Difference between revisions of "EBL Dec OP313"

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(Created page with "The source OP 313 is located at a redshift of 0.997 and then is a very good target for EBL constraints. We use 2 EBL models : * Dominguez et al, 2011 https://arxiv.org/abs/...")
 
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=== Different Check ===
 
=== Different Check ===
  
==== Parameters Values ===  
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==== Parameters Values ====
  
 
For each value of alpha (for the Log-Parabola with an exponential cut-off model) I plotted the SED and the parameters evolution
 
For each value of alpha (for the Log-Parabola with an exponential cut-off model) I plotted the SED and the parameters evolution
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[[File:EBL_sys.png|thumb|centre|400px|Alpha scan  EBL model Saldana-Lopez 2021 for a energy biais of 15%]]
 
[[File:EBL_sys.png|thumb|centre|400px|Alpha scan  EBL model Saldana-Lopez 2021 for a energy biais of 15%]]
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=== Conclusion ===
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With the LST-1 data taken in December, I obtained
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alpha = 0.50 - 0.50 +0.25 stat +/- 0.05 sys

Latest revision as of 06:35, 3 April 2024

The source OP 313 is located at a redshift of 0.997 and then is a very good target for EBL constraints.

We use 2 EBL models :


Methods[edit]

For this calculation, I use the Fermi-LAT data analysed using the same GTI as LST-1 (more details here : https://www.lst1.iac.es/wiki/index.php/Fermi_LAT_Main_OP313)

Data were fitted using the SummedLikelihood tools from Mireia (need a ref) which allows to make a joint Fermi-LAT/LST fit

The EBL is scaled with a factor alpha. alpha=0 means no EBL and alpha = 1 means the EBL model reproduce perfectly our data.

Different Model were used in the case : Power-Law, Log-Parabola, Power-Law with an exponential cut-off, Log-Parabola with an exponential cut-off.


Results[edit]

This plot presents the scan over different values of alpha from 0 to 2 and for the different models.

Alpha scan with the EBL model Saldana-Lopez 2021

The more concervative model is the Log-Parabola with an exponential cut-off. This will be used for the calculation.

alpha = 0.50 - 0.50 +0.25

Different Check[edit]

Parameters Values[edit]

For each value of alpha (for the Log-Parabola with an exponential cut-off model) I plotted the SED and the parameters evolution

Alpha scan EBL SEDs


Alpha scan EBL Parameters

EBL model[edit]

I checked the difference with Dominguez et al, 2011 model for different spectral shape. No big difference found.


Alpha scan EBL model Saldana-Lopez 2021 and Dominguez et al, 2011

Systematics[edit]

I mimics the energy biais of the LST data using this gammapy tutorial https://github.com/bkhelifi/CTAO-CTAC_Meeting_Granada_2023/blob/main/Crab_simulations_systematic_errors_Solution.ipynb

Above 70 GeV I have introduce a biais of + or - 15 %

Alpha scan EBL model Saldana-Lopez 2021 for a energy biais of 15%


Conclusion[edit]

With the LST-1 data taken in December, I obtained


alpha = 0.50 - 0.50 +0.25 stat +/- 0.05 sys