Crab Nebula Performance

Crab Nebula Performance

Draft versions

Version 1, 20220923: [[1]]

Version 2, 20230124: [[2]]

Version 3, 20230126: [[3]]

Version 4, 20230321: [[4]]

Version 5, 20230329: [[5]]

Format was changes after A&A considered the paper topic was not suitable for their journal

Version 6, sent to ApJ, 20230421: [[6]]

Version 9, addressing the ApJ referee's comments, 20230623: [[7]]

Version 10, minor changes (acknowledgements, author list, fig 16 typo, zenodo doi for repo containing the paper's plots data), 20230719: [[8]]

General information

• Name of the source: Crab Nebula and pulsar
• Brief description of the source:
  • Object type: PWN
  • Other relevant information
  • RA: 05 34 31.9 (hh mm ss), Dec: +20 00 52.2 (dd mm ss)
  • RA, Dec in deg (ICRS): 83.6331, 22.0145

• Analysis by:
  • Abelardo Moralejo (IFAE, moralejo@ifae.es)
  • Rubén López-Coto (IAA-CSIC, rlopezcoto@iaa.es)
  • Thomas Vuillaume (LAPP, thomas.vuillaume@lapp.in2p3.fr)
  • Seiya Nozaki (MPP, nozaki@mpp.mpg.de)
  • Daniel Morcuende (UCM, dmorcuen@ucm.es)

Data-taking information

• Data selection based on the notebook: https://github.com/cta-observatory/cta-lstchain/blob/master/notebooks/data_selection.ipynb
  • Excluded runs with issues in interleaved pedestals
  • Run selection also based on "healthy intensity spectra", i.e., rate of cosmics with intensity between 80 and 120 p.e. larger than 800 events/s.
  • Runs taken in wobble mode. Selected wobble pointings at ~0.4 deg from the source [0.35, 0.45] deg

• Observation time: 35.94 hours

• Dates of data-taking:

1 : 2020-11-17 : [2914]
2 : 2020-11-18 : [2929, 2930, 2931, 2932, 2933, 2934]
3 : 2020-11-19 : [2949, 2950]
4 : 2020-11-20 : [2967, 2968, 2969, 2970, 2971, 2972, 2973, 2974, 2975, 2976, 2977]
5 : 2020-11-21 : [2988, 2989, 2990, 2991, 2992]
6 : 2020-11-22 : [3004, 3005, 3006, 3007, 3008]
7 : 2020-12-07 : [3093, 3094, 3095, 3096]
8 : 2020-12-13 : [3231, 3232]
9 : 2020-12-14 : [3243]
10 : 2020-12-15 : [3270, 3271, 3272, 3273, 3274, 3275, 3276, 3277, 3278, 3279]
11 : 2020-12-17 : [3318, 3319, 3320, 3321]
12 : 2020-12-18 : [3328, 3329, 3330]
13 : 2020-12-19 : [3338, 3339, 3340]
14 : 2020-12-20 : [3355, 3356]
15 : 2020-12-21 : [3373]
16 : 2021-02-11 : [3598, 3599, 3600, 3601]
17 : 2021-02-12 : [3615]
18 : 2021-02-13 : [3632, 3633, 3634, 3635]
19 : 2021-02-15 : [3672, 3673, 3674, 3675, 3676, 3677]
20 : 2021-02-16 : [3706, 3707, 3708]
21 : 2021-03-15 : [4067, 4068]
22 : 2021-03-16 : [4086, 4087]
23 : 2021-09-04 : [6045]
24 : 2021-09-05 : [6073]
25 : 2021-09-14 : [6304]
26 : 2022-02-04 : [6872, 6873, 6874, 6875]
27 : 2022-02-05 : [6892, 6893, 6894, 6895]
28 : 2022-02-23 : [7097, 7098, 7099]
29 : 2022-02-28 : [7133, 7136]
30 : 2022-03-01 : [7161]
31 : 2022-03-02 : [7195, 7196, 7197, 7199, 7200]
32 : 2022-03-03 : [7227, 7228, 7231, 7232, 7233]
33 : 2022-03-04 : [7253, 7254, 7255, 7256]
34 : 2022-03-05 : [7274, 7275, 7276, 7277]

• List of all selected runs:

