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PostPosted: Wed Sep 22, 2010 2:16 am 
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Joined: Thu Jul 01, 2010 6:18 am
Posts: 2
Hi,

I'm trying to reproduce the diffuse emission spectra from GALPROP used in the Fermi paper http://arxiv.org/pdf/0912.0973
"Fermi Large Area Telescope Measurement of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes ".

Therefore I copied the datapoints for the GALPROP prediction in Fig. 2, page 5 in the cited paper and tried to reproduce these points with the Galprop webrun v54.

For pion decay and bremsstrahlung it looks very fine. However for IC the fermi model is a factor 2 above the prediction of the conventional model I use (see attached plot).

Can you think of any reason for this? How can it be that the bremsstrahlung emission is the same for both models but the IC isn't? Can this have something to do with another ISRF model used by the Fermi people?

A typical GALDEF file that I'm using is attached.

Many thanks,
Gerrit

n_spatial_dimensions = 2
r_min = 00.0
r_max = 20.00
dr = 1.0
z_min = -4.0
z_max = +4.0
dz = 0.1
x_min = 0.0
x_max = +15.0
dx = 0.2
y_min = 0.0
y_max = +15.0
dy = 0.2
p_Ekin_grid = Ekin
p_min = 1000
p_max = 4000
p_factor = 1.3
Ekin_min = 1.0e1
Ekin_max = 1.0e10
Ekin_factor = 1.3
gamma_rays = 1
pi0_decay = 1
IC_isotropic = 1
IC_anisotropic = 0
bremss = 1
integration_mode = 0
E_gamma_min = 1.0e1
E_gamma_max = 1.0e6
E_gamma_factor = 1.3
ISRF_factors = 1.0,1.0,1.0
synchrotron = 0
nu_synch_min = 1.0e6
nu_synch_max = 1.0e10
nu_synch_factor = 2.0
long_min = 0.50
long_max = 359.50
lat_min = -90.0
lat_max = -10.0
d_long = 1.0
d_lat = 1.0
healpix_order = 6
lat_substep_number = 1
LoS_step = 0.01
LoS_substep_number = 1
DM_positrons = 0
DM_electrons = 0
DM_antiprotons = 0
DM_gammas = 0
D0_xx = 5.75e28
D_rigid_br = 4.0e3
D_g_1 = 0.34
D_g_2 = 0.34
diff_reacc = 1
v_Alfven = 36.
damping_p0 = 1.e6
damping_const_G = 0.02
damping_max_path_L = 3.e21
convection = 0
v0_conv = 0.
dvdz_conv = 10.
nuc_rigid_br = 9.0e3
nuc_g_1 = 1.82
nuc_g_2 = 2.36
inj_spectrum_type = rigidity
electron_g_0 = 1.60
electron_rigid_br0 = 4.0e3
electron_g_1 = 2.50
electron_rigid_br = 1.0e9
electron_g_2 = 5.0
He_H_ratio = 0.11
n_X_CO = 9
X_CO = 1.9E20
X_CO_parameters_0 = 1.0E20
X_CO_parameters_1 = 1
X_CO_parameters_2 = 0
X_CO_parameters_3 = 0
n_HI_model = 1
n_H2_model = 1
n_HII_model = 1
COR_filename = r
HIR_filename = r
fragmentation = 1
momentum_losses = 1
radioactive_decay = 1
K_capture = 1
ionization_rate = 0
start_timestep = 1.0e9
end_timestep = 1.0e1
timestep_factor = 0
timestep_repeat = 20
timestep_repeat2 = 0
timestep_print = 10000
timestep_diagnostics = 10000
control_diagnostics = 0
network_iterations = 2
network_iter_compl = 2
network_iter_sec = 1
prop_r = 1
prop_x = 1
prop_y = 1
prop_z = 1
prop_p = 1
use_symmetry = 0
vectorized = 0
source_specification = 0
source_model = 1
source_parameters_1 = 0.5
source_parameters_2 = 1.0
source_parameters_3 = 20.0
source_parameters_4 = 20.0
source_parameters_5 = 0.0
n_cr_sources = 0
cr_source_x_01 = 10.0
cr_source_y_01 = 10.0
cr_source_z_01 = 0.1
cr_source_w_01 = 0.1
cr_source_L_01 = 1.0
cr_source_x_02 = 3.0
cr_source_y_02 = 4.0
cr_source_z_02 = 0.2
cr_source_w_02 = 2.4
cr_source_L_02 = 2.0
cr_source_x_03 = 0.0
cr_source_y_03 = 0.0
cr_source_z_03 = 0.0
cr_source_w_03 = 0.0
cr_source_L_03 = 0.0
cr_source_x_04 = 0.0
cr_source_y_04 = 0.0
cr_source_z_04 = 0.0
cr_source_w_04 = 0.0
cr_source_L_04 = 0.0
cr_source_x_05 = 0.0
cr_source_y_05 = 0.0
cr_source_z_05 = 0.0
cr_source_w_05 = 0.0
cr_source_L_05 = 0.0
SNR_events = 0
SNR_interval = 1.0e4
SNR_livetime = 1.0e4
SNR_electron_sdg = 0.0
SNR_nuc_sdg = 0.0
SNR_electron_dgpivot = 5.0e3
SNR_nuc_dgpivot = 5.0e3
ISRF_file = ISRF/Standard/Standard.dat
ISRF_filetype = 3
ISRF_healpixOrder = 3
B_field_model = 050100020
proton_norm_Ekin = 1.00e+5
proton_norm_flux = 4.90e-9
electron_norm_Ekin = 34.5e3
electron_norm_flux = .40e-9
max_Z = 28
use_Z_1 = 1
use_Z_2 = 1
use_Z_3 = 1
use_Z_4 = 1
use_Z_5 = 1
use_Z_6 = 1
use_Z_7 = 1
use_Z_8 = 1
use_Z_9 = 1
use_Z_10 = 1
use_Z_11 = 1
use_Z_12 = 1
use_Z_13 = 1
use_Z_14 = 1
use_Z_15 = 1
use_Z_16 = 1
use_Z_17 = 1
use_Z_18 = 1
use_Z_19 = 1
use_Z_20 = 1
use_Z_21 = 1
use_Z_22 = 1
use_Z_23 = 1
