J/A+A/702/A10 Radio and gamma-ray properties of blazars (Behiri+, 2025)
A FLASH on blazars.
Capturing the radio realm of 4FGL blazars with SKAO pathfinders.
Behiri M.. Mahony E., Sadler E., Kerrison E., Traina A., Zanchettin M.V.,
Galluzzi V., Lapi A., Massardi M.
<Astron. Astrophys. 702, A10 (2025)>
=2025A&A...702A..10B 2025A&A...702A..10B (SIMBAD/NED BibCode)
ADC_Keywords: BL Lac objects ; QSOs ; Gamma rays ; Radio sources
Keywords: galaxies: active - BL Lacertae objects: general -
galaxies: evolution - galaxies: jets - quasars: general
Abstract:
This work investigates the multi-wavelength properties of 165 sources
from the Fermi Large Area Telescope Fourth Source Catalog Data Release
4 (4FGL), with the aim of identifying counterparts in the Australian
SKA Pathfinder (ASKAP) First Large Absorption Survey in the HI (FLASH)
continuum. Using high-resolution data from FLASH, complementary radio
datasets, and archival ALMA observations, we performed detailed
spectral energy distribution (SED) analyses across centimetre to
millimetre wavelengths. Our findings reveal that most blazars exhibit
re-triggered peaked spectra, which are indicative of emission
dominated by a single emitting region. Additionally, we identify
strong correlations between radio and gamma-ray luminosities,
highlighting the significant role of relativistic jets in these active
galactic nuclei. The inclusion of spectroscopic redshifts from the
Sloan Digital Sky Survey and Gaia enabled a comprehensive analysis of
the evolutionary trends and physical characteristics of the sources to
be performed. Furthermore, we report a tight radio-X-ray correlation
for flat spectrum radio quasars, thus contrasting with the more
scattered behaviour observed in BL Lacertae objects and reflecting the
distinct accretion and jet-driving mechanisms of the two populations.
These results provide critical insights into the physics of blazars
and their environments, paving the way for future studies with
next-generation facilities such as the SKA Observatory for radio
observations and the Cherenkov Telescope Array for gamma-ray studies.
Description:
We present radio and gamma-ray properties of blazars from the
Fermi-LAT 4FGL catalogue observed with SKAO pathfinder facilities. The
dataset includes redshifts, rest-frame 885MHz radio luminosities,
spectral indices, and gamma-ray luminosities. It provides a
homogeneous resource to investigate the relation between radio and
gamma-ray emission in blazars and spectral features such as turnover
frequencies
This table contains radio and gamma-ray properties of blazars from the
Fermi-LAT Fourth Source Catalog (4FGL) observed with SKAO pathfinder
facilities.
The dataset includes redshifts, rest-frame 885MHz radio luminosities,
spectral features (peak and trough frequencies), spectral indices, and
gamma-ray luminosities. Missing values are indicated by ---.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 89 158 Radio and gamma-ray properties of blazars
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See also:
J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Source name in 4FGL format
(4FGLJHHMM.m+DDMM)
18- 21 F4.2 --- z ?=- Redshift
23- 30 E8.3 W/Hz L885MHz ?=- Rest-frame 885MHz radio luminosity
32- 38 F7.2 GHz nu-peak-rest ?=- Rest-frame spectral peak frequency
40- 46 F7.2 GHz nu-trough-rest ?=- Rest-frame spectral trough frequency
48- 52 F5.2 --- alpha-retrig ?=- Low-frequency spectral index
(retrig. sources) (1)
54- 58 F5.2 --- alpha-thick ?=- Spectral index in optically
thick regime (1)
60- 64 F5.2 --- alpha-thin ?=- Spectral index in optically
thin regime (1)
66- 73 E8.3 W/Hz LFermi ?=- Gamma-ray luminosity (2)
75- 89 A15 --- BestFit Best-fit spectral classification (3)
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Note (1): Spectral indices follow the convention S∼nualpha.
Note (2): Luminosities computed assuming a flat {LAMBDA}CDM cosmology
with H0=70 km/s/Mpc, {OMEGA}m=0.3.
Note (3): Best-fit spectral classification as follows:
Retriggered = sources show evidence of renewed jet activity
Peaked_Spectrum = convex spectra peaking within the observed frequency range
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Acknowledgements:
Meriem Behiri, mbehiri(at)sissa.it
(End) Patricia Vannier [CDS] 13-Aug-2025