J/other/RAA/24.J5004 New gamma-ray sources (Xiang+, 2024)
New gamma-Ray Sources Identified in All-sky Surveys Based on Fermipy's
Advanced Algorithm.
Xiang Y., Feng P., Lam X.
<Res. Astron. Astrophys., 24, 105004 (2024)>
=2024RAA....24j5004X 2024RAA....24j5004X (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays
Keywords: gamma-rays: diffuse background - methods: data analysis - catalogs -
gamma-rays: general
Abstract:
We employ an efficient method for identifying gamma-ray sources across
the entire sky, leveraging advanced algorithms from Fermipy, and
cleverly utilizing the Galactic diffuse background emission model to
partition the entire sky into 72 regions, thereby greatly enhancing
the efficiency of discovering new sources throughout the sky through
multi-threaded parallel computing. After confirming the reliability of
the new method, we applied it for the first time to analyze data from
the Fermi Large Area Telescope (Fermi-LAT) encompassing approximately
15.41 yr of all-sky surveys. Through this analysis, we successfully
identified 1379 new sources with significance levels exceeding
4σ, of which 497 sources exhibited higher significance levels
exceeding 5σ. Subsequently, we performed a systematic analysis
of the spatial extension, spectra, and light variation characteristics
of these newly identified sources. We identified 21 extended sources
and 23 sources exhibiting spectral curvature above 10GeV.
Additionally, we identified 44 variable sources above 1GeV.
Description:
For the first time, we employed this method to identify gamma-ray
sources with a significance level >4σ across the entire sky.
Through this approach, we discovered 1379 new gamma-ray sources and
conducted analyses of their locations, spectra, light curves, and
spatial distributions. Meanwhile, the significance levels of three
different energy bands are provided for future directional research.
We assessed the robustness of the new method within the
parametric degrees of freedom permitted by the binned likelihood
analysis. Under the premise of maintaining consistency among the known
parameters, we conducted a comparative analysis between the results of
the new method and those from 4FGL-DR4. Our findings demonstrate that
the results for the 556 sources involved in the analysis align closely
with those from 4FGL-DR4, suggesting the reliability of the method.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 78 556 Analysis results of robustness verification
table5.dat 118 1379 Information on the gamma-ray emissions of all
new sources
--------------------------------------------------------------------------------
See also:
IX/67 : Incremental Fermi LAT 4th source cat. (4FGL-DR3) (Fermi-LAT col., 2022)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- Name Source name, 4FGL JHHMM.m+DDMMa
20- 25 F6.2 --- Sig14 The significance level above 100MeV
within 14yr
27- 32 F6.2 --- Sig4FGL The significance level above 100MeV
within 14yr in 4FGL-DR4
34- 37 F4.2 --- ratio1 ratio of Ssig14 to sig4FGL
39- 46 E8.3 mW/m2 EFlux14 Energy flux in 4FGL-DR4
48- 55 E8.3 mW/m2 e_EFlux14 1σ error on energy flux in 4FGL-DR4
57- 64 E8.3 mW/m2 EFlux Energy flux above 100 MeV within 14yr
66- 73 E8.3 mW/m2 e_EFlux 1σ error on energy flux above 100MeV
within 14yr
75- 78 F4.2 deg offsetROI Angular offset from each ROI center
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Source name, Fermi JHHMM.m+DDMMa
21- 30 F10.6 deg RAdeg Right ascension (J2000)
32- 41 F10.6 deg DEdeg Declination (J2000)
43- 46 F4.2 --- Index Spectral index of powerlaw
48- 51 F4.2 --- e_Index Spectral index error of powerlaw
53- 64 E12.6 1/cm/s Flux Integral photon flux above 0.5GeV
66- 77 E12.6 1/cm/s e_Flux Error of integral photon flux above 0.5GeV
79- 85 F7.2 --- Np Predicted number of events in the model
above 0.5GeV
87- 91 F5.2 --- Sig0.5 The significance level above 0.5GeV
(in sigma unit)
93- 97 F5.2 --- Sig1 The significance level above 1GeV
(in sigma unit)
99-102 F4.2 --- Sig10 ?=- The significance level above 10GeV
(in sigma unit)
104-110 F7.2 arcsec Posr68 Position error at 68% confidence
112-118 F7.2 arcsec Posr95 Position error at 95% confidence
--------------------------------------------------------------------------------
History:
Copied at https://nadc.china-vo.org/res/r101462/
(End) Patricia Vannier [CDS] 07-Aug-2025