use_Z_24 = 1
use_Z_25 = 1
use_Z_26 = 1
use_Z_27 = 1
use_Z_28 = 1
use_Z_29 = 1
use_Z_30 = 1
iso_abundance_01_001 = 1.06e+06
iso_abundance_01_002 = 34.8
iso_abundance_02_003 = 9.033
iso_abundance_02_004 = 7.199e+04
iso_abundance_03_006 = 0
iso_abundance_03_007 = 0
iso_abundance_04_007 = 0.0
iso_abundance_04_009 = 0
iso_abundance_04_010 = 0.0
iso_abundance_05_010 = 0
iso_abundance_05_011 = 0
iso_abundance_06_012 = 2819
iso_abundance_06_013 = 5.268e-07
iso_abundance_07_014 = 182.8
iso_abundance_07_015 = 5.961e-05
iso_abundance_08_016 = 3822
iso_abundance_08_017 = 6.713e-07
iso_abundance_08_018 = 1.286
iso_abundance_09_019 = 2.664e-08
iso_abundance_10_020 = 312.5
iso_abundance_10_021 = 0.003556
iso_abundance_10_022 = 100.1
iso_abundance_11_023 = 22.84
iso_abundance_12_024 = 658.1
iso_abundance_12_025 = 82.5
iso_abundance_12_026 = 104.7
iso_abundance_13_027 = 76.42
iso_abundance_14_028 = 725.7
iso_abundance_14_029 = 35.02
iso_abundance_14_030 = 24.68
iso_abundance_15_031 = 4.242
iso_abundance_16_032 = 89.12
iso_abundance_16_033 = 0.3056
iso_abundance_16_034 = 3.417
iso_abundance_16_036 = 0.0004281
iso_abundance_17_035 = 0.7044
iso_abundance_17_037 = 0.001167
iso_abundance_18_036 = 9.829
iso_abundance_18_038 = 0.6357
iso_abundance_18_040 = 0.001744
iso_abundance_19_039 = 1.389
iso_abundance_19_040 = 3.022
iso_abundance_19_041 = 0.0003339
iso_abundance_20_040 = 51.13
iso_abundance_20_041 = 1.974
iso_abundance_20_042 = 1.134e-06
iso_abundance_20_043 = 2.117e-06
iso_abundance_20_044 = 9.928e-05
iso_abundance_20_048 = 0.1099
iso_abundance_21_045 = 1.635
iso_abundance_22_046 = 5.558
iso_abundance_22_047 = 8.947e-06
iso_abundance_22_048 = 6.05e-07
iso_abundance_22_049 = 5.854e-09
iso_abundance_22_050 = 6.083e-07
iso_abundance_23_050 = 1.818e-05
iso_abundance_23_051 = 5.987e-09
iso_abundance_24_050 = 2.873
iso_abundance_24_051 = 0
iso_abundance_24_052 = 8.065
iso_abundance_24_053 = 0.003014
iso_abundance_24_054 = 0.4173
iso_abundance_25_053 = 6.499
iso_abundance_25_055 = 1.273
iso_abundance_26_054 = 49.08
iso_abundance_26_055 = 0
iso_abundance_26_056 = 697.7
iso_abundance_26_057 = 21.67
iso_abundance_26_058 = 3.335
iso_abundance_27_059 = 2.214
iso_abundance_28_058 = 28.88
iso_abundance_28_059 = 0
iso_abundance_28_060 = 11.9
iso_abundance_28_061 = 0.5992
iso_abundance_28_062 = 1.426
iso_abundance_28_064 = 0.3039
total_cross_section = 2
cross_section_option = 012
t_half_limit = 1.0e4
primary_electrons = 1
secondary_electrons = 1
knock_on_electrons = 0
secondary_positrons = 1
secondary_protons = 1
secondary_antiproton = 2
tertiary_antiproton = 1
skymap_format = 0
output_gcr_full = 0
warm_start = 0
verbose = 0
test_suite = 0


Attachments:
fermi_conv.gif
fermi_conv.gif [ 12.28 KiB | Viewed 10358 times ]
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PostPosted: Wed Sep 29, 2010 7:59 am 
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Joined: Wed May 17, 2006 7:02 am
Posts: 285
Location: MPE Garching
the ISRF did indeed change, but I did not expect the difference to be a factor 2.
Did you include all the components (CMB, FIR, optical) if you used the ISRF components file ?
I cannot open your attachments by the way.

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Andy Strong, MPE


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PostPosted: Wed Sep 29, 2010 1:09 pm 
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Joined: Wed Oct 21, 2009 6:30 pm
Posts: 47
Location: Stanford U.
The attachment shows now, my bad.

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Andrey Vladimirov
http://galprop.stanford.edu/


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PostPosted: Wed Sep 29, 2010 11:16 pm 
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Joined: Wed May 17, 2006 7:02 am
Posts: 285
Location: MPE Garching
I expect the difference is in the electron injection spectral slope - you have 2.50 but we used 2.42 I think in the Fermi paper.
this does not affect the bremss which comes from low energy electrons but has a big effect on IC from higher energies.
You can see this clearly since the IC slope is flatter in the Fermi than yours.

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Andy Strong, MPE


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