egret and the local interstellar emission
DESCRIPTION
EGRET and the local interstellar emission. Isabelle Grenier & Jean-Marc Casandjian Service d’Astrophysique, CEA Saclay. the local interstellar emission. EGRET, 9 years, 0.5°x0.5° local medium: 5° ≤ |b| ≤ 80°. the local interstellar model. ISM maps. - PowerPoint PPT PresentationTRANSCRIPT
sep-04
EGRET and the local EGRET and the local interstellar emissioninterstellar emissionEGRET and the local EGRET and the local interstellar emissioninterstellar emission
Isabelle Grenier & Jean-Marc Casandjian
Service d’Astrophysique, CEA Saclay
sep-04
the local interstellar the local interstellar emissionemission
the local interstellar the local interstellar emissionemission
EGRET, 9 years, 0.5°x0.5° local medium: 5° ≤ |b| ≤ 80°
sep-04
the local interstellar the local interstellar modelmodel
the local interstellar the local interstellar modelmodel
iipred
iiprediobs
2CRCRHI
2H2
bkgsouICIC)VB(dust)CO(2H)HI(HI
N)Nln(NLln
)H(n)HI(n ifq2
q
)CO(W
)H(NX
TSAIII~
qE~
qW~
qN~
qN
iipred
iiprediobs
2CRCRHI
2H2
bkgsouICIC)VB(dust)CO(2H)HI(HI
N)Nln(NLln
)H(n)HI(n ifq2
q
)CO(W
)H(NX
TSAIII~
qE~
qW~
qN~
qN
sep-04
ISM mapsISM mapsISM mapsISM 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)
oexpN~
ISM
sep-04
interstellar fit without interstellar fit without IC emissionIC emission
interstellar fit without interstellar fit without IC emissionIC 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 interstellar fit without IC emissionIC emission
interstellar fit without interstellar fit without IC emissionIC 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 02
0
270290
19 870
14 5
302 ln
(L)
sep-04
interstellar fit with interstellar fit with dustdust
interstellar fit with interstellar fit with dustdust
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 sources3EG sources3EG sources3EG sources
|b|< 5°
|b|> 5°
sep-04
exposure and albedo exposure and albedo problemsproblems
exposure and albedo exposure and albedo problemsproblems
best model residuals
albedo contamination?
high- exposure
problem?
sep-04
exposure and albedo exposure and albedo problemsproblems
exposure and albedo exposure and albedo problemsproblems
fraction of exposure
at high inclination
with high albedo flux
sep-04
on-going activitieson-going activitieson-going activitieson-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