic Field

p

simulation D. Mazin

Detection of the IGMF ?

- imaging analysis : "pair halos" for IGMF ≳ 10-16 Gtime resolved spectra : "pair echoes" if smaller IGMF

1.5 deg2.5 deg

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- time-resolved spectra : "pair echoes" if smaller IGMF

simulation Elyiv A., Neronov A. & Semikoz 2009

EGAL SURVEY KSP - STRATEGY

pointing strategy (baseline) blind survey of 25% (10 000 deg2) of the egal sky

EGAL SURVEY KSP STRATEGY

mC

rab

p g gy ( ) blind survey of 25% (10,000 deg2) of the egal. sky

- uniform exposure at ~6 mCrab

- observe each FoV with several pointings, spread over two years

> average over source activity states

di t i ti ?

-> average over source activity states

divergent pointing ?

preliminary estimates: FoV ~200 deg2 possible for~ factor 2 degradation in angular and energy resolutionsimulation L. Gérard factor 2 degradation in angular and energy resolution

-> gain in sensitivity by factor ~1.5 for same obs. time-> very interesting for transient searches

( t h l d h t GRB f th i t ?)

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(catch long and short GRBs from their onset ?)

EGAL Survey KSP - expected resultsEGAL Survey KSP expected results

simulation D. Mazin

- expect at least 30 - 40 detections based solely on Fermi (1FHL) spectra + flaresexpect up to 150 detections from current estimates- expect up to ~150 detections from current estimates

- first unbiased view of the egal. VHE sky with unique sensitivity between 100 GeV and 10 TeV

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-> measurement of the luminosity function for nearby VHE blazars-> estimate of diffuse γ-ray background

EGAL SURVEY KSP - DISCOVERY POTENTIALPOTENTIAL

The EGAL Survey is an essential tool for VHE discoveries.

- discovery of new VHE emitters, including "extreme" blazars

- discovery of fast-flaring sources ?

discovery of new VHE classes- discovery of new VHE classes (Seyferts, ULIRGs, "dark sources"...) ?

-> rich target list for GO proposals

simulation P. Padovani & P. Giommi 2014

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TRANSIENTS KSP - FOCUS ON GRBSTRANSIENTS KSP FOCUS ON GRBS

strategy:

- all GRB alerts in accessible FoV followed up with LSTs for 2 hr

( LST repositioning time < 20 s ! )

- if detection > b ith f ll

W f i

-> observe with full array

We expect far superior photon statistics compared to Fermi-LAT statistics above a few GeV.

simulation S. Inoue, J. Granot, P.T. O’Brien et al. 2013

objectives:

- jet velocity and emission site from intrinsic γγ absorption & rapid variability

above a few GeV.

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- probe particle acceleration and radiation for prompt emission & afterglow- probe EBL, IGMF, LIV

MWL SUPPORT

MultiWaveLength / MultiMessenger support organized by dedicated working group:

MWL SUPPORT

g g pp g y g g p

- MWL campaigns to follow up on transients, AGN flares/ active states

- regular MWL coverage of long-term monitoring targets and complete coverage of EGal Survey (at least optical)

- MWL coverage, including VLBI,of radio-galaxy scans

dedicated optical telescopes (photometry / polarimetry)

systematic optical coverage of CTA targets

of radio galaxy scans

- agreements / MoUs for MWL & MM alerts - systematic optical coverage of CTA targets

- AGN monitoring for high optical states & polarimetry swings- link to redshift campaigns for blazars

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SCHEDULE FOR KSPSSCHEDULE FOR KSPS

• KSP scheduling studied for first three years viability exercise• KSP scheduling studied for first three years viability exercise• Successful completion of KSP program using assumed KSP allocation

Target map forE G l S

GPSg p

CTA-S array: ExGal Survey

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CONCLUSIONSCONCLUSIONS

The CTA KSPs cover a range of science topics and are designedThe CTA KSPs cover a range of science topics and are designed to explore important CTA science in a coherent fashion.

Both the Galactic and extragalactic programs will be rich and cover g p ga variety of exciting science topics and sources.

Key point: for the KSP science listed here, there is as much, or more, science in the GO program – e.g. most iconic HE/VHE sources are not part of the KSPs.

Data products are specified for all KSPs; data releases will occurData products are specified for all KSPs; data releases will occur with an eye to inform the community promptly – and, at a minimum, by one year after the calibrated data are delivered.

Flexibility is built into the system – regular reviews of the KSPs are expected before, and during, the CTA operational period.

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BACKUP SLIDES

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LMC KSP

A unique target to studyt G l ti t

LMC KSP

extreme Galactic-type VHE Sources & diffuse emissionemission(CRs)

Face on satelliteFace-on satellite galaxy:- No source confusion- Relatively nearby and- Relatively nearby, and no distance ambiguity

Very active:Very active:- Only 1% mass of theMilky Way

- Yet 10% the SFRPotential pointing patternoverlaid on starry sky image

atomic gas contours

LMC KSP - SIMULATIONS- Includes known sources (N 157B, 30 Dor C, N 132D), luminous point-like sources,CR-enriched regions, & SN 1987A

LMC KSP SIMULATIONS

H.E.S.S.-like performance1 pointing, 16 h, 0.8-100 TeV

CTA performance6 pointings, 340 h, 0.2-100 TeV

C e c ed eg o s, & S 98

``

atomic gas contoursatomic gas contours

SFS KSP:CONNECTING CR’S AND STAR FORMATIONCONNECTING CR S AND STAR FORMATION

Estimated calorimetric gamma raygamma-ray flux

EstimatedEstimated CTA sensitivity