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cosimoNigro / agnpy_paper

Repository containing scripts to produce the plots in the agnpy paper.
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EC comparisons with JetSet: CMB #9

Closed cosimoNigro closed 3 years ago

cosimoNigro commented 3 years ago

Hello,

let us discuss in this thread the comparisons for EC with jetset that were suggested by Justin. I started to work on them in the jetset_ec_test branch. Here let us comment on the CMB.
Here the link to the jetset documentation on External Compton.

For the CMB there is a good agreement! jetset_ec_cmb_comparison

Only though when I specify to transform the electron distribution to the disk frame, not when I use the blob frame... but this is not related to our paper. Ok to add this comparison plot to the draft?

jsitarek commented 3 years ago

Hi @cosimoNigro,

How exactly do you do the transformations? Since we are interested in the emission at particular direction transforming the EED is easy because you only need to change the energies at particular angle, but when you transform the radiation field to the blob's frame it is no longer isotropic so you need to transform energies, densities and also angular distribution.

cosimoNigro commented 3 years ago

I don't do them @jsitarek, there is a function within jetset to choose the reference frame in which the scattering occurs https://jetset.readthedocs.io/en/1.1.2/user_guide/jet_model_phys_EC/Jet_example_phys_EC.html#changing-the-external-field-transformation The details I don't know...

jsitarek commented 3 years ago

Ok, than this is clearly a problem in jetset if both methods give different results, something to report to Andrea

The webpage of jetset explicitely mentioned that IC on CMB can be computed by converting the EED to BH frame as you did in the "matching" plot: "Alternatively, in the case of istropric fields as the CMB or the BLR and DT within the BLR radius, and DT radius, respectively, the it is possible to transform the the electron distribution, moving the blob to the disk/BH frame.", so yes, I think it is worth to add this plot to the paper.

davidsanchez commented 3 years ago

Do you want to had this plot and the plot EC comparisons with JetSet: BLR #7 ? or do you want to add both?

cosimoNigro commented 3 years ago

@davidsanchez I would only add the EC on CMB comparison. I would not show the other EC spectra with factors 2 or 4 difference with agnpy. I don't want to investigate photon field transformations in jetset. I am confident about our results and crosschecks and would stick to the statement that a direct comparison cannot be done due to the different parametrisations and approaches chosen.

jsitarek commented 3 years ago

HI @cosimoNigro

before giving up with jetset, could you make two simple test: 1) compare the two with the case of non-relativistic blob (e.g. Gamma = 1.001) 2) compare the two forcing the observation angle to be on axis (theta << 1/ Gamma).

they should be very fast since you already have everything available, and could tell us where is the difference. I suspect that there might be some issue with the observation angle (we also had some fun with it for the absoprtion as you probably remember)

cosimoNigro commented 3 years ago

Ok @jsitarek, I will do it and we'll keep discussing in the respective issues. I am closing this since the EC on CMB is the only one for which we have decent agreement. I already added a reference SED computed with jetset for EC on CMB in agnpy's data.