observation of Galactic sources

Transcription

1 AGILE observation of Galactic sources Andrea Giuliani Istituto Astrofisica Spaziale e Fisica Cosmica, Milano ( INAF ) on behalf of the AGILE Team

2 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

3 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

4 The AGILE Mission only ~100 kg of Payload only ~100 W of PL absorbed power only 350 kg of satellite

5 The AGILE Mission AGILE combines a gamma-ray imager (30 MeV- 30 GeV) with a hard X-ray imager (18-60 kev) both with large FOVs (1-3 sr) and optimal angular resolution

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8 AGILE performances Field of view: ~ 3 sr 2 times better than EGRET

9 AGILE: 1.5 years in orbit April 23rd, 2007 : Launch from Sriharikota (India) Dec. 1st, 2007 : Starts the Cycle-1 Guest Observer Program Dec. 1st, 2008 : Starts the Cycle-2 Guest Observer Program Feb 2009 : ~ 9300 orbits

10 The AGILE gamma-ray sky (E > 100 MeV)

11 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

12 Why to study the γ ray interstellar emission? As noise : source identification and analysis.

13 Why to study the γ ray interstellar emission? As signal : probe of CR, IS Matter, ISRF

14 Why to study the γ ray interstellar emission? As signal : probe of CR, IS Matter, ISRF Origin of GeV excess (if confirmed!) Electronic harder spectrum? Protonic harder spectrum? Galactic vs local electronic spectrum Inhomogeneous gamma emissivity? X ratio value and variation in Galaxy IC contribution to diffuse emission Galactic vs Extragalactic diffuse emission CR sources SNR Stellar associations?

15 Gamma-Ray Emission of the Interstellar Medium Cosmic rays (p and e-) Interstellar Matter Neutral Hydrogen (60 %, 21 cm line) Molecular Clouds (40 %, CO emission, X ratio) InterStellar Radiation Field (stars, dust, CBM)

16 Gamma ray emission of the ISM Cosmic e- Cosmic p HI regions σbr Fe nhi σpp Fp nhi Mol. Clouds σbr Fe nco Xratio σpp Fp nco Xratio ISRF σic Fe Uph Proton-proton collisions Bremsstrahlung Inverse Compton

17 Gamma Ray Spectrum S E = 1 4π [ q pp r, E n r qbr r, E n r q IC r, E U r ] drd Gamma Ray Intensity [ ph cm-2 s-1 sr-1 MeV-1 ] Electron Bremsstrahlung πo decay Inverse Compton Gamma-Ray energy [MeV]

18 Radio Data deprojection Galactic rotation curve Clemens 1985 Radio Data Gas density

19 The neutral Hydrogen (HI) Two phase medium in pressure balance 2. Cold (100 K) Mass Dense sheet No grav. Bound n = cm-3 3. Warm (6000 K) % volume

20 The neutral Hydrogen (HI) Ground level of neutral hydrogen (12S1/2) is split into two sublevels F = J + I = 0,1 Tiny energy separation (t = years) Radio emission at MHz or 21 cm Spin temperature TS

21 Neutral Hydrogen Survey Leidn-ArgentineBonn (LAB) survey of galactic HI at 21 cm (Kalberla et al 2005) Spatial resolution: 30 Velocity resolution: 1.03 km/s Velocity range: -450,400 km/s Sensitivity: 0.07 K

22 The molecular clouds Concentrated in Giant Clouds ( Msol) self graviting with n > 103 cm-3 Optically thick (dust, H2) Along spirala arms Small scale thickness (120 pc)

23 The molecular clouds H2 is homopolar No vibrational or rotational emission CO is the abundant molecule after H2 CO emits strong line radiation at 2.6 mm (J 1 0) CO tracer of H2 nh2 proportional to LCO

24 CO Survey (Dame et al. 2001) CO observation (J GHz) 31 survey combined Spatial resolution: 12 or more Velocity resolution: 0.65 km/s Sensitivity: 0.62 K X = nhi/nco = cm-2 K-1 km-1 s

25 Hydrogen distribution H mean density (averaged on b < 5 )

26 Interstellar Radiation Field Model of the ISFR: Far Infrared Near Infrared Optical/UV + CBR

27 Cosmic-Rays Trying with different cosmic ray models Physical models GALPROP Sources, diffusion and energy loss simulated GALPROP (Strong & Moskalenko) Fichtel 91

28 HI The γ-ray emission model (I quadrant) ISRF H2

29 The γ-ray emission model (I quadrant)

30 The γ-ray emission model (-90 < l < 90)

31 AGILE Observations (-90 < l < 90)

32 AGILE Observations vs Model (-90 < l < 90)

33 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

34 The first AGILE Bright Sources Catalog

35 The first AGILE Bright Sources Catalog 8 Blazars 9 Pulsars IC 443 LSI ~ 20 UnID

36 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

37 November 2008: 11 detections >3 sigma. New GammaRay Pulsars Pellizzoni et al., 2009, in press

38 A new variable millisecond gamma-ray pulsar in a globular cluster EROT= 2.2x1036 erg/s P = 3 ms d = 4.9 kpc

39 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

40 SNR IC 443

41 IC 443 SNR and Molecular Clouds From Dickman et al. 1992

42 IC 443 SNR and Molecular Clouds

43 TeV source (MAGIC,VERITAS) EGRET source (Hartman et al. 1999)

44 IC 443 Gev Source TeV Source see also : Torres et al. MNRAS, 387, 2008 Aharonian & Atoyan, A&A, 309, 1996

45 IC 443 Fit: αp = αe = Msol see also Gaisser et al., 1998

46 Summary of the Presentation The AGILE Mission The diffuse emission model Galactic Sources Pulsars IC 443 Unidentified Sources

47 Not only pulsars?

48 Center Norma 31 Scutum 315 Crux 51 Sagittarius 285 Carina 80 Cygnus 260 Vela Anticenter

49 The Cygnus Region 3EG J (WR 140) Gamma Cygni? Cyg OB 2? TeV ? Cyg X-3? PSR J ! (Halpern et al., ApJ, 2008) 3EG J

50 The Carina Region Westerlund 2? Eta Carinae? PSR J !

51 Identification of counterparts Source confusion Resolution ~ N. Counts More observations for better positioning --> Cycle 2

52 Conclusions and Future prospects Very exciting time for gamma-ray astrophysics AGILE performances are improving ~ t Cygnus and Carina regions deep covered during Cycle 2

53 End