Fast Analysis IC310 ToO Feb Mar 2024 P062

Fast analysis IC310 ToO P062 (March 2024)

General information

• Name of the source: IC 310
• Brief description of the source:
  • Object type : AGN radio galaxy
  • Redshift (z) : 0.0189
  • Other relevant information: Observations triggered LHAASO ATel #16513, 0.5 CU > 1 TeV (6th and 7th March 2024). VERITAS followup ATel #16535 (0.15 Crab units in 2 hours, 10th - 13th March 2024). LHAASO reported renewed activity in ATel #16540 (1.3 C.U. above 1 TeV in 19th March)
  • RA: 03 16 43.0 (hh mm ss), Dec: +41 19 29 (dd mm ss)
  • RA, Dec in deg (ICRS): 49.17907815, 41.32489322

See also general wiki page of NGC1275 and IC310

• Analysis by:
  • Daniel Morcuende (IAA-CSIC - dmorcuende@iaa.es)

Data-taking information

• Dates of data-taking:
  • Date (time of observation h): 2024-03-10 (1.8 h livetime)
    • ZD range (deg): 45 - 65 deg
    • AZ range (deg):
    • Dark NSB
    • https://www.lst1.iac.es/datacheck/observation_overview/2024/03/run_summary_2024_03_10.pdf
    • Runs:

'2024-03-10': [17018, 17019, 17020, 17021, 17022, 17023]

• Data were taken with a missing module in the camera. The event source plugin of the analysis chain had to be adapted to process the data. Still, data are problematic because the event type identification is wrong for some runs. As can be seen in the DL1 data checks (https://www.lst1.iac.es/datacheck/dl1/v0.10/20240310/DL1_datacheck_20240310.html). So probably, after all these data cannot be used (see subsection below).

• Joint observations with MAGIC? : No

Problems with wrong event tagging

Checking runs one by one in the DL1 check files like: https://www.lst1.iac.es/datacheck/dl1/v0.10/20240310/pdf/datacheck_dl1_LST-1.Run17020.pdf we can see when the event tagging went south. We filter out affected subruns as follows:

• Run 17018: not usable at all (event tagging spoiled from the beginning of the run)

• Run 17019: not usable at all (event tagging spoiled from the beginning of the run)

• Run 17020: usable up to subrun ~68

• Run 17021: usable up to subrun ~95

• Run 17022: the whole run seems OK

• Run 17023: usable up to subrun ~74

After filtering out spoiled subruns. The remaining runs are:

'2024-03-10': [17020, 17021, 17022, 17023] -> 1.1 h effective time

Intensity and pixel spectra after filtering out bad subruns:

General analysis information

• source-independent analysis
• lstchain v0.10.7

Monte Carlo information

• All-sky MC production used: 20240131_allsky_v0.10.5_all_dec_base
  • Declination line (training): dec_3476

DL1 data

LSTOSA standard production (v0.10/tailcut84) of DL1b run-wise merged files.

/fefs/aswg/data/real/DL1/YYYYMMDD/v0.10/tailcut84/dl1_LST-1.Run?????.h5

DL1 files after clean-up are in (together with new DL1 datachecks):

/fefs/aswg/workspace/daniel.morcuende/data/real/DL1/IC310_flare_2040310

Random forest

Source declination is 41.3 deg. The two closest MC declination tracks are 34.76 deg and 48.22 deg. To avoid problems with a declination track with lower culmination than that of the data. I choose the 34.76 deg MC declination path which is the closest one to the source towards La Palma latitude value (28.8 deg)

/fefs/aswg/data/models/AllSky/20240131_allsky_v0.10.5_all_dec_base/dec_3476

DL2 data

Config file:

Files (after filtering out problematic subruns) are in:

/fefs/aswg/workspace/daniel.morcuende/data/real/DL2/IC310_new_cleanup/dec_3476/dl2_LST-1.Run*.h5

DL3 data & IRF

 "EventSelector": {
   "filters": {
     "intensity": [50, Infinity],
     "width": [0, Infinity],
     "length": [0, Infinity],
     "r": [0, 1],
     "wl": [0.01, 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": 0.0,
   "max_theta_cut": 0.2,
   "fill_theta_cut": 0.2,
   "allowed_tels": [1]
 },

• 70 % efficiency for both gammaness and theta gamma-ray selection cuts
• Point-like IRF
• DL3 files (after filtering out problematic subruns due to wrong event tagging):

/fefs/aswg/workspace/daniel.morcuende/data/real/DL3/IC310/20240131_allsky_v0.10.5_all_dec_base/dec_3476/gh_eff_0.7_th_cont_0.7/dl3*.fits

High-level analysis

• Gammapy 1.1
• 1D analysis (point-like IRF)

Analysis Results

Theta2 plot

Settings (from explore DL2 notebook):

• Theta2 cut for signal extraction < 0.02 deg2
• Tight global cut gammaness > 0.95
• 3 off positions
• E > 500 GeV
• Time effective: 1.8 h

• 2024-03-10

No significant excess at energies below

After filtering out problematic subruns (event tagging problem, see data-taking section above) the results are:

Theta2 cut for signal extraction < 0.02 deg2
Tight global cut gammaness > 0.95
3 off positions
E > 200 GeV
Time effective: 1.1 h
Runs: [17020, 17021, 17022, 17023]

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Note: There may be some genuine signal in those first two runs, but they cannot be used as is because the event tagging is completely messed up. Recovering them would require a significant amount of effort at a low level, which is not worth the time.

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Still, I think it is now safe to use the DL3 files (after the spoiled-subrun clean-up) for long-term monitoring of the source.

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