HEPRO VIII GRB221009A analysis (dark)

Dark analysis

This page explains the analysis (source independent) done to produce the high-level results from GRB 221009A for the HEPRO VIII conference. The analysis uses the dark observations of this GRB (see below)

General information

• Name of the source: GRB 221009A
• Brief description of the source:
  • Object type : GRB
  • Redshift (z) : 0.15
  • Other relevant information
  • RA, Dec in deg (ICRS): 288.26452 deg, +19.77350 deg

• Analysis by Arnau Aguasca-Cabot (UB - arnau.aguasca@fqa.ub.edu)

Data-taking information

• • 2022-10-15
    • Zenith range (deg): 23.8 -> 57.9
    • Transmission9km: n/a
    • Observation condition: dark and moon (9629,9630)
    • Observation mode: std wobble
    • Runs: 9625 - 9628
    • Joint observations with MAGIC? : Yes, except the first 2 runs
    • ELOG link: [1]
    • Important comments: Data were affected by timestamp issue. (Reprocessing is already done and results below are from reprocessed data)

• • 2022-10-16
    • Zenith range (deg): 32.1 -> 64.1
    • Transmission9km: n/a
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9640 - 9647
    • Joint observations with MAGIC? : No
    • ELOG link: [2]
    • Important comments: Data were affected by timestamp issue. (Reprocessing is already done and results below are from reprocessed data)

• • 2022-10-17
    • Zenith range (deg): 25.9 -> 58.6
    • Transmission9km: n/a
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9670 - 9677
    • Joint observations with MAGIC? : Yes
    • ELOG link: [3]
    • Important comments: Data were affected by timestamp issue. (Reprocessing is already done and results below are from reprocessed data)

• • 2022-10-18
    • Zenith range (deg): 23.1 -> 43.5
    • Transmission9km: n/a
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9691 - 9696
    • Joint observations with MAGIC? : No
    • ELOG link: [4]
    • Important comments: unstable rate in run 9691

• • 2022-10-21
    • Zenith range (deg): 34.6 -> 55.6
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9802 - 9807
    • Joint observations with MAGIC? : Yes
    • ELOG link: [5]
    • Important comments:

• • 2022-10-23
    • Zenith range (deg): 32.07 -> 59.21
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9829 - 9835
    • Joint observations with MAGIC? : Yes
    • ELOG link: [6]
    • Important comments:

• • 2022-10-24
    • Zenith range (deg): 49.6 -> 58.8
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9861 - 9863
    • Joint observations with MAGIC? : No
    • ELOG link: [7]
    • Important comments: some clouds

• • 2022-10-25
    • Zenith range (deg): 43.6 -> 56
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9888 - 9891
    • Joint observations with MAGIC? : Yes
    • ELOG link: [8]
    • Important comments:

• • 2022-10-26
    • Zenith range (deg): 40 -> 56
    • Observation condition: dark
    • Observation mode: std wobble
    • Runs: 9917 - 9920
    • Joint observations with MAGIC? : Only run 9919
    • ELOG link: [9]
    • Important comments: run 9918,9919 are both in W2

Monte Carlo information

• MC production reprocessed with lstMCpipe (v0.9.9) starting at DL1a level for AllSky production. NSB tuning added at the DL1 level.
• Link to lstMCpipe production: https://github.com/cta-observatory/lstmcpipe/tree/master/production_configs/20221027_v0.9.9_crab_tuned

• Link to MC files used: /fefs/aswg/data/mc/*/AllSky/20221027_v0.9.9_crab_tuned
  • Particle types: Diffuse, point-like gammas, diffuse protons
  • dec band (deg): 22.67

DL1 data

Reprocessed using DL1a files produced by LSTOSA. The files were reprocessed solving the problem with the time stamp.

• original DL1a files (real)
• lstchain v0.9.6
• real data: tailcut8-4 (with cleaning based on pedestal RMS), dynamic cleaning

/fefs/aswg/data/real/DL1/*/v0.9/tailcut84/dl1_LST-1.Run0XXXX.XXXX.h5

• MC: tailcut8-4, dynamic cleaning, NSB tuning
• lstchain v0.9.9

 "image_modifier": {
   "increase_nsb": true,
    "extra_noise_in_dim_pixels": 1.62,
    "extra_bias_in_dim_pixels": 0.655,
    "transition_charge": 8,
    "extra_noise_in_bright_pixels": 2.08,
    "increase_psf": false,
    "smeared_light_fraction": 0
 },

/fefs/aswg/data/mc/DL1/AllSky/20221027_v0.9.9_crab_tuned/*

Random forest

• lstchain-0.9.9
• source-independent analysis (diffuse gamma, disp_norm)

https://github.com/cta-observatory/lstmcpipe/tree/master/production_configs/20221027_v0.9.9_crab_tuned

DL2 data

• lstchain-0.9.9
• source-independent analysis

/fefs/aswg/workspace/arnau.aguasca/Analysis/results/LST/real/DL2/202210*/srcind/v0.9.9/tailcut84_dynclg_tNSBtoCrabPerfPaper/AllSky_20221027_v0.9.9_crab_tuned_dec_2276/

DL3 data selection

DL3 files were produced considering the edisp normalisation correction (using the fix_edisp.py script) and the interpolation mode to compute the IRFs with energy-dependent cuts (both for the gammaness and theta cut).

• lstchain-0.9.14dev (commit: 90d0450, after IRF interpolation method merged to the main branch)

 "filters": {
   "intensity": [50, Infinity],
   "width": [0, Infinity],
   "length": [0, Infinity],
   "r": [0, 1],
   "wl": [0.01, 1],
   "leakage_intensity_width_2": [0, 0.2],
   "event_type": [32, 32]
 }
 "gh_efficiency": 0.9,
 "theta_containment": 0.7,

High-level analysis

• Science Tool: gammapy 1.0
• point-like IRF, 1D analysis
• Energy threshold based on Crab check (200 GeV)

Analysis Results

Spectral results

• 

  Spectral energy distribution using all observations in dark conditions. The Crab spectrum is shown as a dashed red line.

Light curve results

• 

  Energy flux for LST-1 dark observations (Oct. 15-18 and 21-28). The ULs from HAWC (green) and H.E.S.S. (orange) are shown. The dashed line marks the Fermi-GBM trigger time (t0).

Crab check

The quality cuts used to produce the high-level results are based on the analysis of Crab data in similar conditions to the GRB 221009A data in dark conditions

• Crab runs (2022-03-04)

• Runs: 7255, 7256

• Crab runs (2022-03-05)

• Runs: 7277, 7278, 7279, 7280, 7281, 7282

• Crab runs (2022-11-21)

• Runs: 10914, 10915, 10916, 10917, 10918, 10986, 10987

• Crab runs (2022-11-23)

• Runs: 10988, 10989

• 

  Spectral energy distribution.

• 

  Light curve above 200 GeV.

Cross-check by Kenta

The plots below show the cross-check by Kenta (source-dependent analysis, lstchain v0.10.4 with runs 9629 and 9630 included). No edisp normalisation correction was applied.

• 

  Spectral energy distribution.

• 

  Light curve.