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Fermi 衛星による 最新成果と今後の展望

Fermi 衛星による 最新成果と今後の展望. Mar. 04, 2013@ 金沢 ( 高宇連研究会 ) T. Mizuno ( 広島大学　宇宙科学センター ) On behalf of the Fermi-LAT collaboration. Recent Results by Fermi -LAT and Future Prospects. Mar. 04, 2013@Kanazawa (Annual meeting of HEAPA) T. Mizuno (Hiroshima Astrophysical Science Center)

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Fermi 衛星による 最新成果と今後の展望

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  1. Fermi衛星による最新成果と今後の展望 Mar. 04, 2013@金沢 (高宇連研究会) T. Mizuno (広島大学　宇宙科学センター) On behalf of the Fermi-LAT collaboration

  2. Recent Results by Fermi-LATand Future Prospects Mar. 04, 2013@Kanazawa (Annual meeting of HEAPA) T. Mizuno (Hiroshima Astrophysical Science Center) On behalf of the Fermi-LAT collaboration

  3. Fermi Gamma-ray Space Telescope • Fermi = LAT + GBM • LAT = GeV Gamma-ray Space Telescope (20 MeV ~ >300 GeV; All-Sky Survey ) 2008.06launch 2008.08 Sci. Operation 3c454.3 Cape Canaveral, Florida 1873 sources Nolan+ 2012, ApJS 199, 31

  4. Fermi-LAT Performance • New Dataset and Response (Pass7, 2011.08-) • Improved Aeff in low Energy (E<200 MeV) • In-orbit calibration of PSF http://www.slac.stanford.edu/exp/glast/groups/canda/lat_Performance.htm Effective Area(P7) PSF good enough for MW analysis of X-ray sources Ackermann+12, ApJS 203, 70 (CA: Baldini, Charles, Rando)

  5. Fermi-LAT Performance • New Dataset and Response (Pass7, 2011.08-) • Improved Aeff in low Energy (E<200 MeV) • In-orbit calibration of PSF http://www.slac.stanford.edu/exp/glast/groups/canda/lat_Performance.htm Old Aeff(P6) Big improvement over the old P6 response in E<200 MeV If you want to analyze data by yourself, please visit Fermi Science Support Center http://fermi.gsfc.nasa.gov/ssc/

  6. Fermi-LAT Publications • Publications by Fermi-LAT members (Cat I+II+III, as of Dec. 2012) 2010 2012 2011 2008 2009 ~300 papers already published 6-7 papers/month 2FGL catalog paper is the most cited paper in 2012 (in astrophysics) http://www-glast.stanford.edu/cgi-bin/pubpub

  7. Introduction: Gamma-Ray Astrophysics g-rays = CRs x ISM (or ISRF) Cosmic-rays Interstellar Medium Fermi-LAT (2008-present) 2.4psr, 20 MeV-300 GeV • known ISM distribution => CRs • those “measured” CRs => ISM A powerful probe to study CRs and ISM in distant locations

  8. Origin and Propagation of Galactic CRs • uCR~1 eV/cm3 at the solar system • Vgal=1067-68 cm3, tesc~107 yr • ESN~1051 erg, FSN~1/30 yr • If h~0.1 PCR~1041 erg/s g-ray Pinj~1041 erg/s sun • To test this SNR paradigm of CRs, • we need to observe • CR distribution outside of the solar system • CRs accelerated at SNRs

  9. Origin and Propagation of Galactic CRs • uCR~1 eV/cm3 at the solar system • Vgal=1067-68 cm3, tesc~107 yr • ESN~1051 erg, FSN~1/30 yr • If h~0.1 PCR~1041 erg/s g-ray Pinj~1041 erg/s sun • This talk will cover Fermi-LAT obs. of • diffuse gama-rays • SNRs • This talk will also cover • local group galaxies, star-forming galaxies • extragalactic gamma-ray background • (+ISM)

  10. ISM Component not Visible by Standard Tracers • ISM has been mapped by radio surveys (HI by 21 cm, H2 by 2.6 mm CO) • Fermi revealed a component of ISM not measurable by those standard tracers Chamaeleon Molecular Cloud Residual g-rays when fitted by N(HI)+CO g-rays w/ CO contour Ackermann+12, ApJ 755, 22 (CA: Hayashi, TM)

