Blazars as Ideal Reference Frame Objects

• Autores: Sargent, A.; Secrest, N.; Lambert, S.
• Año de publicación: 2025
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: Ciencias Astronómicas; Celestial Reference Frame (CRF); blazars; multi-wavelength astrometric stability
• Institución: Universidad Nacional de La Plata

Despite achieving sub-milliarcsecond per-source position accuracies and an overall celestial reference frame (CRF) stability of a few tens of micro­ arcseconds, consistent source positions and frame orientations across wave­ lengths has not yet been achieved, hampering the goal of producing a wave­ length-independent CRF. Source position discrepancies are seen both between radio frequencies (e.g., X and K) and between the radio and the optical CRFs (i.e., ICRF3 and Gaia-CRF3), with about 15% of ICRF3 sources having statistically significant optical-radio position offsets. It has recently been shown by the U.S. Naval Observatory that the prevalence of optical-radio position offsets is inversely correlated with photometric variability, strongly indicating blazars as astrometrically stable sources. In this presentation, I review important recent results on the relationship between blazars and multi-wavelength astrometric stability and argue that blazars should be the object of choice for the next ICRF and future geodetic observations.
Facultad de Ciencias Astronómicas y Geofísicas