[2914, 2929, 2930, 2931, 2932, 2933, 2934, 2949, 2950, 2967, 2968, 2969,
 2970, 2971, 2972, 2973, 2974, 2975, 2976, 2977, 2988, 2989, 2990, 2991,
 2992, 3004, 3005, 3006, 3007, 3008, 3093, 3094, 3095, 3096, 3231, 3232,
 3243, 3270, 3271, 3272, 3273, 3274, 3275, 3276, 3277, 3278, 3279, 3318,
 3319, 3320, 3321, 3328, 3329, 3330, 3338, 3339, 3340, 3355, 3356, 3373,
 3598, 3599, 3600, 3601, 3615, 3632, 3633, 3634, 3635, 3672, 3673, 3674,
 3675, 3676, 3677, 3706, 3707, 3708, 4067, 4068, 4086, 4087, 6045, 6073,
 6304, 6872, 6873, 6874, 6875, 6892, 6893, 6894, 6895, 7097, 7098, 7099,
 7133, 7136, 7161, 7195, 7196, 7197, 7199, 7200, 7227, 7228, 7231, 7232,
 7233, 7253, 7254, 7255, 7256, 7274, 7275, 7276, 7277]

• ZD range (deg): 0 - 35 deg
• AZ range (deg): 90 - 270 deg

• Transmission at 9 km: See corresponding values in the ELOG entries. We do not use it for data selection. Instead we apply selection cuts based on rates (see above).
• Joint observations with MAGIC? : No

Monte Carlo information

• Link to MC files used:
  • Particle types:
  • ZD (deg): Zenith Range
  • AZ (deg): Azimuth Range

Analysis Code

The code used in the analysis can be found at https://github.com/vuillaut/crab-performance-paper or in the ZIP archive there:

/fefs/aswg/software/lst-crab-performance-paper/crab-performance-paper-1.0.zip

DL1 data

Used standard DL1b files produced by lstosa (using lstchain v0.9.x):

• real data: tailcut8-4 (plus cleaning based on pixel-wise pedestal std dev & dynamic cleaning, see paper):

/fefs/aswg/data/real/DL1/YYYYMMDD/v0.9/tailcut84/dl1_LST-1.Run?????.h5

• MC: tailcut8-4 (plus cleaning based on pixel-wise pedestal std dev, dynamic cleaning). NSB tuning to Crab:

/fefs/aswg/data/mc/DL1/AllSky/20221027_v0.9.9_crab_tuned/TrainingDataset/dec_2276/
/fefs/aswg/data/mc/DL1/AllSky/20221027_v0.9.9_crab_tuned/TestingDataset/ (see paper, closest pointing node used for each data run)

Random forest

Please include your specific .json files used in producing your RFs and for which source analysis (source dependent or independent), and variabules used in the RF.

• lstchain-0.9.9
• source-independent:

config: /fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/srcdep/RF/lstchain_src_dep_config.json
models: /fefs/aswg/data/models/AllSky/20221027_v0.9.9_crab_tuned/dec_2276/
lstmcpipe configuration: https://github.com/cta-observatory/lstmcpipe/tree/master/production_configs/20221027_v0.9.9_crab_tuned

• source-dependent:

config: /fefs/aswg/workspace/seiya.nozaki/Crab_performance_paper/20221027_v0.9.9_crab_tuned/combined_off_axis_1deg/RF/lstchain_src_dep_config.json
models: /fefs/aswg/workspace/seiya.nozaki/Crab_performance_paper/20221027_v0.9.9_crab_tuned/combined_off_axis_1deg/RF

DL2 data

Information about your DL2 data and settings such as: specifc versions of lstchain, specfic .json version used.

• lstchain-0.9.9
• source-indep:

/fefs/aswg/workspace/abelardo.moralejo/Crab_performance_paper/data_v0.9.9/DL2/dl2*.h5  (selected runs for final analysis)

• source-dep

real data: /fefs/aswg/workspace/seiya.nozaki/Crab_performance_paper/20221027_v0.9.9_crab_tuned/combined_off_axis_1deg/DL2/data/dl2*.h5
MC data: /fefs/aswg/workspace/seiya.nozaki/Crab_performance_paper/20221027_v0.9.9_crab_tuned/combined_off_axis_1deg/DL2_MC/data

DL3 data selection

Information about DL3 data selection.

