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PostPosted: Mon Aug 30, 2010 9:18 am 
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Joined: Tue Aug 24, 2010 5:46 pm
Posts: 11
Hello,

the output from my GALPROP run
http://galprop.stanford.edu/wrxiv/0353/ ... uo2.tar.gz
contains the following gamma-ray maps for Bremsstrahlung emission:
bremss_ionized_mapcube_54_03530002.gz
bremss_mapcube_54_03530002.gz

Judging from the manual, the bremss_ionized component is the Bremsstrahlung emission produced by interactions with ionized gas, whereas bremss is the total Bremsstrahlung emission, i.e. from interactions with molecular, atomic and ionized gas?

This can't be right, because the 1e4 energy slices have the following mean values in cm^-2 s^-1 sr^-1 MeV^-1:
bremss_ionized ~ 1.6e-5
bremss ~ 3.5e-12

Why is the bremss_ionized component so large and why is it larger than bremss?
Can someone enlighten me?

Christoph

PS: I just noticed that the GALPROP manual (http://galprop.stanford.edu/download/ma ... nual54.pdf, Section 3.4) mentions that the sky maps have units MeV^2 cm^-2 sr^-1 s^-1 MeV^-1. But I think they are not multiplied by E^2, i.e. have units cm^-2 sr^-1 s^-1 MeV^-1.

Is that correct or did I mix things up?


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PostPosted: Tue Aug 31, 2010 4:38 pm 
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Joined: Wed May 17, 2006 2:35 pm
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Location: Santa Cruz, California
Hi Christoph,

Some components are multiplied by E^2 and others are not. If I recall, the components are multiplied by E^2, while the total ones are plain differential intensities. There is no good reason for this.

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Dr. Troy A. Porter
Hansen Experimental Physics Laboratory
452 Lomita Mall
Stanford University
Stanford, CA 94305


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PostPosted: Wed Sep 01, 2010 1:10 am 
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Joined: Tue Aug 24, 2010 5:46 pm
Posts: 11
Is making all output maps consistent (either multiplied by E^2 or not) an option?
Or would that cause too much confusion with existing users?

Maybe you could update the GALPROP manual to state which maps were multiplied by E^2 and which were not to avoid confusion. New users like me don't even know the order of magnitude to expect, especially at high energies (say 1 to 100 TeV) where there are very few publications to compare with.

Just to be clear about the magnitude of the bremss_ionized component at 1e4 MeV:
bremss_ionized ~ 1.6e-5 MeV cm^-2 s^-1 sr^-1
bremss_ionized ~ 1.6e-13 cm^-2 s^-1 sr^-1 MeV^-1
Is that right?


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