GALPROP tutorial - Stanford University

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Transcript GALPROP tutorial - Stanford University

GALPROP tutorial
Igor Moskalenko (Stanford U.)
Obtaining GALPROP
The link:
http://www.mpe.mpg.de/~aws/dlp/zxc/kty/v42.3p/
Contains c++, fortran routines & input files (dat-files, compass
gas maps, and isrf)
Dedicated GALPROP Web-site will go online soon!
– Controlled changes in GALPROP: tests + documentation +…
– New version(s) + archive versions
– Post relevant information: best models, gas maps, ISRF, nuclear
cross sections…
– Allow for communication with users
– Ability to run GALPROP on-line…
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I/O
same
level
dirs
GALDEF
FITS
v42.3
galdef-file
gas: COR, HIR, IAQ-files
RFComposite –(fits) file
dat-files (xsec, nuc.network)
GALPROP
(c++ & fortran)
v42.3
FITS
nuclei –(fits) file (R=Rsun)
nuclei_full –(fits) file (whole galaxy)
γ-ray emissivities –(fits) files (brems, IC, π0)
γ-ray skymaps –(fits) files (rings; brems, IC, π0)
Heliospheric modulation: on-the-fly in a plotting routine
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Example Makefile
#CXX = g++-2.95
#FC = g77-2.95
CFITSIO = ${GLAST_EXT}/cfitsio/v2470
CPPFLAGS = -O3 -Wno-deprecated -I${CFITSIO}/include
FFLAGS =
LIBS = -lm -lg2c
FITSLIB = -L$(CFITSIO)/lib -lcfitsio -Wl, rpath,$(CFITSIO)/lib
LDFLAGS = $(FITSLIB) $(LIBS)
FOBJS := $(patsubst %.f,%.o,$(wildcard *.f))
CCOBJS := $(patsubst %.cc,%.o,$(wildcard *.cc))
galprop: ${FOBJS} ${CCOBJS}
$(CXX) *.o -o $@ ${LDFLAGS}
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Some Editing
Tested for g++ v2.9x compiler.
New g++ compiler v3.x is more strict –routines require some
editing:
using namespace std;
#include<iostream>
#include<cstdlib>
#include<string>
#include<cctype>
#include<fstream>
#include<cmath>
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GALPROP Input: galdef-files
GALPROP is parameter-driven (user can specify everything!)
Grids
• 2D/3D –options; symmetry options (full 3D, 1/8 -quadrants)
• Spatial, energy/momentum, latitude & longitude grids
• Ranges: energy, R, x, y, z, latitude & longitude
• Time steps
Propagation parameters
• Dxx, VA, VC & injection spectra (p,e)
• X-factors (including R-dependence)
Sources
• Parameterized distributions
• Known SNRs
• Random SNRs (with given/random spectra), time dependent eq.
Other
• Source isotopic abundances, secondary particles (pbar , e±, γ,
synchro), anisotropic IC, energy losses, nuclear production cross
sections…
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Algorithm
primary source functions (p, He, C .... Ni)
source abundances, spectra
primary propagation -starting from maxA=64
source functions (Be, B...., e+,e-, pbars)
using primaries and gas distributions
secondary propagation
(i) CR –fixing propagation
(ii) γ-rays
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tertiary source functions
tertiary propagation
-rays (IC, bremsstrahlung, πo-decay)
radio: synchrotron
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GALPROP Output/FITS files
Provides literally everything:
• All nuclei and particle spectra in every grid point
(x,y,R,z,E) -FITS files
Separately for π0-decay, IC, bremsstrahlung:
• Emissivities in every grid point (x,y,R,z,E,process)
• Skymaps with a given resolution (l,b,E,process)
• Output of maps separated into HI, H2, and rings to
allow fitting X, metallicity gradient etc.
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Spatial Grids
Z
1
0
1
2
3
4
5
6
7
R,x,y
-1
Typical grid steps (can be arbitrary!)
Δz = 0.1 kpc, ΔΔz = 0.01 kpc (gas averaging)
ΔR = 1 kpc
ΔE = x1.2 (log-grid)
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GALPROP Calculations
Constraints
• Bin size (x,y,z) depends on the computer speed, RAM; final run can be done
on a very fine grid !
• No other constraints ! –any required process/formalism can be implemented
Calculations (γ -ray related)
Vectorization options
 Now 64 bit to allow unlimited arrays
 Heliospheric modulation: routinely force-field, more sophisticated model ?
1. For a given propagation parameters: propagate p, e, nuclei, secondaries
(currently in 2D)
2. The propagated distributions are stored
3. With propagated spectra: calculate the emissivities (π0-decay, IC, bremss)
in every grid point
4. Integrate the emissivities over the line of sight:
• GALPROP has a full 3D grid, but currently only 2D gas maps (H2, H I, H II)
• Using actual annular maps (column density) at the final step
• High latitudes above b=40˚ -using integrated H I distribution
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Dark Matter in GALPROP
DM annihilation products:
χ0χ0−> p, pbar, e+, e−, γ
A set of routines (gen_DM_source.cc) to assign
• The DM density profile (NFW, isothermal etc.)
• Source functions for p, pbar, e+, e−
• Source function for γ’s
• A set of user-defined parameters (10 int, 10
double precision) in galdef-file
 DM annihilation products particles are propagated
in the same model as CR particles.
 Calculation of skymaps for DM γ-rays
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galdef_44_599278 -I
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galdef_44_599278 -II
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galdef_44_599278 -III
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galdef_44_599278 -IV
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Nuclear Reaction Network+Cross Sections
Secondary,
radioactive ~1 Myr
& K-capture isotopes
55
V
Fe
Mn54
Cr51
49
Co57
Ca41
Ar37
36
Cl
26
Al
β-, n
p,EC,β+
Be7 Be10
Plus some dozens of more complicated reactions.
But many cross sections are not well known…
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Nuclear Reaction Network
I
II
III
IV
V
nuc_package.cc
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nuc_package.cc: Stable & Long-lived Isotopes
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nuc_package.cc: Long-Lived Isotopes
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nuc_package.cc: “Boundary” Nuclei
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isotope_cs_eval.dat
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Transport Equations ~90 (no. of CR species)


