GRB221009A

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Alert Information

• Name/type of the alert:
• GCN notice: []
• Triggered by: Fermi GBM/Swift BAT
• Alert coordinates:
  • RA: h m s, Dec: deg m s
  • RA, Dec in deg (ICRS): 288.26452 deg, +19.77350 deg
• Alert arrival time:
• Other relevant information:
  • Redshift (z): 0.151

LST Observations

• Dates of data-taking: 2022-10-10,12,15-18,21,23-28
  • 2022-10-10
    • Zenith range (deg): 38.8 -> 57.9
    • Transmission9km: n/a
    • Observation condition: moon
    • Observation mode: std wobble, reduced HV
    • Runs: 9604 - 9607
    • Joint observations with MAGIC? : No
    • ELOG link: [1]
    • Important comments: Data were affected by timestamp issue. (Reprocessing is already done and results below are from reprocessed data)
  • 2022-10-12
    • Zenith range (deg): 34.6 -> 50.5
    • Transmission9km: n/a
    • Observation condition: moon
    • Observation mode: std wobble, reduced HV
    • Runs: 9613 - 9617
    • Joint observations with MAGIC? : Yes
    • ELOG link: [2]
    • Important comments: Data were affected by timestamp issue. (Reprocessing is already done and results below are from reprocessed data). Run 9613 taken with HV setting "set_hv_reduced_0.5", the others with "set_hv_reduced_0.3"
  • 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 - 9630
    • Joint observations with MAGIC? : Yes, except the first 2 runs
    • ELOG link: [3]
    • 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: [4]
    • 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: [5]
    • 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: [6]
    • 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: [7]
    • 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: [8]
    • 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: [9]
    • 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: [10]
    • Important comments: some clouds

Src indep analysis by Kenta (Kyoto)

• Email address of analyser: terauchi.kenta.74s@st.kyoto-u.ac.jp

Data info

• Overall selected observation time: min ( h)
• Selected runs: 9604 - 9607
• Position analyzed: RA 288.26452 deg, Dec +19.77350 deg

DL1 data

Used DL1b files produced by LSTOSA (lstchain v0.9.6)

/fefs/aswg/data/real/DL1/20221010/v0.9/tailcut84/

DL2 data

• Random forest:

/fefs/aswg/data/models/AllSky/20220511_allsky_std/dec_2276

• lstchain v0.9.6 with config file taken from the All Sky model

/fefs/aswg/data/models/AllSky/20220511_allsky_std/dec_2276/lstchain_84.json

Theta2 plot

• Cuts and parameters used:
  • intensity > 100
  • gammaness > 0.6, 0.3
  • leakage < 0.2
  • Eest range: 0.3 - 10 TeV
  • th2 cut = 0.04
  • background normalization range: 0.2 < th2 < 0.4

1 OFF position; gammaness > 0.6; no background normalization

1 OFF position; gammaness > 0.6; background normalization applied

1 OFF position; gammaness > 0.3; no background normalization

1 OFF position; gammaness > 0.3; background normalization applied

Significance evolution

1 OFF position; gammaness > 0.6; with background normalization

1 OFF position; gammaness > 0.3; with background normalization