It is currently Fri Aug 07, 2020 10:48 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 4 posts ] 
Author Message
 Post subject: CR dipole anisotropy
PostPosted: Tue Jun 02, 2015 9:54 am 
Offline

Joined: Fri Mar 20, 2015 6:44 pm
Posts: 2
Hi,

I've come across a large number of papers that show plots of the "dipole anisotropy", delta, predicted by GALPROP and limits set from data. However, not a single one defines a formula for delta, and nowhere can I find a way to generate this myself from a GALPROP model. Admittedly, part of the problem is the number of places "anisotropic" appears in GALPROP documentation, making it very difficult to google. So can anyone tell me how to do this?

thanks,
Mike


Top
 Profile  
 
 Post subject: Re: CR dipole anisotropy
PostPosted: Tue Jun 02, 2015 11:19 am 
Offline

Joined: Wed May 17, 2006 7:02 am
Posts: 285
Location: MPE Garching
galprop does not explictly compute anisotropy, but it follows from the standard formula e.g. equation (1) in http://arxiv.org/abs/1505.02720
But that paper and others also demonstrates that this a far too simple approach, which requires more physics than is in galprop.

_________________
Andy Strong, MPE


Top
 Profile  
 
 Post subject: Re: CR dipole anisotropy
PostPosted: Thu Jun 04, 2015 7:51 am 
Offline

Joined: Fri Mar 20, 2015 6:44 pm
Posts: 2
Thanks for the response, but that formula seems far too simple. I'm trying to estimate the CR anisotropy as a function of energy using the galprop output (e.g. figure 8 of http://arxiv.org/pdf/1108.1023.pdf). I've seen a bunch of plots that show the "galprop" prediction for anisotropy, but I haven't been able to find any detail on the calculation


Top
 Profile  
 
 Post subject: Re: CR dipole anisotropy
PostPosted: Thu Jun 04, 2015 9:33 am 
Offline

Joined: Wed May 17, 2006 7:02 am
Posts: 285
Location: MPE Garching
That is the standard formula following from the definition of diffusion. But certainly it is too simple, as many papers have pointed out. Probably however it was used in the paper you cite.

_________________
Andy Strong, MPE


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
cron
Powered by phpBB® Forum Software © phpBB Group