The Fundamental Reference Image Data Archive (FRIDA)

• Autores: DiLullo, C.; Sexton, R.; Cigan, P.; Bruzewski, S.; Gordon, D.
• Año de publicación: 2025
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: Ciencias Astronómicas; ICRF source structure; VLBI imaging; Astrometric accuracy
• Institución: Universidad Nacional de La Plata

The International Celestial Reference Frame (ICRF) is defined by making precise astrometric measurements of active galaxies (AGN) using very long baseline interferometry (VLBI). Astrometric VLBI measurements simply measure the position of the brightest point in the observed field on the sky. This position is then reported as the position of the galaxy and is used to build the ICRF. However, a large problem with this is that AGN are highly variable, especially on the physical scales which VLBI is sensitive to. VLBI is capable of resolving structure in many of the ICRF sources which can change in brightness or even move position on the sky. If this structure is either not accounted for or not well understood, it will obscure the precision of astrometric measurements. Imaging ICRF sources allows for these bright components to be separated and monitored using photometric and morphological techniques. The US Naval Observatory (USNO) has been consistently imaging ICRF sources since 1997. The data are available through a web-accessible data archive known as the Fundamental Reference Image Data Archive (FRIDA). In recent years, USNO has been supporting monthly dedicated imaging observations on the Very Long Baseline Array (VLBA) at S-, X , and K-bands. These observations are part of our 50% time allocation on the VLBA in agreement with the National Radio Astronomy Observatory (NRAO). A calibration and imaging pipeline has been developed using the Common Astronomical Software Application (CASA). A new major overhaul of both the imaging pipeline and the FRIDA user interface is underway. We present on the current status of FRIDA and look towards the future, focusing on what data products it can offer to the astrometric, geodetic, and the astronomical communities.
Facultad de Ciencias Astronómicas y Geofísicas