CosmoCoffee Forum Index CosmoCoffee

 
 FAQFAQ   SearchSearch  MemberlistSmartFeed   MemberlistMemberlist    RegisterRegister 
   ProfileProfile   Log inLog in 
Arxiv New Filter | Bookmarks & clubs | Arxiv ref/author:

CosmoMC: light element abundance datasets
 
Post new topic   Reply to topic    CosmoCoffee Forum Index -> Computers and software
View previous topic :: View next topic  
Author Message
Graeme Addison



Joined: 17 Jul 2014
Posts: 18
Affiliation: Johns Hopkins University
PostPosted: February 15 2017  Reply with quote
Hi,

I'm interested in including measurements of deuterium / helium3 abundances in a fit. In batch2/abundances.ini it says

Code:
abundance_dataset[Izotov]= %DATASETDIR%Yp_Izotov2014.dataset

#Do not include Cooke, current AlterBBN grid is not accurate enough (rate issues etc)
#abundance_dataset[Cooke]= %DATASETDIR%D_Cooke2013.dataset


What exactly is the issue for the Cooke2013 deuterium constraint? Is the comment saying that the conversion from input obh2 / nnu etc params to a predicted D/H is not accurate enough given the Cooke2013 error?

For helium is there any similar issue? Or can I replace Izotov with other Yp constraints without worrying about this?

Thanks a lot
Back to top
View user's profile  
Antony Lewis



Joined: 23 Sep 2004
Posts: 1332
Affiliation: University of Sussex
PostPosted: February 15 2017  Reply with quote
The comment may be old, the default grid is not based on AlterBBN. The Helium results are also more stable.
Back to top
View user's profile [ Hidden ] Visit poster's website
Graeme Addison



Joined: 17 Jul 2014
Posts: 18
Affiliation: Johns Hopkins University
PostPosted: February 15 2017  Reply with quote
OK I see. I had missed the data/bbn.py file initially. Looking at that file, it seems that the assumed neutron lifetime can be adjusted (just by editing tau_n in line 25) but that the reaction rate that dominates the deuterium uncertainty d(p,γ)3He is hardcoded. Do you know if there have been any PArthENoPE updates using different / more recent numbers for the d(p,γ)3He rate? E.g. from this paper http://adsabs.harvard.edu/abs/2016PhRvL.116j2501M , which was used in one of the recent Cooke et al. deuterium analyses https://arxiv.org/abs/1607.03900

Thanks again for your help.
Back to top
View user's profile  
Antony Lewis



Joined: 23 Sep 2004
Posts: 1332
Affiliation: University of Sussex
PostPosted: February 15 2017  Reply with quote
I don't know of any updates - you could ask them. (would be great if they could produce a numerical interpolation table, rather than a fitting formula which is presumably less accurate).
Back to top
View user's profile [ Hidden ] Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    CosmoCoffee Forum Index -> Computers and software All times are GMT + 5 Hours
Page 1 of 1

 
Jump to:  
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 vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group. Sponsored by WordWeb online dictionary and dictionary software.