 ( r , p, t )
 q( r , p ) sources (SNR, nuclear reactions…)
t
diffusion

   [D
xx


  V  ]
convection
  2
  
p D

diffusive reacceleration 
pp p p 2 
p 


  dp
1   
  p  V  convection
E-loss 

p  dt
3

fragmentation 





f
radioactive decay
d
ψ(r,p,t) – density per total momentum
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Finite Differencing
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Finite Differencing: Example
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Tri-Diagonal Matrix
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Coefficients for the Crank-Nicholson Method
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Near Future Developments
Full 3D Galactic structure:
• 3D gas maps (from S.Digel, S.Hunter and/or smbd else)
• 3D interstellar radiation & magnetic fields (A.Strong & T.Porter)
Cross sections:
• Blattnig et al. formalism for π0-production
• Diffractive dissociation with scaling violation (T.Kamae –param.)
• Isotopic cross sections (with S.Mashnik, LANL; try to motivate BNL,
JENDL-Japan, other Nuc. Data Centers)
Modeling the local structure:
• Local SNRs with known positions and ages
• Local Bubble, local clouds –may be done at the final calculation step
(grid bin size ??)
Energy range:
• Extend toward sub-MeV range to compare with INTEGRAL diffuse
emission (continuum; 511 keV line)
Heliospheric modulation:
• Implementing a modern formalism (Potgieter, Zank etc.)
Visualization tool (started) using the classes of CERN ROOT package:
images, profiles, and spectra from GALPROP to be directly compared
with data
Improving the GALPROP module structure (for DM studies)
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More developments
 Point sources: develop algorithm(s) for modeling the background
and interface to the rest of GLAST software
 Instrumental response: how to implement
 Diffuse emission analysis has to include point source catalog!
 At least, two diffuse models: with/without the “excess”
 Develop test case(s) to test the accuracy of the numerical model
(simple gas distribution, no energy losses, uniform ISRF etc.)
 Complete C++ package: rewrite several fortran routines in C++
 Develop a fitting procedure to make automatic fitting to B/C
ratio, CR spectra and abundances
 Develop a dedicated Web-site:
– 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…
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Fixing Propagation Parameters: Standard Way
Using secondary/primary nuclei ratio:
•Diffusion coefficient and its index
•Propagation mode and its parameters
(e.g., reacceleration VA, convection Vz)
B/C
Be10/Be9
Ek, MeV/nucleon
Radioactive isotopes:
Galactic halo size Zh
Zh increase
Ek, MeV/nucleon
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Peak in the Secondary/Primary Ratio
• Leaky-box model:
fitting path-length distribution -> free function
• Diffusion models:
 Diffusive reacceleration
 Convection
 Damping of interstellar turbulence
 Etc.
B/C
Ek, MeV/nucleon
too
sharp
max?
Accurate measurements in a wide energy range
may help to distinguish between the models
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Distributed Stochastic Reacceleration
Simon et al. 1986
Seo & Ptuskin 1994
Scattering on
magnetic turbulences
Dpp~ p2Va2/D
D ~ vR1/3 - Kolmogorov spectrum
Icr
B
1/3
ΔE
Fermi 2-nd order mechanism
Dxx = 5.2x1028 (R/3 GV)1/3cm-2 s-1
Va = 36 km s-1
γ ~ R-δ, δ=1.8/2.4 below/above 4 GV
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strong
reacceleration
weak
reacceleration
E
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Convection
Galactic wind
Jones 1979
Escape length
Xe
v
wind or
turbulent
diffusion
D~R0.6
R-0.6
resonant
diffusion
E
