GALACTIC PHYSICS WITH CTA Ryan C. G. Chaves 1 for the the CTA Consortium 1 CNRS/IN2P3 / Univ. Montpellier, France
THE NEXT GENERATION: CTA The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 2
GALACTIC PHYSICS: CORE THEMES THEME 1 Understanding the origin and role of relativistic cosmic particles What are the sites of high-energy particle acceleration in the Galaxy? What are the mechanisms for cosmic particle acceleration? What role do accelerated particles play in feedback on star formation? THEME 2 Probing extreme environments What physical processes are at work close to neutron stars and black holes? What are the characteristics of relativistic jets, winds, and explosions? The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 3
GALACTIC KEY SCIENCE PROGRAMS Galactic Plane Survey Cosmic-ray PeVatrons / Supernova remnant RX J1713.7-3946 Dubus+ (CTA) 13 The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 4
GALACTIC KEY SCIENCE PROGRAMS Large Magellanic Cloud Star Forming Systems Credit: R. Gendler The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 5
LMC A unique target to study extreme Galactic-type VHE sources & difguse emission (CRs) Face-on satellite galaxy: - No source confusion - Relatively nearby, and no distance ambiguity Very active: - Only 1% mass of the Milky Way - Yet 10% the SFR Potential pointing pattern overlaid on starry sky image N.B. Advantage of large CTA FoV The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 6
LMC SIMULATIONS Include: ● known VHE sources ● N 157B: most energetic pulsar, ~10 38 erg/s ● 30 Dor C: superbubble ● N 132D: radio-loud SNR (50% L radio Cas A) ● luminous point-like sources ● CR-enriched regions ● Youngest SNR: SN 1987A The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 7
LMC SIMULATIONS H.E.S.S.-like performance CTA performance 1 pointing, 16 h, 0.8-100 TeV 6 pointings, 340 h, 0.2-100 TeV ` ` atomic gas contours The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 8
STAR FORMATION & COSMIC RAYS Key science questions: What is the impact of CRs on the ISM & how do they propagate? What is the relationship between star formation & particle acceleration in systems on difgerent scales? Motivated also by: well-established correlation in FIR ● correlation seen recently in GeV -rays ● The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 9
GALACTIC STAR FORMING SYSTEMS Cygnus & Carina regions will be mapped at high resolution The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 10
TESTING UNIVERSAL RELATIONS Complementary Galactic and extragalactic science Estimated calorimetric gamma-ray flux Estimated CTA sensitivity Current detections The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 11
GPS IN CONTEXT CTA Survey The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 12
GPS IN CONTEXT The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 13
GPS IN CONTEXT Deil, Chaves+ ( H.E.S.S. ) 15 ~mCrab and uniform sensitivity with CTA GPS in just 2 years The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 14
GRADED SENSITIVITY APPROACH CTA N First 2 years: ~2 – 4 mCrab CTA S 10-yr program The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 15
GPS OBJECTIVES Increase population of known Galactic VHE sources x 3–9+ Discover new VHE source classes and unexpected phenomena Search for Galatic CR PeVatrons Measure large-scale difguse emission Detect new -ray binaries & other variable or transient sources Provide fjrst-look science data to other KSPs & General Observers Produce a multi-purpose legacy dataset to MWL community The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 16
SOURCE POPULATION Increase population of known Galactic VHE sources x 3–9++ log N – log S plot Renaud+09 T A R G E T R A N G E The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 17
