Transcript summary of session

Splinter section: Diffuse emission
• Diffuse emission: practical questions
• What needs to be done (volunteers?)
• Publication plan
Igor V. Moskalenko/NASA-GSFC 1
GLAST meeting/SLAC
2005/05/23-24
GLAST diffuse emission model 1/2
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Size of the grids: should correspond to GLAST resolution ?
(l,b)-grid with variable size in the plane and halo; perhaps 0.1
degree at 10 GeV
Dealing with local structure
Do not try to model it, but we need to understand it and estimate
gamma-ray flux; having a list of SNR’s with ages and positions would
be useful
Building the diffuse emission model: all sky, sky regions,
renormalization of components, make adjustments at every energy
bin to account for uncertainties in the e,p injection spectra and
cross section (mostly pions)
May need to be adjusted at small scale (e.g. CR intensity) using
bumps and dips in real GLAST data
Inclusion of extended and point sources
Have source catalog fed into the model and processed with
instrument response; updating DEM at least every ~3 months
(instrument orbital precession, instrumental background)
Igor V. Moskalenko/NASA-GSFC 2
GLAST meeting/SLAC
2005/05/23-24
GLAST diffuse emission model 2/2
• Develop at least 2 DEM: with/without “GeV excess”
Must be clear if “GeV excess” exists after first weeks
• Variable X-factor
GLAST will give the best estimate of X-factor & its Rdependence; ISRF depends on H2, dust -thus must be
precomputed for X=const and X=X(R)
Remember: there will be ~4 3D gas models
• GALPROP games: play with variable Dxx (vs. gas density,
magnetic field etc.), variable halo boundaries etc.
Igor V. Moskalenko/NASA-GSFC 3
GLAST meeting/SLAC
2005/05/23-24
Near Future Developments
1. Full 3D Galactic structure:
• 3D gas maps (from S.Digel, S.Hunter, T.Kamae, M.Pohl)
• 3D interstellar radiation & magnetic fields (A.Strong & T.Porter)
Develop 2D model with variable X-factor; start working on 3D with a
realistic gas model (ask Seth, Stan to share their models)
3D formats (gas, ISRF): Cartesian (x,y,z)
2. Cross sections:
• Diffractive dissociation with scaling violation (T.Kamae –param.: ~2
months)
• Isotopic cross sections (IMOS with S.Mashnik, LANL; try to motivate
BNL, JENDL-Japan, other Nuc. Data Centers)
3. Energy range:
• Extend toward sub-MeV range to compare with INTEGRAL diffuse
MeV emission –may be useful to fix low-energy part of the model (pion
production is uncertain, but is not major component)
4. Modeling the local structure:
• Local SNRs with known positions and ages
• Local Bubble, local clouds (Moriguchi + ??)
Igor V. Moskalenko/NASA-GSFC 4
GLAST meeting/SLAC
2005/05/23-24
More developments
5. Heliospheric modulation:
• Implementing a modern formalism (IMOS, Potgieter, Zank etc.)
6. Visualization tool (Andy started) using the classes of CERN ROOT
package: images, profiles, and spectra from GALPROP to be directly
compared with data
Cooperate with other people (Python)
7. Improving the GALPROP module structure,e.g. for DM studies (IMOS+…)
9. Develop test case(s) to test the accuracy of the numerical model (simple
gas distribution, no energy losses, uniform ISRF etc.)
10. Complete C++ package: rewrite several fortran routines in C++ (IMOS,
Troy?)
11. Develop a dedicated Web-site (IMOS + all):
• Controlled changes in GALPROP: tests +documentation +…
• Allow for communication with users
• Post relevant information: best models, gas maps, ISRF, nuclear cross
sections…
• Ability to run GALPROP on-line…
12. Develop a fitting procedure to make automatic fitting to B/C ratio, CR
spectra and abundances
Igor V. Moskalenko/NASA-GSFC 5
GLAST meeting/SLAC
2005/05/23-24
Papers to be published before the launch 8/07
• Interstellar Radiation Field (Strong, Porter)
• Parameterization of pp→π˚ reaction and further analysis of ppinteractions (Tune & ???)
• X & metallicity gradients in the Galaxy from EGRET data (Strong,
Moskalenko, Digel?, Hunter?)
• Modeling diffuse emission in 3D (gas & ISRF) (Strong, Moskalenko,
Porter?, Hunter?, Digel?, all)
• Early stages of particle propagation from SNR (Pohl+)
Igor V. Moskalenko/NASA-GSFC 6
GLAST meeting/SLAC
2005/05/23-24