GALPROP
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Status of Updated Central Gas Models
https://galprop.stanford.edu/forum/viewtopic.php?f=5&t=185		 Page 1 of 1
Author:  erccarls [ Tue Apr 08, 2014 7:29 pm ]
Post subject:  Status of Updated Central Gas Models
Hi,

Is there any updated timetable, or do there exist development versions which have incorporated the 3-d central gas models alluded to in the current explanatory supplement?

Quote:
"nHII: The ionized component currently calculated using a cylindrically symmetrical model based on NE2001
by Cordes et al. (5), Eq.(6) and Table 1. More sophisticated 3D model for the inner Galaxy is developed by
Taylor & Cordes (54) and outer Galaxy by Lazio & Cordes (19). Galactic center region has been considered
by Lazio & Cordes (20). These latter models can be used in future for 3D calculations. A revised scale-height
using more pulsar DMs was determined by Gaensler et al. (2008) which has been implemented as option to
replace this component in NE2001. more details required."


Sincerely,

-Eric
Author:  strong [ Tue Apr 08, 2014 11:16 pm ]
Post subject:  Re: Status of Updated Central Gas Models
You mean for HII? so far not, only the new scale-height alluded to is already included in http://sourceforge.net/projects/galprop
The documentation here is certainly in need of improvement (like most of the Explanatory Supplement).
Author:  erccarls [ Mon Apr 14, 2014 7:10 pm ]
Post subject:  Re: Status of Updated Central Gas Models
Thank you for the update. I do have two other questions that you may be able to help with.

Is it possible to use higher resolution gas maps for computing the pion emissivity? Or to obtain the quarter degree maps that are used by webrun? I have custom modifications to the GALPROP code and cannot use the online interface.

I am also somewhat confused by the descriptions of how the pion_decay skymap is computed. The gas distributions are cylindrically symmetric in e.g. Moskalenko et al 2002, but clearly the pion decay skymap contains gas structure that would not be part of this model and are presumably based upon the gas surveys. Could you briefly explain how this actually works, especially in the context of a 3-d simulation? I don't quite understand where the 3-d gas models are used and where the surveys are used in the context of pion decay.

EDIT: Question two is answered in detail at http://iopscience.iop.org/0004-637X/750/1/3/pdf/apj_750_1_3.pdf
Author:  strong [ Mon Apr 14, 2014 11:45 pm ]
Post subject:  Re: Status of Updated Central Gas Models
Higher resolution maps would probably work if they were in the right format. For the quarter-degree maps, you have to ask Gulli Johannesson who made them.

For the gamma maps, the principle is that while CR are axisymmetric in 2D, the gas rings do have plenty of structure since they are based on surveys. So the gas structure is accounted for even if the CR structure (e.g. spiral arms) is absent.
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