Study of Variability in Long-term Multiwavelength Optical Lightcurves of Blazar AO 0235+164

We present a long-term and intraday variability study of optical multiwaveband (UBVRI) data from the blazar AO 0235+164 collected by various telescopes for ∼44 yr (1975–2019). The blazar was found to be significantly variable over the years in all wave bands with a variation of about 6 mag between i...

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Detalles Bibliográficos
Autores: Cellone, Sergio Aldo, Romero, Gustavo Esteban
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2023
País:Argentina
Institución:Universidad Nacional de La Plata
Repositorio:SEDICI (UNLP)
Idioma:inglés
OAI Identifier:oai:sedici.unlp.edu.ar:10915/152611
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/152611
Access Level:acceso abierto
Palabra clave:Ciencias Astronómicas
Galaxies
Active galaxies
BL Lacertae objects
Quasars
Descripción
Sumario:We present a long-term and intraday variability study of optical multiwaveband (UBVRI) data from the blazar AO 0235+164 collected by various telescopes for ∼44 yr (1975–2019). The blazar was found to be significantly variable over the years in all wave bands with a variation of about 6 mag between its low and active states. The variations in the different wave bands are highly correlated without any time lag. We did not observe any significant trend in color variation with time, but we observed a bluer-when-brighter trend between the B − I color index and the R magnitude. Optical BVR-band spectral energy distributions always show a convex shape. Significant intraday variability was frequently seen in the quasi-simultaneous observations of AO 0235+164 made on 22 nights in the R and V bands by the CASLEO and CAHA telescopes during 1999–2019. We also estimated a central supermassive black hole mass of 7.9 × 10⁷ M☉ by analyzing the broad Mg II emission line in AO 0235 +164ʼs spectrum. We briefly explore the probable physical scenarios responsible for the observed variability.