OP313 Dec2023 Jan2024 LST1 analysis details

LST analysis OP313 Dec 2023 and Jan 2024

Wiki page with general information on all results for the paper: December_January_paper

Data-taking information

• NSB level: all data was taken in dark NSB conditions
• Zenith angles: 15-54 deg (December 2023 data have zenith angle > 30 deg)

Good-quality selected dataset

The list of data runs below was obtained using the notebook https://github.com/cta-observatory/cta-lstchain/blob/main/notebooks/data_quality.ipynb.

We used default settings, but min_drdi_at_422pe = 1.2 instead of the default 1.5 to recover 1.7 h from January 2024 where low statistics limit us. Still, the data selected have a relative light yield above ~80%.

Also, short data runs (< 5 min) were excluded, because usually short runs are a symptom of problems during data acquisition.

'2023-12-09': [15942, 15943, 15944, 15945],
'2023-12-10': [15975, 15976, 15977, 15978],
'2023-12-11': [16007, 16008, 16009, 16010],
'2023-12-12': [16042, 16043, 16044, 16045],
'2023-12-13': [16079, 16080, 16081, 16082, 16083],
'2023-12-14': [16114, 16116, 16117, 16118, 16119],
'2023-12-15': [16150, 16151, 16152, 16153, 16154, 16155, 16156],
'2023-12-16': [16188, 16189, 16191, 16192, 16193],
'2023-12-17': [16220, 16221, 16222, 16223, 16224, 16225],
'2023-12-18': [16240, 16241, 16242, 16243, 16244, 16246],
'2024-01-09': [16293, 16294, 16295],
'2024-01-13': [16350, 16351, 16352, 16353, 16354, 16356, 16357, 16358, 16359],
'2024-01-17': [16391, 16392],
'2024-01-19': [16412, 16413, 16414, 16415],
'2024-01-21': [16418, 16419, 16420]

In total, there are 19.8 hours effective time.

• Relative light yield of the selected data:

lstchain settings

• lstchain version: v0.10.7
• MC production: 20230901_v0.10.4_allsky_base_prod
• RF models: /fefs/aswg/data/models/AllSky/20230901_v0.10.4_allsky_base_prod/dec_3476/
• DL2 MC for IRF calculation: /fefs/aswg/data/mc/DL2/AllSky/20230901_v0.10.4_allsky_base_prod/TestingDataset/dec_3476
• Used IRF interpolation
• Energy threshold: ~ 40 GeV
• Selection cuts IRF and DL3: 70% efficiency in both gammaness and theta gamma-ray selection cuts. Intensity > 50 p.e.

Gammapy settings

• Gammapy version: v1.1
• Energy binning:

reco energy axis: 5 GeV - 10 TeV, 5 bins per decade
true energy axis: 1 GeV - 20 TeV, 10 bins per decade

• 3 off positions for SED and LC calculation
• Safe mask: 5% of max. Aeff
• Energy range for spectral fitting: 70 GeV - 1 TeV
• EBL model: Saldaña-Lopez 2021

Analysis cross-check

Cross-checks of different LST-1 analysis results.

• Source-dependent analysis (Seiya)

alpha: 2.37 +/- 0.88
E_ref: 100 GeV
alpha_norm: 1.0
redshift: 0.997
amplitude: (0.82 +/- 0.14)e-08 TeV-1 s-1 cm-2

• Source-independent analysis (Jorge)

alpha: 2.07 +/- 0.51
E_ref: 100 GeV
alpha_norm: 1.0
redshift: 0.997
amplitude: (1.15 +/- 0.13)e-08 TeV-1 s-1 cm-2

• Source-independent analysis (Daniel)

alpha: 2.00 +/- 0.45
E_ref: 100 GeV
alpha_norm: 1.0
redshift: 0.997
amplitude: (1.14 +/- 0.13)e-08 TeV-1 s-1 cm-2

• Source-independent analysis (Mireia)

alpha: 1.86 +/- 0.50
E_ref: 100 GeV
alpha_norm: 1.0
redshift: 0.997
amplitude: (0.93 +/- 0.11)e-08 TeV-1 s-1 cm-2

Cross-check of LST-1 SED from OP313 during high-flux period (Dec 2023).

Cross-check of LST-1 LC from OP313 (Dec 9th 2023 to Jan 21th 2024).

Go back to wiki page with general information on all results for the paper