GRB220501A

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Status

Step	Status	Comment
DL2 Production	Done
Low Level Check	Done
DL3 Production	Not done	No sig. detection
High Level Analysis	Not done	No sig. detection

Green color code : 00BA00

Red Color code : FF0000

Orange Color code : FF8000

Multi-wavelength Observations

Timeline

T0+	Instrument	Outcome	Outcome specific value (flux/UL/...)	Comment	Link
22.3 min	BOOTES-1	No detection	up to 17.5 mag		https://gcn.gsfc.nasa.gov/gcn3/31990.gcn3
8.8 to 38.9 min	GRANDMA/TJML	No detection	r(AB) > 16.0 mag		https://gcn.gsfc.nasa.gov/gcn3/31984.gcn3

Alert Information

• Name/type of the alert: Name
• GCN notice:
• Triggered by: Swift-BAT and Fermi GBM
• Alert coordinates:
  • RA: 05 42 18 (hh mm ss), Dec: +14 02 00 (dd mm ss)
  • RA, Dec in deg (ICRS): 85.577, +14.033
• Alert arrival time: 2022-05-01T19:51:54 (TYPE_INTEGRAL_WAKEUP)
• Other relevant information: We observed Swift-BAT position because the position error was lower than Fermi GBM error.
  • Redshift (z):

LST Observations

• Dates of data-taking: 2022-05-01
  • 2022-05-01
    • Zenith range (deg): 65 -> 70
    • Transmission9km: n/a
    • Observation condition: twilight
    • Observation mode: std wobbles (W1 and W2)
    • Runs: 8043 - 8044
    • Joint observations with MAGIC? : No
    • ELOG link: Logbook URL
    • Important comments:

Analysis

Analysis configuration

• Analyzer: Arnau Aguasca-Cabot (Barcelona Univ., email: arnau.aguasca@fqa.ub.edu)

• Software versions:
  • lstchain v0.9.6
  • lstMCpipe v0.9.2

• Cuts and parameters used:
  • intensity > 50
  • gammaness > 0.7
  • leakage < 0.2

• DL1 files :

Used DL1a files produced by LSTOSA (lstchain v0.9)

/fefs/aswg/data/real/DL1/20220311/v0.9/tailcut84/dl1_LST-1.Run0{8043-8044}.h5

Since the data taking is in twilight conditions, a tail cut 10 5 cleaning is applied using lstchain_dl1ab.py and standard configuration file from lstchain v0.9.4.

• Random Forest :

src-indep (diffuse gamma, disp_norm) and tuned to run 8044.0000, PSF tuning, tail cut 10 5 and dynamic cleaning.

/fefs/aswg/workspace/arnau.aguasca/Analysis/results/MC/lstMCpipe/models/20200629_prod5_trans_80/zenith_40deg/south_pointing/20220504_v0.9.1_prod5_trans_80_tailcut105_dynclg_tNSBtoGRB220501A_PSF

parameters used to tune the MC files:

 "image_modifier": {
   "increase_nsb": true,
   "extra_noise_in_dim_pixels": 1.801,
   "extra_bias_in_dim_pixels": 1.098,
   "transition_charge": 8,
   "extra_noise_in_bright_pixels": 4.557,
   "increase_psf": true,
   "smeared_light_fraction": 0.125
 },

• DL2 MC data for IRF:

Not done, no significant detection.

• Overall selected observation time: 25 min

• Position analyzed: 85.577, +14.033 (deg)

• Analysis/data problems: The 2D distribution of reco. position of the events forms two over-densities if the data is processed using an RF trained with point gammas. As a consequence, I obtained a significance of -20 for run 8043 and +20 for run 8044. This problem disappears if diffuse gammas are used.

Theta2 plot

• theta < 0.2

Theta2 plot for GRB220501A.