Long term variability and correlation study of the blazar 3C 454.3 in radio, NIR and optical wavebands

Loading...
Thumbnail Image
Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This publication is imported from Aalto University research portal.
View publication in the Research portal
View/Open full text file from the Research portal
Date
2019-12-20
Major/Subject
Mcode
Degree programme
Language
en
Pages
Series
Astrophysical Journal, Volume 887, issue 2
Abstract
We performed a long-term optical (B, V, R bands), infra-red (J and K bands) and radio band (15, 22, 37 GHz band) study on the flat spectrum radio quasar, 3C 454.3, using the data collected over a period of more than 8 years (MJD 54500–57500). The temporal variability, spectral properties and inter-waveband correlations were studied by dividing the available data into smaller segments with more regular sampling. This helped us constrain the size and the relative locations of the emission regions for different wavebands. Spectral analysis of the source revealed the interplay between the accretion disk and jet emission. The source predominantly showed a redder-when-brighter trend, though we observed a bluer-when-brighter trend at high flux levels which could be signatures of particle acceleration and radiative cooling. Significant correlations with near-zero lag were seen between various optical/infra-red bands, indicating that these emission regions are co-spatial. Correlations with a time lag of about 10–100 days are seen between optical/infra-red and radio bands indicating these emissions arise from different regions. We also observe the DCF peak lag change from year to year. We try to explain these differences using a curved jet model where the different emission regions have different viewing angles resulting in a frequency dependent Doppler factor. This variable Doppler factor model explains the variability timescales and the variation in DCF peak lag between the radio and optical emissions in different segments. Lags of 6-180 days are seen between emissions in various radio bands, indicating a core-shift effect.
Description
Keywords
galaxies: active, galaxies:jets, methods: observational, quasars: individual (3C 454.3), techniques: photometric
Other note
Citation
Sarkar, A, Chitnis, V R, Gupta, A C, Gaur, H, Patel, S R, Wiita, P J, Volvach, A E, Tornikoski, M, Chamani, W, Enestam, S, Lähteenmäki, A, Tammi, J, Vera Rodríguez, R & Volvach, L N 2019, ' Long term variability and correlation study of the blazar 3C 454.3 in radio, NIR and optical wavebands ', The Astrophysical Journal, vol. 887, no. 2, 185 . https://doi.org/10.3847/1538-4357/ab5281