J/A+A/707/A61 Catalog of gamma-ray source candidates (Akhondi+, 2026)
A catalog of gamma-ray source candidates from 16 years of Fermi-LAT data at
|b| > 10°.
Akhondi F., Soor M., Hedayati K.
<Astron. Astrophys. 707, A61 (2026)>
=2026A&A...707A..61A 2026A&A...707A..61A (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays ; Surveys
Keywords: methods: data analysis - methods: numerical - methods: statistical -
catalogs - galaxies: active - galaxies: general -
gamma rays: galaxies - gamma rays: general
Abstract:
Sixteen years of continuous observations with the Fermi Large Area
Telescope (LAT) provide an unprecedented opportunity to search for
faint or previously unrecognized gamma-ray emitters, particularly at
high energies where the angular resolution improves and the diffuse
background is reduced.
We present a new catalog of gamma-ray source candidates identified
using a data-driven, clustering-based analysis of Pass 8 LAT data
above 3GeV at Galactic latitudes |b|>10°.
The pipeline integrates the SIeving MEthod for FInding Core, version 3
(SIMEFIC III) for photon denoising with the density-based spatial
clustering of applications with noise (DBSCAN) algorithm.
We detect 3112 gamma-ray cluster candidates, of which 2932 are
associated with known gamma-ray sources. Cross-matching yields 37
counterparts in 1CGH, 23 in CRATES, 21 in Roma-BZCAT, 17 in MST-12yr.
The remaining 370 clusters have no known gamma-ray counterpart and are
proposed as new source candidates.
Description:
Main catalog table of gamma-ray source candidates detected using the
SIMEFIC III + DBSCAN pipeline. Each row corresponds to a single
cluster candidate, providing its sky position, clustering parameters,
and possible associations with known gamma-ray sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 264 428 Main catalog table of gamma-ray source candidates
detected using the SIMEFIC III + DBSCAN pipeline
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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: catalog.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Unique identifier of the gamma-ray source
candidate, SIM0N_JHHMM+DDMM (1)
18- 25 F8.4 deg GLON Galactic longitude of the cluster center
27- 34 F8.4 deg GLAT Galactic latitude of the cluster center
36- 44 F9.5 deg RAdeg Right ascension (J2000) of the cluster
center
46- 54 F9.5 deg DEdeg Declination (J2000) of the cluster center
56- 60 A5 --- CatName Name of the external catalog providing the
closest associated source, when available
(e.g., 4FGL, 1CGH, CRATES, BZCAT, 3HSP)
62- 76 A15 --- Source Source designation in the associated
external catalog
78- 85 F8.4 deg GLONS ?=- Galactic longitude of the associated
catalog source
87- 94 F8.4 deg GLATS ?=- Galactic latitude of the associated
catalog source
96-104 F9.5 deg RASdeg ?=- Right ascension (J2000) of the
associated catalog source
106-114 F9.5 deg DESdeg ?=- Declination (J2000) of the
associated catalog source
116-121 F6.4 deg AngDist ?=- Angular separation between the cluster
center and the associated catalog source
123-126 I4 --- N Number of photons assigned to the cluster
128-133 F6.3 --- S Statistical significance of the cluster as
derived from the DBSCAN-based analysis
135-144 A10 --- Region Sky region identifier used in the analysis
pipeline
146 I1 --- SIMstep Denoising iteration step at which the
cluster is detected
148-157 F10.4 MeV AvgEnergy Mean photon energy of the cluster
159-176 F18.16 deg AngRadius Angular radius of the cluster, defined as
the characteristic spatial extent of the
photon distribution
178-196 F19.17 deg FermiDist ?=- Angular distance between the cluster and
the nearest source in the
Fermi-LAT 4FGL-DR4 catalog
198-216 F19.17 deg BridgedDist ?=- Angular distance between components of
bridged (merged) clusters, when applicable
218-224 A7 --- Type Classification of the source candidate
(e.g., satellite-like, bridged, or
catalog-associated)
226-264 A39 --- FermiSource Name of the associated Fermi-LAT source in
the 4FGL-DR4 catalog
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Note (1): following the convention SIM_#JHHMM.m+DDMMaa, where SIM denotes a
SIMEFIC-identified source, # indicates the denoising stage at which the source
was last detected, and the suffix encodes the J2000 equatorial coordinates of
the cluster center.
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Acknowledgements:
F. Akhondi, f.akhondi(at)email.kntu.ac.ir
(End) Patricia Vannier [CDS] 07-Jan-2026