problem: too broad sec/prim peak
Dxx = 2.5x1028 (R/4 GV)0.6cm-2 s-1
dV/dz = 10 km s-1 kpc-1
γ ~ R-δ, δ=2.46/2.16 below/above 20 GV
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Damping of Interstellar Turbulence
Kolmogorov cascade:
Iroshnikov-Kraichnan cascade:
nonlinear
cascade
W(k)
1/1012cm
•
•
l(p)
Simplified case:
dissipation
1/1020cm
Mean free path
1-D diffusion
No energy losses
k
p
Ptuskin et al. 2003, 2005
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Dxx – Diffusion Coefficient
~β-3
Plain
diffusion
Reacceleration
with damping
~R0.6
Diffusive
reacceleration
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How It Is Really Done: Secondary Particles
• Positrons/electrons p+p->π,K->e± (MS 1998)
– Dermer 1986 method: LE –Stecker Δ-isobar model (isotropic
decay), HE –scaling (inv. x-section: Stephens & Badhwar 1981), plus
interpolation in between
– Pion decay “includes” polarization of muons
– Kaon decay – scaling (Stephens & Badhwar 1981)
• Antiprotons (M et al. 2002)
– pp Inclusive production x-section (Tan & Ng 1983)
– pA, AA-> pbar –scaling using Gaisser & Schaeffer 1992 or Simon
et al. 1998 –results similar
– Total inelastic x-section (p: TN’83, A: Moiseev & Ormes 1997)
– p+pbar annihilation x-section = (p+pbar)tot – (p+p)tot (LE: TN’83, HE:
PDG’00 –Regge parameterization)
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Elemental Abundances: CR vs. Solar System
CR abundances: ACE
“output”
O
Si
Na
Fe
S
CNO
Al
Cl
LiBeB
CrMn
F
ScTiV
Solar system abundances
“input”
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Fitting to Measured CR Abundances (ACE vs HEAO-3)
Fitting to measured CR
abundances in the wide
energy range (~0.1 – 30
GeV) is problematic:
May indicate systematic
or cross-calibration
errors
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Total Nuclear Cross Sections
Ekin, MeV/nucleon
Wellisch & Axen 1996
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Isotopic Production Cross Sections of LiBeB
Semi-empirical systematics are
not always correct.
Results obtained by different
groups are often inconsistent and
hard to test.
Very limited number of nuclear
measurements:
Evaluating the cross section is
very laborious and can’t be done
without modern nuclear codes.
Use LANL nuclear database and
modern computer codes.
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LiBeB: Major Production Channels
Propagated Abundance * Cross-section
6
Li
O
C
Li
Be
B
N
A=
•Well defined (65%):
C12, O16 ->LiBeB
N14 -> Be7
(see Moskalenko &
Mashnik 28 ICRC,
2003)
•Few measurements:
C13,N -> LiBeB
B -> BeB
•Unknown:
LiBeB,C13,N -> LiBeB
“Tertiary”
reactions also
important! -35%
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Effect of Cross Sections: Radioactive Secondaries
Different size from different ratios…
27Al+p26Al
T1/2=?
W
ST
ST
natSi+p26Al
W
Zhalo,kp
c
Ek, MeV/nucleon
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• Errors in CR measurements (HE & LE)
• Errors in production cross sections
• Errors in the lifetime estimates
• Different origin of elements (Local Bubble ?)
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How It Is Really Done: Nucleons
•
•
Calculated for p+A reactions and scaled for α+A (Ferrando et al. 1988)
Calculation of total nuclear cross sections
– Letaw et al. 1983
– Wellisch & Axen 1996 (corrected), Z>5
– Barashenkov & Polanski 2001
•
Calculation of isotopic production cross sections
– Webber et al. 1993 (non-renormalized, renormalized); E>200 MeV/nucleon,
essentially flat
– Silberberg & Tsao 2000 (non-renormalized, renormalized); claim that it
works at all energies, but is problematic sometimes
– Fits to the available data (LANL, Webber et al., etc.) in the form of a