• source-independent analysis

- For the analysis of the entire dataset from Nov 2020 to Mar 2022 we applied an intensity cut of >80 p.e. - For the analysis of the dataset >Aug 2021 (when trigger settings became stable) we applied an intensity cut of >50 p.e.

We did not apply further cuts in any of the other parameters

The config file used to produce the DL3 and corresponding IRFs is:

{
  "EventSelector": {
    "filters": {
      "intensity": [80, Infinity],
      "width": [0, Infinity],
      "length": [0, Infinity],
      "r": [0, 1],
      "wl": [0, 1],
      "leakage_intensity_width_2": [0, 1],
      "event_type": [32, 32]
    }
  },
  "DL3Cuts": {   
    "min_event_p_en_bin": 100,
    "min_gh_cut": 0.1,
    "max_gh_cut": 0.95,
    "min_theta_cut": 0.05,
    "max_theta_cut": 0.32,
    "fill_theta_cut": 0.32,
    "allowed_tels": [1]
  },
  "DataBinning": {
    "true_energy_min": 0.002,
    "true_energy_max": 200,
    "true_energy_n_bins_per_decade": 5,
    "reco_energy_min": 0.002,
    "reco_energy_max": 200,
    "reco_energy_n_bins_per_decade": 5,
    "energy_migration_min": 0.2,
    "energy_migration_max": 5,
    "energy_migration_n_bins": 31,
    "fov_offset_min": 0.1,
    "fov_offset_max": 1.1,
    "fov_offset_n_edges": 9,
    "bkg_fov_offset_min": 0,
    "bkg_fov_offset_max": 10,
    "bkg_fov_offset_n_edges": 21,
    "source_offset_min": 0.0001,
    "source_offset_max": 1.0001,
    "source_offset_n_edges": 1000
  }
}

After the pre-selection of events based on intensity, the final selection of gamma-ray-like events is based on energy-dependent gammaness and theta selection cuts with a given efficiency. The baseline efficiency in the gamma-ray selection cuts is 70% for these two parameters. We also produce DL3 files assuming a grid of efficiency values: 40-90% for gammaness and 70-90% for theta. All these efficiency cut combinations are used to test the stability of the resulting spectrum against the choice of the cut values (see Spectral results).

• source-dependent analysis

min_event_p_en_bin": 100,
min_gh_cut": 0.1,
max_gh_cut": 0.95,
min_alpha_cut": 1,
max_alpha_cut": 20,
fill_alpha_cut": 20,

High-level analysis

Information about the production of higher-level analysis.

• lstchain 0.9.9 to generate source-indep, source-dep IRFs and DL3 files (see DL3 data selection)
• Science Tool: Gammapy 0.20.1
• Point-like IRF (closest MC pointing node), 1D analysis

Analysis Results

Higher-level analysis results (Spectra, SkyMaps, Lightcurves, etc.) included in the publication.

Pulsar analysis

For the Crab Pulsar analysis we applied the same cuts as those applied for source-dependent analysis, taken from:

/fefs/aswg/workspace/seiya.nozaki/Crab_performance_paper/20221027_v0.9.9_crab_tuned/combined_off_axis_1deg/DL3/8bin_80pe/g0.7_a0.7/irf/irf_20221027_v0.9.9_crab_tuned_node_theta_10.0_az_102.199__merged.fits.gz

The DL2 files with the phases added are in:

/fefs/aswg/workspace/ruben.lopez/analysis/crabnebula/data/2022_03_Performance_paper/dl2_src_dep_pulsar_parameters_20230206_test_Seiya_ring_wobble_up_to_1deg_extra_params/

The notebook to process them:

/fefs/aswg/workspace/ruben.lopez/analysis/crabnebula/data/2022_03_Performance_paper/notebooks/Crab_pulsar_src_dependent_efficiency_cuts_test_Seiya_ring_wobble_up_to_1deg_extra_params.ipynb

and to plot the results:

/fefs/aswg/workspace/ruben.lopez/analysis/crabnebula/data/2022_03_Performance_paper/notebooks/Plot_phaseogram.ipynb

The phases selected for P1, P2 and the OFF region to carry out the analysis are:

P1  = [0.983, 0.026]
P2  = [0.377, 0.422]
OFF = [0.520, 0.870]