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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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Presentation Transcript
slide1

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

slide2

From COS-B to EGRET

Tip(s) of the iceberg(s)

Cos-B

Egret

slide3

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

slide4

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%

slide5

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

slide6

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 ….

unidentified g ray sources
Unidentified g-ray sources

Diversity?

Craig Kanarick

unidentified g ray sources1
Unidentified g-ray sources

Similarity ?

With some degree of

freedom

slide10

UGOs’ presence: is it anomalous ?

206 without ID

339 sources

slide11

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

slide12

Big error boxes require additional inputs

pulsars

variability is the only viable tool

AGNs

If not, multiwavelength strategy

Long, complex, success is not guaranteed

slide14

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

slide15

1

4

3

2

3EG J0616-3310: 146 sources

slide16

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

slide17

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

slide18

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

slide19

Alternative, 2-step approach

1 -From detection to association

2 -From association to

identification

slide20

1 -From detection to association

Figure of merit approach

Smart use of catalogues

FoM suggests plausible associations

slide21

Defining a FoM

how good is a potential

counterpart?

Customized for each source class

Error box c.o.p.

variability

energetics

spectrum

slide22

2 -From association to

identification

Multilll ob’s of high FoM targets can secure identifications

e.g.:Swift filler obs time

slide24

Once we have

identified new classes of galactic g-ray sources

Binary systems, OB ass,

microquasars, stars

slide25

It will be possible to

proceed to population study