J/A+A/698/A101 Classification of gamma-ray bursts from blazars (Cerruti, 2025)
Characterization and classification of gamma-ray bursts from blazars.
Cerruti M.
<Astron. Astrophys. 698, A101 (2025)>
=2025A&A...698A.101C 2025A&A...698A.101C (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; Active gal. nuclei ; Gamma rays
Keywords: BL Lacertae objects: general - quasars: general - gamma rays: galaxies
Abstract:
Blazars are the most common sources of gamma-ray photons in the
extra-galactic sky. Their gamma-ray light-curves are characterized by
bright flaring episodes, similarly to what is observed at longer
wavelengths. These Gamma-Ray Bursts from Blazars (GRBBLs) have been
extensively studied individually, but never in terms of a population.
The goal of this work is to provide a global characterization of
GRBBLs, to investigate the parameter space of the population, and
ultimately to classify GRBBLs. Their global properties could give
insights on the physical mechanisms responsible for the gamma-ray
radiation and on the origin of the observed variability. I analyze a
sample of publicly available Fermi-LAT light-curves, utilizing only
blazars with certain redshift measurements. The redshift-corrected
light-curves are then automatically scanned to identify GRBBLs. A
simple flare profile, with exponential rise and decay, is then fitted
to all events. The fit parameters, together with the information on
spectral variability during the events, and the global properties from
the LAT catalog, are then used as input for unsupervised machine
learning classification.
The analysis shows that the GRBBL population is remarkably
homogeneous. The classifier splits the population into achromatic
(the large majority) and chromatic (the outliers) GRBBLs, but the
transition between the two classes is smooth, with significant
overlap. When the information on the spectral variability is removed,
there is evidence for a classification into two classes, mainly driven
by the peak luminosities. As by-product of this study, I identify a
correlation between the rising/decay time-scales of the GRBBLs and
their peak luminosity.
Description:
In this work I perform a comprehensive characterization and
classification of all gamma-ray-bursts from blazars (GRBBLs) I can
analyze and identify.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 120 732 List of blazars analyzed in this work.
tableb1.dat 158 114 List of blazars removed due to uncertain redshift
tabled1.dat 31 50 List of GRBBLs that are classified as chromatic
in the fiducial sample
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See also:
IX/67 : Incremental Fermi LAT 4th source cat. (4FGL-DR3) (Fermi-LAT col., 2022)
Byte-by-byte Description of file: tablea1.dat tableb1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- 4FGL 4FGL name (JHHMM.m+DDMM)
14- 38 A25 --- OName Other name
40- 47 F8.6 --- z Redshift
49-158 A110 --- Comment Comment
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Byte-by-byte Description of file: tabled1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- 4FGL 4FGL name
14- 23 A10 "date" t0 Date
25- 31 F7.4 --- chi2 chi2 value, chi2Gamma
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Acknowledgements:
Matteo Cerruti, cerruti(at)apc.in2p3.fr
(End) Patricia Vannier [CDS] 19-Mar-2025