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

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

the local interstellar model sep-04

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

interstellar fit without IC emission both models with ISMHI+CO and ISMEGRET badly need IC emission 2ln(L) increase by ~ 15000 and ~19000 ! ISMHI+CO ISMEGRET sep-04

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

interstellar fit with dust NHI + WCO + EBV + IC + sou + Ibkgd very preliminary! Xlocal ~ (1.1 ± 0.1) 1020 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

3EG sources |b|< 5° |b|> 5° sep-04

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

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

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