Analysis April 2022 with lstchain v0.9.X Jurysek

General information

• Name of the source: LHAASO J2108+5157
• Brief description of the source:

- Object type : Unidentified Galactic PeVatron candidate

- Distance (pc) : Unknown

- RA, Dec in deg (ICRS): 317.22, 51.95

• Analysis by Jakub Jurysek (UNIGE, jakub.jurysek@unige.ch)

Run selection

• Run selection with the use of the notebook from Abelardo Moralejo [1]
• Atmospheric transmission extracted from ELOG
• In total 178 runs selected, obstime 51.9 hours (57% of all observations)

• Summary of selection cuts:

- Zenith > 55 deg

- Wobble in (0.45, 0.55)

- elapsed_time > 5 min

- transmission_cut > 0.65

- pedestal charge std dev < 1.8 p.e.

- Cosmic rate > 3000 ev/s

- Cosmic rate( > 10 p.e.) > 20 ev/s

- Cosmic rate( > 30 p.e.) > 3 ev/s

- muon ring width std dev < 0.023

• List of selected runs:

- 2021-06-04 : [4913, 4914, 4915, 4916, 4917]

- 2021-06-05 : [4935, 4936]

- 2021-06-12 : [5028, 5029, 5030, 5031]

- 2021-06-30 : [5071, 5072]

- 2021-07-01 : [5080, 5081, 5082, 5083, 5084]

- 2021-07-02 : [5091, 5092, 5093]

- 2021-07-03 : [5101, 5102, 5103, 5104, 5105, 5106, 5107, 5108]

- 2021-07-04 : [5115, 5116, 5117, 5118, 5119, 5120, 5121]

- 2021-07-05 : [5135, 5136, 5137, 5138, 5139, 5140, 5141, 5142]

- 2021-07-15 : [5270, 5272]

- 2021-07-30 : [5411, 5412]

- 2021-08-01 : [5440, 5441, 5442]

- 2021-08-03 : [5461, 5462, 5463, 5464, 5465]

- 2021-08-04 : [5473, 5474, 5475, 5476, 5477, 5478, 5479, 5480]

- 2021-08-05 : [5491, 5492, 5493, 5494, 5497, 5498, 5499, 5500]

- 2021-08-06 : [5505, 5506, 5507, 5508, 5509, 5510, 5511, 5512, 5513, 5514, 5515, 5516, 5517]

- 2021-08-08 : [5576]

- 2021-08-09 : [5590, 5591]

- 2021-08-10 : [5641, 5642, 5643]

- 2021-08-11 : [5681, 5682, 5683, 5684, 5685, 5686, 5687]

- 2021-08-12 : [5707, 5708, 5709, 5710, 5711, 5712, 5713]

- 2021-08-13 : [5727]

- 2021-09-01 : [5947, 5948, 5949, 5950, 5952]

- 2021-09-02 : [5980, 5981, 5982, 5983, 5984, 5985, 5986, 5987, 5988, 5989, 5990, 5991]

- 2021-09-03 : [5999, 6000, 6001, 6002, 6003, 6004, 6005, 6006, 6007, 6008, 6009, 6010]

- 2021-09-04 : [6023, 6024, 6034, 6035, 6036, 6037, 6038]

- 2021-09-05 : [6058, 6059, 6060, 6061, 6062, 6063, 6064, 6065, 6066]

- 2021-09-06 : [6079, 6080, 6082, 6083, 6084, 6085]

- 2021-09-07 : [6130, 6131, 6132, 6133, 6134]

- 2021-09-09 : [6175, 6176, 6177, 6178, 6179, 6180, 6181, 6182, 6183]

- 2021-09-11 : [6230, 6231, 6233]

- 2021-09-12 : [6254, 6255, 6256, 6257]

MC information

- 20200629_prod5_trans_80

- 20, 40 deg zenith angle, south pointing

- Note: 20 deg zenith angle MC was tuned manually using lstchain scripts, while for 40 deg MC we used lstmcpipe production [2] and thus the directory structure for the two is different

• PSF and NSB tuned:

"image_modifier": {
      "increase_nsb": true,
      "extra_noise_in_dim_pixels": 0.705,
      "extra_bias_in_dim_pixels": 0.269,
      "transition_charge": 8,
      "extra_noise_in_bright_pixels": 0.673,
      "increase_psf": true,
      "smeared_light_fraction": 0.125
      }

• Tuned DL1b MC:

- 20 deg zenith angle:

/fefs/aswg/workspace/jakub.jurysek/simulations/dl1/20200629_prod5_trans_80/gamma/zenith_20deg/south_pointing/20220225_v0.9.1_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/off0.4deg/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl1/20200629_prod5_trans_80/gamma-diffuse/zenith_20deg/south_pointing/20220225_v0.9.1_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl1/20200629_prod5_trans_80/proton/zenith_20deg/south_pointing/20220225_v0.9.1_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl1/20200629_prod5_trans_80/electron/zenith_20deg/south_pointing/20220225_v0.9.1_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/

- 40 deg zenith angle:

/fefs/aswg/data/mc/DL1/20200629_prod5_trans_80/gamma/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/off0.4deg/
/fefs/aswg/data/mc/DL1/20200629_prod5_trans_80/gamma-diffuse/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/
/fefs/aswg/data/mc/DL1/20200629_prod5_trans_80/electron/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/
/fefs/aswg/data/mc/DL1/20200629_prod5_trans_80/proton/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/

