Speaker
Description
The current Fermi-LAT source catalog (4FGL-DR4: 7194 sources over 14 years) was built incrementally from the 8-year catalog by adding newly discovered sources but keeping the positions of existing sources fixed. Now, after 16 years (reached in August 2024) there are twice as many data as used in the original 4FGL catalog, enabling much more precise source positions. It is thus time to generate a new original catalog (5FGL). Like the incremental catalogs, this will contain the new sources detectable with the additional two years of data; but unlike the incremental catalogs it will require revision of the existing source names (derived from their coordinates) and a review of associations with counterparts at other wavelengths.
The systematic errors due to our imperfect knowledge of the Galactic diffuse emission, which dominates the gamma-ray sky, are the major limiting factor of the sensitivity and quality of the point source catalog at low energies (a few 100 MeV over the extragalactic sky, up to a few GeV in the Galactic ridge). Two parallel efforts are ongoing to improve on this situation, using more advanced methods to modulate the interstellar gas templates with the LAT data themselves.
I will summarize those efforts toward a new interstellar emission model and present an early 16-year source list (FL16Y) that relocalizes all sources and improves a few aspects of the catalog analysis, but still uses the same diffuse model as 4FGL-DR4.
| Collaboration(s) | Fermi-LAT |
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