Difference between revisions of "EBL Dec OP313"
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=== Different Check === | === Different Check === | ||
| − | ==== Parameters Values === | + | ==== 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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| + | === Systematics === | ||
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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 | ||
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 :
- Dominguez et al, 2011 https://arxiv.org/abs/1007.1459
- Saldana-Lopez, 2021 https://arxiv.org/abs/2012.03035
Contents
Methods
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
This plot presents the scan over different values of alpha from 0 to 2 and for the different models.
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
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
EBL model
I checked the difference with Dominguez et al, 2011 model for different spectral shape. No big difference found.
Systematics
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 %
Systematics
With the LST-1 data taken in December, I obtained
alpha = 0.50 - 0.50 +0.25 stat +/- 0.05 sys
