PKS1424+240 (LST) analysis - neutrino candidate

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Revision as of 00:13, 14 September 2024 by Gloria Maria Cicciari (talk | contribs) (→‎Light Curve (LC) and Spectral Energy Distribution (SED))
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General information

Name of the source: PKS 1424+240

Pks1424+240 aladin.png

Brief description of the source:

  • It is the farthest BL Lac detected at TeV
  • It is an IBL/HBL
  • z ~ 0.6
  • RA, Dec (deg) : 216.75163247, 23.80001042

Analysis by Name (Institute - email)

  • Davide Cerasole
  • Gloria Maria Cicciari (gloriamaria.cicciari@unipa.it)
  • Sara Fogliaceo
  • Serena Loporchio
  • Manuela Mallamaci
  • Salvatore Mangano
  • Giovanni Marsella
  • Elisa Prandini
  • Ilaria Viale
  • Elisa Visentin

Data-taking information

Cycle I observations 2023-01-23 to 2023-07-17

  • Dates of data-taking: 2023/01/23, 2023/01/27, 2023/03/10, 2023/04/18, 2023/05/12, 2023/05/15, 2023/05/22, 2023/07/17
  • Observation runs selected are: [11805 11806 11807 11808 11933 11934 11935 11936 11937 12747 12748 12749 12750 12957 12958 12959 12960]
  • Total livetime of all observations (hrs): 19.7
  • Total livetime of selected observations (hrs): 4.5
  • ZD range (deg): 0 - 60

Analysis steps

  • R0 : uncalibrated RAW waveforms from the camera
  • R1 : calibrated waveforms from the camera
  • DL1a : integrated charge and peak position of the waveform
  • DL1b : image parameters (width, length, intensity…)
  • DL2 : event parameters (energy, direction, time…)
  • DL3 : lists of reconstructed events after event selection with corresponding IRFs

Analysis steps.png

Analysis information

Data quality

Data quality.png

The list with the runs passing data quality

Data quality list.png

Data storage

Monte Carlo simulations

/fefs/aswg/data/mc/DL2/AllSky 20240131_allsky_v0.10.5_all_dec_base/TestingDataset/dec_2276/

DL1 data

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

Random forest

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

DL2 data

 /fefs/aswg/workspace/gloriamaria.cicciari/DL3/PKS1424/

DL3 data and IRF

 /fefs/aswg/workspace/gloriamaria.cicciari/DL3/PKS1424/


Analysis results

Preliminary Theta2 plots

Theta2 plots obtained from DL2 data using the explore_DL2.ipynb code

Theta2 low energy PKS1424 nu candidate.png 

Energy range: 0.0 - 0.2 TeV
Excess: 690.000; Off: 155056
Gamma rate: 0.675 events / minute
Off rate: 151.779 events / minute
alpha (backg normalization): 1.000
Li & Ma Significance: 1.24 standard deviations

Theta2 high energy PKS1424 nu candidate.png 

Energy range: 0.2 - 1000000.0 TeV
Excess: -6.333; Off: 415
Gamma rate: -0.006 events / minute
Off rate: 0.406 events / minute
alpha (backg normalization): 0.333
Li & Ma Significance: 0.00 standard deviations

Inspect the DL3 file content

  • Spatial distribution of events (typically on a plane of celestial coordinates such as RA/Dec or local altitude/azimuth coordinates)
  • Energy distribution (spectrum of events)
  • Temporal distribution (histogram of events over time)
  • Angular offset distribution (angular distance from the centre of the field of view)


Event peek 1.png

Event peek 2.png


Selection of observations

Filters applied to select just a subset of the observation list based on source name, zenith angle or livetime

max_zen = 70 (in deg for a maximum limit on zenith pointing of observations)

min_time = 300 (in seconds for minimum livetime of each observation) 

Observation runs selected are: [11805 11806 11807 11808 11933 11934 11935 11936 11937 12747 12748 12749 12750 12957 12958 12959 12960]
Total livetime of all observations: 19.7 h
Total livetime of selected observations 4.5 hrs

