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SAS-2

SAS-2. COS-B. EGRET. 900,000 g 271 sources. 8,000 g 3 sources. 158,000 g 25 sources. More g s mean more sources. From COS-B to EGRET. Tip(s) of the iceberg(s). Cos-B. Egret. Glast will detect hundreds of sources which will be positioned at a 5-10 arcmin level.

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SAS-2

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  1. SAS-2 COS-B EGRET 900,000 g 271 sources 8,000 g 3 sources 158,000 g 25 sources More gs mean more sources

  2. From COS-B to EGRET Tip(s) of the iceberg(s) Cos-B Egret

  3. Glast will detect hundreds of sources which will be positioned at a 5-10 arcmin level

  4. 22 sources with b< 10° 80 sources with b<10° 2 pulsars5(8) pulsars +Geminga 20 UGOs74 UGOs [1 solar flare] GLOBAL UGOs’ characteristics are unchanged 3 sources with b> 10° 181 sources with b>10° 3C273 66 AGNs (VARIABLE) r Oph 28 probable AGNs 1 weak unid. source LMC, Cen A 96 unid. sources From COS-Bto EGRET 90% 50%

  5. The majority of the sources are unidentified Few,isolated cases have been solved Geminga 73-93INS Few are being solved 2CG 342-02PSR1706-49INS 3 EGJ1835+5918radio quietINS  2 CG 135+01 GT 61.303- MAGIC  3 EGJ2020+4017g Cyg. SNR 3 EGJ1420-6038, pulsar nebulae 3 EGJ0634+0521 msec pul +Be Few more pulsars …for sure

  6. The rate of Identification is very low 1source/10y. It will take centuries to finish No general solution Euler was in the same position vis-à-vis the Fermat theorem He was unable to find a general solution, special cases were not satisfactory and said “without a bright idea …” It took 300 y to get a bright idea ….

  7. The state of the art in g-ray astronomy • 271 sources 172 UGO

  8. Unidentified g-ray sources Diversity? Craig Kanarick

  9. Unidentified g-ray sources Similarity ? With some degree of freedom

  10. UGOs’ presence: is it anomalous ? 206 without ID 339 sources

  11. Known (catalogued) objects, floating in big error boxes Genuinely new class of objects Known objects with a new phenomenology The presence of unidentified sources is normal, when a field is (still) in its infancy Improving angular resolution if always beneficial

  12. Big error boxes require additional inputs pulsars variability is the only viable tool AGNs If not, multiwavelength strategy Long, complex, success is not guaranteed

  13. Geminga is a success story based on - luck - endurance

  14. At “low” galactic latitudes 3EG 1835+5918 is the next Geminga even more difficult than the original one In g rays 5 times fainter than Geminga In X-rays 10 times fainter than Geminga In the optical 20 times fainter than Geminga No radio detection

  15. 1 4 3 2 3EG J0616-3310: 146 sources

  16. 2O G. Belanger et al. INTEGRAL Map of the Central Galactic Region 10 ___ 0 __ Not enough for a straighforward identification -10 ___ Multiwavelength zooming is still needed |350 |0 |10

  17. Glast will detect hundreds of sources which will be positioned at a 5-10 arcmin level

  18. a standard multilll approach cannot be applied to hundreds of sources Observing time (impossibly) intensive • Often not conclusive • Shallow XMM observations (10 ksec) yield 150 sources /sq deg., i.e.: • Error radius 10’  15 sources • Error radius 5’  4 sources • Error radius 3’  1-2 sources Optical/radio follow-up difficult

  19. Alternative, 2-step approach 1 -From detection to association 2 -From association to identification

  20. 1 -From detection to association Figure of merit approach Smart use of catalogues FoM suggests plausible associations

  21. Defining a FoM how good is a potential counterpart? Customized for each source class Error box c.o.p. variability energetics spectrum

  22. 2 -From association to identification Multilll ob’s of high FoM targets can secure identifications e.g.:Swift filler obs time

  23. Once we have identified new classes of galactic g-ray sources Binary systems, OB ass, microquasars, stars

  24. It will be possible to proceed to population study

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