  11. ISM Component not Visible by Standard Tracers • ISM has been mapped by radio surveys (HI by 21 cm, H2 by 2.6 mm CO) • Fermi revealed a component of ISM not measurable by those standard tracers, confirming an earlier claim based on EGRET study (Grenier+05) Residual g-rays when fitted by N(HI)+CO Residual gas inferred by dust See also Abdo+10 (ApJ 710, 133), Ackermann+11 (ApJ 726, 81) and Ackermann+12 (ApJ 756, 4)

  12. CRs outside the Solar System (1) • Mid-high lat. region in 3rdquadrant • small contamination of IC and molecular gas • correlate g-ray intensity with N(HI) LAT data model from the LIS • Local CR spectra ~ those directly measured at the Earth(uCR~1 eV/cm3) nucleon-nucleon electron-bremsstrahlung Abdo+09, ApJ 703, 1249 (CA: TM)

  13. CRs outside the Solar System (2) Data Model • on average, local CR spectra ~ those measured at the Earth(uCR~1 eV/cm3) Casandjian+ in prep.

  14. CRs on Galactic Scale No single model to reproduce the all-sky data, but overall agreement is good Outer Galaxy Diffuse model (total) Local pi0 e- brems. IC Inner Galaxy Ackermann+12, ApJ 750, 3 (CA: Johannesson, Porter, Strong) 1GeV 10 100

  15. CR Luminosity inferred from a model • PCR=(6-8)x1040 erg/s and Lg=(7-10)x1038 erg/s are inferred by (particular) set of models • MW is electron calorimeter if IC is included Luminosity of MW CR p CR a CR e- Radio g-ray CR e+ Halo size: 2kpc 4 10 2kpc 4 10 Models by numerical calculation, Strong+10 (ApJ 722, L58) Diffusive Reacceleration, zh=4kpc

  16. SNRs seen by Fermi-LAT • ten 2FGL sources are now identified as, or associated with SNR (# of possible association ~60) • Hadronic scenario is usually favored

  17. SNRs seen by Fermi-LAT • ten 2FGL sources are now identified as, or associated with SNR (# of possible association ~60) • Hadronic scenario is usually favored

  18. IC443 Image and Spectrum g-ray spectrum w/ pi0-decay dominated model 5-10 GeVg-ray image w/ radio contour 2-10 GeV 2-10 GeV EGRET Fermi MAGIC VERITAS PSF PSF Hadronic scenario gives Wp=1x1049 erg (ECR>500 MeV) Abdo+10, ApJ 712, 459 (CA: Giordan, Kamae, Rodriguez, Torres)

  19. W44 Image and Spectrum Deconvolvedg-ray image w/ Spitzer 4.5um contour (tracer of shocked H2) g-ray spectrum w/ pi0-decay dominated model 2-10 GeV Wp=6x1049 erg, We=1x1048 erg (ECR>100 MeV) Abdo+10, Science 327, 1103 (CA: Tajima, Tanaka, Uchiyama)

  20. Pion-Decay Bump in LowE Spectrum • Spectrum below 200 MeV clearly deviates from bremsstrahlung and agrees well with a hadronic scenario Convincing evidence of proton acceleration, ESNh=WCR~1050 erg Ackermann+13, Science 339, 807 (CA: Funk, Tanaka, Uchiyama)

  21. Local Group/Starburst Galaxies • Study CR/ISM interaction in wide range of samples • Contribution to EGB LMC M82 N253 M31 SMC

  22. Energy Spectrum • Starburst -- Hard spectrum by Fermi+IACT (G~2) • Local Group -- Softer spectrum (G>2.5) • Escape limited in MW. Short diffusion length in LMC MW(+) & LMC(+) M82 G=2.2 G=2.7 Abdo+10, ApJL709, 152 (CA: Bechtol, Dermer, Reimer, Rodriguez, Torres) Abdo+10, A&A 512, A7 (CA: Jean, Knodlseder, Porter)