NEW SOURCE CLASSES Discover new VHE source classes and unexpected phenomena CTA discovery space Deil, Chaves+ ( H.E.S.S. ) 15 The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 18
PEVATRON SEARCH Search for Galatic CR PeVatrons CTA South SST s further improve multi-T eV sensitivity + Access to inner Galaxy The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 19
GPS SIMULATIONS Source populations modeled: Both SNRs & PWNe ● Fitted to known detections (T eVCat) ● Expected difguse emission : Both IC & π 0 components (GALPROP) Energy range: 1-10 T eV ctools open-source software with latest IRFs for North & South arrays Actual GPS observation scheme ( 1620 h ) Most realistic simulations to date & work on-going The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 20
GPS SIMULATIONS Full-plane coverage: longitude ± 180°, latitude b ± 10° Deeper inner galaxy exposure: ℓ ± 80 ° Fine detail revealed with ~arcmin PSF Knoedlseder+ (CTA) The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 21
GPS SIMULATIONS: ZOOM The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 22
CR/PEVATRON OBJECTIVES Discover Galactic CR PeVatrons responsible for CR knee Specifically: Where & how in the Galaxy are CRs accelerated up to PeV energies? What is the distribution of PeVatrons in the Galaxy? Are we sitting in a particular location of the Galaxy, or is there a uniform CR sea within the whole Galaxy (understanding diffusion by observing gamma-ray accelerators and their surroundings)? Do young shell-type SNRs accelerate hadronic CRs up to PeV energies? If so, up to which energies, and how effective is this acceleration (probing the theory of non-linear DSA)? The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 23
WHERE ARE THE PEVATRONS? O n e w a y t o g e t t o C R k n e e ( ~ 3 P e V ) e n e r g i e s , q u i t e s p e c i fj c : Y o u n g , f a s t ( 2 0 , 0 0 0 k m s - 1 ) S N R s h o c k i n d e n s e w i n d ( C S M ) f r o m a T y p e I I S N & R S G p r o g e n i t o r e . g . 3 3 0 - y r - o l d C a s A , b u t = 2 . 6 ± 0 . 2 ± 0 . 2 Г s t a t s y s t O t h e r h i s t o r i c a l S N R s a r e c h a l l e n g i n g a s w e l l , c . f . u p d a t e d T y c h o ( S N I a ) s p e c t r u m f r o m V E R I T A S ( = 1 . 9 5 ± 0 . 5 1 ± 0 . 3 0 → = 2 . 9 2 ± 0 . 4 1 ) Г Г s t a t s y s t s t a t A r e P e V a t r o n s s h o r t l i v e d ? M H D i n s t a b i l i t y q u e n c h e d a f t e r ~ 1 0 0 0 y r s ( ~ a g e R X J 1 7 1 3 ) , e . g . S c h u r e & B e l l 2 0 1 3 E ~ P e V f o r o n l y ~ 1 0 0 y r s o r l e s s m a x O b s e r v a t i o n s t r a t e g y f o r C h e r e n k o v t e l e s c o p e s ? H i d d e n i n t h e e x i s t i n g d a t a b u t c o n f u s e d / o b s c u r e d ? J u s t n e e d m o r e s t a t i s t i c s / b e t t e r s e n s i t i v i t y a t m u l t i - T e V E ? N o t l o o k i n g a t t h e r i g h t o b j e c t s , b i a s e d b y w e l l - k n o w n S N R s ? M o l e c u l a r c l o u d s ? The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 24
WHERE ARE THE PEVATRONS? CTA GPS GPS ideal strategy to horizon identify PeVatron candidates HGPS - few mCrab sensitivity horizon along entire plane - E-range up to hundreds of T eV - arcmin PSF to reduce source confusion Adapted from Carrigan, Chaves+ (H.E.S.S.) 13 The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 25
PEVATRON IDENTIFICATION Specifjcally, candidates should exhibit: No VHE cut-ofg or break: 3- signal above 50 T eV ● Hard photon spectrum: 2.0 ● de O ñ a Wilhelmi+ (CTA) The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 26
PEVATRON CHARACTERIZATION KSP follow-up of top 3 candidates: +50 h deep observations of each to confjrm & measure spectra Solid lines: = 2.0 CTA simulations Dashed lines: = 2.2 de O ñ a Wilhelmi+ (CTA) The Future of Research on Cosmic Gamma Rays – Galactic Physics with CTA, August 2015 27
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