Analysis BLLac Aug 2021 Nozaki

BL Lacertae flare July 2021

General information

• Name of the source: BL Lacertae
• Brief description of the source:
  • IBL / LBL
  • highly variable
  • z = 0.069
  • RA: 22 02 43.3 (hh mm ss), Dec: +42 16 40 (dd mm ss)
  • RA, Dec in deg (ICRS): 330.68038, 42.277772

• Analysis by Seiya Nozaki (Kyoto U, - nozaki@cr.scphys.kyoto-u.ac.jp)
• Crab check
  • https://indico.cta-observatory.org/event/3671/contributions/31276/attachments/20319/28344/20211118_SourceDepAnalysis.pdf
• Presentation in LST General meeting (Nov 2021)
  • https://indico.cta-observatory.org/event/3671/contributions/31287/attachments/20340/28378/20211119_BLLac.pdf

Data-taking information

• Dates of data-taking:
  • 2021-08-08 (0.41 h)
    • ZD: 13 - 32 deg
    • Transmission9km: >80%
    • Runs: 5552-5559
    • Joint observations with MAGIC

DL1 data

Reprocessed using DL1a files procuded by LSTOSA (lstchain v0.7.3) and dl1ab script (v0.7.5)

/fefs/aswg/data/real/DL1/20210808/v0.7.3/tailcut84/dl1_LST-1.Run0XXXX.XXXX.h5
/fefs/aswg/data/mc/DL1/20200629_prod5_trans_80/XXX/zenith_20deg/south_pointing/20210416_v0.7.3_prod5_trans_80_local_taicut_8_4/

• lstchain v0.7.5
• real data: tailcut8-4 (with cleaning based on pedestal RMS), dynamic cleaning

 /fefs/aswg/workspace/seiya.nozaki/data/BLLac/v0.7.3/tailcut84_dynamic_v075/DL1_raw/lstchain_standard_config.json

• MC: tailcut8-4 (with cleaning based on pedestal RMS), dynamic cleaning, PSF+NSB tuning

 /fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/DL1_raw/lstchain_dl1ab_tune_MC_to_BLLac_config.json

Random forest

• lstchain-0.7.6.dev242+g2086cb9

• source-indep (diffuse gamma, src_r<3deg, disp_norm)

/fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/srcdep/RF/lstchain_src_dep_config.json

• source-dep

/fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/srcindep/RF/lstchain_standard_config.json

DL2 data

• lstchain-0.7.6.dev242+g2086cb9

• source-indep

/fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/srcindep/DL2/data/
/fefs/aswg/workspace/seiya.nozaki/data/BLLac/v0.7.3/tailcut84_dynamic_v075/srcindep/DL2/data/dl2_LST-1.Run0XXXX_merged.h5

• source-dep

/fefs/aswg/workspace/seiya.nozaki/data/MC/v0.7.5/tailcut84_dynamic_bllac/srcdep/DL2/data/ 
/fefs/aswg/workspace/seiya.nozaki/data/BLLac/v0.7.3/tailcut84_dynamic_v075/srcdep/DL2/data/dl2_LST-1.Run0XXXX_merged.h5

DL3 data selection

• intensity > 30
• r: [0, 1 ]
• wl: [0.05, 1]
• leakage_intensity_width_2: [0, 0.2 ]
• fixed_gh_cut: 0.7
• fixed_theta_cut: 0.2

High-level analysis

• Science Tool: gammapy 0.18.2 (+ bugfix https://github.com/gammapy/gammapy/pull/3374)

Significance of the detection

1 Off reflected position
Theta2 cut: 0.04 deg

• Squares: Background
• Circles: Signal events

Date: 2021-07-09

• List of runs: [5219, 5220]
• Observation time: 0.41 h
• Number of ON events: 257
• Number of OFF events: 234 +/- 15
• Excess: 23 +/- 22
• Li&Ma significance: 1.0 sigma

Date: 2021-07-10

• List of runs: [5229, 5230, 5231, 5232, 5233, 5234, 5235]
• Observation time: 1.56 h
• Number of ON events: 598
• Number of OFF events: 351 +/- 19
• Excess: 247 +/- 31
• Li&Ma significance: 8.1 sigma

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