  23. SFR-Lg Relation • A sample of 69 is examined: quasi-linear relation between star-formation rate and Lg (Lg∝LIR1.0-1.2) • SFR-Lg relation and hard spectrum implies hadroncalorimetry N1068 N4945 M82 N253 M31 MW LMC SMC Ackermann+12, ApJ 755, 164 (CA: Bechtol, Cillis, Funk, Torres)

  24. SFR-Lg Relation • A sample of 69 is examined: quasi-linear relation between star-star-formation rate and Lg (Lg∝LIR1.0-1.2) • SFR-Lg relation and hard spectrum implies hadroncalorimetry • NB MW is escape limited N1068 N4945 M82 N253 M31 MW LMC SMC Ackermann+12, ApJ 755, 164 (CA: Bechtol, Cillis, Funk, Torres)

  25. Extragalactic g-ray Background • GeV gamma-ray sky = Point sources + Gal. Diffuse gs + ExtraGal. Diffuse gs Geminga Vela Crab 3c454.3 Fermi-LAT 1 year all-sky map

  26. Extragalactic g-ray Background (EGB)

  27. Why is EGB Important? • The EGB may encrypt the signature of the most powerful processes in astrophysics Star forming galaxies, etc. Point sources or diffuse 73% Dark Energy 4% Atoms 23%Dark Matter Blazars contribute 20-100% of the EGB Annihilation of Cosmological Dark Matter Particles accelerated in Intergalactic shocks Markevitch+05

  28. EGB of EGRET Era • “Cosmic” Extragalactic Gamma-ray Background (EGB) • known since 1970s (SAS-2) G ~ 2.1 E2 x Flux CXB (resolved into AGNs) GeV background (EGRET) Sreekumar+98 keVMeVGeV

  29. The Fermi EGB LAT sky • Fermi data + improved diffuse model • new EGB spectrum in 0.2-100 GeV = gal. diffuse Featureless PL softer than EGRET result + point sources G ~ 2.4 + Instrumental BG Abdo+10, PRL 104, 101101  0.1 1 GeV 10 100 (CA: Ackermann, Porter, Sellerholm) +”EGB”

  30. Contribution of Blazars • >70% of resolved high-lat. sources are blazars • Unresolved Blazars account for23+/-5(stat)+/-12(sys)% of the EGB logN-logS: Most of un-associated sources are likely to be blazars Fermi EGB vs. source contribution 0.1 1 GeV 10 100 Abdo+10, ApJ 720, 435 (CA: Ajello, Tramacere)

  31. Contribution of Star-forming Galaxies • Use Lg-LIR scaling to estimate contribution • Star-forming galaxies account for4-23% of the EGB (~60% at the maximum if we add Blazars and SFGs) • Radio galaxies can account for ~25% (e.g., Inoue+11). Still some room for other source type or truly diffuse emission. • Ackermann+12, ApJ755, 164 • (CA: Bechtol, Cillis, Funk, Torres)

  32. Future Prospects • Detailed modeling of Galactic CRs • CR density gradient, CR density variation (e.g., Ackermann+11, ApJ 726, 81; Ackermann+12, ApJ 755, 22) • Injection of CRs to the interstellar space • Detailed observation of SNRs and other accelerators, Cygnus Cocoon and other star-forming regions (e.g., Ackermann+11, Science 334, 1103) • New event classification (Pass8) • Further improvement of acceptance Pass 8 (new IRF) Cygnus Cocoon (g-ray excess)

  33. Summary • Fermi衛星により宇宙線の探査が大きく進んできた(広がったガンマ線放射, 宇宙線源候補, 星生成銀河) • 太陽系は「特別」ではない • SNR起源説で概ね説明可能 • 星生成銀河はCR p Calorimeter (天の川銀河はescape limited) • 系外ガンマ線放射に対する点源の寄与を定量評価 • 宇宙線の注入, 伝播, 分布を調べることが重要 • 宇宙線分布の詳細観測 • SNRほか加速源の詳細観測 (花畑講演も参照) • 触れられなかった話題：AGN, GRB, PSR/PWN, DM探査など Thank you for your Attention

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