Define Target position and energy ranges for reconstructed events

OrderedDict([('CREATOR', 'pyirf v0.10.1'),
            ('HDUDOC',
             'https://github.com/open-gamma-ray-astro/gamma-astro-data-formats'),
            ('HDUVERS', '0.2'),
            ('HDUCLASS', 'GADF'),
            ('HDUCLAS1', 'RESPONSE'),
            ('HDUCLAS2', 'EFF_AREA'),
            ('HDUCLAS3', 'POINT-LIKE'),
            ('HDUCLAS4', 'AEFF_2D'),
            ('DATE', '2024-06-27 16:42:06.949'),
            ('TELESCOP', 'CTA-N'),
            ('INSTRUME', 'LST-1'),
            ('FOVALIGN', 'RADEC'),
            ('B_TOTAL', 38.592769622802734),
            ('B_INC', 0.6519277095794678),
            ('ZEN_PNT', 38.11381),
            ('AZ_PNT', 88.21244),
            ('B_DELTA', 60.12539),
            ('EXTNAME', 'EFFECTIVE AREA')])



Spectral Fit will be done in energy edges: [ 0.01584893  0.02511886  0.03981072  0.06309573  0.1  0.15848932 
0.25118864 0.39810717  0.63095734  1  1.58489319  2.51188643 3.98107171  6.30957344 10] TeV
LC will be estimated from  0.10000000000000002 TeV to  10.000000000000002 TeV

Data Reduction chain

safe_min_energy = 50 * u.GeV
safe_max_energy = 20 * u.TeV

Spectrum Dataset for all observations

obs_id: 11805
obs_id: 11806 
obs_id: 11807
obs_id: 11808
obs_id: 11933
obs_id: 11934
obs_id: 11935
obs_id: 11936
obs_id: 11937
obs_id: 12747
obs_id: 12748
obs_id: 12749
obs_id: 12750
obs_id: 12957
obs_id: 12958
obs_id: 12959
obs_id: 12960
CPU times: user 10min 31s, sys: 1min 4s, total: 11min 35s
Wall time: 11min 41s


The target position and OFF regions used for the calculation of the excess

Target position OFF regions.png

Theta2 plots

Theta2 plots obtained from DL3 data using the post_DL3_analysis.ipynb code

Theta2 PKS1424 nu candidate.png

Excess plots

Excess plots obtained from DL3 data using the post_DL3_analysis.ipynb code

Excess plot PKS1424 nu candidate.png

Plot temporal evolution of excess events and significance value

The following plots may indicate that there are problems with the observation (e.g. instrumental noise or incorrectly modelled background effects) Square root Livetime.png

Examples of plots of counts+excess, exposure and energy migration of each selected dataset

Dataset 11806.png

Final spectral model

 {'type': 'LogParabolaSpectralModel',
 'parameters': [{'name': 'amplitude',
  'value': 5e-12,
  'unit': 'TeV-1 s-1 cm-2'},
  {'name': 'reference', 'value': 0.5578072365055083, 'unit': 'TeV'},
  {'name': 'alpha', 'value': 2.0},
  {'name': 'beta', 'value': 0.1}]}

The LC Estimator on a run-by-run basis and nightly

 {'name': 'amplitude',
  'value': 4.7785201782428055e-12,
  'unit': 'TeV-1 s-1 cm-2',
  'error': 5.275533147495292e-12},
 {'name': 'reference', 'value': 0.5578072365055083, 'unit': 'TeV'},
 {'name': 'alpha', 'value': 2.8325177157861554, 'error': 4.102202154886328},
 {'name': 'beta', 'value': 4.767544739308446, 'error': 12.26726001202649}

Final Model

{'name': 'PKS1424',
'type': 'SkyModel',
'spectral': {'type': 'LogParabolaSpectralModel',
 'parameters': [{'name': 'amplitude',
   'value': 4.7785201782428055e-12,
   'unit': 'TeV-1 s-1 cm-2',
   'error': 5.275533147495292e-12},
  {'name': 'reference', 'value': 0.5578072365055083, 'unit': 'TeV'},
  {'name': 'alpha', 'value': 2.8325177157861554, 'error': 4.102202154886328},
  {'name': 'beta', 'value': 4.767544739308446, 'error': 12.26726001202649}]},
 'FitResult': {'Optimize': OptimizeResult
       backend    : minuit
 	method     : migrad
 	success    : True
 	message    : Optimization terminated successfully..
 	nfev       : 152
 	total stat : 4.41
 'Covariance': CovarianceResult
       backend    : minuit
 	method     : hesse
 	success    : True
 	message    : Hesse terminated successfully.}}


Light Curve (LC) and Spectral Energy Distribution (SED)

SED and LC obtained from DL3 data using the post_DL3_analysis.ipynb code

LC.png

SED and LC preliminaries that only give us the upper limits. (We reserve the use of a more polished code for analysis).

Sed and light curve pks1424 nu candidate.png 


The analysis will need to be fine-tuned because of the lack of detection.
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