• Random Forests - source independent:

- 20 deg zenith angle:

/fefs/aswg/workspace/jakub.jurysek/simulations/models/20200629_prod5_trans_80/zenith_20deg/south_pointing/20220225_v0.9.2_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/

- 40 deg zenith angle:

/fefs/aswg/data/models/20200629_prod5_trans_80/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/

• DL2 MC (testing only):

- 20 deg zenith angle:

/fefs/aswg/workspace/jakub.jurysek/simulations/dl2/20200629_prod5_trans_80/gamma/zenith_20deg/south_pointing/20220225_v0.9.2_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/off0.4deg/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl2/20200629_prod5_trans_80/gamma-diffuse/zenith_20deg/south_pointing/20220225_v0.9.2_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl2/20200629_prod5_trans_80/proton/zenith_20deg/south_pointing/20220225_v0.9.2_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/
/fefs/aswg/workspace/jakub.jurysek/simulations/dl2/20200629_prod5_trans_80/electron/zenith_20deg/south_pointing/20220225_v0.9.2_prod5_trans_80_dl1ab_tune_MC_to_LHAASO/

- 40 deg zenith angle:

/fefs/aswg/data/mc/DL2/20200629_prod5_trans_80/proton/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/
/fefs/aswg/data/mc/DL2/20200629_prod5_trans_80/gamma/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/off0.4deg/
/fefs/aswg/data/mc/DL2/20200629_prod5_trans_80/gamma-diffuse/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/
/fefs/aswg/data/mc/DL2/20200629_prod5_trans_80/electron/zenith_40deg/south_pointing/20220308_v0.9.3_prod5_trans_80_zen40az180_dl1ab_tuned_nsb_psf_src2/

DL1 data

• DL1a files produced by LSTOSA (lstchain v0.9)
• lstchain v0.9 tailcut8-4 (with cleaning based on pedestal RMS, dynamical cleaning)
• cfg /fefs/aswg/data/real/DL1/{date}/v0.9/tailcut84/log/lstchain_config_tailcut84_v092.json

/fefs/aswg/data/real/DL1/{date}/v0.9/tailcut84/

DL2 data

• data in range of zenith angles (0, 30) reconstructed with 20 deg RFs

/fefs/aswg/workspace/jakub.jurysek/data_analysis/lhaaso_J2108/DL2/ze0_30/

• data in range of zenith angles (30, 55) reconstructed with 40 deg RFs

/fefs/aswg/workspace/jakub.jurysek/data_analysis/lhaaso_J2108/DL2/ze30_45/
/fefs/aswg/workspace/jakub.jurysek/data_analysis/lhaaso_J2108/DL2/ze45_55/

DL3 data

• Fixed cuts:

"intensity": [50, Infinity],
"width": [0, Infinity],
"length": [0, Infinity],
"r": [0, 1],
"wl": [0.1, 1],
"leakage_intensity_width_2": [0, 1.0],
"event_type": [32, 32]

• Global gammaness and theta2 cuts optimized on Crab detection significance, point-like source assumption

global_gh_cut: 0.75
global_theta_cut: 0.2236067 (0.05 deg^2)

• Cut optimization

- Crab data from 2021, zenith < 35 deg, good runs selected by Abelardo [3]

- DL1->DL2 (Crab) with RFs trained on 20deg MC tuned on the Crab field

• extended source assumption

- 95% UL on extension from the LHAASO paper [4] used

global_theta_cut: 0.26 (~0.07 deg^2)

IRFs

• Full enclosure
• Two different IRFs merged with DL2 depending on the run zenith angle
• IRF path: /fefs/aswg/workspace/jakub.jurysek/data_analysis/IRFs/v0.9/

irf_20deg_180deg_20200629_prod5_trans_80_local_taicut_8_4_dynamic_dl2ab_tune_MC_int50_leak10_gh075_th005_DIFFUSE.fits.gz
irf_40deg_180deg_20200629_prod5_trans_80_local_taicut_8_4_dynamic_dl2ab_tune_MC_int50_leak10_gh075_th005_DIFFUSE.fits.gz

High-level analysis

• Performed with gammapy-v0.19

1D Spectral analysis

bkg_maker = ReflectedRegionsBackgroundMaker(exclusion_mask=exclusion_mask,
                                           min_distance=1 * u.rad,
                                           max_region_number=2
                                          )
safe_mask_masker = SafeMaskMaker(methods=["aeff-max"], aeff_percent=10)

e_min, e_max = 0.1, 100
nbin = 6
energy_axis = MapAxis.from_energy_bounds(
   e_min, e_max, nbin=nbin, per_decade=False, unit="TeV", name="energy"
)
energy_axis_true = MapAxis.from_energy_bounds(
   0.05, 100, nbin=20, per_decade=False, unit="TeV", name="energy_true"
)

• Spectral fitting of stacked LST dataset
• Performed for point-like and extended source assumption
• LST-1 data alone: Power-law spectral model
• Joint likelihood forward folding with LHAASO SED data points: Exponential cutoff power-law spectral model

Results

Power-law model of LST-1 data

Point-like

Extended

Joint likelihood forward folding with LHAASO flux points

Point-like

Extended