function or a table (see .dat files), but data may not be always available
– Use the best of all three, but very time consuming work
•
Nuclear reaction network
– Nuclear Data Tables (includes several decay channels + branching)
– Standard β± -decay, emission of p, n
– K-capture isotopes can be treated separately
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Interstellar Gas
►
Extend CO surveys to high latitudes
– newly-found small molecular clouds will otherwise be interpreted as
20
0
-20
-40
220
200
180
160
140
120
100
80
Galactic Longitude
►
60
40
20
0
CfA 1.2m
Dame, Hartmann, & Thaddeus (2001)
Dame & Thaddeus (2004)
Galactic Latitude
unidentified sources, and clearly limit dark matter studies
C18O observations (optically thin tracer) of special directions
(e.g. Galactic center, arm tangents)
– assess whether velocity crowding is affecting calculations of molecular
column density, and for carefully pinning down the diffuse emission
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Distribution of Interstellar Gas
• Neutral interstellar medium
– 21-cm H I & 2.6-mm CO (stand in for H2)
(25°, 0°)
CO
Dame et al.
(1987)
G.C.
HI
Hartmann &
Burton (1997)
W. Keel
• Near-far distance ambiguity, rotation curve, optical depth
effects, …
Seth Digel
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Seth Digel’05
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Gas Distribution
Z=0,0.1,0.2 kpc
Molecular hydrogen H2
is traced using J=1-0
transition of 12CO,
concentrated mostly in
the plane
(z~70 pc, R<10 kpc)
Atomic hydrogen H I
(radio 21 cm) has a
wider distribution
(z~1 kpc, R~30 kpc)
Sun
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Ionized hydrogen H II
(visible, UV, X) small
proportion, but exists
even in halo (z~1 kpc)
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Gas Rings: HI (Inner & Outer Galaxy)
Seth Digel’05
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Gas Rings: HI (Our Neighborhood)
Seth Digel’05
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How It Is Really Done: Gammas
• Bremsstrahlung (Koch & Motz 1959, SMR2000) –many
different regimes:
– LE: 0.01 < Ekin < 0.07 MeV –nonrelativistic non-screened brems
– Intermediate: 0.07 < Ekin <2 MeV
– HE: Ekin > 2 MeV arbitrary screening: unshielded charge, 1-, 2electron atoms (form factors, Hylleraas, Hertree-Fock wave
functions)
– Fano-Sauter limit: k->Ekin
• “Anisotropic” IC (MS2000)
– Takes into account the anisotropic angular distribution of
background photons
• Neutral pion decay (see “secondary positrons/electrons”)
• Synchrotron radiation (Ginzburg 1979, Ghisellini et al. 1988)
– Averaging over pitch angle
– Uses total magnetic field (regular + random)
• Emissivities: uses “real” H2, H I gas column densities (“rings”)
• Skymap calculations: integration over the line of sight
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Uncertainties in the Propagation Models
•
•
Production cross sections of isotopes and pbars
Typical errors ~50%
 Fitting to B/C ratio may introduce errors in Dxx
Propagation models and parameters
 Gas distribution in the Galaxy
Ambient spectrum of CR (solar modulation, GeV excess in γ’s !)
 Current knowledge of CR diffusion
•
Heliospheric modulation
 Depends on rigidity
 Similar for all nuclei A/Z~ +2
Different for protons A/Z=+1 and pbars A/Z=-1
•
Systematic errors of measurements
Difficult to account for
e +,
_
Simultaneous measurements of Li, Be, B, C, secondary
p in a wide
energy range ~100 MeV/nucleon – 100 GeV/nucleon are needed to
understand CR propagation and distinguish between the models:
looking forward to Pamela launch!
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