1. EGRET and the local interstellar emission
Isabelle Grenier & Jean-Marc Casandjian
Service d’Astrophysique, CEA Saclay
sep-04

2. the local interstellar emission
EGRET, 9 years, 0.5°x0.5°
local medium: 5° ≤ |b| ≤ 80°
sep-04

3. the local interstellar model
sep-04

4. ISM maps NHI from Hartmann & Burton ’97 and Dickey & Lockman ’90
WCO from Dame et al. ’01
dust extinction from Finkbeiner ’99 and Schlegel ‘98
IC from GALPROP (Strong & Moskalenko)
sep-04

5. interstellar fit without IC emission
both models with ISMHI+CO and ISMEGRET badly need IC emission
2ln(L) increase by ~ and ~19000 !
ISMHI+CO
ISMEGRET
sep-04

6. interstellar fit without IC emission
NHI+WCO >> ISMEGRET because Xlocal ~ 1.0 ± 0.1 < XGal ~ 1.56 ± 0.05
warm dust 
total dust 
HI+CO+EBV
HI+CO+I100
HI+CO
ISMEGRET+EBV
EBV
ISMEGRET
I100
830
180
1 020
270
290
19 870
14 530
2 ln(L)
sep-04

7. interstellar fit with dust
NHI + WCO + EBV + IC + sou + Ibkgd very preliminary!
Xlocal ~ (1.1 ± 0.1) mol. cm-2 K-1 km-1 s
(1.00 ± 0.05)  sources  little bias on the IS model parameters
cold gas associated with cold dust?
or IC emission from FIR dust emission?
sep-04

8. 3EG sources
|b|< 5°
|b|> 5°
sep-04

9. exposure and albedo problems
best model residuals
albedo contamination?
high- exposure
problem?
sep-04

10. exposure and albedo problems
fraction of exposure
at high inclination
with high albedo flux
sep-04

11. on-going activities implementation of HealPix maps
equal area bins even near poles
factor of ~2 fewer bins
careful with flux conservation !
and likelihood analysis
fast convolution (nested)
PSF in spherical harmonics
update EGRET source list off the plane
compute the IC emission from the local dust mm ISRF
sep-04